聚(2-甲氧基-5-丁氧基)对苯乙炔/Eu2O3纳米复合材料的合成及其光学效应

采用原位脱氯化氢缩合聚合法制备了聚(2-甲氧基-5-丁氧基)对苯乙炔/氧化铕(PMOBOPV/Eu2O3)纳米复合材料. 傅里叶变换红外(FT-IR)光谱证实了在Eu2O3表面的包覆层为PMOBOPV. 高分辨透射电子显微镜(HRTEM)观察发现, PMOBOPV/Eu2O3纳米复合材料具有核-壳结构, 直径为75-145 nm, 其中PMOBOPV包覆层厚度约为25 nm. 紫外-可见(UV-Vis)吸收光谱表明, 随着Eu2O3含量增加, PMOBOPV/Eu2O3的最大吸收峰发生红移且强度提高. 荧光光谱研究表明, 随着Eu2O3含量增加, PMOBOPV/Eu2O3的最大发射波长发生蓝移且强度提高, Eu2O3与PMOBOPV之间形成了光致电子转移体系, 使π电子离域程度增加, 并且导致荧光量子效率提高. 根据光学禁带宽度(Eg)与入射光子能量(hυ)的关系, 拟合了PMOBOPV/Eu2O3薄膜的光学禁带宽度, 发现随着Eu2O3含量增加, Eg逐步减小. 采用简并四波混频方法测试它们的三阶非线性极化率(χ(3)), 发现随着Eu2O3含量增加, PMOBOPV/Eu2O3纳米复合体的非线性光学响应逐渐增强, 这说明PMOBOPV与Eu2O3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.

Synthesis and Optical Effects of Poly(2-methoxy-5-butoxy)-p-phenylene Vinylene/Eu2O3 Nanocomposites

The photoelectric nanocomposite poly(2-methoxy-5-butoxy)-p-phenylene vinylene/Eu_2O_3(PMOBOPV/ Eu_2O_3) was prepared by a dehydrochlorination in situ polymerization. Results from Fourier transform infrared (FT-IR) spectroscopy indicate that PMOBOPV is coated onto the surface of Eu_2O_3. The composite dimensions were observed by high resolution transmission electron microscopy (HRTEM). PMOBOPV/Eu_2O_3 nanocomposites possess core-shell structures and their diameters were about 75-145 nm with a PMOBOPV coating thickness of about 25 nm. A stronger red-shifted absorption peak was observed with an increase in Eu_2O_3 content for PMOBOPV/Eu_2O_3 in the UV-Vis spectrum. Photoluminescence spectroscopy indicates that the maximum emission wavelength of the PMOBOPV/Eu_2O_3 is blue-shifted and the intensity of photoluminescence increases with increasing Eu_2O_3 content. PMOBOPV/Eu_2O_3 shows increased fluorescence because of an intermolecular photo-induced charge transfer process. The optical band gap (E_g) of PMOBOPV/Eu_2O_3 decreased gradually with increasing Eu_2O_3 content. The third-order optical nonlinear susceptibility of PMOBOPV/Eu_2O_3 nanocomposites was measured by degenerate four wave mixing. Results show that the third-order nonlinear optical response of PMOBOPV/Eu_2O_3 nanocomposites increases gradually with increasing Eu_2O_3 content. This can be attributed to intermolecular photo-induced electron transfer and delocalized π electron coupling between PMOBOPV and Eu_2O_3.