TY  - JOUR
AU  - Srivastava, Alok M.
AU  - Brik, Mikhail G.
AU  - Ma, Chong-Geng
AU  - Beers, William W.
AU  - Cohen, William E.
AU  - Piasecki, Michal
PY  - 2024
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/13190
AB  - The spectroscopic properties of the Mn4+ ion are investigated in the series of isostructural double perovskite compounds, Ba2BTaO6 (B = Y, Lu, Sc). A comparison of these properties highlights the influence of covalent bonding within the perovskite framework and the degree of order between the B3+–Ta cations on the energy and intensity of the Mn4+2E → 4A2 emission transition (R-line). These two parameters of the emission spectrum are of importance for practical application since they determine the phosphor luminous efficacy. The influence of covalent bonding within the corner shared BO6/2 and TaO6/2 perovskite framework on the energy of the R-line energy is investigated. From the spectroscopic data, we have derived information on the influence of the degree of order between the B3+ and Ta5+ cations on the intensity of the R-line. The lowest energy and the highest intensity of the R-line are found in the double perovskite, Ba2ScTaO6. The purpose of this work is to propose for first time an explanation of these effects in the considered double perovskites. The obtained results are useful guidelines for practical improvement and tuning of key parameters of phosphors to the desired values.
T2  - The Journal of Physical Chemistry Letters
T1  - Effect of Covalence and Degree of Cation Order on the Luminous Efficacy of Mn4+ Luminescence in the Double Perovskites, Ba2BTaO6 (B = Y, Lu, Sc)
VL  - 15
SP  - 4175
EP  - 4184
DO  - 10.1021/acs.jpclett.4c00205
ER  - 

@article{
author = "Srivastava, Alok M. and Brik, Mikhail G. and Ma, Chong-Geng and Beers, William W. and Cohen, William E. and Piasecki, Michal",
year = "2024",
abstract = "The spectroscopic properties of the Mn4+ ion are investigated in the series of isostructural double perovskite compounds, Ba2BTaO6 (B = Y, Lu, Sc). A comparison of these properties highlights the influence of covalent bonding within the perovskite framework and the degree of order between the B3+–Ta cations on the energy and intensity of the Mn4+2E → 4A2 emission transition (R-line). These two parameters of the emission spectrum are of importance for practical application since they determine the phosphor luminous efficacy. The influence of covalent bonding within the corner shared BO6/2 and TaO6/2 perovskite framework on the energy of the R-line energy is investigated. From the spectroscopic data, we have derived information on the influence of the degree of order between the B3+ and Ta5+ cations on the intensity of the R-line. The lowest energy and the highest intensity of the R-line are found in the double perovskite, Ba2ScTaO6. The purpose of this work is to propose for first time an explanation of these effects in the considered double perovskites. The obtained results are useful guidelines for practical improvement and tuning of key parameters of phosphors to the desired values.",
journal = "The Journal of Physical Chemistry Letters",
title = "Effect of Covalence and Degree of Cation Order on the Luminous Efficacy of Mn4+ Luminescence in the Double Perovskites, Ba2BTaO6 (B = Y, Lu, Sc)",
volume = "15",
pages = "4175-4184",
doi = "10.1021/acs.jpclett.4c00205"
}

Srivastava, A. M., Brik, M. G., Ma, C., Beers, W. W., Cohen, W. E.,& Piasecki, M.. (2024). Effect of Covalence and Degree of Cation Order on the Luminous Efficacy of Mn4+ Luminescence in the Double Perovskites, Ba2BTaO6 (B = Y, Lu, Sc). in The Journal of Physical Chemistry Letters, 15, 4175-4184.
https://doi.org/10.1021/acs.jpclett.4c00205

Srivastava AM, Brik MG, Ma C, Beers WW, Cohen WE, Piasecki M. Effect of Covalence and Degree of Cation Order on the Luminous Efficacy of Mn4+ Luminescence in the Double Perovskites, Ba2BTaO6 (B = Y, Lu, Sc). in The Journal of Physical Chemistry Letters. 2024;15:4175-4184.
doi:10.1021/acs.jpclett.4c00205 .

Srivastava, Alok M., Brik, Mikhail G., Ma, Chong-Geng, Beers, William W., Cohen, William E., Piasecki, Michal, "Effect of Covalence and Degree of Cation Order on the Luminous Efficacy of Mn4+ Luminescence in the Double Perovskites, Ba2BTaO6 (B = Y, Lu, Sc)" in The Journal of Physical Chemistry Letters, 15 (2024):4175-4184,
https://doi.org/10.1021/acs.jpclett.4c00205 . .

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  - 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  - 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 . .