摘要
Mn^(4+)掺杂的氟化物红色荧光粉的耐湿性差,严重影响了白色发光二极管(WLEDs)的光色稳定性。本工作基于绿矾溶液的还原性,将K_(2)SiF_(6)∶Mn^(4+)颗粒表面的Mn^(4+)还原成可溶的低价态Mn^(2+),实现了氟化物粒子的表面钝化及高耐湿性。在水浸360 h后,表面钝化的K_(2)SiF_(6)∶Mn^(4+)粒子的发光强度仍保持初始强度的95%,而未处理的K_(2)SiF_(6):Mn^(4+)颗粒发光强度迅速降为初始值的46%。此外,采用绿矾溶液对表面已水解的氟化物荧光粉进行简单的浸泡,可使其完全恢复原来的发光强度。电感耦合等离子体-原子发射光谱、X射线光电子谱、元素能谱等表征结果显示,经绿矾溶液处理的K_(2)SiF_(6):Mn^(4+)粒子表面的Mn^(4+)浓度显著减小,证实了惰性壳层K_(2)SiF_(6)的形成,揭示了氟化物粒子耐湿性显著提升的原因。此外,经高温(85℃)高湿(85%)的条件老化1 000 h后,WLEDs器件中表面钝化的K_(2)SiF_(6)∶Mn^(4+)粒子仍保持着100%的红色发光强度,明显高于未钝化的氟化物的59%,进一步证实了绿矾溶液钝化的K_(2)SiF_(6)∶Mn^(4+)红色荧光粉具有非常优异的环境稳定性。
The poor moisture resistance of Mn^(4+)doped fluoride red fluorescent powder significantly impacts the photochromic stability of white light-emitting diodes(WLEDs).This study focuses on the reducibility of green alum solution to reduce Mn^(4+)on the surface of K_(2)SiF_(6)∶Mn^(4+)particles,converting it to soluble low-valent Mn^(2+).This process achieves surface passivation and enhances the humidity resistance of the fluoride particles.After a 360-h immersion in water,the luminescence intensity of the surface-passivated K_(2)SiF_(6)∶Mn^(4+)particles remained at 95%of the initial intensity,whereas the untreated K_(2)SiF_(6)∶Mn^(4+)phosphors experienced a rapid decrease to only 46%of their initial val‐ue.Additionally,simply soaking the surface-hydrolyzed fluoride fluorescent powder in green alum solution fully restored its original luminescence intensity.Characterization techniques such as Inductively coupled plasma-atomic emission spectroscopy,X-ray photoelectron spectroscopy and elemental spectroscopy confirmed a significant reduction in Mn^(4+)concentration on the surface of K_(2)SiF_(6)∶Mn^(4+)particles treated with green alum solution,indicating the formation of an inert shell K_(2)SiF_(6).This finding elucidates the reason behind the notable improvement in moisture resistance of the fluoride particles.Moreover,even after aging under harsh conditions of high temperature(85℃)and high humidity(85%)for 1000 h,the surface-passivated K_(2)SiF_(6)∶Mn^(4+)particles in the WLEDs devices still maintained 100%of the red luminescence intensity,which was significantly higher than that of the unpassivated fluoride(59%),further validating the exceptional environmental stability achieved by the green alum solution-passivated K_(2)SiF_(6)∶Mn^(4+)red phosphors.
作者
杨晨
叶梦琳
周文理
YANG Chen;YE Menglin;ZHOU Wenli(Key Laboratory of Light Energy Conversion Materials of Hunan Province College,Changsha 410081,China;College of Chemistry and Chemical Engineering,Hunan Normal University,Changsha 410081,China)
出处
《发光学报》
EI
CAS
CSCD
北大核心
2024年第2期299-307,共9页
Chinese Journal of Luminescence
基金
长沙市自然科学基金(kq2202235)
化学生物学及中药分析教育部重点实验室开放基金(KLCBTCMR20-23)。
