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 ±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.
出处
《中国光学》
EI
CAS
CSCD
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)
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
quantum dots solar cell
semiconductor nanocrystals
surface modification
CdSe
hot electron injection