丁胺包裹的CdSe量子点敏化的TiO_2纳米晶薄膜电子转移机制  

Electron transfer mechanism of butylamine-capped CdSe quantum dot sensitized nanocrystalline TiO_2 films

作　　者：李正顺[1] 岳圆圆[1] 张艳霞[1] 王岩[2] 王雷[1] 王海宇[1] 

机构地区：[1]吉林大学电子科学与工程学院,吉林长春130012 [2]吉林大学物理学院,吉林长春130012

出　　处：《中国光学》2015年第3期428-438,共11页Chinese Optics

基　　金：国家自然科学基金资助项目(No.20973081;No.60525412;No.60677016;No.10904049)

摘　　要：利用超快光谱技术系统研究了在丁胺包裹的CdSe量子点敏化的TiO2纳米晶薄膜起始时刻界面间电子转移动力学。与之前的报道不同,该实验结果表明：CdSe量子点经过表面修饰后,两相电子注入机制——热电子和冷电子注入得以被证实,即：电子能分别从CdSe量子点导带中高的振动能级和导带底转移到TiO2的导带。该机制详细描绘了电子在纳米界面间转移的图景。进一步研究发现：热电子注入的电子耦合强度（3.6±0.1 meV）比弛豫后的基态电子注入高两个数量级,基于Marcus理论,伴随着0.083 eV的重组能,冷电子注入的耦合强度值为-50μeV。In this paper, we have investigated the initial interfacial electron transfer dynamics in butylamine-capped CdSe quantum dot（ QD）-sensitized nanocrystalline TiO2 films by ultrafast spectroscopy.Different with previous reports, the experiment results indicate that after surface modification of CdSe QDs, a two-phase electron injection mechanism （ hot and cold electron injection ） is validated, namely, electrons transfer from high vibration energy levels in conduction band and conduction band bottom of CdSe quantum dots into conduction band of TiO2 , respectively.This mechanism depicts a picture on the detailed charge transfer processes at the nano interfaces.We further find that the electron coupling strength （3.6 ＆#177;0.1 meV） of hot electron in-jection is two orders of magnitude larger than that of relaxed ground-state electron injection, which gives a val-ue of -50 μeV accompanied with reorganization energy 0.083 eV on the basis of Marcus theory.

关 键 词：量子点太阳能电池 半导体纳米晶 表面修饰 CDSE 热电子注入 

分 类 号：TN249[电子电信—物理电子学]