Ag-Ag2Se共敏化ZnO花-棒异质结构的合成及其光电化学特性

摘要

ZnO flower-rod ordered arrays (ZFRs) were synthesized via a liquid phase method,and the ZFRs were sensitized with Ag and Ag2Se quantum dots (AA-ZFRs) by ion exchange.Scanning electron microscopy (SEM),powder X-ray diffraction (XRD),energy dispersive X-ray spectra (EDS),and transmission electron microscopy (TEM) were used to characterize Ag and Ag2Se sensitized ZnO flower-rods (AA-ZFRs).And the photoelectrochemical properties and quantum efficiency were also investigated.The results indicate that the optical absorption of AAZFRs can be controllably tuned to cover almost the entire visible spectrum.The sensitization with Ag-Ag2Se restrains the recombination of photogenerated electron-hole pairs due to the heterojunction between Ag-Ag2Se and ZFRs,and enhances the incident photon-to-electron conversion efficiency.Thus,the as-prepared AA-ZFRs exhibit a higher open-circuit photovoltage (-0.77 V Ag/AgCl) and short-circuit photocurrent (0.64 mA ·cm-2) under visible light.%采用水相法合成ZnO花-棒(ZFRs)有序阵列结构,同时利用离子交换法,制备Ag和Ag2Se量子点共敏化光ZnO光阳极(AA-ZFRs).通过扫描电子显微镜(SEM)、X射线粉末衍射(XRD) 、X射线能量色散谱(EDS)和透射电子显微镜(TEM)等手段对样品进行了分析和表征,并测试其光电化学特性以及量子效应.结果表明,Ag-Ag2Se共敏化ZnO花-棒三维有序结构对太阳光的吸收范围延展至近红外区(750 nm),并且在敏化层与ZnO基质界面形成异质结,有效的抑制光生电子-空穴对复合,增强光转换量子效应,从而提高光电化学性能,开路电压达到-0.77 V,短路电流为0.64 mA.