植物补光用In^(3+)掺杂Zn_(3)Ga_(2)Ge_(2)O_(10)∶Cr^(3+)远红光发光材料的性能研究

采用高温固相法制备了Cr^(3+)掺杂的远红光荧光粉,并通过引入In^(3+)对Zn_(3)Ga_(2)Ge_(2)O_(10)∶Cr^(3+)发光特性进行了调控。通过XRD对Zn_(3)(Ga_(1-x)In_(x))_(2)Ge_(2)O_(10)∶2%Cr^(3+)(摩尔分数)的晶体结构进行了分析。利用室温荧光光谱和热释光光谱分析了Zn_(3)(Ga_(1-x)In_(x))_(2)Ge_(2)O_(10)∶2%Cr^(3+)的发光特性,其发射光谱由^(4)T_(2)(^(4)F)→^(4)A_(2)和^(2)E→^(4)A_(2)跃迁的705、721 nm两发光峰叠加而成。随着Zn_(3)(Ga_(1-x)In_(x))_(2)Ge_(2)O_(10)∶2%Cr^(3+)中In^(3+)掺杂浓度增加,材料发射光谱呈现展宽的现象,这是Cr^(3+)所处晶体场环境的改变导致了晶体场劈裂程度的变化。光谱展宽后荧光材料的发光特性与植物中光敏色素吸收谱更加匹配,因此其有望应用于植物照明领域。此外,随着In^(3+)掺杂浓度增加,荧光材料表现出红色长余辉现象,并且余辉时间与In^(3+)掺杂浓度有关。

紫外-近紫外基白光LEDs用荧光粉的研究进展

白光LEDs作为新一代照明光源,和前几代照明光源相比,具有发光效率高、使用寿命长、节能环保等一系列突出的优点。本文总结了最近几年用于白光LEDs的紫外-近紫外激发型荧光粉的研究结果,梳理了各个基质体系荧光粉的发展现状,并展望了白光LEDs用荧光粉的研究趋势。

橙红色荧光粉Ca_(10)Li(PO_4)_7∶Sm^(3+)的合成及其发光特性研究

采用固相法合成了Ca10Li(PO4)7∶x Sm3+橙红色荧光粉,研究了材料的发光性质。结果表明,以404 nm近紫外光作为激发源时,Ca10Li(PO4)7∶x Sm3+表现为多峰特征,主峰位于569 nm、606 nm、651 nm和713 nm,分别对应Sm3+的4G5/2→6H5/2、4G5/2→6H7/2、4G5/2→6H9/2和4G5/2→6H11/2跃迁发射,且606 nm发射峰最强,材料发射橙红光;监测606 nm发射峰,对应的激发光谱包含363 nm、376 nm、404 nm和478 nm多个激发峰;改变Sm3+的掺杂量,发现Ca10Li(PO4)7∶Sm3+的发射强度表现出先增大、后减小的变化趋势,x=0.05时发射强度最大,即存在浓度猝灭现象,造成浓度猝灭的机理为电多极相互作用,Ca10Li(PO4)7∶Sm3+的色坐标基本不变,位于橙红色区域。Ca10Li(PO4)7∶Sm3+具有较好的温度特性,激活能为0.188 e V。

新型红色荧光粉KMgLa(PO_4)_2∶Eu^(3+)的发光特性（英文）

采用高温固相法制备了Eu^(3+)掺杂的KMgLa(PO_4)_2荧光粉。采用X射线衍射技术及光谱技术研究了材料的晶相及发光特性。研究结果显示,少量的Eu^(3+)并未影响KMgLa(PO_4)_2的晶相;以260 nm紫外光或394 nm近紫外光作为激发源时,KMgLa(PO_4)_2∶Eu^(3+)都发射红色光,主发射峰位于595 nm,对应Eu^(3+)的~5D_0→~7F_2跃迁发射;随着Eu^(3+)掺杂量的逐渐增大,对应KMgLa(PO_4)_2∶Eu^(3+)材料的发射强度随之增大,当掺杂量为0.06Eu^(3+)时,发射强度最大,且存在浓度猝灭现象,对应的临界距离为1.696 nm;材料的CIE参数显示,材料位于红色区域。

Impeding anion exchange to improve composition stability of CsPbX3（X= Cl, Br） nanocrystals through facilely fabricated Cs4Pb6 shell

Inorganic lead halide perovskite nanocrystals(NCs)with superior photoelectric properties are expected to have excellent performance in many fields.However,the anion exchange changes their features and is unfavorable for their applications in many fields.Hence,impeding anion exchange is important for improving the composition stability of inorganic lead halide perovskite NCs.Herein,CsPb X3(X=Cl,Br)NCs are coated with Cs4PbX6 shell to impede anion exchange and reduce anion mobility.The Cs4PbX6 shell is facily fabricated on CsPbX3 NCs through high temperature injection method.Anion exchange experiments demonstrate that the Cs4 PbX6 shell completely encapsulates CsPbX3 NCs and greatly improves the composition stability of CsPbX3 NCs.Moreover,our work also sheds light on the potential design approaches of various heterostructures to expand the application of CsPbM3(M=Cl,Br,I)NCs.