TY - JOUR
T1 - Ab Initio -Aided Sensitizer Design for Mn4+-Activated Mg2TiO4 as an Ultrabright Fluoride-Free Red-Emitting Phosphor
AU - Huang, Chieh Szu
AU - Huang, Cheng Liang
AU - Liu, Yu Chen
AU - Lin, Shih Kang
AU - Chan, Ting Shan
AU - Tu, Hao Wei
N1 - Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/3/13
Y1 - 2018/3/13
N2 - Red-light phosphor materials are crucial components in solid-state lighting (SSL) for simulating natural sunlight. Mn-doped Mg2TiO4 is a promising fluoride-free red-emitting phosphor; however, a sensitizer is necessary to enhance its brightness. In this work, we perform ab initio calculations based on the density functional theory (DFT) to systematically examine the electronic-band coupling between the luminescent center, Mn, and several possible sensitizers, Zn, Nb, Mo, In, Sn, and Ta. Nb was identified as the optimal sensitizer. Well-crystallized 0.1 at. % Mn and 0.0-0.7 at. % Nb-codoped Mg2TiO4 were synthesized at 1450 °C. Synchrotron-radiation-based X-ray absorption spectroscopy (XAS) experimentally validated the proposed atomistic structure, indicating that the Nb5+ dopant substitutes Ti4+ at the 16d sites, leading to the formation of Ti vacancies and of a parasitic MgTiO3 phase. Effective sensitization, resulting in a 243% enhancement of the photoluminescence intensity, was achieved. The 0.1 at. % Mn and 0.5 at. % Nb-codoped Mg2TiO4 were obtained as an ultrabright "rare-earth-free" (RE-free) and "fluoride-free" red-light phosphor.
AB - Red-light phosphor materials are crucial components in solid-state lighting (SSL) for simulating natural sunlight. Mn-doped Mg2TiO4 is a promising fluoride-free red-emitting phosphor; however, a sensitizer is necessary to enhance its brightness. In this work, we perform ab initio calculations based on the density functional theory (DFT) to systematically examine the electronic-band coupling between the luminescent center, Mn, and several possible sensitizers, Zn, Nb, Mo, In, Sn, and Ta. Nb was identified as the optimal sensitizer. Well-crystallized 0.1 at. % Mn and 0.0-0.7 at. % Nb-codoped Mg2TiO4 were synthesized at 1450 °C. Synchrotron-radiation-based X-ray absorption spectroscopy (XAS) experimentally validated the proposed atomistic structure, indicating that the Nb5+ dopant substitutes Ti4+ at the 16d sites, leading to the formation of Ti vacancies and of a parasitic MgTiO3 phase. Effective sensitization, resulting in a 243% enhancement of the photoluminescence intensity, was achieved. The 0.1 at. % Mn and 0.5 at. % Nb-codoped Mg2TiO4 were obtained as an ultrabright "rare-earth-free" (RE-free) and "fluoride-free" red-light phosphor.
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U2 - 10.1021/acs.chemmater.8b00149
DO - 10.1021/acs.chemmater.8b00149
M3 - Article
AN - SCOPUS:85043759256
SN - 0897-4756
VL - 30
SP - 1769
EP - 1775
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 5
ER -