新型掺铒碲酸盐玻璃光谱性质和热稳定性研究

采用高温熔融法制备了掺Er3 :TeO2-B2O3-SiO2-Na2O系列玻璃样品.对样品吸收光谱、发射光谱、差热曲线和Er3 :4I13/2能级的荧光寿命进行了测试和分析.计算得到Er3 的J-O强度参数Ωλ(λ=2,4,6),讨论了SiO2的含量对Er3 在该系列玻璃样品中发光性能的影响.结果表明,SiO2的引入有效提高了玻璃材料的有效发射带宽和热稳定性,有效抑制了材料的荧光上转换效应.同时,计算得到Er3 :4I13/2→4I15/2能级的量子效率为ηmax＝63%.     

Sr2SiO4:Eu2 荧光粉的发光性质及在白光二极管中的应用

用高温固相反应法制成了Sr2SiO4:xEu2 荧光粉.随着Eu2 掺杂浓度的增加,Sr2SiO4晶体结构从β相转换为α'相.Eu2 掺杂浓度小于等于0.5 mol%时,Sr2SiO4:Eu2 为β相,大于等于2 mol%时是α'相.β-Sr2SiO4:Eu2 的发光颜色为黄绿色,发射光谱由两个谱带组成,分别位于470 nm,535 nm处.α'-Sr2SiO4:Eu2 发光颜色为黄色,发射光谱由两个谱带组成,分别位于490 nm,570 nm处.这两个谱带具有不同的荧光寿命,归结为处于不同格位上Eu2 的发射.用近紫外芯片和这两种荧光粉制成了白光二极管.正向驱动电流为20mA时,用β-Sr2SiO4:0.0035 E2 抖制成的白光LED色温为5562 K;色坐标为x=0.32,y=0.40;显色指数为61;流明效率为15.7 lm/W.用α'-Sr2SiO4:0.02 Eu2 制成的白光LED色温为4 707 K;色坐标为x=0.36,y=0.37;最色指数为73;流明效率为6.7 lm/W.     

Study on UV Excitation Properties of Eu^3＋ at S6 Site in Bulk and Nanocrystalline Cubic Y2O3

Increases of emission intensities for Eu^3 at the S6 site relative to that at the C2 site were observed as UV excitation wavelength decreases from 300 nm to 200 nm in both bulk and nanocrystalline cubic Y2O3:Eu^3 . Decomposition of excitation spectra shows that the charge transfer band of Eu^3 at the S6 site lies in the high-energy side of that at the C2 site, resulting in that the energy transfer from the host prefers to the S6 site. Detailed emission and excitation spectral characteristics were analyzed and discussed. In addition, spectral red-shift were found in both charge transfer bands in nanocrystalline Y2O3: Eu^3 compared to the bulk material. The number ratio of S6 sites to C2 sites is also smaller in nanocrystalline Y2O3:Eu^3 than that in the bulk one.     

Er^3＋掺杂玻璃的1．5μm发射光谱及其带宽

用高温熔融法制备了Er^3 掺杂的氧化物玻璃，研究了Er^3 在11～300K温度范围内对应于^4I13/2→^4I15/2跃迁的1．5μm发射光谱，将^4I13/2多重态中的高能态和最低能态向基态跃迁发射的光谱成分从测量的发射光谱中分离开来，讨论了光谱成分对1．5μm发射带宽的影响。提出了等效四能级模型，并用此模型解释了Er^3 ^4I13/2→^4I15/2辐射跃迁的线形及其变温特性。分析表明，提高^4I13/2多重态中高能态的辐射跃迁几率是获得室温下宽带1．5μm发射的关键。最后，根据Mc Cumber理论，利用吸收光谱变换得到了与测量一致的发射光谱形状及相应的受激发射截面。     

新型掺铒碲酸盐玻璃光谱性质和热稳定性研究

采用高温熔融法制备了掺Er^3＋：TeO2-B2O3-SiO2-Na2O系列玻璃样品。对样品吸收光谱、发射光谱、差热曲线和Er^3＋：4I 13／2能级的荧光寿命进行了测试和分析。计算得到Er^3＋的J-O强度参数Ωλ（λ=2,4,6）,讨论了SiO2的含量对Er^3＋在该系列玻璃样品中发光性能的影响。结果表明,SiO2的引入有效提高了玻璃材料的有效发射带宽和热稳定性,有效抑制了材料的荧光上转换效应。同时,计算得到Er^3＋：^4 I13／2→^4I 15/2能级的量子效率为ηmax=63％。     

A green-yellow emitting β-SreSiO4：Eu^2＋ phosphor for near ultraviolet chip white-light-emitting diode

Sr2SiO4：xEu^2＋ phosphors were synthesized through the solid-state reaction technique. The crystal phase of Sr2SiO4：xEu^2＋ phosphor manipulated by Eu^2＋ concentration was studied. The phase transited from β to α＇ in Sr2SiO4：xEu^2＋ phosphor with increasing europium concentration. The single β phase was formed as x≤005 and changed α＇ phase when x〉0.01. The emission spectrum of the β-Sr2SiO4：Eu^2＋ phosphor consisted of a green-yellow broadband peaking at around 540 nm and a blue band at 470 nm under near ultraviolet excitation. The white LEDs by combining near ultraviolet chips with β-Sr2SiO4：Eu^2＋ phosphors were fabricated. The luminous efficiency （15.7lm/W） was higher than α＇-Sr2SiO4：Eu^2＋ phosphor white LED.     

用微区光学方法研究GaP:ZnO红光外延片

用微区光致发光和拉曼散射光谱比较了国内外Gap:ZnO红光二极管产品的结构，在国内首先实现了用微区光学方法检测LED外延片并进行生产工艺的改进，对典型样品进行了微区光致发光的测试，比较外延片横截面上不同厚度层的光致发光，非常明显地看出主要发光区是在P区。通过合理扩展P层发光区的厚度相应地增加了光致发光的总光强，提高了产品的生产成品率。     

Eu3 ,Li 共掺杂ZnO:Zn荧光粉的制备及发光性质

在还原气氛下利用高温固相反应法制备了Eu3 ,Li 共掺杂的ZnO:Zn 荧光粉.在近紫外光激发基质条件下,该荧光粉材料具有强的来自Eu3 的4f组态内跃迁线状发射及来自基质缺陷相关的绿色可见宽带发射.测量了稳态光谱,漫反射及时间分辨光谱以研究该材料的发光性质及基质向稀土离子的能量传递过程.在还原气氛下因在导带下形成了一系列浅施主能级,暂时储存激发能,施主中心浓度增加使得基质向稀土离子的能量传递效率增强.通过与纯Eu2O3粉末的光谱对比分析,确定了在此材料体系中存在处于两种局域环境的Eu3 .由于在近紫外区的强且有效的吸收,此材料有望成为应用于近紫外激发发光二极管的新型荧光粉.