Rup_2P表面敏化TiO_2基复合薄膜光致界面电荷转移

采用离子束溅射技术制备出TiO2/ITO、Zn2+掺杂的TiO2(TiO2-Zn)/ITO和TiO2/ZnO/ITO薄膜,采用表面敏化技术和旋转涂膜法,制备出(1,10-邻菲咯啉)2-2-(2-吡啶基)苯咪唑钌混配配合物(Rup2P)表面敏化的TiO2基复合薄膜Rup2P/TiO2/ITO、Rup2P/TiO2-Zn/ITO和Rup2P/TiO2/ZnO/ITO.表面光电压谱(SPS)结果发现:敏化后的TiO2基薄膜在可见区(400-600nm)产生SPS响应;TiO2基薄膜的能带结构不同,其在400-600nm和350nm处的SPS响应的峰高比不同.利用电场诱导表面光电压谱(EFISPS),测定TiO2基薄膜和表面敏化TiO2基复合薄膜各种物理参数,并确定其能带结构.分析可知,表面敏化TiO2基复合薄膜在400-600nm的SPS响应峰主要源于Rup2P分子的中心离子Ru4d能级到配体1,10-邻菲咯啉π*1和2-(2-吡啶基)苯咪唑π*2能级的跃迁;TiO2中Zn2+掺杂能级有利于Ru4d能级到配体π*1和π*2跃迁的光生电子向TiO2-Zn导带的注入;TiO2/ZnO异质结构有利于光生电子向ITO表面的转移,从而导致可见光(400-600nm)SPS响应增强以及光电转换效率的提高.

Light Induced Interfacial Electron Transfer in Rup2P Surface-Sensitized TiO2-Based Films

TiO2/ITO, TiO2-Zn/ITO and TiO2/ZnO/ITO films were prepared by ion-beamsputtering, and then further surface-sensitized with the Ru(phen)2(PIBH) complex (Rup2P) of Rup2P/TiO2/ITO, Rup2P/TiO2-Zn/ITO, and Rup2P/TiO2/ZnO/ITOby the spin-coating method. Surface photovoltage spectra (SPS) of the films revealed that SPS responses were present at 400-600 nm after surface-sensitization and the SPS intensity ratios between the peaks at 400-600 nm and 350 nm were different because of the different energy band structures in the TiO2-based films. The physical parameters and energy band structures of TiO2-based and Rup2P modified TiO2-based films were determined by electric field induced surface photovoltage spectroscopy (EFISPS). We found that the 400-600 nm SPS peaks of the Rup2P modified films came from the Ru 4d to phen π*1 and PIBH π*2 electron transitions. The Zn2+ doping level in TiO2-Zn benefits the injection of photogenerated electrons from the ligand levels to the conduction band. The TiO2/ZnO heterostructure favors electron transfer to the surface of ITO, which can enhance the SPS response in the visible light region (400-600 nm) as well as the photoelectron transformation efficiency.