Blue-to-Orange Tunable Luminescence from Europium Doped Yttrium--Silicon--Oxide--Nitride Phosphors

Europium-doped yttrium-silicon-oxide-nitride phosphors are synthesized by carbothermal reduction and nitridation method. The crystal structure of the phosphors changed gradually from oxide Y2Si2O7 to nitride YSi3N5 state with increasing dosage of Si3N4 and carbon powder. The Y2Si2O7：Eu phosphor shows a blue emission at 465 nm with 300 nm excitation and a characteristic red emission of Eu^3＋ at 612 nm with 230 nm excitation. The YSi3N5：EU phosphor shows a broad emission band centred at 595nm with some sharp peaks of Eu^3＋ with 325nm excitation. The absorption of the studied phosphors increases from 450 to 700hm with an increment in nitrogen content. Blue-to-orange tunable luminescence is observed with 390 nm excitation.     

(Ce,Gd,Mn)MgB5O10磷光体的合成及其发光

本文采用固相反应的方法合成了一系列(Ce,Gd,Mn)MgB5O10磷光体。观察到合成温度、灼烧时间、原料配比对磷光体的形成和发光亮度有重要影响。X射线衍射分析表明,磷光体结构与LaMgB5O10相同,属单斜晶系、空间群P21/c。用EPR确定了磷光体中锰离子为二价。测定了(Ce0.2La0.2)MgB5O10,(Gd0.7La0.3)MgB5O10,(Mn0.05La0.95)MgB5O10,(Ce0.2Mn0.05La0.75)MgB5O10,(Gd0.95Mn0.05)MgB5O10、(Ce0.2Gd0.8)MgB5O10和(Ce0.2Gd0.75Mn0.05)MgB5O15等磷光体的光谱。根据光谱数据讨论了(Ce0.2Gd0.75Mn0.05)MgB5O10磷光体中能量传递过程为:Ce3+→Mn2+,Gd3+→Mn2+以及Ce3+→Gd3+→Mn2+,其中Ce3+离子可将能量高效地传递给Gd3+,Gd3+离子起着中间体的作用。     

Y3Al5O12：Eu^3＋磷光体的溶胶—凝胶法合成及发光特性

以金属烷氧基化合物为原料．采用溶胶-凝胶法在1000℃下合成了Eu^3 掺杂的Y3Al5O12(YAG)磷光体。利用TG-DSC，XRD和发光光谱等对样品进行了表征。结果表明，YAG：Eu^3 的晶相形成温度为991℃。Eu^3 在非晶态和晶态YAG中的发射光谱有明显差异。研究了Eu^3 含量和烧结温度对Eu^3 的^5D0→^7F1和^5D0→^7F2发射峰强度的影响。随煅烧温度的升高和Eu^3 浓度的增加，Eu^3 发射峰强度增强。     

A mechanistic study of flame retardance of novel copolyester phosphorus containing linked pendant groups by TG/XPS/direct Py-MS

The flame retardant mechanism of the copolyester phosphorus containing linked pendant groups was investigated by thermogravimetric （TG）, X-ray photoelectron spectroscopy （XPS） and direct insertion probe pyrolysis mass spectrometry （DP-MS） technique. TG results show that the incorporation of phosphorus containing unit linked pendant groups can destabilize the copolyester due to the cleavage of P-CH2 bond, and phosphorus containing units cannot promote the char-formation of the copolyester during the thermal degradation of the copolyester. XPS spectra indicate that with the increase of the temperature, the P-CH2 bonds of the copolyester break down gradually, the concentration of phosphorus in the condensed phase products decrease gradually and the chemical state of phosphorus does not change in the temperature of 250-380 ℃. Direct pyrolysis MS suggests that the P-CH2 bonds cleavage occurs at pendant groups and species containing phosphorus can volatilize into the gas phase. A flame retardant mechanism is proposed for the gas phase mode of action of the halogen-free copolyester phosphorus containing linked pendant groups.     

(Zn、Cd)S:Cu、Br黄色交流电致发光材料的晶体结构和发光特性

本文首次提出一种制备黄色交流粉末电致发光材料的新方法.在以ZnS为基质的绿色材料的基础上,低温扩散CdS,获得系列黄材料.并测量了晶体结构和发光特性.     

用磷光寿命变化测定碘离子与磷光体反应动力学参数

利用Ｉ＾－促进系间窜越，加快发现过程，缩短磷光寿命的特点，研究Ｉ＾－量改变与色氨酸，色胺磷光寿命关系，分别为：τ＝３．９８ｅ＾－０．０６５８ｘ，与τ＝３．５ｅ＾－０．０８９９ｘ，应用静态分析，推导Ｓｔｅｒｎ－Ｖｏｌｍｅｒ式，计算平衡常数Ｋｓ与ｋｉ，分别为：０．１０９与０．２００ｍｍｏｌ；０．０２７与０．０５１ｓｍｍｏｌ＾－１。利用本法分析了酷氨酸，苯丙氨酸，Ｌ－色氨酸，牛血清白蛋白，葡糖苷酸酶。     

铝酸锶铕的合成与发光的研究

本文详细报导4(SrEu)O·7Al2O3.磷光体的合成及激活剂Eu2+离子浓度、硼酸、五氧化二磷等对磷光体发光强度,发射光谱和激发光谱的影响.讨论了不同Eu2+离子之间的能量传递.测量了不同Eu2+浓度下磷光体的荧光寿命和长余辉特性.     

掺杂LiF的ESR谱和ENDOR谱研究

LiF:Mg,Cu热释光(TL)磷光体在γ辐照后产生F⁰顺磁中心,其g因子为g_xx=2.0030,g_yy=2.0450,g_zz=2.0251,裂分为A_xx=511.04G,A_yy=505.42G,A_zz=507.26G。F⁰中心的浓度随Mg⁺⁺浓度的增加而下降。磷光体的ENDOR谱显示F⁰中心附近有铜核存在。照射前和照射后24h测量均未发现Cu⁺⁺的ESR谱,表明铜是以Cu⁺形式掺入的,照射并未引起Cu⁺离子化合价的改变。LiF:Mg,Cu,P在γ辐照前具有轴对称的Cu⁺⁺离子的ESR谱,辐照后产生了O^-空穴中心和PO₃^2-自由基,改变了Cu⁺⁺的环境,使Cu⁺⁺的谱发     

以BAlq为主体的高效高色纯度的红色有机电致磷光器件

以铱配合物红色磷光体Ir(piq)₂(acac)为掺杂剂,制备了基于BAlq材料的红色电致磷光器件,其结构为ITO/NPB(30nm)/Ir(piq)₂(acac):BAlq(25nm)/BCP(13nm)/Alq₃(35nm)/LiF(1nm)/Al(1000nm),当掺杂浓度为8%的时候,器件发光的色坐标为(x=0.67,y=0.32),基本满足了全色显示对红色发光的要求。在电压为16V时,器件达到最高亮度9380cd/m²。在电流密度为5.45mA/cm²时,外量子效率达到最大5.7%。由于磷光体Ir(piq)₂(acac)的磷光寿命较短,所以器件在高电流密度下,仍然保持较高的外量子效率。电流密度为100mA/cm²时,外量子效率仍然维持在4.7%。进一步研究表明在器件中短程的Dexter能量传递以及红光染料对空穴的直接捕获两种机制同时存在。