掺Bi离子锗铌酸盐红外发光玻璃的研究

用高温熔融法制备了Bi₂O₃掺杂的(0.9-x) GeO₂-xNb₂O₅-0.1BaO (含量x为摩尔分数, x=0, 0.04, 0.07, 0.1)系列玻璃. 测定了玻璃样品的差热分析(DTA)曲线、吸收光谱、发射光谱及X射线光电子能谱(XPS). 从DTA曲线分析得到玻璃的结晶起始温度与软化温度之差(T_x-T_g)达200℃以上. 吸收光谱中可观察到位于500, 700, 808和1000 nm处的吸收峰, 并随着Nb₂O₅含量x的增加吸收边带发生红移. 在波长为808 nm激光激发下, 观察到发光中心位于1300 nm处、荧光光谱半高宽约为200 nm的宽带发光. 荧光强度随Bi₂O₃掺杂量δ的增加先增强后减弱, 当掺杂量δ达到约0.01时, 荧光强度达到最强. 随着Nb₂O₅含量x从0.04增加到0.1时, 荧光强度逐步减弱. 样品的XPS峰分别位于159.6和164.7 eV, 它们介于Bi³⁺与Bi⁵⁺的特征结合能之间, 因此Bi³⁺与Bi⁵⁺可能同时存在于玻璃基质中. 从XPS及Bi离子的发光特性推断, 宽带的荧光发射可能起因于Bi⁵⁺. 随着Nb₂O₅含量x的增加, 荧光强度逐步减弱. 分析认为, Nb₂O₅取代GeO₂后形成了NbGe缺陷, 需要低价Bi离子进行电子补偿, 因而抑制了Bi⁵⁺形成, 致使荧光强度减弱.

Bi-doped germanium niobate glasses with near-infrared broad-band emission

The Bi₂O₃ doped glasses with concentrations 5 of（0.9 - x） GeO_2-xNb2_O5-0.1BaO（x = 0.04,0.07,0.1） glasses are prepared by the conventional melting method.The differential thermal analysis（DTA） curves,the absorption spectra,the fluorescence decay curve and the X-ray photoelectron spectra are measured.The difference between glass crystallization onset temperature and transition temperature（T_x—T_g） of the glasses is up to 200℃from the DTA curve.Absorption peaks at 500,700,and 1000 nm are observed. The absorption edges show a red-shift with the increase of Nb₂O₅ content x.The emission band at 1300 nm with the full width at half maximum near 200 nm is observed under the excitation of 808 nm laser.The fluorescence intensity increases with the increase of the concentration 5 of Bi₂O₃.The fluorescence intensity reaches a maximal value when the concentration 8 of Bi₂O₃ is about 0.01.The peaks of binding energy in XPS are located at 159.6 and 164.7 eV respectively.The binding energy peaks are located between those of Bi³⁺ and Bi⁵⁺ by comparing with those of Bi₂O₃(Bi³⁺) and NaBiO₃(Bi⁵⁺).According to the XPS results,one may conclude that Bi³⁺ and Bi⁵⁺ ions co-exist in the glass.The near infrared broadband emission may be assigned to Bi⁶⁺ ion based on the results of emission spectra and X-ray photoelectron spectra.The broadband intensity is gradually weakened as the Nb₂O₅ content x increases from 0.04 to 0.1.As GeO₂ is substituted by NO₂O₅,complex NbGe defects are formed and the lower valence state of Bi ions will be inevitably formed to compensate the extra electric charge from Nb⁵⁺,thus resulting in the inhibition of Bi⁵⁺ and weakening the fluorescence aforementioned.