Er3+浓度对Er3+/Yb3+共掺氟氧化物玻璃陶瓷上下转换发光的调控

在980 nm激光激发下,Er³⁺/Yb³⁺共掺的发光材料既可以在可见光范围产生上转换发光,也可以在近红外波段产生下转换发光,二者存在竞争关系。本文利用熔融淬火法制备了一系列掺杂不同Er³⁺/Yb³⁺浓度的氟氧化物玻璃陶瓷,测量了样品在980 nm激光激发下的上转换及下转换发射光谱。研究发现,改变Er³⁺的掺杂浓度可以调控上下转换的发光强度。在此基础上,提出了上下转换发光的能量传递模型。本文的研究结果有利于该类材料在不同领域中的应用。     

Red Up-Conversion Luminescence Process in Oxyfluoride Glass Ceramics Doped with Er^3＋／Yb^3＋

The phonon-assisted quantum cutting (PQC) model is presumed to clarify the red up-conversion luminescence process in Er^3 /yb^3 co-doped glass ceramics by the excitation and emission spectra. The red up-conversion luminescence of Er^3 ions mainly comes from three-photon absorption by the PQC process when the rare earth ions are doped in the g/ass ceramics and excited by 98Ohm pumped-laser. Er^3 ions absorb three-photons and relax to the ^4G11/2 state and then emit red up-conversion luminescence by the PQC process. The factor coefficient for the relation of pump-laser power and up-conversion intensity (P-I) is found by the analysis of excitation spectra of the red luminescence, which plays a major role to understand the true red up-conversion luminescence process. The new P-I relation is explained by the model of PQC.     

Al2O3对氟氧化物玻璃微结构和析晶的影响

采用红外, Raman, X射线衍射测试分析方法, 研究了Al₂O₃对氟氧化物玻璃微结构和析晶的影响.结果表明, Al³⁺主要以[AlO₄]的形式与[SiO₄]以顶角相连的方式构成基本网络骨架, Al₂O₃含量的增加, 使氧化物玻璃基质的网络向单体和二聚体结构转变, 并使氟化物微晶尺寸有一个先变小后增大的趋势, 但不影响微晶结构.     

高能量激发的发光材料

从不同材料在高能量密度激发下在激发、传递和发光等不同阶段中的效率变化,了解各种材料在高密度激发时的能量损失的主要环节,分清基质和发光中心的选择原则。为投影电视荧光粉和细管灯粉寻找具有较高效率的发光材料,在X线影像板的光激励材料的研制和γ线影像板的可行性分析方面也得到了一些结果。     

利用热释光和光激励技术研究合成工艺对BaFBr：Eu^2＋,Al^3＋发光性质的影响

利用热释发光谱和光激励发光谱表征了不同合成工艺条件对合成BaFBr:Eu^2 ,Al^3 发光性质的影响，利用理论分析找出了热释发光衰减与光激励衰减的异同，理论上计算了不同的合成工艺对BaFBr:Eu^2 ,Al^3 色心能级的影响，其热释发光谱和光激励发光谱的理论计算值能较好的吻合，并且能够很好的表征实验结果。     

Luminescent Enhancement in Mg- and Er-Codoped LiNbO3 Crystals

We investigate the MgO codoping-induced effect on the luminescent properties of Er^3 -doped and Er/Mg codoped LiNbO3 crystals. The emission and excitation spectra and the absorption spectra are measured. The results show that the luminescent behaviour of Er^3 ions is very sensitive to the codoping of Mg^2 ions. According to the photorefractive level theory, we propose a quench model for the Er/Mg codoped lithium niobate crystal. The quench centres are suggested to be the bipolaron (NbLi-NbNb), we attribute the luminescent enhancement to the decreasing concentration of these centres. The luminescent enhancement effect is successfully explained.     

一种新型蓝光BaKBP2O8:Eu2+荧光粉的合成与性能研究

通过高温固相法成功合成了一种新型蓝光荧光粉BaKBP₂O₈:Eu²⁺,分别用XRD和荧光光谱表征了其结构与光学性能。结果表明,Eu²⁺的引入并没有显著改变其四方相的晶体结构。样品的激发光谱(监测波长为443 nm)是由主晶格吸收的307 nm吸收肩与Eu²⁺离子4f⁷-4f⁶5d 跃迁的346 nm主峰组成。在紫光激发下,样品的发射光谱为蓝色。当Eu²⁺离子摩尔分数为0.03时,样品的发射强度达到最大值。然而,随着Eu²⁺浓度的进一步增加,由于浓度猝灭机制,其发射强度开始降低。在超过370 K的温度下,荧光粉样品的相对发光强度仍然超过50%。BaKBP₂O₈:Eu²⁺的色坐标为(0.176 6,0.168 1)。     

Nanocrystal formation and structure in oxyfluoride glass ceramics

The up-conversion luminescent property of the oxyfluoride glass ceramics 30SiO_{2}\cdot15Al_{2}O_{3}\cdot (50--x)PbF_{2}\cdot xCdF_{2} doped with 4ErF_{3}\cdot1YbF_{3} has been investigated. Up-conversion luminescent intensity of Er^{3+} ions increased obviously after heat-treatment due to co-doping with CdF_{2}. The structure model of nanocrystals Pb_{x}Cd_{1-x}F_{2} was determined and the effect of CdF_{2} in oxyfluoride glass ceramics was explained by the analysis of x-ray diffraction data. Different nucleation temperatures of samples with different compositions were obtained by differential thermal analysis curves and the results showed the growth process of different nanocrystals in glass ceramics.     

ZnS∶Zn,Pb宽带蓝色发光和发光机制

用固相反应法制备了一系列ZnS∶Zn,Pb荧光粉.改变不同的灼烧温度和激活剂的掺杂量,通过对灼烧后荧光粉进行光谱分析,我们发现Pb2+在ZnS基质中的发光与制备条件有关:灼烧温度为800～950℃时,能得到Pb2+在ZnS基质中的蓝色发光.测量了其光致发射光谱、激发光谱,以及灼烧后荧光粉的成分.研究了阴极射线下ZnS∶Zn,Pb荧光粉的相对发光亮度与荧光粉电压的关系,ZnS∶Zn,Pb的相对亮度比ZnS∶Ag,Cl的高,比ZnS∶Zn更高.研究了发光衰减时间与温度的关系,得到了ZnS∶Zn,Pb的蓝色发光可能来源于Pb2+的D波段发射的结论.并对其发光机制进行了一些探讨.这种新型蓝粉可应用于VFD和FED等低压显示屏.     

一种LED用红色荧光粉BaZn_2(BO_3)_2∶Eu~(3+)的合成与发光性能研究（英文）

通过高温固相法制得双峰可调节本征半导体发光Ba Zn_2(BO_3)_2∶Eu~(3+)荧光粉,此类荧光粉在300~400nm的紫外波段有很强的吸收。在375 nm的紫外光激发下,该荧光粉产生了两个宽带的发射峰,分别位于550nm和615 nm处。并且,在395 nm的紫光激发下,荧光粉会由于Eu~(3+)离子的~5D_0→~7F_2电偶极跃迁产生一个位于615 nm的强宽发射峰,这表明Eu~(3+)离子占据了反演对称中心的位置,取代了Ba Zn_2(BO_3)_2中部分的Ba~(2+)离子。当Eu~(3+)的摩尔分数达到10%时,发生浓度猝灭。在不同浓度的Eu~(3+)离子的掺杂下,Ba Zn_2(BO_3)_2∶Eu~(3+)荧光粉的发光从黄色延伸到红色,实现了荧光粉的色度可调。