摘要
Thermal quenching(TQ)at elevated temperature is a major factor affecting the luminescent intensity and efficiency of phosphors.Improving the thermal stability of phosphors and weakening the TQ effect are of significance for the high-quality illumination of phosphor-converted WLEDs.Here,a novel red-emitting phosphor K_(2)Zn(PO_(3))_(4)∶Mn^(2+)is synthesized by standard high temperature solid state reaction in ambient atmosphere,which is a new member of self-reduction system.An effective synthesis strategy is proposed to optimize its photoluminescent performances.Combined with X-ray photoelectron spectroscopy and X-ray absorption fine structure spectroscopy,oxygen vacancy defects introduced by Mn doping are proved to play an important role in the transition of Mn^(4+)→Mn^(2+).Thermoluminescence analysis reveals that the distribution of trap levels,especially the deep ones,is effectively regulated by the controllable crystallization and significantly affect the thermal stability of phosphors.Then a defect-assisted model is proposed to address the inner mechanism of the phenomenon.The carriers trapped by deep trap levels can be released under the high-temperature stimulus,which return back to the luminescent centers and participate in the radiative recombination to improve thermal stability.This study provides a new crystallographic idea and theoretical support for obtaining luminescent materials with high thermal stability.
高温下热猝灭(TQ)是影响荧光粉发光强度与发光效率的主要因素。提高荧光粉的热稳定性、减少热猝灭对于光转换型白光LED的高质量照明至关重要。本文报道了一种新型红色荧光粉K_(2)Zn(PO_(3))_(4)∶Mn^(2+),该材料以标准高温固相法在空气中合成,属自还原体系。同时,提出了一种有效合成策略优化其发光性能。结合X射线光电子能谱和X射线吸收精细结构谱,证实Mn^(2+)掺杂引入的氧空位缺陷在锰离子价态转移过程中起重要作用。热释光分析表明,可控结晶过程有效地调节了深陷阱能级的分布,显著提高了荧光粉的热稳定性。本文提出了一种缺陷辅助模型来解释这一现象的内在机理。深陷阱能级俘获的载流子在高温刺激下释放,返回发光中心并参与辐射复合,进而提高荧光粉的热稳定性。该研究为获得高热稳定性荧光粉提供了新的晶体学思路和理论支持。
出处
《发光学报》
北大核心
2025年第2期285-295,共11页
Chinese Journal of Luminescence
基金
国家自然科学基金(12274244)
高等学校学科创新引智计划(B23045)。
