TY  - JOUR
AU  - Srivastava, Alok M
AU  - Suchocki, Andrzej
AU  - Bulyk, Lev-Ivan
AU  - Zhydachevskyy, Yaroslav
AU  - Brik, Mikhail G.
AU  - Beers, William W
AU  - Cohen, Willian E
PY  - 2024
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/13124
AB  - We have measured the excitation and emission spectra, and lifetime for Fe3+ in the Ca8Mg(SiO4)4Cl2 compound. The spectroscopic data of the ferric ion (Fe3+) is interpreted within the framework of the Tanabe-Sugano crystal field theory for ions with the d5 electronic configuration. Quantitative evaluation of the Racah parameters B and C and the crystal field parameter (10 Dq) is provided. The emission and excitation data are consistent for Fe3+ in a tetrahedral-site occupancy. The red emission is assigned to the 4T1 (4G)→6A1 (6S) crystal field transition. The remarkable feature of the luminescence is the positioning of the emission band; it is centered at 623 nm with a Full Width at Half Maximum of 51 nm. To the best of our knowledge this is one of the highest energy emission for the tetrahedral-site Fe3+ ion. The practical implication of this spectral power distribution is discussed. The temperature dependency of the luminescence lifetime and emission intensity are reported.
T2  - Optical Materials
T1  - Narrowband red luminescence of tetrahedral-site Fe3+ In Ca8Mg(SiO4)4Cl2
VL  - 150
SP  - 115290
DO  - 10.1016/j.optmat.2024.115290
ER  - 

@article{
author = "Srivastava, Alok M and Suchocki, Andrzej and Bulyk, Lev-Ivan and Zhydachevskyy, Yaroslav and Brik, Mikhail G. and Beers, William W and Cohen, Willian E",
year = "2024",
abstract = "We have measured the excitation and emission spectra, and lifetime for Fe3+ in the Ca8Mg(SiO4)4Cl2 compound. The spectroscopic data of the ferric ion (Fe3+) is interpreted within the framework of the Tanabe-Sugano crystal field theory for ions with the d5 electronic configuration. Quantitative evaluation of the Racah parameters B and C and the crystal field parameter (10 Dq) is provided. The emission and excitation data are consistent for Fe3+ in a tetrahedral-site occupancy. The red emission is assigned to the 4T1 (4G)→6A1 (6S) crystal field transition. The remarkable feature of the luminescence is the positioning of the emission band; it is centered at 623 nm with a Full Width at Half Maximum of 51 nm. To the best of our knowledge this is one of the highest energy emission for the tetrahedral-site Fe3+ ion. The practical implication of this spectral power distribution is discussed. The temperature dependency of the luminescence lifetime and emission intensity are reported.",
journal = "Optical Materials",
title = "Narrowband red luminescence of tetrahedral-site Fe3+ In Ca8Mg(SiO4)4Cl2",
volume = "150",
pages = "115290",
doi = "10.1016/j.optmat.2024.115290"
}

Srivastava, A. M., Suchocki, A., Bulyk, L., Zhydachevskyy, Y., Brik, M. G., Beers, W. W.,& Cohen, W. E.. (2024). Narrowband red luminescence of tetrahedral-site Fe3+ In Ca8Mg(SiO4)4Cl2. in Optical Materials, 150, 115290.
https://doi.org/10.1016/j.optmat.2024.115290

Srivastava AM, Suchocki A, Bulyk L, Zhydachevskyy Y, Brik MG, Beers WW, Cohen WE. Narrowband red luminescence of tetrahedral-site Fe3+ In Ca8Mg(SiO4)4Cl2. in Optical Materials. 2024;150:115290.
doi:10.1016/j.optmat.2024.115290 .

Srivastava, Alok M, Suchocki, Andrzej, Bulyk, Lev-Ivan, Zhydachevskyy, Yaroslav, Brik, Mikhail G., Beers, William W, Cohen, Willian E, "Narrowband red luminescence of tetrahedral-site Fe3+ In Ca8Mg(SiO4)4Cl2" in Optical Materials, 150 (2024):115290,
https://doi.org/10.1016/j.optmat.2024.115290 . .

TY  - JOUR
AU  - Antić, Željka
AU  - Racu, Andrei V.
AU  - Medić, Mina
AU  - Alodhayb, Abdullah N.
AU  - Kuzman, Sanja
AU  - Brik, Mikhail G.
AU  - Dramićanin, Miroslav
PY  - 2024
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/13020
AB  - La(PO3)3 activated with different concentrations of Pr3+ was synthesized by a solid-state process. The obtained powder was composed of chunks of several microns in size, typical for this type of synthesis. X-ray diffraction confirmed an orthorhombic crystal structure with the C2221 space group. The electronic band structures and density of states of La(PO3)3 and La(PO3)3:Pr3+ are calculated and presented. The visible and near-infrared emissions from Pr3+ [Xe]4f2 [Xe]4f2 electronic transitions were detected under 442 nm excitation. The red emission from the 1D2 state dominates visible spectra while emissions from the 3P0,1,2 states have smaller intensities. The 1D2 emission centered around 1020 nm is detected in the near-infrared spectral range. Intensities of 3P0 emissions increased with an increase in Pr concentration, while 1D2 emissions decreased in intensity. We found that the main process responsible for the 1D2 state decay is the Pr(1D2) + Pr(3H4) Pr(1G4) + Pr(3F3,4) cross-relaxation between two Pr ions of electric dipole-dipole character. This finding is supported by 1D2 emission decay measurements, which revealed a reduction of average decay constants from 242 μs for a 0.5 mol% doped sample to 11 μs for a 10 mol% doped sample and an increasingly stronger non-exponential behavior of emission decay patterns with an increase in Pr3+ concentration.
T2  - Optical Materials
T1  - Concentration and temperature dependence of Pr3+ f-f emissions in La(PO3)3
VL  - 150
SP  - 115226
DO  - 10.1016/j.optmat.2024.115226
ER  - 

@article{
author = "Antić, Željka and Racu, Andrei V. and Medić, Mina and Alodhayb, Abdullah N. and Kuzman, Sanja and Brik, Mikhail G. and Dramićanin, Miroslav",
year = "2024",
abstract = "La(PO3)3 activated with different concentrations of Pr3+ was synthesized by a solid-state process. The obtained powder was composed of chunks of several microns in size, typical for this type of synthesis. X-ray diffraction confirmed an orthorhombic crystal structure with the C2221 space group. The electronic band structures and density of states of La(PO3)3 and La(PO3)3:Pr3+ are calculated and presented. The visible and near-infrared emissions from Pr3+ [Xe]4f2 [Xe]4f2 electronic transitions were detected under 442 nm excitation. The red emission from the 1D2 state dominates visible spectra while emissions from the 3P0,1,2 states have smaller intensities. The 1D2 emission centered around 1020 nm is detected in the near-infrared spectral range. Intensities of 3P0 emissions increased with an increase in Pr concentration, while 1D2 emissions decreased in intensity. We found that the main process responsible for the 1D2 state decay is the Pr(1D2) + Pr(3H4) Pr(1G4) + Pr(3F3,4) cross-relaxation between two Pr ions of electric dipole-dipole character. This finding is supported by 1D2 emission decay measurements, which revealed a reduction of average decay constants from 242 μs for a 0.5 mol% doped sample to 11 μs for a 10 mol% doped sample and an increasingly stronger non-exponential behavior of emission decay patterns with an increase in Pr3+ concentration.",
journal = "Optical Materials",
title = "Concentration and temperature dependence of Pr3+ f-f emissions in La(PO3)3",
volume = "150",
pages = "115226",
doi = "10.1016/j.optmat.2024.115226"
}

Antić, Ž., Racu, A. V., Medić, M., Alodhayb, A. N., Kuzman, S., Brik, M. G.,& Dramićanin, M.. (2024). Concentration and temperature dependence of Pr3+ f-f emissions in La(PO3)3. in Optical Materials, 150, 115226.
https://doi.org/10.1016/j.optmat.2024.115226

Antić Ž, Racu AV, Medić M, Alodhayb AN, Kuzman S, Brik MG, Dramićanin M. Concentration and temperature dependence of Pr3+ f-f emissions in La(PO3)3. in Optical Materials. 2024;150:115226.
doi:10.1016/j.optmat.2024.115226 .

Antić, Željka, Racu, Andrei V., Medić, Mina, Alodhayb, Abdullah N., Kuzman, Sanja, Brik, Mikhail G., Dramićanin, Miroslav, "Concentration and temperature dependence of Pr3+ f-f emissions in La(PO3)3" in Optical Materials, 150 (2024):115226,
https://doi.org/10.1016/j.optmat.2024.115226 . .

TY  - JOUR
AU  - Novita, Mega
AU  - Chauhan, Alok Singh
AU  - Ujianti, Rizky Muliani Dwi
AU  - Marlina, Dian
AU  - Kusumo, Haryo
AU  - Anwar, Muchamad Taufiq
AU  - Piasecki, Michał
AU  - Brik, Mikhail G.
PY  - 2024
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12869
AB  - In the pursuit of enhancing red phosphor materials, integrating Deep Learning (DL) and machine Learning (ML) techniques has emerged as a transformative avenue. Challenges persist, necessitating comprehensive exploration and detailed comparative analysis of methods, focusing on predictive accuracy, interpretability, and computational demands. The role of regression models and their coefficients in material property prediction requires in-depth investigation. A systematic approach was employed, leveraging literature reviews and comparative analyses. Relevant articles were meticulously selected, focusing on methodologies and algorithms in predicting material properties. The study aimed to explore the integration of DL and ML in advancing red phosphor materials, evaluating algorithms and seven different regression models. Linear Regression, Robust Regression, and Lasso Regression emerged as top-performing models in predicting red phosphor material properties, specifically the 2E energy of Mn4+ doped crystals, supported by comprehensive coefficient analysis. This research offers valuable insights, informing the selection of models for specific tasks and optimizing the integration of DL and ML techniques in the field of red phosphor materials.
T2  - Journal of Luminescence
T1  - Exploring deep learning and machine learning for novel red phosphor materials
VL  - 269
SP  - 120476
DO  - 10.1016/j.jlumin.2024.120476
ER  - 

@article{
author = "Novita, Mega and Chauhan, Alok Singh and Ujianti, Rizky Muliani Dwi and Marlina, Dian and Kusumo, Haryo and Anwar, Muchamad Taufiq and Piasecki, Michał and Brik, Mikhail G.",
year = "2024",
abstract = "In the pursuit of enhancing red phosphor materials, integrating Deep Learning (DL) and machine Learning (ML) techniques has emerged as a transformative avenue. Challenges persist, necessitating comprehensive exploration and detailed comparative analysis of methods, focusing on predictive accuracy, interpretability, and computational demands. The role of regression models and their coefficients in material property prediction requires in-depth investigation. A systematic approach was employed, leveraging literature reviews and comparative analyses. Relevant articles were meticulously selected, focusing on methodologies and algorithms in predicting material properties. The study aimed to explore the integration of DL and ML in advancing red phosphor materials, evaluating algorithms and seven different regression models. Linear Regression, Robust Regression, and Lasso Regression emerged as top-performing models in predicting red phosphor material properties, specifically the 2E energy of Mn4+ doped crystals, supported by comprehensive coefficient analysis. This research offers valuable insights, informing the selection of models for specific tasks and optimizing the integration of DL and ML techniques in the field of red phosphor materials.",
journal = "Journal of Luminescence",
title = "Exploring deep learning and machine learning for novel red phosphor materials",
volume = "269",
pages = "120476",
doi = "10.1016/j.jlumin.2024.120476"
}

Novita, M., Chauhan, A. S., Ujianti, R. M. D., Marlina, D., Kusumo, H., Anwar, M. T., Piasecki, M.,& Brik, M. G.. (2024). Exploring deep learning and machine learning for novel red phosphor materials. in Journal of Luminescence, 269, 120476.
https://doi.org/10.1016/j.jlumin.2024.120476

Novita M, Chauhan AS, Ujianti RMD, Marlina D, Kusumo H, Anwar MT, Piasecki M, Brik MG. Exploring deep learning and machine learning for novel red phosphor materials. in Journal of Luminescence. 2024;269:120476.
doi:10.1016/j.jlumin.2024.120476 .

Novita, Mega, Chauhan, Alok Singh, Ujianti, Rizky Muliani Dwi, Marlina, Dian, Kusumo, Haryo, Anwar, Muchamad Taufiq, Piasecki, Michał, Brik, Mikhail G., "Exploring deep learning and machine learning for novel red phosphor materials" in Journal of Luminescence, 269 (2024):120476,
https://doi.org/10.1016/j.jlumin.2024.120476 . .

TY  - JOUR
AU  - Umar, Zafari
AU  - Kurboniyon, Mekhrdod S.
AU  - Khyzhun, Oleg
AU  - Yamamoto, Tomoyuki
AU  - Ma, Chong-Geng
AU  - Brik, Mikhail G.
AU  - Piasecki, Michal
PY  - 2024
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11826
AB  - We report on the results of the first principles calculations based on density functional theory (DFT) of the electronic structure and mechanical properties of K2LiAlF6, both non-doped and doped with Cr3+ ions. The densities of states of K2LiAlF6 and the K2LiAlF6:Cr3+ phosphor as well as the crystal-field strength 10Dq, the Cr3+ 2E→4A2 emission energy, elastic constants, bulk and shear moduli, sound velocities and Debye temperature as functions of hydrostatic pressure ranging from 0 up to 40 GPa were calculated. The present DFT calculations indicate that, the band gap of non-doped K2LiAlF6 increases quadratically with increasing pressure. Further, the crystal field strength 10Dq and the 2E→4A2 emission energy, the Debye temperature, sound velocities and shear moduli of Cr-doped K2LiAlF6 increase with increasing pressure, while the 2E→4A2 emission energy becomes red-shifted, which indicates potential applicability of the studied system for pressure sensing. Such calculations for the title system were performed for the first time; the obtained results provide a firm basis for a deeper understanding of physical properties of both neat and doped functional materials.
T2  - Journal of Luminescence
T1  - First-principles calculations of the electronic structure and mechanical properties of non-doped and Cr3+-Doped K2LiAlF6 under pressure
VL  - 266
SP  - 120278
DO  - 10.1016/j.jlumin.2023.120278
ER  - 

@article{
author = "Umar, Zafari and Kurboniyon, Mekhrdod S. and Khyzhun, Oleg and Yamamoto, Tomoyuki and Ma, Chong-Geng and Brik, Mikhail G. and Piasecki, Michal",
year = "2024",
abstract = "We report on the results of the first principles calculations based on density functional theory (DFT) of the electronic structure and mechanical properties of K2LiAlF6, both non-doped and doped with Cr3+ ions. The densities of states of K2LiAlF6 and the K2LiAlF6:Cr3+ phosphor as well as the crystal-field strength 10Dq, the Cr3+ 2E→4A2 emission energy, elastic constants, bulk and shear moduli, sound velocities and Debye temperature as functions of hydrostatic pressure ranging from 0 up to 40 GPa were calculated. The present DFT calculations indicate that, the band gap of non-doped K2LiAlF6 increases quadratically with increasing pressure. Further, the crystal field strength 10Dq and the 2E→4A2 emission energy, the Debye temperature, sound velocities and shear moduli of Cr-doped K2LiAlF6 increase with increasing pressure, while the 2E→4A2 emission energy becomes red-shifted, which indicates potential applicability of the studied system for pressure sensing. Such calculations for the title system were performed for the first time; the obtained results provide a firm basis for a deeper understanding of physical properties of both neat and doped functional materials.",
journal = "Journal of Luminescence",
title = "First-principles calculations of the electronic structure and mechanical properties of non-doped and Cr3+-Doped K2LiAlF6 under pressure",
volume = "266",
pages = "120278",
doi = "10.1016/j.jlumin.2023.120278"
}

Umar, Z., Kurboniyon, M. S., Khyzhun, O., Yamamoto, T., Ma, C., Brik, M. G.,& Piasecki, M.. (2024). First-principles calculations of the electronic structure and mechanical properties of non-doped and Cr3+-Doped K2LiAlF6 under pressure. in Journal of Luminescence, 266, 120278.
https://doi.org/10.1016/j.jlumin.2023.120278

Umar Z, Kurboniyon MS, Khyzhun O, Yamamoto T, Ma C, Brik MG, Piasecki M. First-principles calculations of the electronic structure and mechanical properties of non-doped and Cr3+-Doped K2LiAlF6 under pressure. in Journal of Luminescence. 2024;266:120278.
doi:10.1016/j.jlumin.2023.120278 .

Umar, Zafari, Kurboniyon, Mekhrdod S., Khyzhun, Oleg, Yamamoto, Tomoyuki, Ma, Chong-Geng, Brik, Mikhail G., Piasecki, Michal, "First-principles calculations of the electronic structure and mechanical properties of non-doped and Cr3+-Doped K2LiAlF6 under pressure" in Journal of Luminescence, 266 (2024):120278,
https://doi.org/10.1016/j.jlumin.2023.120278 . .

TY  - JOUR
AU  - Brik, Mikhail G.
AU  - Ma, Chong-Geng
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11378
AB  - Fast development of computer facilities and quantum chemical calculations made computational materials science be a very important tool in modern research aimed at design, development and understanding of novel functional materials with enhanced performance. This special issue is focused on applications of various computational methods to the description of physical properties of optical materials. Density Functional Theory (DFT)-based computational techniques, semiempirical crystal field models, machine learning and other tools used for explanation of experimental results, deeper understanding of optical materials properties and smart search for new materials with advanced characteristics are discussed in the special issue papers. All authors of these selected papers are well-known scientists who made solid contributions to their respective fields of research. Wide range of presented methods and approaches, together with broad scope of the considered materials and phenomena (phosphors, optical thermometers, radiative and non-radiative transitions) will make this collection of papers an interesting and valuable source of scientific information for an audience ranging from postgraduate students to experienced researchers
T2  - Optical Materials: X
T1  - Computational methods in their application to optical materials
VL  - 19
SP  - 100251
DO  - 10.1016/j.omx.2023.100251
ER  - 

@article{
author = "Brik, Mikhail G. and Ma, Chong-Geng",
year = "2023",
abstract = "Fast development of computer facilities and quantum chemical calculations made computational materials science be a very important tool in modern research aimed at design, development and understanding of novel functional materials with enhanced performance. This special issue is focused on applications of various computational methods to the description of physical properties of optical materials. Density Functional Theory (DFT)-based computational techniques, semiempirical crystal field models, machine learning and other tools used for explanation of experimental results, deeper understanding of optical materials properties and smart search for new materials with advanced characteristics are discussed in the special issue papers. All authors of these selected papers are well-known scientists who made solid contributions to their respective fields of research. Wide range of presented methods and approaches, together with broad scope of the considered materials and phenomena (phosphors, optical thermometers, radiative and non-radiative transitions) will make this collection of papers an interesting and valuable source of scientific information for an audience ranging from postgraduate students to experienced researchers",
journal = "Optical Materials: X",
title = "Computational methods in their application to optical materials",
volume = "19",
pages = "100251",
doi = "10.1016/j.omx.2023.100251"
}

Brik, M. G.,& Ma, C.. (2023). Computational methods in their application to optical materials. in Optical Materials: X, 19, 100251.
https://doi.org/10.1016/j.omx.2023.100251

Brik MG, Ma C. Computational methods in their application to optical materials. in Optical Materials: X. 2023;19:100251.
doi:10.1016/j.omx.2023.100251 .

Brik, Mikhail G., Ma, Chong-Geng, "Computational methods in their application to optical materials" in Optical Materials: X, 19 (2023):100251,
https://doi.org/10.1016/j.omx.2023.100251 . .

TY  - JOUR
AU  - Racu, Andrei V.
AU  - Ristić, Zoran
AU  - Ćirić, Aleksandar
AU  - Ðorđević, Vesna
AU  - Buse, Gabriel
AU  - Poienar, Maria
AU  - Gutmann, Michael J.
AU  - Ivashko, Oleh
AU  - Stef, Marius
AU  - Vizman, Daniel
AU  - Dramićanin, Miroslav
AU  - Piasecki, Michal
AU  - Brik, Mikhail G.
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10561
AB  - The understanding of complex relationships between luminescent properties, local symmetry of an emitting center, and the host crystal structure provides a better insight into optical properties of materials. In this work, the alkaline earths CaF2 and BaF2 fluoride crystals doped with 0.1 mol% ErF3 were investigated. The crystals structure has been studied using a synchrotron and laboratory X-ray diffraction. The C3v and C4v sites symmetry were determined using erbium probed high resolution emission spectroscopy (HRPL) at low temperature (LT) of 10 K. The considerable difference in room temperature (RT) optical properties for CaF2 compared to BaF2 crystals was observed. Such difference in absorption intensity of 4.7 times of erbium 4G11/2 manifold in UV, and 7.5 times in green emission from 4S3/2 manifold, could be due to the distinction in the host crystals cationic radius (ΔrCa,Ba) and the dopant-host ionic radius (ΔrCa-Er, ΔrBa-Er). Those Δr differences influence the structure and lead to the following symmetry formation: In CaF2, the C4v and C3v isolated centers were identified, with the determined Er3+- F−i bond lengths of 2.734 Å and 4.735 Å respectively; In BaF2, only C3v isolated centers were identified with the determined Er3+- F−i bond lengths of 5.380 Å. The present work is the first study that takes into account correlations of optical properties, the local symmetry and the structure in mentioned fluorides crystals, and it could be a step forward in the lanthanide doped optical materials systematics.
T2  - Optical Materials
T1  - Analysis of site symmetries of Er3+ doped CaF2 and BaF2 crystals by high resolution photoluminescence spectroscopy
VL  - 136
SP  - 113337
DO  - 10.1016/j.optmat.2022.113337
ER  - 

@article{
author = "Racu, Andrei V. and Ristić, Zoran and Ćirić, Aleksandar and Ðorđević, Vesna and Buse, Gabriel and Poienar, Maria and Gutmann, Michael J. and Ivashko, Oleh and Stef, Marius and Vizman, Daniel and Dramićanin, Miroslav and Piasecki, Michal and Brik, Mikhail G.",
year = "2023",
abstract = "The understanding of complex relationships between luminescent properties, local symmetry of an emitting center, and the host crystal structure provides a better insight into optical properties of materials. In this work, the alkaline earths CaF2 and BaF2 fluoride crystals doped with 0.1 mol% ErF3 were investigated. The crystals structure has been studied using a synchrotron and laboratory X-ray diffraction. The C3v and C4v sites symmetry were determined using erbium probed high resolution emission spectroscopy (HRPL) at low temperature (LT) of 10 K. The considerable difference in room temperature (RT) optical properties for CaF2 compared to BaF2 crystals was observed. Such difference in absorption intensity of 4.7 times of erbium 4G11/2 manifold in UV, and 7.5 times in green emission from 4S3/2 manifold, could be due to the distinction in the host crystals cationic radius (ΔrCa,Ba) and the dopant-host ionic radius (ΔrCa-Er, ΔrBa-Er). Those Δr differences influence the structure and lead to the following symmetry formation: In CaF2, the C4v and C3v isolated centers were identified, with the determined Er3+- F−i bond lengths of 2.734 Å and 4.735 Å respectively; In BaF2, only C3v isolated centers were identified with the determined Er3+- F−i bond lengths of 5.380 Å. The present work is the first study that takes into account correlations of optical properties, the local symmetry and the structure in mentioned fluorides crystals, and it could be a step forward in the lanthanide doped optical materials systematics.",
journal = "Optical Materials",
title = "Analysis of site symmetries of Er3+ doped CaF2 and BaF2 crystals by high resolution photoluminescence spectroscopy",
volume = "136",
pages = "113337",
doi = "10.1016/j.optmat.2022.113337"
}

Racu, A. V., Ristić, Z., Ćirić, A., Ðorđević, V., Buse, G., Poienar, M., Gutmann, M. J., Ivashko, O., Stef, M., Vizman, D., Dramićanin, M., Piasecki, M.,& Brik, M. G.. (2023). Analysis of site symmetries of Er3+ doped CaF2 and BaF2 crystals by high resolution photoluminescence spectroscopy. in Optical Materials, 136, 113337.
https://doi.org/10.1016/j.optmat.2022.113337

Racu AV, Ristić Z, Ćirić A, Ðorđević V, Buse G, Poienar M, Gutmann MJ, Ivashko O, Stef M, Vizman D, Dramićanin M, Piasecki M, Brik MG. Analysis of site symmetries of Er3+ doped CaF2 and BaF2 crystals by high resolution photoluminescence spectroscopy. in Optical Materials. 2023;136:113337.
doi:10.1016/j.optmat.2022.113337 .

Racu, Andrei V., Ristić, Zoran, Ćirić, Aleksandar, Ðorđević, Vesna, Buse, Gabriel, Poienar, Maria, Gutmann, Michael J., Ivashko, Oleh, Stef, Marius, Vizman, Daniel, Dramićanin, Miroslav, Piasecki, Michal, Brik, Mikhail G., "Analysis of site symmetries of Er3+ doped CaF2 and BaF2 crystals by high resolution photoluminescence spectroscopy" in Optical Materials, 136 (2023):113337,
https://doi.org/10.1016/j.optmat.2022.113337 . .

TY  - JOUR
AU  - Antić, Željka
AU  - Đorđević, Vesna R.
AU  - Ristić, Zoran
AU  - Srivastava, A.M.
AU  - Beers, W.W.
AU  - Dramićanin, Miroslav
AU  - Brik, Mikhail G.
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11576
AB  - The importance of structural disorder of crystal lattice for the formation of the optical properties of impurity ions is studied by evaluating the optical properties of Cr3+ impurity ions in Mg1-xZnxAl2O4:Cr3+ (x = 0; 0.25; 0.50; 0.75; 1.0) spinel solid solutions. It is demonstrated that the gradual replacement of Zn by Mg, which transforms the normal spinel ZnAl2O4 into the inverse spinel MgAl2O4, leads to an enhancement of the Cr3+ red emission. In addition, the Cr3+ decay rate (inverse to the emitting excited state lifetime) increases linearly when Zn is gradually replaced by Mg. These observations are explained by the lifting of the parity selection rule due to the random distribution of the Zn and Mg cations in the second coordination sphere around the emitting ion, which lowers the local symmetry at the impurity ion site. The strategy of deliberately creating disorder in the crystalline lattice is a successful way of increasing brightness and decreasing the excited state lifetime of the impurity ions, which can be applied for improving emission properties of the phosphor materials used in solid state lighting.
T2  - Journal of Luminescence
T1  - Influence of composition on the emission properties of impurities in solids: Case study of Mg1-xZnxAl2O4:Cr3+ with the spinel structure
VL  - 264
SP  - 120190
DO  - 10.1016/j.jlumin.2023.120190
ER  - 

@article{
author = "Antić, Željka and Đorđević, Vesna R. and Ristić, Zoran and Srivastava, A.M. and Beers, W.W. and Dramićanin, Miroslav and Brik, Mikhail G.",
year = "2023",
abstract = "The importance of structural disorder of crystal lattice for the formation of the optical properties of impurity ions is studied by evaluating the optical properties of Cr3+ impurity ions in Mg1-xZnxAl2O4:Cr3+ (x = 0; 0.25; 0.50; 0.75; 1.0) spinel solid solutions. It is demonstrated that the gradual replacement of Zn by Mg, which transforms the normal spinel ZnAl2O4 into the inverse spinel MgAl2O4, leads to an enhancement of the Cr3+ red emission. In addition, the Cr3+ decay rate (inverse to the emitting excited state lifetime) increases linearly when Zn is gradually replaced by Mg. These observations are explained by the lifting of the parity selection rule due to the random distribution of the Zn and Mg cations in the second coordination sphere around the emitting ion, which lowers the local symmetry at the impurity ion site. The strategy of deliberately creating disorder in the crystalline lattice is a successful way of increasing brightness and decreasing the excited state lifetime of the impurity ions, which can be applied for improving emission properties of the phosphor materials used in solid state lighting.",
journal = "Journal of Luminescence",
title = "Influence of composition on the emission properties of impurities in solids: Case study of Mg1-xZnxAl2O4:Cr3+ with the spinel structure",
volume = "264",
pages = "120190",
doi = "10.1016/j.jlumin.2023.120190"
}

Antić, Ž., Đorđević, V. R., Ristić, Z., Srivastava, A.M., Beers, W.W., Dramićanin, M.,& Brik, M. G.. (2023). Influence of composition on the emission properties of impurities in solids: Case study of Mg1-xZnxAl2O4:Cr3+ with the spinel structure. in Journal of Luminescence, 264, 120190.
https://doi.org/10.1016/j.jlumin.2023.120190

Antić Ž, Đorđević VR, Ristić Z, Srivastava A, Beers W, Dramićanin M, Brik MG. Influence of composition on the emission properties of impurities in solids: Case study of Mg1-xZnxAl2O4:Cr3+ with the spinel structure. in Journal of Luminescence. 2023;264:120190.
doi:10.1016/j.jlumin.2023.120190 .

Antić, Željka, Đorđević, Vesna R., Ristić, Zoran, Srivastava, A.M., Beers, W.W., Dramićanin, Miroslav, Brik, Mikhail G., "Influence of composition on the emission properties of impurities in solids: Case study of Mg1-xZnxAl2O4:Cr3+ with the spinel structure" in Journal of Luminescence, 264 (2023):120190,
https://doi.org/10.1016/j.jlumin.2023.120190 . .

TY  - JOUR
AU  - Li, Song
AU  - Zhang, ZhenZhen
AU  - Zhang, Jilin
AU  - Wu, Jiayu
AU  - Qiu, Zhongxian
AU  - Brik, Mikhail G.
AU  - Lian, Shixun
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12041
AB  - Many research efforts have focused on designing new inorganic phosphors to meet different application requirements. The structure-photoluminescence relationship between activator ions and the matrix lattice plays an irreparable role in designing target phosphors. Herein, a series of ABP2O7:Mn2+ (A = Ba/Sr; B = Mg/Zn) phosphors are prepared for a detailed study on the relationship between the luminescence performance and spatial structure and symmetry of the doping site of Mn2+. Due to the weak interaction between nearest B-B pairs, [BO5] is defined as an isolated coordination polyhedron whose structure and symmetry directly influence the photoluminescence of Mn2+. The emission wavelength of Mn2+ is ∼620 nm when it occupies the triangular bipyramid [MgO5] in BaMgP2O7. When Mn2+ occupies the quadrangular pyramid-typed [MgO5] or [ZnO5] in SrMgP2O7, SrZnP2O7, and BaZnP2O7, the emission wavelengths peak at ∼670 nm. We propose a conception of isolated coordination polyhedral confinement to clarify the luminescence performance of Mn2+ in the fivefold coordination configuration with different geometries, which has great theoretical research significance for designing inorganic phosphors.
T2  - Inorganic Chemistry
T1  - Isolated Coordination Polyhedron Confinement in ABP2O7:Mn2+(A=Ba/Sr; B=Mg/Zn)
VL  - 62
IS  - 45
SP  - 18740
EP  - 18749
DO  - 10.1021/acs.inorgchem.3c03238
ER  - 

@article{
author = "Li, Song and Zhang, ZhenZhen and Zhang, Jilin and Wu, Jiayu and Qiu, Zhongxian and Brik, Mikhail G. and Lian, Shixun",
year = "2023",
abstract = "Many research efforts have focused on designing new inorganic phosphors to meet different application requirements. The structure-photoluminescence relationship between activator ions and the matrix lattice plays an irreparable role in designing target phosphors. Herein, a series of ABP2O7:Mn2+ (A = Ba/Sr; B = Mg/Zn) phosphors are prepared for a detailed study on the relationship between the luminescence performance and spatial structure and symmetry of the doping site of Mn2+. Due to the weak interaction between nearest B-B pairs, [BO5] is defined as an isolated coordination polyhedron whose structure and symmetry directly influence the photoluminescence of Mn2+. The emission wavelength of Mn2+ is ∼620 nm when it occupies the triangular bipyramid [MgO5] in BaMgP2O7. When Mn2+ occupies the quadrangular pyramid-typed [MgO5] or [ZnO5] in SrMgP2O7, SrZnP2O7, and BaZnP2O7, the emission wavelengths peak at ∼670 nm. We propose a conception of isolated coordination polyhedral confinement to clarify the luminescence performance of Mn2+ in the fivefold coordination configuration with different geometries, which has great theoretical research significance for designing inorganic phosphors.",
journal = "Inorganic Chemistry",
title = "Isolated Coordination Polyhedron Confinement in ABP2O7:Mn2+(A=Ba/Sr; B=Mg/Zn)",
volume = "62",
number = "45",
pages = "18740-18749",
doi = "10.1021/acs.inorgchem.3c03238"
}

Li, S., Zhang, Z., Zhang, J., Wu, J., Qiu, Z., Brik, M. G.,& Lian, S.. (2023). Isolated Coordination Polyhedron Confinement in ABP2O7:Mn2+(A=Ba/Sr; B=Mg/Zn). in Inorganic Chemistry, 62(45), 18740-18749.
https://doi.org/10.1021/acs.inorgchem.3c03238

Li S, Zhang Z, Zhang J, Wu J, Qiu Z, Brik MG, Lian S. Isolated Coordination Polyhedron Confinement in ABP2O7:Mn2+(A=Ba/Sr; B=Mg/Zn). in Inorganic Chemistry. 2023;62(45):18740-18749.
doi:10.1021/acs.inorgchem.3c03238 .

Li, Song, Zhang, ZhenZhen, Zhang, Jilin, Wu, Jiayu, Qiu, Zhongxian, Brik, Mikhail G., Lian, Shixun, "Isolated Coordination Polyhedron Confinement in ABP2O7:Mn2+(A=Ba/Sr; B=Mg/Zn)" in Inorganic Chemistry, 62, no. 45 (2023):18740-18749,
https://doi.org/10.1021/acs.inorgchem.3c03238 . .

TY  - JOUR
AU  - Rudysh, Myron Ya.
AU  - Fedorchuk, Anatolii O.
AU  - Brik, Mikhail G.
AU  - Grechenkov, Jurij
AU  - Bocharov, Dmitry
AU  - Piskunov, Sergei
AU  - Popov, Anatoli I.
AU  - Piasecki, Michal
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12044
AB  - The aim of this study is to comprehensively examine the structural composition and
properties of the AgAlS2 crystal during its high-pressure phase. This analysis delves into the second
coordination environment of the crystal structure and elucidates the distinct transformations it
undergoes during the phase transition. The band energy structure was calculated, and the origin
of electronic levels was clarified. It is shown that the crystal becomes non-stratified during the
phase transition. This study also determined the values of the crystal’s carrier effective masses,
underscoring its spatial anisotropy. It was found that the calculated optical functions are similar to
the crystal in the chalcopyrite structure, and their differences are shown. Further, this study involved
the calculation of the crystal’s phonon spectrum, revealing the spectrum’s transformation during the
phase transition. The vibrational frequencies were also obtained, with a symmetrical classification of
vibrational modes. Finally, this study derived the infrared and Raman spectra of the AgAlS2 crystal,
thereby providing a comprehensive picture of the crystal during its high-pressure phase.
T2  - Materials
T1  - Electronic, Optical, and Vibrational Properties of an AgAlS2 Crystal in a High-Pressure Phase
VL  - 16
IS  - 21
SP  - 7017
DO  - 10.3390/ma16217017
ER  - 

@article{
author = "Rudysh, Myron Ya. and Fedorchuk, Anatolii O. and Brik, Mikhail G. and Grechenkov, Jurij and Bocharov, Dmitry and Piskunov, Sergei and Popov, Anatoli I. and Piasecki, Michal",
year = "2023",
abstract = "The aim of this study is to comprehensively examine the structural composition and
properties of the AgAlS2 crystal during its high-pressure phase. This analysis delves into the second
coordination environment of the crystal structure and elucidates the distinct transformations it
undergoes during the phase transition. The band energy structure was calculated, and the origin
of electronic levels was clarified. It is shown that the crystal becomes non-stratified during the
phase transition. This study also determined the values of the crystal’s carrier effective masses,
underscoring its spatial anisotropy. It was found that the calculated optical functions are similar to
the crystal in the chalcopyrite structure, and their differences are shown. Further, this study involved
the calculation of the crystal’s phonon spectrum, revealing the spectrum’s transformation during the
phase transition. The vibrational frequencies were also obtained, with a symmetrical classification of
vibrational modes. Finally, this study derived the infrared and Raman spectra of the AgAlS2 crystal,
thereby providing a comprehensive picture of the crystal during its high-pressure phase.",
journal = "Materials",
title = "Electronic, Optical, and Vibrational Properties of an AgAlS2 Crystal in a High-Pressure Phase",
volume = "16",
number = "21",
pages = "7017",
doi = "10.3390/ma16217017"
}

Rudysh, M. Ya., Fedorchuk, A. O., Brik, M. G., Grechenkov, J., Bocharov, D., Piskunov, S., Popov, A. I.,& Piasecki, M.. (2023). Electronic, Optical, and Vibrational Properties of an AgAlS2 Crystal in a High-Pressure Phase. in Materials, 16(21), 7017.
https://doi.org/10.3390/ma16217017

Rudysh MY, Fedorchuk AO, Brik MG, Grechenkov J, Bocharov D, Piskunov S, Popov AI, Piasecki M. Electronic, Optical, and Vibrational Properties of an AgAlS2 Crystal in a High-Pressure Phase. in Materials. 2023;16(21):7017.
doi:10.3390/ma16217017 .

Rudysh, Myron Ya., Fedorchuk, Anatolii O., Brik, Mikhail G., Grechenkov, Jurij, Bocharov, Dmitry, Piskunov, Sergei, Popov, Anatoli I., Piasecki, Michal, "Electronic, Optical, and Vibrational Properties of an AgAlS2 Crystal in a High-Pressure Phase" in Materials, 16, no. 21 (2023):7017,
https://doi.org/10.3390/ma16217017 . .

TY  - JOUR
AU  - Srivastava, Alok M.
AU  - Brik, Mikhail G.
AU  - Beers, William W.
AU  - Ma, Chong-Geng
AU  - Piasecki, Michal
AU  - Cohen, William E.
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10610
AB  - A comparative study of Eu3+ luminescence in an isostructural series of phosphate and vanadate compounds correlates the hypersensitivity of the 5D0→7F2 transition to the covalence and polarizability of the (XO4)3- (X = P, V) polyanion. The intensity of this transition, as measured by the ratio, [Formula presented], is always higher in the vanadate system [R (PO4)3-« R (VO4)3-]. Electronic energy band structure of these systems establishes higher covalence and polarizability of the (VO4)3- polyanion, which is due to strong V 3 d - O 2p covalent interaction via hybridization. The difference in the intensity of the hypersensitive transition between the phosphate and vanadate systems is consistent with the prediction of the ligand dipolar polarization model for the 4f-4f dipolar intensities. Our analysis supports the polarizability of (XO4)3- (X = P, V) over local site distortion effects as the intensity enhancing mechanism of the 5D0→7F2 transition. It is pointed out that the hybridization effect that serves as the source of the intensity of hypersensitive transition also accounts for the origin of second harmonic generation (SHG) in Li3VO4 and its absence in Li3PO4. © 2023 Elsevier B.V.
T2  - Journal of Luminescence
T1  - Intensity of the Eu3+ hypersensitive transition in isostructural phosphate and vanadate compounds
VL  - 257
DO  - 10.1016/j.jlumin.2023.119709
ER  - 

@article{
author = "Srivastava, Alok M. and Brik, Mikhail G. and Beers, William W. and Ma, Chong-Geng and Piasecki, Michal and Cohen, William E.",
year = "2023",
abstract = "A comparative study of Eu3+ luminescence in an isostructural series of phosphate and vanadate compounds correlates the hypersensitivity of the 5D0→7F2 transition to the covalence and polarizability of the (XO4)3- (X = P, V) polyanion. The intensity of this transition, as measured by the ratio, [Formula presented], is always higher in the vanadate system [R (PO4)3-« R (VO4)3-]. Electronic energy band structure of these systems establishes higher covalence and polarizability of the (VO4)3- polyanion, which is due to strong V 3 d - O 2p covalent interaction via hybridization. The difference in the intensity of the hypersensitive transition between the phosphate and vanadate systems is consistent with the prediction of the ligand dipolar polarization model for the 4f-4f dipolar intensities. Our analysis supports the polarizability of (XO4)3- (X = P, V) over local site distortion effects as the intensity enhancing mechanism of the 5D0→7F2 transition. It is pointed out that the hybridization effect that serves as the source of the intensity of hypersensitive transition also accounts for the origin of second harmonic generation (SHG) in Li3VO4 and its absence in Li3PO4. © 2023 Elsevier B.V.",
journal = "Journal of Luminescence",
title = "Intensity of the Eu3+ hypersensitive transition in isostructural phosphate and vanadate compounds",
volume = "257",
doi = "10.1016/j.jlumin.2023.119709"
}

Srivastava, A. M., Brik, M. G., Beers, W. W., Ma, C., Piasecki, M.,& Cohen, W. E.. (2023). Intensity of the Eu3+ hypersensitive transition in isostructural phosphate and vanadate compounds. in Journal of Luminescence, 257.
https://doi.org/10.1016/j.jlumin.2023.119709

Srivastava AM, Brik MG, Beers WW, Ma C, Piasecki M, Cohen WE. Intensity of the Eu3+ hypersensitive transition in isostructural phosphate and vanadate compounds. in Journal of Luminescence. 2023;257.
doi:10.1016/j.jlumin.2023.119709 .

Srivastava, Alok M., Brik, Mikhail G., Beers, William W., Ma, Chong-Geng, Piasecki, Michal, Cohen, William E., "Intensity of the Eu3+ hypersensitive transition in isostructural phosphate and vanadate compounds" in Journal of Luminescence, 257 (2023),
https://doi.org/10.1016/j.jlumin.2023.119709 . .

TY  - JOUR
AU  - Szymczak, Maja
AU  - Runowski, M.
AU  - Brik, Mikhail G.
AU  - Marciniak, Lukasz
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10922
AB  - The remote pressure readout is of vital application importance as it will facilitate and in many cases enable rapid diagnostics. For most of the luminescent manometers described to date, the sensitivity of the pressure readout is limited by the relatively small pressure-induced spectral shift of the emission band. In response to this limitation, in this work, we present a super-sensitive and temperature-invariant NIR emitting luminescent manometer based on LiScGeO4:Cr3+. The 4T2→4A2 emission band of Cr3+ ions undergoes in this manometer a linear spectral shift with a rate of dλ/dp = 23.63 nm/GPa, which is the highest value reported in the literature to date. In addition, by using a ratiometric approach, this manometer has a relative sensitivity exceeding 120%/GPa. Importantly, the developed optical manometer operates in the NIR spectral region, providing good light permeability in the non-transparent systems, having high absorption in the visible range. Moreover, in the case of high-pressure luminescence experiments, the use of the developed sensor will eliminate spectral overlapping issues, as the vast majority of the organic and inorganic phosphors emitting in the visible range.
T2  - Chemical Engineering Journal
T1  - Multimodal, super-sensitive luminescent manometer based on giant pressure-induced spectral shift of Cr3+ in the NIR range
VL  - 466
SP  - 143130
DO  - 10.1016/j.cej.2023.143130
ER  - 

@article{
author = "Szymczak, Maja and Runowski, M. and Brik, Mikhail G. and Marciniak, Lukasz",
year = "2023",
abstract = "The remote pressure readout is of vital application importance as it will facilitate and in many cases enable rapid diagnostics. For most of the luminescent manometers described to date, the sensitivity of the pressure readout is limited by the relatively small pressure-induced spectral shift of the emission band. In response to this limitation, in this work, we present a super-sensitive and temperature-invariant NIR emitting luminescent manometer based on LiScGeO4:Cr3+. The 4T2→4A2 emission band of Cr3+ ions undergoes in this manometer a linear spectral shift with a rate of dλ/dp = 23.63 nm/GPa, which is the highest value reported in the literature to date. In addition, by using a ratiometric approach, this manometer has a relative sensitivity exceeding 120%/GPa. Importantly, the developed optical manometer operates in the NIR spectral region, providing good light permeability in the non-transparent systems, having high absorption in the visible range. Moreover, in the case of high-pressure luminescence experiments, the use of the developed sensor will eliminate spectral overlapping issues, as the vast majority of the organic and inorganic phosphors emitting in the visible range.",
journal = "Chemical Engineering Journal",
title = "Multimodal, super-sensitive luminescent manometer based on giant pressure-induced spectral shift of Cr3+ in the NIR range",
volume = "466",
pages = "143130",
doi = "10.1016/j.cej.2023.143130"
}

Szymczak, M., Runowski, M., Brik, M. G.,& Marciniak, L.. (2023). Multimodal, super-sensitive luminescent manometer based on giant pressure-induced spectral shift of Cr3+ in the NIR range. in Chemical Engineering Journal, 466, 143130.
https://doi.org/10.1016/j.cej.2023.143130

Szymczak M, Runowski M, Brik MG, Marciniak L. Multimodal, super-sensitive luminescent manometer based on giant pressure-induced spectral shift of Cr3+ in the NIR range. in Chemical Engineering Journal. 2023;466:143130.
doi:10.1016/j.cej.2023.143130 .

Szymczak, Maja, Runowski, M., Brik, Mikhail G., Marciniak, Lukasz, "Multimodal, super-sensitive luminescent manometer based on giant pressure-induced spectral shift of Cr3+ in the NIR range" in Chemical Engineering Journal, 466 (2023):143130,
https://doi.org/10.1016/j.cej.2023.143130 . .

TY  - JOUR
AU  - Novita, Mega
AU  - Ristanto, Sigit
AU  - Saptaningrum, Ernawati
AU  - Supriyadi, Slemet
AU  - Marlina, Dian
AU  - Rondonuwu, Ferdy Semuel
AU  - Chauhan, Alok Singh
AU  - Walker, Benjamin
AU  - Ogasawara, Kazuyoshi
AU  - Piasecki, Michal
AU  - Brik, Mikhail G.
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11098
AB  - The crystals of Mn4+-activated fluorides, such as those of the hexafluorometallate family, are widely known for their luminescence properties. The most commonly reported red phosphors are A2XF6: Mn4+ and BXF6: Mn4+ fluorides, where A represents alkali metal ions such as Li, Na, K, Rb, Cs; X=Ti, Si, Ge, Zr, Sn, B = Ba and Zn; and X = Si, Ge, Zr, Sn, and Ti. Their performance is heavily influenced by the local structure around dopant ions. Many well-known research organizations have focused their attention on this area in recent years. However, there has been no report on the effect of local structural symmetrization on the luminescence properties of red phosphors. The purpose of this research was to investigate the effect of local structural symmetrization on the polytypes of K2XF6 crystals, namely Oh-K2MnF6, C3v-K2MnF6, Oh-K2SiF6, C3v-K2SiF6, D3d-K2GeF6, and C3v-K2GeF6. These crystal formations yielded seven-atom model clusters. Discrete Variational Xα (DV-Xα) and Discrete Variational Multi Electron (DVME) were the first principles methods used to compute the Molecular orbital energies, multiplet energy levels, and Coulomb integrals of these compounds. The multiplet energies of Mn4+ doped K2XF6 crystals were qualitatively reproduced by taking lattice relaxation, Configuration Dependent Correction (CDC), and Correlation Correction (CC) into account. The 4A2g→4T2g (4F) and 4A2g→4T1g (4F) energies increased when the Mn-F bond length decreased, but the 2Eg → 4A2g energy decreased. Because of the low symmetry, the magnitude of the Coulomb integral became smaller. As a result, the decreasing trend in the R-line energy could be attributed to a decreased electron–electron repulsion. © 2023 by the authors.
T2  - Materials
T1  - Study on Local-Structure Symmetrization of K2XF6 Crystals Doped with Mn4+ Ions by First-Principles Calculations
VL  - 16
IS  - 11
DO  - 10.3390/ma16114046
ER  - 

@article{
author = "Novita, Mega and Ristanto, Sigit and Saptaningrum, Ernawati and Supriyadi, Slemet and Marlina, Dian and Rondonuwu, Ferdy Semuel and Chauhan, Alok Singh and Walker, Benjamin and Ogasawara, Kazuyoshi and Piasecki, Michal and Brik, Mikhail G.",
year = "2023",
abstract = "The crystals of Mn4+-activated fluorides, such as those of the hexafluorometallate family, are widely known for their luminescence properties. The most commonly reported red phosphors are A2XF6: Mn4+ and BXF6: Mn4+ fluorides, where A represents alkali metal ions such as Li, Na, K, Rb, Cs; X=Ti, Si, Ge, Zr, Sn, B = Ba and Zn; and X = Si, Ge, Zr, Sn, and Ti. Their performance is heavily influenced by the local structure around dopant ions. Many well-known research organizations have focused their attention on this area in recent years. However, there has been no report on the effect of local structural symmetrization on the luminescence properties of red phosphors. The purpose of this research was to investigate the effect of local structural symmetrization on the polytypes of K2XF6 crystals, namely Oh-K2MnF6, C3v-K2MnF6, Oh-K2SiF6, C3v-K2SiF6, D3d-K2GeF6, and C3v-K2GeF6. These crystal formations yielded seven-atom model clusters. Discrete Variational Xα (DV-Xα) and Discrete Variational Multi Electron (DVME) were the first principles methods used to compute the Molecular orbital energies, multiplet energy levels, and Coulomb integrals of these compounds. The multiplet energies of Mn4+ doped K2XF6 crystals were qualitatively reproduced by taking lattice relaxation, Configuration Dependent Correction (CDC), and Correlation Correction (CC) into account. The 4A2g→4T2g (4F) and 4A2g→4T1g (4F) energies increased when the Mn-F bond length decreased, but the 2Eg → 4A2g energy decreased. Because of the low symmetry, the magnitude of the Coulomb integral became smaller. As a result, the decreasing trend in the R-line energy could be attributed to a decreased electron–electron repulsion. © 2023 by the authors.",
journal = "Materials",
title = "Study on Local-Structure Symmetrization of K2XF6 Crystals Doped with Mn4+ Ions by First-Principles Calculations",
volume = "16",
number = "11",
doi = "10.3390/ma16114046"
}

Novita, M., Ristanto, S., Saptaningrum, E., Supriyadi, S., Marlina, D., Rondonuwu, F. S., Chauhan, A. S., Walker, B., Ogasawara, K., Piasecki, M.,& Brik, M. G.. (2023). Study on Local-Structure Symmetrization of K2XF6 Crystals Doped with Mn4+ Ions by First-Principles Calculations. in Materials, 16(11).
https://doi.org/10.3390/ma16114046

Novita M, Ristanto S, Saptaningrum E, Supriyadi S, Marlina D, Rondonuwu FS, Chauhan AS, Walker B, Ogasawara K, Piasecki M, Brik MG. Study on Local-Structure Symmetrization of K2XF6 Crystals Doped with Mn4+ Ions by First-Principles Calculations. in Materials. 2023;16(11).
doi:10.3390/ma16114046 .

Novita, Mega, Ristanto, Sigit, Saptaningrum, Ernawati, Supriyadi, Slemet, Marlina, Dian, Rondonuwu, Ferdy Semuel, Chauhan, Alok Singh, Walker, Benjamin, Ogasawara, Kazuyoshi, Piasecki, Michal, Brik, Mikhail G., "Study on Local-Structure Symmetrization of K2XF6 Crystals Doped with Mn4+ Ions by First-Principles Calculations" in Materials, 16, no. 11 (2023),
https://doi.org/10.3390/ma16114046 . .

TY  - JOUR
AU  - Grechenkov, Jurij
AU  - Gopejenko, Aleksejs
AU  - Bocharov, Dmitry
AU  - Isakoviča, Inta
AU  - Popov, Anatoli I.
AU  - Brik, Mikhail G.
AU  - Piskunov, Sergei.
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11225
AB  - Chalcopyrites are ternary semiconductor compounds with successful applications in photovoltaics. Certain chalcopyrites are well researched, yet others remain understudied despite showing promise. In this study, we use ab initio methods to study CuGaS2, AgGaS2, and CuGaSe2 chalcopyrites with a focus on their less studied solid solutions. We use density functional theory (DFT) to study the effects that atomic configurations have on the properties of a solid solution and we calculate the optical absorption spectra using a many-body perturbation theory. Our theoretical simulations predict that excess of In and Se in the solid solutions leads to narrowing of the band gap and to the broadening of the absorption spectra. Obtained results show promise for possible photovoltaic applications, as well as developed methodology can be used for further study of other promising chalcopyritic compounds.
T2  - Energies
T1  - Ab Initio Modeling of CuGa1−xInxS2, CuGaS2(1−x)Se2x and Ag1−xCuxGaS2 Chalcopyrite Solid Solutions for Photovoltaic Applications
VL  - 16
IS  - 12
SP  - 4823
DO  - 10.3390/en16124823
ER  - 

@article{
author = "Grechenkov, Jurij and Gopejenko, Aleksejs and Bocharov, Dmitry and Isakoviča, Inta and Popov, Anatoli I. and Brik, Mikhail G. and Piskunov, Sergei.",
year = "2023",
abstract = "Chalcopyrites are ternary semiconductor compounds with successful applications in photovoltaics. Certain chalcopyrites are well researched, yet others remain understudied despite showing promise. In this study, we use ab initio methods to study CuGaS2, AgGaS2, and CuGaSe2 chalcopyrites with a focus on their less studied solid solutions. We use density functional theory (DFT) to study the effects that atomic configurations have on the properties of a solid solution and we calculate the optical absorption spectra using a many-body perturbation theory. Our theoretical simulations predict that excess of In and Se in the solid solutions leads to narrowing of the band gap and to the broadening of the absorption spectra. Obtained results show promise for possible photovoltaic applications, as well as developed methodology can be used for further study of other promising chalcopyritic compounds.",
journal = "Energies",
title = "Ab Initio Modeling of CuGa1−xInxS2, CuGaS2(1−x)Se2x and Ag1−xCuxGaS2 Chalcopyrite Solid Solutions for Photovoltaic Applications",
volume = "16",
number = "12",
pages = "4823",
doi = "10.3390/en16124823"
}

Grechenkov, J., Gopejenko, A., Bocharov, D., Isakoviča, I., Popov, A. I., Brik, M. G.,& Piskunov, Sergei.. (2023). Ab Initio Modeling of CuGa1−xInxS2, CuGaS2(1−x)Se2x and Ag1−xCuxGaS2 Chalcopyrite Solid Solutions for Photovoltaic Applications. in Energies, 16(12), 4823.
https://doi.org/10.3390/en16124823

Grechenkov J, Gopejenko A, Bocharov D, Isakoviča I, Popov AI, Brik MG, Piskunov S. Ab Initio Modeling of CuGa1−xInxS2, CuGaS2(1−x)Se2x and Ag1−xCuxGaS2 Chalcopyrite Solid Solutions for Photovoltaic Applications. in Energies. 2023;16(12):4823.
doi:10.3390/en16124823 .

Grechenkov, Jurij, Gopejenko, Aleksejs, Bocharov, Dmitry, Isakoviča, Inta, Popov, Anatoli I., Brik, Mikhail G., Piskunov, Sergei., "Ab Initio Modeling of CuGa1−xInxS2, CuGaS2(1−x)Se2x and Ag1−xCuxGaS2 Chalcopyrite Solid Solutions for Photovoltaic Applications" in Energies, 16, no. 12 (2023):4823,
https://doi.org/10.3390/en16124823 . .

TY  - JOUR
AU  - Kurboniyon, Mekhrdod S.
AU  - Lou, Bibo
AU  - Zafari, Umar
AU  - Rahimi, Farhod
AU  - Srivastava, Alok M.
AU  - Yamamoto, Tomoyuki
AU  - Brik, Mikhail G.
AU  - Ma, Chong-Geng
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11381
AB  - In this study, we present the results of first-principles calculations conducted within the density functional theory to investigate the geometric and electronic structures of the ground 4 A2 and excited 2 E and 4 T2 states, as well as the optical transition energies between these states, in the prototype system of K2SiF6:Mn4+. To achieve this, we employed a comprehensive evaluation of the five representative exchange-correlation functionals, enabling the development of a state-of-art calculation scheme that effectively describes the geometric and electronic structures of the excited 2 E and 4 T2 states. The calculated excitation, emission and zero-phonon line energies of the optical transitions between the ground 4 A2 state and the excited 2 E and 4 T2 states demonstrate a better agreement with experimental results. However, we observed that the conventional and widely-used approach based on the analysis of the electronic density of states diagrams derived from the ground state calculations failed to accurately evaluate the vertical optical transition energies from the 4 A2 ground state to the excited 2 E and 4 T2 states when compared to experimental data. The calculation technique developed in this study holds the potential for widespread application to other combinations of host materials and impurity ion, which is of great importance for future developments in the field of optical materials.
T2  - Journal of Luminescence
T1  - First-principles study of geometric and electronic structures, and optical transition energies of Mn4+ impurity ions: K2SiF6 as a prototype
VL  - 263
SP  - 120103
DO  - 10.1016/j.jlumin.2023.120103
ER  - 

@article{
author = "Kurboniyon, Mekhrdod S. and Lou, Bibo and Zafari, Umar and Rahimi, Farhod and Srivastava, Alok M. and Yamamoto, Tomoyuki and Brik, Mikhail G. and Ma, Chong-Geng",
year = "2023",
abstract = "In this study, we present the results of first-principles calculations conducted within the density functional theory to investigate the geometric and electronic structures of the ground 4 A2 and excited 2 E and 4 T2 states, as well as the optical transition energies between these states, in the prototype system of K2SiF6:Mn4+. To achieve this, we employed a comprehensive evaluation of the five representative exchange-correlation functionals, enabling the development of a state-of-art calculation scheme that effectively describes the geometric and electronic structures of the excited 2 E and 4 T2 states. The calculated excitation, emission and zero-phonon line energies of the optical transitions between the ground 4 A2 state and the excited 2 E and 4 T2 states demonstrate a better agreement with experimental results. However, we observed that the conventional and widely-used approach based on the analysis of the electronic density of states diagrams derived from the ground state calculations failed to accurately evaluate the vertical optical transition energies from the 4 A2 ground state to the excited 2 E and 4 T2 states when compared to experimental data. The calculation technique developed in this study holds the potential for widespread application to other combinations of host materials and impurity ion, which is of great importance for future developments in the field of optical materials.",
journal = "Journal of Luminescence",
title = "First-principles study of geometric and electronic structures, and optical transition energies of Mn4+ impurity ions: K2SiF6 as a prototype",
volume = "263",
pages = "120103",
doi = "10.1016/j.jlumin.2023.120103"
}

Kurboniyon, M. S., Lou, B., Zafari, U., Rahimi, F., Srivastava, A. M., Yamamoto, T., Brik, M. G.,& Ma, C.. (2023). First-principles study of geometric and electronic structures, and optical transition energies of Mn4+ impurity ions: K2SiF6 as a prototype. in Journal of Luminescence, 263, 120103.
https://doi.org/10.1016/j.jlumin.2023.120103

Kurboniyon MS, Lou B, Zafari U, Rahimi F, Srivastava AM, Yamamoto T, Brik MG, Ma C. First-principles study of geometric and electronic structures, and optical transition energies of Mn4+ impurity ions: K2SiF6 as a prototype. in Journal of Luminescence. 2023;263:120103.
doi:10.1016/j.jlumin.2023.120103 .

Kurboniyon, Mekhrdod S., Lou, Bibo, Zafari, Umar, Rahimi, Farhod, Srivastava, Alok M., Yamamoto, Tomoyuki, Brik, Mikhail G., Ma, Chong-Geng, "First-principles study of geometric and electronic structures, and optical transition energies of Mn4+ impurity ions: K2SiF6 as a prototype" in Journal of Luminescence, 263 (2023):120103,
https://doi.org/10.1016/j.jlumin.2023.120103 . .

TY  - JOUR
AU  - Nazarov, Michael V.
AU  - Spassky, Dmitry A.
AU  - Brik, Mikhail G.
AU  - Tsukerblat, Boris S.
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11586
AB  - In this paper we report the luminescence properties of nanosized undoped and Eu2+ (1%) doped SrAl2O4 phosphors. The samples were prepared by combustion method at 600 ◦C followed by annealing of the resultant combustion ash at 1000 ◦C in a reductive (Ar + H2) atmosphere. Photo luminescence (PL) and cathodoluminescence (CL) analyses were applied to characterize the phosphors. The qualitative energy level scheme of doped crystal SrAl2O4:Eu2+ and nature of defects in undoped phosphor is proposed and discussed. Within a simplified model of a single vibration and linear vibronic coupling the shape-function of the vibrationally assisted band (Pekarian) is analyzed with the emphasis on the vibrational structure. We propose an approximate approach to pass from the discrete Pekarian distribution to the structureless crystal field spectra taking into account phonon dispersion. This approach is expected to be useful for the description of the shape of the bands when the electronic levels are close to the conduction band of the host crystal.
T2  - Optical Materials
T1  - About the nature of luminescent bands in undoped and Eu2+ doped SrAl2O4 phosphors
VL  - 145
SP  - 114377
DO  - 10.1016/j.optmat.2023.114377
ER  - 

@article{
author = "Nazarov, Michael V. and Spassky, Dmitry A. and Brik, Mikhail G. and Tsukerblat, Boris S.",
year = "2023",
abstract = "In this paper we report the luminescence properties of nanosized undoped and Eu2+ (1%) doped SrAl2O4 phosphors. The samples were prepared by combustion method at 600 ◦C followed by annealing of the resultant combustion ash at 1000 ◦C in a reductive (Ar + H2) atmosphere. Photo luminescence (PL) and cathodoluminescence (CL) analyses were applied to characterize the phosphors. The qualitative energy level scheme of doped crystal SrAl2O4:Eu2+ and nature of defects in undoped phosphor is proposed and discussed. Within a simplified model of a single vibration and linear vibronic coupling the shape-function of the vibrationally assisted band (Pekarian) is analyzed with the emphasis on the vibrational structure. We propose an approximate approach to pass from the discrete Pekarian distribution to the structureless crystal field spectra taking into account phonon dispersion. This approach is expected to be useful for the description of the shape of the bands when the electronic levels are close to the conduction band of the host crystal.",
journal = "Optical Materials",
title = "About the nature of luminescent bands in undoped and Eu2+ doped SrAl2O4 phosphors",
volume = "145",
pages = "114377",
doi = "10.1016/j.optmat.2023.114377"
}

Nazarov, M. V., Spassky, D. A., Brik, M. G.,& Tsukerblat, B. S.. (2023). About the nature of luminescent bands in undoped and Eu2+ doped SrAl2O4 phosphors. in Optical Materials, 145, 114377.
https://doi.org/10.1016/j.optmat.2023.114377

Nazarov MV, Spassky DA, Brik MG, Tsukerblat BS. About the nature of luminescent bands in undoped and Eu2+ doped SrAl2O4 phosphors. in Optical Materials. 2023;145:114377.
doi:10.1016/j.optmat.2023.114377 .

Nazarov, Michael V., Spassky, Dmitry A., Brik, Mikhail G., Tsukerblat, Boris S., "About the nature of luminescent bands in undoped and Eu2+ doped SrAl2O4 phosphors" in Optical Materials, 145 (2023):114377,
https://doi.org/10.1016/j.optmat.2023.114377 . .

TY  - JOUR
AU  - Buryi, M.
AU  - Neykova, N.
AU  - Brik, Mikhail G.
AU  - Wang, Yu-Min
AU  - Remeš, Z.
AU  - Ridzonova, K.
AU  - Babin, V.
AU  - Davydova, M.
AU  - Drahokoupil, J.
AU  - Chertopalov, S.
AU  - Landová, L.
AU  - Pop-Georgievski, O.
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11721
AB  - Molybdenum doped ZnO was hydrothermally grown as the arrays of nanorods deposited onto the fused silica glass substrate. The molybdenum doping level varied from 1 to 30 %. The influence of Mo on the electronic and crystalline structure as well as luminescence and defects in the ZnO nanorods is under study of the bundle of experimental techniques complemented with density functional theory calculations. The tendency of Mo to create energy states within the bandgap of ZnO and their influence on the energy levels of native defects as well as excitons were proven by the synergy of experiment and theory. The improvement of the timing characteristics of the exciton- and zinc vacancy-related emission bands upon Mo doping (1–10 %) was observed. This paves the way for the defect engineering strategy in the search of effective and ultrafast scintillator with the improved light yield as well as compared to other materials. The new concept is based on the combination of the exciton and the defect emission. It is expected to have the potential of application in the detection of gamma rays implemented in time-of-flight positron emission tomography (TOFPET). The 20 and 30 % Mo doping levels resulted in the zinc molybdates creation strongly outnumbering ZnO nanorods.
T2  - Optical Materials
T1  - Hydrothermally grown molybdenum doped ZnO nanorod arrays. The concept of novel ultrafast nanoscintillator
VL  - 145
SP  - 114445
DO  - 10.1016/j.optmat.2023.114445
ER  - 

@article{
author = "Buryi, M. and Neykova, N. and Brik, Mikhail G. and Wang, Yu-Min and Remeš, Z. and Ridzonova, K. and Babin, V. and Davydova, M. and Drahokoupil, J. and Chertopalov, S. and Landová, L. and Pop-Georgievski, O.",
year = "2023",
abstract = "Molybdenum doped ZnO was hydrothermally grown as the arrays of nanorods deposited onto the fused silica glass substrate. The molybdenum doping level varied from 1 to 30 %. The influence of Mo on the electronic and crystalline structure as well as luminescence and defects in the ZnO nanorods is under study of the bundle of experimental techniques complemented with density functional theory calculations. The tendency of Mo to create energy states within the bandgap of ZnO and their influence on the energy levels of native defects as well as excitons were proven by the synergy of experiment and theory. The improvement of the timing characteristics of the exciton- and zinc vacancy-related emission bands upon Mo doping (1–10 %) was observed. This paves the way for the defect engineering strategy in the search of effective and ultrafast scintillator with the improved light yield as well as compared to other materials. The new concept is based on the combination of the exciton and the defect emission. It is expected to have the potential of application in the detection of gamma rays implemented in time-of-flight positron emission tomography (TOFPET). The 20 and 30 % Mo doping levels resulted in the zinc molybdates creation strongly outnumbering ZnO nanorods.",
journal = "Optical Materials",
title = "Hydrothermally grown molybdenum doped ZnO nanorod arrays. The concept of novel ultrafast nanoscintillator",
volume = "145",
pages = "114445",
doi = "10.1016/j.optmat.2023.114445"
}

Buryi, M., Neykova, N., Brik, M. G., Wang, Y., Remeš, Z., Ridzonova, K., Babin, V., Davydova, M., Drahokoupil, J., Chertopalov, S., Landová, L.,& Pop-Georgievski, O.. (2023). Hydrothermally grown molybdenum doped ZnO nanorod arrays. The concept of novel ultrafast nanoscintillator. in Optical Materials, 145, 114445.
https://doi.org/10.1016/j.optmat.2023.114445

Buryi M, Neykova N, Brik MG, Wang Y, Remeš Z, Ridzonova K, Babin V, Davydova M, Drahokoupil J, Chertopalov S, Landová L, Pop-Georgievski O. Hydrothermally grown molybdenum doped ZnO nanorod arrays. The concept of novel ultrafast nanoscintillator. in Optical Materials. 2023;145:114445.
doi:10.1016/j.optmat.2023.114445 .

Buryi, M., Neykova, N., Brik, Mikhail G., Wang, Yu-Min, Remeš, Z., Ridzonova, K., Babin, V., Davydova, M., Drahokoupil, J., Chertopalov, S., Landová, L., Pop-Georgievski, O., "Hydrothermally grown molybdenum doped ZnO nanorod arrays. The concept of novel ultrafast nanoscintillator" in Optical Materials, 145 (2023):114445,
https://doi.org/10.1016/j.optmat.2023.114445 . .

TY  - JOUR
AU  - Srivastava, Alok M.
AU  - Brik, Mikhail
AU  - Beers, William W.
AU  - Lou, B.
AU  - Ma, C.-G.
AU  - Piasecki, Michal
AU  - Cohen, William E.
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11170
AB  - A comparative study of Eu3+ ion luminescence in YXO4 (X=P, As, V) with the tetragonal zircon structure is conducted in relation to the intensity of the hypersensitivity 5D0 → 7F2 Δ J = 2 transition. Both the asymmetry ratio, R = I 5 D 0 − 7 F 2 I 5 D 0 − 7 F 1 , and the Judd-Ofelt Ω2 intensity parameter increases in the order YPO4 < YAsO4 < YVO4. This correlation is interpreted qualitatively in terms of the covalency and polarizability of (XO4)3−, which increases in the order (PO4)3− < (AsO4)3− < (VO4)3−. The trend is supported by the results of electronic band structure calculations of the three compounds which establish the strength of hybridization between the X cation and the oxygen 2p states. The electronic structure of YAsO4 is calculated to probe the covalence of As-O bonding. The increasing oscillator strength of the Eu3+5D0 → 7F2 transition in going from YPO4 to YAsO4 to YVO4 is consistent with the expectation of ligand dipolar polarization model for hypersensitivity which states that the oscillator strength of the 5D0 → 7F2 transition is proportional to the square of the ligand dipolar polarizability. The connection between the mechanism of hypersensitivity and second harmonic generation (SHG) is presented. © 2023 The Electrochemical Society (“ECS”). Published on behalf of ECS by IOP Publishing Limited.
T2  - ECS Journal of Solid State Science and Technology
T1  - Orbital Hybridization and Hypersensitivity of Eu3+ in YXO4 (X=P, As, V)
VL  - 12
IS  - 6
SP  - 066001
DO  - 10.1149/2162-8777/acd80f
ER  - 

@article{
author = "Srivastava, Alok M. and Brik, Mikhail and Beers, William W. and Lou, B. and Ma, C.-G. and Piasecki, Michal and Cohen, William E.",
year = "2023",
abstract = "A comparative study of Eu3+ ion luminescence in YXO4 (X=P, As, V) with the tetragonal zircon structure is conducted in relation to the intensity of the hypersensitivity 5D0 → 7F2 Δ J = 2 transition. Both the asymmetry ratio, R = I 5 D 0 − 7 F 2 I 5 D 0 − 7 F 1 , and the Judd-Ofelt Ω2 intensity parameter increases in the order YPO4 < YAsO4 < YVO4. This correlation is interpreted qualitatively in terms of the covalency and polarizability of (XO4)3−, which increases in the order (PO4)3− < (AsO4)3− < (VO4)3−. The trend is supported by the results of electronic band structure calculations of the three compounds which establish the strength of hybridization between the X cation and the oxygen 2p states. The electronic structure of YAsO4 is calculated to probe the covalence of As-O bonding. The increasing oscillator strength of the Eu3+5D0 → 7F2 transition in going from YPO4 to YAsO4 to YVO4 is consistent with the expectation of ligand dipolar polarization model for hypersensitivity which states that the oscillator strength of the 5D0 → 7F2 transition is proportional to the square of the ligand dipolar polarizability. The connection between the mechanism of hypersensitivity and second harmonic generation (SHG) is presented. © 2023 The Electrochemical Society (“ECS”). Published on behalf of ECS by IOP Publishing Limited.",
journal = "ECS Journal of Solid State Science and Technology",
title = "Orbital Hybridization and Hypersensitivity of Eu3+ in YXO4 (X=P, As, V)",
volume = "12",
number = "6",
pages = "066001",
doi = "10.1149/2162-8777/acd80f"
}

Srivastava, A. M., Brik, M., Beers, W. W., Lou, B., Ma, C.-G., Piasecki, M.,& Cohen, W. E.. (2023). Orbital Hybridization and Hypersensitivity of Eu3+ in YXO4 (X=P, As, V). in ECS Journal of Solid State Science and Technology, 12(6), 066001.
https://doi.org/10.1149/2162-8777/acd80f

Srivastava AM, Brik M, Beers WW, Lou B, Ma C, Piasecki M, Cohen WE. Orbital Hybridization and Hypersensitivity of Eu3+ in YXO4 (X=P, As, V). in ECS Journal of Solid State Science and Technology. 2023;12(6):066001.
doi:10.1149/2162-8777/acd80f .

Srivastava, Alok M., Brik, Mikhail, Beers, William W., Lou, B., Ma, C.-G., Piasecki, Michal, Cohen, William E., "Orbital Hybridization and Hypersensitivity of Eu3+ in YXO4 (X=P, As, V)" in ECS Journal of Solid State Science and Technology, 12, no. 6 (2023):066001,
https://doi.org/10.1149/2162-8777/acd80f . .

TY  - JOUR
AU  - Dramićanin, Miroslav
AU  - Marciniak, Lukasz
AU  - Kuzman, Sanja
AU  - Piotrowski, Wojciech
AU  - Ristić, Zoran
AU  - Periša, Jovana
AU  - Evans, Ivana
AU  - Mitrić, Jelena
AU  - Đorđević, Vesna
AU  - Tadić, Julijana D.
AU  - Brik, Mikhail G.
AU  - Ma, Chong-Geng
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10439
AB  - The near-infrared luminescence of Ca6Ba(PO4)4O:Mn5+ is demonstrated and explained. When excited into the broad and strong absorption band that spans the 500–1000 nm spectral range, this phosphor provides an ultranarrow (FWHM = 5 nm) emission centered at 1140 nm that originates from a spin-forbidden 1E → 3A2 transition with a 37.5% internal quantum efficiency and an excited-state lifetime of about 350 μs. We derived the crystal field and Racah parameters and calculated the appropriate Tanabe–Sugano diagram for this phosphor. We found that 1E emission quenches due to the thermally-assisted cross-over with the 3T2 state and that the relatively high Debye temperature of 783 K of Ca6Ba(PO4)4O facilitates efficient emission. Since Ca6Ba(PO4)4O also provides efficient yellow emission of the Eu2+ dopant, we calculated and explained its electronic band structure, the partial and total density of states, effective Mulliken charges of all ions, elastic constants, Debye temperature, and vibrational spectra. Finally, we demonstrated the application of phosphor in a luminescence intensity ratio thermometry and obtained a relative sensitivity of 1.92%K−1 and a temperature resolution of 0.2 K in the range of physiological temperatures.
T2  - Light: Science & Applications
T1  - Mn5+-activated Ca6Ba(PO4)4O near-infrared phosphor and its application in luminescence thermometry
VL  - 11
IS  - 1
SP  - 279
DO  - 10.1038/s41377-022-00958-7
ER  - 

@article{
author = "Dramićanin, Miroslav and Marciniak, Lukasz and Kuzman, Sanja and Piotrowski, Wojciech and Ristić, Zoran and Periša, Jovana and Evans, Ivana and Mitrić, Jelena and Đorđević, Vesna and Tadić, Julijana D. and Brik, Mikhail G. and Ma, Chong-Geng",
year = "2022",
abstract = "The near-infrared luminescence of Ca6Ba(PO4)4O:Mn5+ is demonstrated and explained. When excited into the broad and strong absorption band that spans the 500–1000 nm spectral range, this phosphor provides an ultranarrow (FWHM = 5 nm) emission centered at 1140 nm that originates from a spin-forbidden 1E → 3A2 transition with a 37.5% internal quantum efficiency and an excited-state lifetime of about 350 μs. We derived the crystal field and Racah parameters and calculated the appropriate Tanabe–Sugano diagram for this phosphor. We found that 1E emission quenches due to the thermally-assisted cross-over with the 3T2 state and that the relatively high Debye temperature of 783 K of Ca6Ba(PO4)4O facilitates efficient emission. Since Ca6Ba(PO4)4O also provides efficient yellow emission of the Eu2+ dopant, we calculated and explained its electronic band structure, the partial and total density of states, effective Mulliken charges of all ions, elastic constants, Debye temperature, and vibrational spectra. Finally, we demonstrated the application of phosphor in a luminescence intensity ratio thermometry and obtained a relative sensitivity of 1.92%K−1 and a temperature resolution of 0.2 K in the range of physiological temperatures.",
journal = "Light: Science & Applications",
title = "Mn5+-activated Ca6Ba(PO4)4O near-infrared phosphor and its application in luminescence thermometry",
volume = "11",
number = "1",
pages = "279",
doi = "10.1038/s41377-022-00958-7"
}

Dramićanin, M., Marciniak, L., Kuzman, S., Piotrowski, W., Ristić, Z., Periša, J., Evans, I., Mitrić, J., Đorđević, V., Tadić, J. D., Brik, M. G.,& Ma, C.. (2022). Mn5+-activated Ca6Ba(PO4)4O near-infrared phosphor and its application in luminescence thermometry. in Light: Science & Applications, 11(1), 279.
https://doi.org/10.1038/s41377-022-00958-7

Dramićanin M, Marciniak L, Kuzman S, Piotrowski W, Ristić Z, Periša J, Evans I, Mitrić J, Đorđević V, Tadić JD, Brik MG, Ma C. Mn5+-activated Ca6Ba(PO4)4O near-infrared phosphor and its application in luminescence thermometry. in Light: Science & Applications. 2022;11(1):279.
doi:10.1038/s41377-022-00958-7 .

Dramićanin, Miroslav, Marciniak, Lukasz, Kuzman, Sanja, Piotrowski, Wojciech, Ristić, Zoran, Periša, Jovana, Evans, Ivana, Mitrić, Jelena, Đorđević, Vesna, Tadić, Julijana D., Brik, Mikhail G., Ma, Chong-Geng, "Mn5+-activated Ca6Ba(PO4)4O near-infrared phosphor and its application in luminescence thermometry" in Light: Science & Applications, 11, no. 1 (2022):279,
https://doi.org/10.1038/s41377-022-00958-7 . .

TY  - JOUR
AU  - Mironova-Ulmane, Nina
AU  - Brik, Mikhail G.
AU  - Grube, Jurgis
AU  - Krieke, Guna
AU  - Kemere, Meldra
AU  - Antuzevics, Andris
AU  - Gabrusenoks, E.
AU  - Skvortsova, Vera N.
AU  - Elsts, Edgars
AU  - Sarakovskis, Anatolijs
AU  - Piasecki, Michal
AU  - Popov, Anatoli I.
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10397
AB  - The optical spectra of a single crystal of α-Al2O3Cr3+ were studied in a wide temperature range. The crystal was demonstrated to have a potential for optical thermometric applications. Three ways of measuring temperature were tested and analyzed: i) luminescence intensity ratio of the R1 and R2 lines; ii) change of the full width of half maxima of the R1 and R2 lines, and iii) thermal shifts of the R1 and R2 lines maxima. The highest absolute and relative sensitivities were obtained at cryogenic temperatures. In addition, the thermal shifts of the R lines were analyzed using the McCumber-Sturge equation to estimate the Debye temperature and the electron-vibrational interaction parameter.
T2  - Optical Materials
T1  - EPR, optical and thermometric studies of Cr3+ ions in the α-Al2O3 synthetic single crystal
VL  - 132
SP  - 112859
DO  - 10.1016/j.optmat.2022.112859
ER  - 

@article{
author = "Mironova-Ulmane, Nina and Brik, Mikhail G. and Grube, Jurgis and Krieke, Guna and Kemere, Meldra and Antuzevics, Andris and Gabrusenoks, E. and Skvortsova, Vera N. and Elsts, Edgars and Sarakovskis, Anatolijs and Piasecki, Michal and Popov, Anatoli I.",
year = "2022",
abstract = "The optical spectra of a single crystal of α-Al2O3Cr3+ were studied in a wide temperature range. The crystal was demonstrated to have a potential for optical thermometric applications. Three ways of measuring temperature were tested and analyzed: i) luminescence intensity ratio of the R1 and R2 lines; ii) change of the full width of half maxima of the R1 and R2 lines, and iii) thermal shifts of the R1 and R2 lines maxima. The highest absolute and relative sensitivities were obtained at cryogenic temperatures. In addition, the thermal shifts of the R lines were analyzed using the McCumber-Sturge equation to estimate the Debye temperature and the electron-vibrational interaction parameter.",
journal = "Optical Materials",
title = "EPR, optical and thermometric studies of Cr3+ ions in the α-Al2O3 synthetic single crystal",
volume = "132",
pages = "112859",
doi = "10.1016/j.optmat.2022.112859"
}

Mironova-Ulmane, N., Brik, M. G., Grube, J., Krieke, G., Kemere, M., Antuzevics, A., Gabrusenoks, E., Skvortsova, V. N., Elsts, E., Sarakovskis, A., Piasecki, M.,& Popov, A. I.. (2022). EPR, optical and thermometric studies of Cr3+ ions in the α-Al2O3 synthetic single crystal. in Optical Materials, 132, 112859.
https://doi.org/10.1016/j.optmat.2022.112859

Mironova-Ulmane N, Brik MG, Grube J, Krieke G, Kemere M, Antuzevics A, Gabrusenoks E, Skvortsova VN, Elsts E, Sarakovskis A, Piasecki M, Popov AI. EPR, optical and thermometric studies of Cr3+ ions in the α-Al2O3 synthetic single crystal. in Optical Materials. 2022;132:112859.
doi:10.1016/j.optmat.2022.112859 .

Mironova-Ulmane, Nina, Brik, Mikhail G., Grube, Jurgis, Krieke, Guna, Kemere, Meldra, Antuzevics, Andris, Gabrusenoks, E., Skvortsova, Vera N., Elsts, Edgars, Sarakovskis, Anatolijs, Piasecki, Michal, Popov, Anatoli I., "EPR, optical and thermometric studies of Cr3+ ions in the α-Al2O3 synthetic single crystal" in Optical Materials, 132 (2022):112859,
https://doi.org/10.1016/j.optmat.2022.112859 . .

TY  - JOUR
AU  - Andreici Etimie, E. L.
AU  - Avram, Nicolae M.
AU  - Brik, Mikhail G.
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10452
AB  - The normal spinels (Mg, Zn)Al2O4 doped with transition metal (TM) ions Cr3+/Co2+ are versatile materials with important electronic, optical and spectral properties. In addition to being used in many applications, they are excellent systems for testing some models and simulation features. The aim of this paper is to present, in the unified frame, the results on d-d transitions and ligand field parameters (LFPs) for the title systems, based on ab initio calculations, combining periodic density functional theory (DFT) supercell approach with ab initio (AI) multi -reference perturbation theory (MRPT) and multi-reference configuration interaction (MRCI) methods. These AI methods, based on complete active space self-consistent-field (CASSCF) reference, allow to calculate and investigate the energy levels of TM ions and the d-d transitions between them. From the AI results the B and C Racah parameters, the spin-orbit coupling (SOC) constant and the LFPs in the frame of the angular overlap model (AOM) were accurately extracted with ab initio ligand field theory (AILFT) protocol, all with subsequent comparison with the experimental data or existing theoretical results in the literature. The calculation technique presented in this paper serves as a predictive formalism for further studies of larger monomer clusters, for which experimental data is unreliable or unavailable.
T2  - Optical Materials: X
T1  - The d-d transitions and ligand field parameters for Cr3+/Co2+ doped (Mg, Zn)Al2O4: Multi-reference Ab initio investigations
VL  - 16
SP  - 100188
DO  - 10.1016/j.omx.2022.100188
ER  - 

@article{
author = "Andreici Etimie, E. L. and Avram, Nicolae M. and Brik, Mikhail G.",
year = "2022",
abstract = "The normal spinels (Mg, Zn)Al2O4 doped with transition metal (TM) ions Cr3+/Co2+ are versatile materials with important electronic, optical and spectral properties. In addition to being used in many applications, they are excellent systems for testing some models and simulation features. The aim of this paper is to present, in the unified frame, the results on d-d transitions and ligand field parameters (LFPs) for the title systems, based on ab initio calculations, combining periodic density functional theory (DFT) supercell approach with ab initio (AI) multi -reference perturbation theory (MRPT) and multi-reference configuration interaction (MRCI) methods. These AI methods, based on complete active space self-consistent-field (CASSCF) reference, allow to calculate and investigate the energy levels of TM ions and the d-d transitions between them. From the AI results the B and C Racah parameters, the spin-orbit coupling (SOC) constant and the LFPs in the frame of the angular overlap model (AOM) were accurately extracted with ab initio ligand field theory (AILFT) protocol, all with subsequent comparison with the experimental data or existing theoretical results in the literature. The calculation technique presented in this paper serves as a predictive formalism for further studies of larger monomer clusters, for which experimental data is unreliable or unavailable.",
journal = "Optical Materials: X",
title = "The d-d transitions and ligand field parameters for Cr3+/Co2+ doped (Mg, Zn)Al2O4: Multi-reference Ab initio investigations",
volume = "16",
pages = "100188",
doi = "10.1016/j.omx.2022.100188"
}

Andreici Etimie, E. L., Avram, N. M.,& Brik, M. G.. (2022). The d-d transitions and ligand field parameters for Cr3+/Co2+ doped (Mg, Zn)Al2O4: Multi-reference Ab initio investigations. in Optical Materials: X, 16, 100188.
https://doi.org/10.1016/j.omx.2022.100188

Andreici Etimie EL, Avram NM, Brik MG. The d-d transitions and ligand field parameters for Cr3+/Co2+ doped (Mg, Zn)Al2O4: Multi-reference Ab initio investigations. in Optical Materials: X. 2022;16:100188.
doi:10.1016/j.omx.2022.100188 .

Andreici Etimie, E. L., Avram, Nicolae M., Brik, Mikhail G., "The d-d transitions and ligand field parameters for Cr3+/Co2+ doped (Mg, Zn)Al2O4: Multi-reference Ab initio investigations" in Optical Materials: X, 16 (2022):100188,
https://doi.org/10.1016/j.omx.2022.100188 . .

TY  - JOUR
AU  - Srivastava, Alok M.
AU  - Brik, Mikhail G.
AU  - Beers, William W.
AU  - Cohen, William E.
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10601
AB  - The relationship between the Stokes shift of Bi3+ emission and the volume of the unit-cell in two series of orthorhombic perovskites, LnB 3+O3 (Ln = La, Gd, Y; B 3+ = Al, In, Ga) and AB 4+O3 (A = Ca, Sr; B 4+ = Zr, Sn) is explored. The Stokes shift increases linearly with increasing cell volume. This is explained qualitatively by the lattice chemical pressure acting on the Bi3+ ion. The degree of Bi3+ ion off-centering displacement, which is due to the stereochemical activity of the lone-pair electrons (6 s2), is controlled by the chemical pressure. A small cell suppresses the off-centering displacement to produce a small Stokes shift of emission by limiting the excited state structural distortion. In large cell, the off-centering displacement is more easily accommodated. The elimination of ground state distortion in the excited state gives larger Stokes shift of emission. These qualitative arguments are supplemented by recent first-principles calculations on Bi3+ luminescence in these perovskites. The Bi3+ luminescence in SrZrO3, previously assigned to emission from the D-state, is now assigned to the localized 3P0,1 → 1S0 transition. The energy of the 1S0 → 3P1 transition is correlated with the covalence of the BO6/2 perovskite framework. Discussion on the effective ionic radius of the Bi3+ ion in these perovskites is presented.
T2  - ECS Journal of Solid State Science and Technology
T1  - Chemical Pressure Effects on the Stokes Shift of Bi3+ Luminescence in Orthorhombic Perovskites
VL  - 11
IS  - 9
SP  - 096003
DO  - 10.1149/2162-8777/ac915b
ER  - 

@article{
author = "Srivastava, Alok M. and Brik, Mikhail G. and Beers, William W. and Cohen, William E.",
year = "2022",
abstract = "The relationship between the Stokes shift of Bi3+ emission and the volume of the unit-cell in two series of orthorhombic perovskites, LnB 3+O3 (Ln = La, Gd, Y; B 3+ = Al, In, Ga) and AB 4+O3 (A = Ca, Sr; B 4+ = Zr, Sn) is explored. The Stokes shift increases linearly with increasing cell volume. This is explained qualitatively by the lattice chemical pressure acting on the Bi3+ ion. The degree of Bi3+ ion off-centering displacement, which is due to the stereochemical activity of the lone-pair electrons (6 s2), is controlled by the chemical pressure. A small cell suppresses the off-centering displacement to produce a small Stokes shift of emission by limiting the excited state structural distortion. In large cell, the off-centering displacement is more easily accommodated. The elimination of ground state distortion in the excited state gives larger Stokes shift of emission. These qualitative arguments are supplemented by recent first-principles calculations on Bi3+ luminescence in these perovskites. The Bi3+ luminescence in SrZrO3, previously assigned to emission from the D-state, is now assigned to the localized 3P0,1 → 1S0 transition. The energy of the 1S0 → 3P1 transition is correlated with the covalence of the BO6/2 perovskite framework. Discussion on the effective ionic radius of the Bi3+ ion in these perovskites is presented.",
journal = "ECS Journal of Solid State Science and Technology",
title = "Chemical Pressure Effects on the Stokes Shift of Bi3+ Luminescence in Orthorhombic Perovskites",
volume = "11",
number = "9",
pages = "096003",
doi = "10.1149/2162-8777/ac915b"
}

Srivastava, A. M., Brik, M. G., Beers, W. W.,& Cohen, W. E.. (2022). Chemical Pressure Effects on the Stokes Shift of Bi3+ Luminescence in Orthorhombic Perovskites. in ECS Journal of Solid State Science and Technology, 11(9), 096003.
https://doi.org/10.1149/2162-8777/ac915b

Srivastava AM, Brik MG, Beers WW, Cohen WE. Chemical Pressure Effects on the Stokes Shift of Bi3+ Luminescence in Orthorhombic Perovskites. in ECS Journal of Solid State Science and Technology. 2022;11(9):096003.
doi:10.1149/2162-8777/ac915b .

Srivastava, Alok M., Brik, Mikhail G., Beers, William W., Cohen, William E., "Chemical Pressure Effects on the Stokes Shift of Bi3+ Luminescence in Orthorhombic Perovskites" in ECS Journal of Solid State Science and Technology, 11, no. 9 (2022):096003,
https://doi.org/10.1149/2162-8777/ac915b . .

TY  - JOUR
AU  - Ristić, Zoran
AU  - Đorđević, Vesna R.
AU  - Medić, Mina M.
AU  - Kuzman, Sanja
AU  - Brik, Mikhail G.
AU  - Antić, Željka
AU  - Dramićanin, Miroslav
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9910
AB  - This paper presents the Cr3+-activated Mg2TiO4 phosphor temperature dependance of its near infrared luminescence and its potential in the optical thermometry applications. In this respect, temperature dependences of three emission features were tested over the broad temperature range (10–500 K): (i) the luminescence intensity ratio (LIR) between emissions from 4T2→4A2 and 2E→4A2 transitions, (ii) the emission lifetime, and (iii) the shift of the 2E→4A2 emission band. We observed that LIR follows the Boltzmann equation for T > 300 K with the maximal value of relative sensitivity of 1.73 %K−1. The lifetime value of the 2E→4A2 transition strongly decreases with temperature with a maximal relative sensitivity of about 0.75 %K−1 at around 430K. Finally, the shift of the emission band is about 65 cm−1 over the complete temperature range.
T2  - Optical Materials
T1  - Temperature dependence of the Cr3+-DOPED Mg2TiO4 near-infrared emission
VL  - 120
SP  - 111468
DO  - 10.1016/j.optmat.2021.111468
ER  - 

@article{
author = "Ristić, Zoran and Đorđević, Vesna R. and Medić, Mina M. and Kuzman, Sanja and Brik, Mikhail G. and Antić, Željka and Dramićanin, Miroslav",
year = "2021",
abstract = "This paper presents the Cr3+-activated Mg2TiO4 phosphor temperature dependance of its near infrared luminescence and its potential in the optical thermometry applications. In this respect, temperature dependences of three emission features were tested over the broad temperature range (10–500 K): (i) the luminescence intensity ratio (LIR) between emissions from 4T2→4A2 and 2E→4A2 transitions, (ii) the emission lifetime, and (iii) the shift of the 2E→4A2 emission band. We observed that LIR follows the Boltzmann equation for T > 300 K with the maximal value of relative sensitivity of 1.73 %K−1. The lifetime value of the 2E→4A2 transition strongly decreases with temperature with a maximal relative sensitivity of about 0.75 %K−1 at around 430K. Finally, the shift of the emission band is about 65 cm−1 over the complete temperature range.",
journal = "Optical Materials",
title = "Temperature dependence of the Cr3+-DOPED Mg2TiO4 near-infrared emission",
volume = "120",
pages = "111468",
doi = "10.1016/j.optmat.2021.111468"
}

Ristić, Z., Đorđević, V. R., Medić, M. M., Kuzman, S., Brik, M. G., Antić, Ž.,& Dramićanin, M.. (2021). Temperature dependence of the Cr3+-DOPED Mg2TiO4 near-infrared emission. in Optical Materials, 120, 111468.
https://doi.org/10.1016/j.optmat.2021.111468

Ristić Z, Đorđević VR, Medić MM, Kuzman S, Brik MG, Antić Ž, Dramićanin M. Temperature dependence of the Cr3+-DOPED Mg2TiO4 near-infrared emission. in Optical Materials. 2021;120:111468.
doi:10.1016/j.optmat.2021.111468 .

Ristić, Zoran, Đorđević, Vesna R., Medić, Mina M., Kuzman, Sanja, Brik, Mikhail G., Antić, Željka, Dramićanin, Miroslav, "Temperature dependence of the Cr3+-DOPED Mg2TiO4 near-infrared emission" in Optical Materials, 120 (2021):111468,
https://doi.org/10.1016/j.optmat.2021.111468 . .

TY  - JOUR
AU  - Wu, Bing
AU  - Yang, Menglin
AU  - Yan, Yanci
AU  - Ma, Chonggeng
AU  - Zhang, Hongwu
AU  - Brik, Mikhail G.
AU  - Dramićanin, Miroslav
AU  - Valiev, Uygun V.
AU  - Piasecki, Michał M.
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9758
AB  - Elpasolite crystals are very important materials, both from the applied and fundamental points of view. Those elpasolites, which contain rare earth ions with a high atomic number Z, are very much suitable for the low-cost high-performance gamma-ray detection, applications in medicine, food industry, nuclear energy production, processing, and detection of nuclear proliferation. The thermal and structural stabilities are important parameters required for detecting applications, because the performance conditions for such devices are usually very harsh. Since it is widely believed that elpasolites may have even better detection properties, the lack of systematic studies on the elpasolites and thus the unavailability of reliable data on their physical properties and trends in their variation caused by chemical composition considerably hinders search for more efficient new materials. Therefore, to fill in this gap and provide with all essential information about a large number of elpasolites crystals, for the first time, the structural stability, elastic, vibrational, and electronic properties of 60 cubic elpasolite Cs2NaLnX6 (Ln = La, …, Lu, X = F, Cl, Br, I) crystals were consistently calculated in the framework of the same computational approach based on the density functional theory (DFT). Variation of all calculated parameters (such as the lattice constants, elastic constants, Debye temperature, normal vibrational modes frequencies, Mulliken effective charges, bond populations, and band gaps) across the considered groups of crystals was analyzed and several trends, which are important for the search and preparation of new stable materials with improved performance, were identified. © 2020 The American Ceramic Society (ACERS)
T2  - Journal of the American Ceramic Society
T1  - Effects of chemical composition on the structural stability, elastic, vibrational, and electronic properties of Cs2NaLnX6 (Ln = La…Lu, X = F, Cl, Br, I) elpasolites
VL  - 104
IS  - 3
SP  - 1489
EP  - 1500
DO  - 10.1111/jace.17565
ER  - 

@article{
author = "Wu, Bing and Yang, Menglin and Yan, Yanci and Ma, Chonggeng and Zhang, Hongwu and Brik, Mikhail G. and Dramićanin, Miroslav and Valiev, Uygun V. and Piasecki, Michał M.",
year = "2021",
abstract = "Elpasolite crystals are very important materials, both from the applied and fundamental points of view. Those elpasolites, which contain rare earth ions with a high atomic number Z, are very much suitable for the low-cost high-performance gamma-ray detection, applications in medicine, food industry, nuclear energy production, processing, and detection of nuclear proliferation. The thermal and structural stabilities are important parameters required for detecting applications, because the performance conditions for such devices are usually very harsh. Since it is widely believed that elpasolites may have even better detection properties, the lack of systematic studies on the elpasolites and thus the unavailability of reliable data on their physical properties and trends in their variation caused by chemical composition considerably hinders search for more efficient new materials. Therefore, to fill in this gap and provide with all essential information about a large number of elpasolites crystals, for the first time, the structural stability, elastic, vibrational, and electronic properties of 60 cubic elpasolite Cs2NaLnX6 (Ln = La, …, Lu, X = F, Cl, Br, I) crystals were consistently calculated in the framework of the same computational approach based on the density functional theory (DFT). Variation of all calculated parameters (such as the lattice constants, elastic constants, Debye temperature, normal vibrational modes frequencies, Mulliken effective charges, bond populations, and band gaps) across the considered groups of crystals was analyzed and several trends, which are important for the search and preparation of new stable materials with improved performance, were identified. © 2020 The American Ceramic Society (ACERS)",
journal = "Journal of the American Ceramic Society",
title = "Effects of chemical composition on the structural stability, elastic, vibrational, and electronic properties of Cs2NaLnX6 (Ln = La…Lu, X = F, Cl, Br, I) elpasolites",
volume = "104",
number = "3",
pages = "1489-1500",
doi = "10.1111/jace.17565"
}

Wu, B., Yang, M., Yan, Y., Ma, C., Zhang, H., Brik, M. G., Dramićanin, M., Valiev, U. V.,& Piasecki, M. M.. (2021). Effects of chemical composition on the structural stability, elastic, vibrational, and electronic properties of Cs2NaLnX6 (Ln = La…Lu, X = F, Cl, Br, I) elpasolites. in Journal of the American Ceramic Society, 104(3), 1489-1500.
https://doi.org/10.1111/jace.17565

Wu B, Yang M, Yan Y, Ma C, Zhang H, Brik MG, Dramićanin M, Valiev UV, Piasecki MM. Effects of chemical composition on the structural stability, elastic, vibrational, and electronic properties of Cs2NaLnX6 (Ln = La…Lu, X = F, Cl, Br, I) elpasolites. in Journal of the American Ceramic Society. 2021;104(3):1489-1500.
doi:10.1111/jace.17565 .

Wu, Bing, Yang, Menglin, Yan, Yanci, Ma, Chonggeng, Zhang, Hongwu, Brik, Mikhail G., Dramićanin, Miroslav, Valiev, Uygun V., Piasecki, Michał M., "Effects of chemical composition on the structural stability, elastic, vibrational, and electronic properties of Cs2NaLnX6 (Ln = La…Lu, X = F, Cl, Br, I) elpasolites" in Journal of the American Ceramic Society, 104, no. 3 (2021):1489-1500,
https://doi.org/10.1111/jace.17565 . .

TY  - JOUR
AU  - Wang, Zhengliang
AU  - Yang, Zhiyu
AU  - Wang, Nan
AU  - Zhou, Qiang
AU  - Zhou, Jianbang
AU  - Ma, Li
AU  - Wang, Xiaojun
AU  - Xu, Yiqing
AU  - Brik, Mikhail G.
AU  - Dramićanin, Miroslav
AU  - Wu, Mingmei
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8791
AB  - Crystal phosphors have many unique advantages compared with powdery ones. Herein, room-temperature-grown millimeter-sized single-crystal phosphors of Cs2XF6:Mn4+ (X = Ge, Si, and Ti) with remarkably higher external quantum efficiency than the corresponding powdery samples are reported. In addition, as compared with the powdery ones, the crystal samples exhibit much better stability toward water under different pH conditions. The red light-emitting diodes (LEDs) based on Cs2XF6:Mn4+ crystals show significantly improved luminous efficiency than those based on their corresponding powders. An assembled white LED device composed of the two layers of phosphors, i.e., the crystal (such as Cs2GeF6:Mn4+) and commercial Y3Al5O12:Ce3+, on a blue chip exhibits intense warm white light with high luminous efficiency (up to 193 lm W−1), high color rendering indexes (88), and low correlated color temperatures (3107 K). Hence, these crystals with greatly improved efficiency and stability can be potentially applied in high-quality LED backlighting display and white LED lighting, especially inside the micro-LED devices. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
T2  - Advanced Optical Materials
T1  - Single‐Crystal Red Phosphors: Enhanced Optical Efficiency and Improved Chemical Stability for wLEDs
VL  - 8
IS  - 6
SP  - 1901512
DO  - 10.1002/adom.201901512
ER  - 

@article{
author = "Wang, Zhengliang and Yang, Zhiyu and Wang, Nan and Zhou, Qiang and Zhou, Jianbang and Ma, Li and Wang, Xiaojun and Xu, Yiqing and Brik, Mikhail G. and Dramićanin, Miroslav and Wu, Mingmei",
year = "2020",
abstract = "Crystal phosphors have many unique advantages compared with powdery ones. Herein, room-temperature-grown millimeter-sized single-crystal phosphors of Cs2XF6:Mn4+ (X = Ge, Si, and Ti) with remarkably higher external quantum efficiency than the corresponding powdery samples are reported. In addition, as compared with the powdery ones, the crystal samples exhibit much better stability toward water under different pH conditions. The red light-emitting diodes (LEDs) based on Cs2XF6:Mn4+ crystals show significantly improved luminous efficiency than those based on their corresponding powders. An assembled white LED device composed of the two layers of phosphors, i.e., the crystal (such as Cs2GeF6:Mn4+) and commercial Y3Al5O12:Ce3+, on a blue chip exhibits intense warm white light with high luminous efficiency (up to 193 lm W−1), high color rendering indexes (88), and low correlated color temperatures (3107 K). Hence, these crystals with greatly improved efficiency and stability can be potentially applied in high-quality LED backlighting display and white LED lighting, especially inside the micro-LED devices. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim",
journal = "Advanced Optical Materials",
title = "Single‐Crystal Red Phosphors: Enhanced Optical Efficiency and Improved Chemical Stability for wLEDs",
volume = "8",
number = "6",
pages = "1901512",
doi = "10.1002/adom.201901512"
}

Wang, Z., Yang, Z., Wang, N., Zhou, Q., Zhou, J., Ma, L., Wang, X., Xu, Y., Brik, M. G., Dramićanin, M.,& Wu, M.. (2020). Single‐Crystal Red Phosphors: Enhanced Optical Efficiency and Improved Chemical Stability for wLEDs. in Advanced Optical Materials, 8(6), 1901512.
https://doi.org/10.1002/adom.201901512

Wang Z, Yang Z, Wang N, Zhou Q, Zhou J, Ma L, Wang X, Xu Y, Brik MG, Dramićanin M, Wu M. Single‐Crystal Red Phosphors: Enhanced Optical Efficiency and Improved Chemical Stability for wLEDs. in Advanced Optical Materials. 2020;8(6):1901512.
doi:10.1002/adom.201901512 .

Wang, Zhengliang, Yang, Zhiyu, Wang, Nan, Zhou, Qiang, Zhou, Jianbang, Ma, Li, Wang, Xiaojun, Xu, Yiqing, Brik, Mikhail G., Dramićanin, Miroslav, Wu, Mingmei, "Single‐Crystal Red Phosphors: Enhanced Optical Efficiency and Improved Chemical Stability for wLEDs" in Advanced Optical Materials, 8, no. 6 (2020):1901512,
https://doi.org/10.1002/adom.201901512 . .

TY  - JOUR
AU  - Ćirić, Aleksandar
AU  - Stojadinović, Stevan
AU  - Brik, Mikhail G.
AU  - Dramićanin, Miroslav
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8496
AB  - Traditional applications of the Judd-Ofelt (JO) theory to the analysis of the Eu3+ optical spectra make use of the emission transitions originating from the 5D0 manifold. In the present paper, we report an alternative method of evaluating the JO intensity parameters from the Eu3+ emission spectra based on the 5D1 → 7F0,1 transitions. The reduced matrix elements of the unit tensor operators are re-calculated for the 5D0,1,2 → 7F0,1,…,6 Eu3+ transitions in the intermediate coupling approximation using the average electrostatic and spin-orbit coupling parameters. The suggested method was tested by analyzing the emission spectra of the Eu3+ doped GdAlO3, LaF3, NaYF4, Y2O3, ZrO2, YNbO4, ZBLA and PIGLZ hosts. It is shown that the developed method is more accurate for the hosts with relatively high 5D1 level population, which emphasizes its high potential and applicability. In addition to the JO analysis, the CIE chromaticity coordinates are calculated for the investigated spectra. © 2019 Elsevier B.V.
T2  - Chemical Physics
T1  - Judd-Ofelt parametrization from emission spectra: The case study of the Eu3+ 5D1 emitting level
VL  - 528
SP  - 110513
DO  - 10.1016/j.chemphys.2019.110513
ER  - 

@article{
author = "Ćirić, Aleksandar and Stojadinović, Stevan and Brik, Mikhail G. and Dramićanin, Miroslav",
year = "2020",
abstract = "Traditional applications of the Judd-Ofelt (JO) theory to the analysis of the Eu3+ optical spectra make use of the emission transitions originating from the 5D0 manifold. In the present paper, we report an alternative method of evaluating the JO intensity parameters from the Eu3+ emission spectra based on the 5D1 → 7F0,1 transitions. The reduced matrix elements of the unit tensor operators are re-calculated for the 5D0,1,2 → 7F0,1,…,6 Eu3+ transitions in the intermediate coupling approximation using the average electrostatic and spin-orbit coupling parameters. The suggested method was tested by analyzing the emission spectra of the Eu3+ doped GdAlO3, LaF3, NaYF4, Y2O3, ZrO2, YNbO4, ZBLA and PIGLZ hosts. It is shown that the developed method is more accurate for the hosts with relatively high 5D1 level population, which emphasizes its high potential and applicability. In addition to the JO analysis, the CIE chromaticity coordinates are calculated for the investigated spectra. © 2019 Elsevier B.V.",
journal = "Chemical Physics",
title = "Judd-Ofelt parametrization from emission spectra: The case study of the Eu3+ 5D1 emitting level",
volume = "528",
pages = "110513",
doi = "10.1016/j.chemphys.2019.110513"
}

Ćirić, A., Stojadinović, S., Brik, M. G.,& Dramićanin, M.. (2020). Judd-Ofelt parametrization from emission spectra: The case study of the Eu3+ 5D1 emitting level. in Chemical Physics, 528, 110513.
https://doi.org/10.1016/j.chemphys.2019.110513

Ćirić A, Stojadinović S, Brik MG, Dramićanin M. Judd-Ofelt parametrization from emission spectra: The case study of the Eu3+ 5D1 emitting level. in Chemical Physics. 2020;528:110513.
doi:10.1016/j.chemphys.2019.110513 .

Ćirić, Aleksandar, Stojadinović, Stevan, Brik, Mikhail G., Dramićanin, Miroslav, "Judd-Ofelt parametrization from emission spectra: The case study of the Eu3+ 5D1 emitting level" in Chemical Physics, 528 (2020):110513,
https://doi.org/10.1016/j.chemphys.2019.110513 . .