Zinc strontium phosphate glasses doped with different trivalent praseodymium ion(Pr3t) concentrations are presented and their photoluminescence properties are investigated upon 442 nm excitation. With the Pr3tconcentration decreasing, the orange emission of Pr3t(1D2-3HJ) is enhanced steadily at the cost of its blue emission(3P1;0-3H4). Monochromic orange emission of Pr3tions is obtained when the Pr3tdoping is reduced to 0.05 mol.%. The mechanism controlling the monochromatic characteristic of Pr3temissions is supposed to be associated with the phonon-aided nonradiative relaxation process of Pr3t:3Pj→1D2, which depends on the Pr3tconcentration as well as the phonon energy of the glass matrix. Sodium zinc tellurite and barium gadolinium germinate glasses with the lower phonon energy are used as reference hosts to clarify this mechanism, and the results obtained support this suggestion.
采用弯曲性能测试,动态热机械分析和X射线光电子能谱分析研究了γ辐照对环氧树脂性能的影响,并分析了辐照损伤机理。结果表明:辐照会使得环氧树脂中键能较弱的C-N和C-O断裂,断裂形成的自由基再重组生成新C-C键,从而发生进一步交联。低剂量辐照下,材料的弯曲强度增大了5 MPa,玻璃化转变温度提高6℃。随着辐照剂量的继续增加,辐照降解加剧,弯曲强度和玻璃化转变温度都有所下降,但仍高于未辐照样品。因而当辐照剂量小于10 k Gy时,环氧树脂的辐照交联效应大于降解效应。
Tb^(3+)and Sn^(2+)co-doped strontium phosphate glasses are prepared and their unique photoluminescence(PL)properties for deep UV excitation are investigated. With the co-doped Sn^(2+)ions, Tb^(3+)keeps the original PL behaviors under near UV excitation while its PL action for deep UV excitation is enhanced tremendously.PL emission and excitation spectra demonstrate the sensitization role of Sn^(2+)on the Tb^(3+)emissions for deep UV excitation that is associated with the strong deep UV absorption of Sn^(2+)for greatly enhancing the resonance of the Tb^(3+)excitation with the deep UV light source. The decay curves of Sn^(2+)and Tb^(3+)emissions for both singly doped and co-doped samples are single exponentially well fitted with almost the same emission lifetime(τ) values in the microsecond and millisecond time regimes, respectively, confirming that Sn^(2+)and Tb^(3+)act as an independent activator in the present phosphate glass matrix while an involved energy transfer from Sn^(2+)to Tb^(3+)is radiative. Moreover, Sn^(2+)and Tb^(3+)can be co-excited with deep UV light to emit tunable light from blue to green with the definite CIE chromaticity coordinate for different applications.
