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通过溶胶凝胶法制备了不同浓度的有机荧光分子BBOT(2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene)分散的纳米多孔二氧化硅凝胶薄膜,并获得了亮蓝色发光。本工作通过光谱技术研究了薄膜的发光特性;用扫描电子显微镜(SEM)技术表征了BBOT/SiO2薄膜的表面形貌,分析了BBOT在二氧化硅凝胶中的表观分散行为和聚集态。通过研究有机荧光分子BBOT在介电常数从2到81的几种不同介质环境中的吸收和发射光谱的变化,揭示了BBOT在二氧化硅凝胶中吸收和发射主峰位相对于其在共溶剂1,4二氧六环中红移的原因是由于BBOT分子的电子基态比其激发态极性弱、与极性较大的二氧化硅凝胶相互作用的结果。薄膜发光强度随BBOT掺杂浓度的增加而增强,在6×10-3M时达到最强。通过SEM技术表明,在掺杂浓度6×10-3M及以下薄膜没有相分离,仅在10-2M时出现BBOT分子聚集形成的针状结晶形貌。本研究表明杂化薄膜通过纳米多孔二氧化硅的“笼”的作用获得BBOT有机分子在二氧化硅凝胶中的高度分散而抑制其浓度猝灭,得到高强度蓝色发光。
Different concentrations of 2,5-bis (5-tert-butyl-2-benzoxazolyl) thiophene (BBOT) dispersed nano-porous silica gel were prepared by sol-gel method. Glow In this work, the luminescent properties of the films were studied by spectroscopic techniques. The surface morphology of BBOT / SiO2 films was characterized by scanning electron microscopy (SEM), and the apparent dispersion behavior and aggregation state of BBOT in silica gel were analyzed. By studying the changes of absorption and emission spectra of the organic fluorescent molecule BBOT in several different dielectric constants from 2 to 81, it reveals that BBOT absorbs and emits the main peak in the silica gel with respect to its absorption in the co-solvent 1 The reason for the red-shift in 4-dioxane is the result of the interaction between the BBOT molecule's ground state and its more polar silica gel. The luminescence intensity of the film enhanced with the increase of BBOT doping concentration, reaching the strongest at 6 × 10-3M. SEM showed that there was no phase separation in the film with doping concentration of 6 × 10-3M and below, and the needle-like crystal morphology formed by the aggregation of BBOT molecules appeared only at 10-2M. The present study shows that the hybrid thin film can be highly dispersed in a silica gel to inhibit the concentration quenching of the BBOT organic molecules by the action of the “cage” of the nanoporous silica to obtain high intensity blue luminescence.