聚(2-甲氧基-5-辛氧基)对苯乙炔/Y_2O_3:Eu^(3+)纳米复合材料的光致电子转移效应

Photo-Induced Electron Transfer Effects of Poly(2-Methoxy-5-Octyloxy)-p-Phenylene Vinylene/Y_2O_3:Eu^(3+)Nano-Composites

采用原位脱氯化氢缩合聚合法制备了聚(2-甲氧基-5-辛氧基)对苯乙炔/Y_2O_3:E^(3+)(PMOCOPV/Y_2 O_3:Eu^(3+))纳米复合材料。红外光谱证实了在Y_2O_3:Eu^(3+)表面的包覆层为PMOCOPV。紫外-可见吸收光谱表明与PMOCOPV相比,PMOCOPV/Y_2O_3:Eu^(3+)的最大吸收峰发生红移且强度提高。荧光光谱研究表明PMOCOPV/Y_2O_3:Eu^(3+)的最大发射波长发生红移且强度提高,荧光寿命得到增强,Y_2O_3:Eu^(3+)与PMOCOPV之间形成了光致电子转移体系,使得π电子离域程度增加,并且导致荧光量子效率提高。根据E_g与入射光子能量hv的关系,拟合了PMOCOPV/Y_2O_3:Eu^(3+)薄膜的光学禁带宽度,发现E_g减小。采用简并四波混频方法测试它们的三阶非线性极化率x^((3)),结果发现与PMOCOPV相比,PMOCOPV/Y_2O_3:Eu^(3+)纳米复合体的非线性光学响应逐渐增强,进一步说明PMOCOPV与Y_2O_3:Eu^(3+)之间形成了分子间光致电子转移体系,产生了复杂的分子间离域π电子非线性运动。

The photoelectric nano-composites of poly（2 methoxy-5-0ctyloxy）-p-phenylene vinylene/Y2O3 ： Eu^3＋ （PMOCOPV/ Y2O3 ： Eu^3＋ ） were prepared by dehydrochlorination in-situ polymerization. The result of Fourier transform infrared spectroscopy indicates that PMOCOPV is coated on the surface of Y2O3 ： Eu^3＋. Compared with PMOCOPV, the absorption of PMOCOPV/Y2O3 ： Eu^3＋ is strengthened, and a red shift of the absorption peak can be clearly observed in the UV-Vis spectrum. Photoluminescence spectroscopy indicates that the maximum emission wavelength of the PMOCOPV/Y2O3 ： Eu^3＋ is red.shifted and the intensity of photoluminescence increases in comparison with PMOCOPV. PMOCOPV/Y2O3 ： Eu^3＋ shows fluorescence increasing, which involved the inter-molecular photo-induced charge transfer process. The optical band gap of PMOCOPV/Y2O3 ： Eu^3＋ decreases. The third-order optical nonlinear susceptibility of PMOCOPV/Y2O3 ： Eu^3＋ nano-composites was measured by degenerate four wave mixing. The results show that the third-order nonlinear optical responses of PMOCOPV/Y2O3 ： Eu^3＋ nano-composites are enhanced in comparison with PMOCOPV, which can be attributed to inter-molecular photo-induced electron transfer and delocalized π electron coupling between PMOCOPV and Y2O3 ： Eu^3＋.