飞秒瞬态吸收技术研究有机/无机异质结的超快电荷转移过程

本文检测SQ02在氯苯溶液、Al₂O₃薄膜和TiO₂薄膜中的弛豫过程,从而探究SQ02在单分散态和聚集态下的光物理性质以及相应过程中界面电荷转移过程.实验数据表明,单分散态下SQ02 的寿命约为2 ns,但是,在Al₂O₃薄膜中显著减小到21 ps.电子从激发态SQ02转移到TiO₂薄膜的时间约为2.6 ps,摄入电子量约为89.1%,与基于SQ02的染料敏化太阳能电池光电效应的效率相匹配.此外,一些染料和其他染料一起嵌入纳米晶薄膜中的弛豫时间可达到60 ps.由于其远离TiO₂界面,因此不参与界面电荷转移.

Investigation of Ultrafast Electronic Transfer Process on Organic/Inorganic Heterojunction by Femtosecond Transient Absorption

We detect a relaxation process of excited SQ02 dye in the chlorobenzene solution and an-chor SQ02 on Al₂O₃ and TiO₂ lm, so as to investigate the photophysical properties of pristine SQ02 in the monodisperse system, aggregation state, and the corresponding inter-facial electron transfer process. The experimental data show that the lifetime of SQ02 in the monondisperse system is ~2.0 ns, but that of SQ02 anchored on the Al₂O₃ lm could obviously decrease to ~21 ps. The time of electron transfer from excited SQ02 to TiO₂ lm is estimated to be ~2.6 ps and the yield of electron injection is estimated to be ~89.1%, which matches the incident photon to current e ciency of dye-sensitized solar cell based on SQ02. In addition, some dyes are found to pack on the other dyes anchored on the nanocrystal lm, and their relaxation time could reach ~60 ps. They couldn''t participate in the interfacial electron transfer, since they are far away from the TiO₂ interface.