TY  - JOUR
AU  - Milićević, Bojana R.
AU  - Chen, Yingyuan
AU  - Li, Junhao
AU  - Dramićanin, Miroslav
AU  - Zhou, Jianbang
AU  - Wu, Mingmei
PY  - 2022
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10148
AB  - We report an organic solvent–assisted (OSA) co-precipitation strategy for the production of Mn4+-activated K2TiF6 phosphor. The phosphor particle size was controlled through the selection of organic solvents with an alcohol functional group and different carbon chain lengths used in the synthesis. The synergistic effect of the organic solvent and hydrofluoric acid results in large smoothed hexagonal-shaped crystal sheets of particles that become larger as the carbon chain length of the organic solvent increases. The photoluminescence (PL) properties of K2TiF6:Mn powders strongly depend on the size and thickness of the particles. The addition of n-butanol during the synthesis increases the emission intensity of K2TiF6:Mn by 208%. The PL quantum efficiency of phosphors prepared using the n-butanol-assisted strategy is much higher (98.2%) than that of conventionally prepared phosphors (89.9%). Our findings demonstrate a way to prepare the K2TiF6:Mn phosphor with targeted morphology and very high quantum efficiency and also provide the route for the optimization of all Mn4+-activated fluoride phosphors used in white light-emitting diodes.
T2  - Dalton Transactions
T1  - Organic solvent-assisted co-precipitation synthesis of red-emitting K2TiF6:Mn phosphors with improved quantum efficiency and optimized morphology
VL  - 51
IS  - 4
SP  - 1378
EP  - 1383
DO  - 10.1039/d1dt03679c
ER  - 

@article{
author = "Milićević, Bojana R. and Chen, Yingyuan and Li, Junhao and Dramićanin, Miroslav and Zhou, Jianbang and Wu, Mingmei",
year = "2022",
abstract = "We report an organic solvent–assisted (OSA) co-precipitation strategy for the production of Mn4+-activated K2TiF6 phosphor. The phosphor particle size was controlled through the selection of organic solvents with an alcohol functional group and different carbon chain lengths used in the synthesis. The synergistic effect of the organic solvent and hydrofluoric acid results in large smoothed hexagonal-shaped crystal sheets of particles that become larger as the carbon chain length of the organic solvent increases. The photoluminescence (PL) properties of K2TiF6:Mn powders strongly depend on the size and thickness of the particles. The addition of n-butanol during the synthesis increases the emission intensity of K2TiF6:Mn by 208%. The PL quantum efficiency of phosphors prepared using the n-butanol-assisted strategy is much higher (98.2%) than that of conventionally prepared phosphors (89.9%). Our findings demonstrate a way to prepare the K2TiF6:Mn phosphor with targeted morphology and very high quantum efficiency and also provide the route for the optimization of all Mn4+-activated fluoride phosphors used in white light-emitting diodes.",
journal = "Dalton Transactions",
title = "Organic solvent-assisted co-precipitation synthesis of red-emitting K2TiF6:Mn phosphors with improved quantum efficiency and optimized morphology",
volume = "51",
number = "4",
pages = "1378-1383",
doi = "10.1039/d1dt03679c"
}

Milićević, B. R., Chen, Y., Li, J., Dramićanin, M., Zhou, J.,& Wu, M.. (2022). Organic solvent-assisted co-precipitation synthesis of red-emitting K2TiF6:Mn phosphors with improved quantum efficiency and optimized morphology. in Dalton Transactions, 51(4), 1378-1383.
https://doi.org/10.1039/d1dt03679c

Milićević BR, Chen Y, Li J, Dramićanin M, Zhou J, Wu M. Organic solvent-assisted co-precipitation synthesis of red-emitting K2TiF6:Mn phosphors with improved quantum efficiency and optimized morphology. in Dalton Transactions. 2022;51(4):1378-1383.
doi:10.1039/d1dt03679c .

Milićević, Bojana R., Chen, Yingyuan, Li, Junhao, Dramićanin, Miroslav, Zhou, Jianbang, Wu, Mingmei, "Organic solvent-assisted co-precipitation synthesis of red-emitting K2TiF6:Mn phosphors with improved quantum efficiency and optimized morphology" in Dalton Transactions, 51, no. 4 (2022):1378-1383,
https://doi.org/10.1039/d1dt03679c . .

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  - Dramićanin, Miroslav
AU  - Milićević, Bojana R.
AU  - Đorđević, Vesna R.
AU  - Ristić, Zoran
AU  - Zhou, Jianbang
AU  - Milivojević, Dušan
AU  - Papan, Jelena
AU  - Brik, Mikhail G.
AU  - Ma, Chong‐Geng
AU  - Srivastava, Alok M
AU  - Wu, Mingmei
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8360
AB  - Luminescence of monoclinic lithium metatitanate (Li2TiO3) powders activated with different quantities of Mn4+ is studied in detail. Its strong deep-red emission arising from the Mn4+ 2Eg → 4A2g spin forbidden transition is centered at around 688 nm and is suitable for luminescence thermometry. Structural and electron paramagnetic resonance analyses show that Mn4+ ions are equally distributed in two almost identical Ti4+ sites in which they are octahedrally coordinated by six oxygen ions. Calculations based on the exchange charge model of the crystal field provided values of Racah parameters (B=760 cm−1, C= 2993 cm−1), crystal-field splitting Dq= 2043 cm−1, and the nephelauxetic parameter β1=0.9775. The maximal quantum efficiency of 24.1% at room temperature is found for 0.126% Mn4+ concentration. Temperature quenching of emission occurs by a cross-over via 4T2 excited state of the Mn4+ ions with T1/2=262 K and is quite favorable for the application in the lifetime-based luminescence thermometry since relative changes in emission decay values are exceptionally-large (around 3.21% at room temperature). We derived theoretical expressions for the temperature dependence of the absolute and relative sensitivities and discuss the influence of host material properties on lifetime sensitivities. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
T2  - ChemistrySelect
T1  - Li2TiO3:Mn4+ Deep‐Red Phosphor for the Lifetime‐Based Luminescence Thermometry
VL  - 4
IS  - 24
SP  - 7067
EP  - 7075
DO  - 10.1002/slct.201901590
ER  - 

@article{
author = "Dramićanin, Miroslav and Milićević, Bojana R. and Đorđević, Vesna R. and Ristić, Zoran and Zhou, Jianbang and Milivojević, Dušan and Papan, Jelena and Brik, Mikhail G. and Ma, Chong‐Geng and Srivastava, Alok M and Wu, Mingmei",
year = "2019",
abstract = "Luminescence of monoclinic lithium metatitanate (Li2TiO3) powders activated with different quantities of Mn4+ is studied in detail. Its strong deep-red emission arising from the Mn4+ 2Eg → 4A2g spin forbidden transition is centered at around 688 nm and is suitable for luminescence thermometry. Structural and electron paramagnetic resonance analyses show that Mn4+ ions are equally distributed in two almost identical Ti4+ sites in which they are octahedrally coordinated by six oxygen ions. Calculations based on the exchange charge model of the crystal field provided values of Racah parameters (B=760 cm−1, C= 2993 cm−1), crystal-field splitting Dq= 2043 cm−1, and the nephelauxetic parameter β1=0.9775. The maximal quantum efficiency of 24.1% at room temperature is found for 0.126% Mn4+ concentration. Temperature quenching of emission occurs by a cross-over via 4T2 excited state of the Mn4+ ions with T1/2=262 K and is quite favorable for the application in the lifetime-based luminescence thermometry since relative changes in emission decay values are exceptionally-large (around 3.21% at room temperature). We derived theoretical expressions for the temperature dependence of the absolute and relative sensitivities and discuss the influence of host material properties on lifetime sensitivities. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim",
journal = "ChemistrySelect",
title = "Li2TiO3:Mn4+ Deep‐Red Phosphor for the Lifetime‐Based Luminescence Thermometry",
volume = "4",
number = "24",
pages = "7067-7075",
doi = "10.1002/slct.201901590"
}

Dramićanin, M., Milićević, B. R., Đorđević, V. R., Ristić, Z., Zhou, J., Milivojević, D., Papan, J., Brik, M. G., Ma, C., Srivastava, A. M.,& Wu, M.. (2019). Li2TiO3:Mn4+ Deep‐Red Phosphor for the Lifetime‐Based Luminescence Thermometry. in ChemistrySelect, 4(24), 7067-7075.
https://doi.org/10.1002/slct.201901590

Dramićanin M, Milićević BR, Đorđević VR, Ristić Z, Zhou J, Milivojević D, Papan J, Brik MG, Ma C, Srivastava AM, Wu M. Li2TiO3:Mn4+ Deep‐Red Phosphor for the Lifetime‐Based Luminescence Thermometry. in ChemistrySelect. 2019;4(24):7067-7075.
doi:10.1002/slct.201901590 .

Dramićanin, Miroslav, Milićević, Bojana R., Đorđević, Vesna R., Ristić, Zoran, Zhou, Jianbang, Milivojević, Dušan, Papan, Jelena, Brik, Mikhail G., Ma, Chong‐Geng, Srivastava, Alok M, Wu, Mingmei, "Li2TiO3:Mn4+ Deep‐Red Phosphor for the Lifetime‐Based Luminescence Thermometry" in ChemistrySelect, 4, no. 24 (2019):7067-7075,
https://doi.org/10.1002/slct.201901590 . .

TY  - JOUR
AU  - Yan, Jing
AU  - Zhang, Ziwang
AU  - Milićević, Bojana R.
AU  - Li, Junhao
AU  - Liang, Qiongyun
AU  - Zhou, Jianbang
AU  - Wang, Yunfeng
AU  - Shi, Jianxin
AU  - Wu, Mingmei
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8346
AB  - The local crystal structure engineering becomes an important strategy to design new phosphors with enhanced optical and thermal performance of white light-emitting diodes. Herein, a series of Na3Sc2(PO4)3: Eu2+ and KyNa2.97-ySc2(PO4)3: 0.03Eu2+ phosphors were synthesized via traditional high temperature solid-state reaction method. X-ray powder diffraction analysis and Rietveld refinement provide insight in the detailed crystal structure. Furthermore, Eu2+ doped Na3Sc2(PO4)3 exhibits bright blue emission in 400–540 nm spectral range with a maximum value at ~ 460 nm under n-UV light excitation. The concentration quenching mechanism of Eu2+ in Na3Sc2(PO4)3 is certified to be a dipole-dipole interaction. Additionally, crystal structure tailoring is a potential strategy to design new phosphors for particular applications. Therefore, the effects of K+ substitution on the structure and photoluminescence of Eu2+ activated Na3Sc2(PO4)3 is presented in detail. Rietveld refinement data revealed that unit cell volume and Na/K–O band length increase when K+ occupy the Na+ sites. This sensitive local structure resulted in a considerable enhancement of the photoluminescence intensity of Eu2+. Incorporation of K+ in the crystal structure is a feasible route to realize fine-tuning of emission color and broaden the color gamut. In the meantime, Na2.7K0.27Sc2(PO4)3: 0.03Eu2+ phosphor exhibits excellent thermal stability at high temperature over a significant radiative recombination of energy transfer from traps to Eu2+. These results confirm that Na2.7K0.27Sc2(PO4)3: 0.03Eu2+ phosphor might be used as a blue component in n-UV chip activated white light-emitting diodes for the next-generation of indoor solid-state lighting applications. © 2019 Elsevier B.V.
T2  - Optical Materials
T1  - The enhancement of emission intensity and enlargement of color gamut by a simple local structure substitution with highly thermal stability preserved
VL  - 95
SP  - 109201
DO  - 10.1016/j.optmat.2019.109201
ER  - 

@article{
author = "Yan, Jing and Zhang, Ziwang and Milićević, Bojana R. and Li, Junhao and Liang, Qiongyun and Zhou, Jianbang and Wang, Yunfeng and Shi, Jianxin and Wu, Mingmei",
year = "2019",
abstract = "The local crystal structure engineering becomes an important strategy to design new phosphors with enhanced optical and thermal performance of white light-emitting diodes. Herein, a series of Na3Sc2(PO4)3: Eu2+ and KyNa2.97-ySc2(PO4)3: 0.03Eu2+ phosphors were synthesized via traditional high temperature solid-state reaction method. X-ray powder diffraction analysis and Rietveld refinement provide insight in the detailed crystal structure. Furthermore, Eu2+ doped Na3Sc2(PO4)3 exhibits bright blue emission in 400–540 nm spectral range with a maximum value at ~ 460 nm under n-UV light excitation. The concentration quenching mechanism of Eu2+ in Na3Sc2(PO4)3 is certified to be a dipole-dipole interaction. Additionally, crystal structure tailoring is a potential strategy to design new phosphors for particular applications. Therefore, the effects of K+ substitution on the structure and photoluminescence of Eu2+ activated Na3Sc2(PO4)3 is presented in detail. Rietveld refinement data revealed that unit cell volume and Na/K–O band length increase when K+ occupy the Na+ sites. This sensitive local structure resulted in a considerable enhancement of the photoluminescence intensity of Eu2+. Incorporation of K+ in the crystal structure is a feasible route to realize fine-tuning of emission color and broaden the color gamut. In the meantime, Na2.7K0.27Sc2(PO4)3: 0.03Eu2+ phosphor exhibits excellent thermal stability at high temperature over a significant radiative recombination of energy transfer from traps to Eu2+. These results confirm that Na2.7K0.27Sc2(PO4)3: 0.03Eu2+ phosphor might be used as a blue component in n-UV chip activated white light-emitting diodes for the next-generation of indoor solid-state lighting applications. © 2019 Elsevier B.V.",
journal = "Optical Materials",
title = "The enhancement of emission intensity and enlargement of color gamut by a simple local structure substitution with highly thermal stability preserved",
volume = "95",
pages = "109201",
doi = "10.1016/j.optmat.2019.109201"
}

Yan, J., Zhang, Z., Milićević, B. R., Li, J., Liang, Q., Zhou, J., Wang, Y., Shi, J.,& Wu, M.. (2019). The enhancement of emission intensity and enlargement of color gamut by a simple local structure substitution with highly thermal stability preserved. in Optical Materials, 95, 109201.
https://doi.org/10.1016/j.optmat.2019.109201

Yan J, Zhang Z, Milićević BR, Li J, Liang Q, Zhou J, Wang Y, Shi J, Wu M. The enhancement of emission intensity and enlargement of color gamut by a simple local structure substitution with highly thermal stability preserved. in Optical Materials. 2019;95:109201.
doi:10.1016/j.optmat.2019.109201 .

Yan, Jing, Zhang, Ziwang, Milićević, Bojana R., Li, Junhao, Liang, Qiongyun, Zhou, Jianbang, Wang, Yunfeng, Shi, Jianxin, Wu, Mingmei, "The enhancement of emission intensity and enlargement of color gamut by a simple local structure substitution with highly thermal stability preserved" in Optical Materials, 95 (2019):109201,
https://doi.org/10.1016/j.optmat.2019.109201 . .