巯基丙酸分子对CdSe核壳量子点和ZnO纳米粒子薄膜之间电荷转移的影响

Effect of Mercaptopropionic Acid Molecules on Electron Transfer from CdSe Core/Shell Quantum Dots to ZnO Nanocrystal Films

通过稳态光谱和时间分辨荧光光谱研究了巯基丙酸(MPA)分子对由量子点到ZnO纳米粒子薄膜的电荷转移过程的影响。研究发现,相对于CdSe纳米粒子薄膜样品,没有MPA分子参与作用的CdSe/ZnO薄膜样品和有MPA分子连接的CdSe/MPA/ZnO薄膜样品中都存在从CdSe量子点到ZnO纳米粒子薄膜的有效电荷分离过程,但是相对于CdSe/ZnO样品,CdSe/MPA/ZnO样品中电荷转移速率明显变小。这表明MPA分子本身它并不能促进CdSe到ZnO电荷分离过程,因此可以认为用金属氧化物薄膜直接吸附量子点吸收材料,将能获得高功率转换效率的量子点敏化太阳能电池。

The effect of mercaptopropionic acid（MPA） molecules on the charge transfer process from the quantum dots to ZnO nanocrystal films was studied in this paper by the steady-state and time-resolved photoluminescence spectroscopy.The obtained high efficiently photoluminescent CdSe-core CdS/ZnS-multishell quantum dots with few defects are air stable in quantum dot based devices.Three samples were prepared to make the measurements of time-resolved photoluminescence spectra,CdSe quantum dots film,CdSe quantum dots spun cast on ZnO nanocrystal film（CdSe/ZnO）,and MPA molecules linked CdSe quantum dots and ZnO nanocrystal film（CdSe/MPA/ZnO）.The shortening of photoluminescence life times of CdSe quantum dots deposited on ZnO nanocrystal films with and without MPA molecules indicated the electron transfer process happened in the interface between CdSe quantum dots and ZnO nanocrystals.But the decreased rate of electron transfer from CdSe quantum dots to ZnO nanocrystal films with MPA molecules was found,compared to the electron transfer rate of the CdSe/ZnO sample.Considering the fact that MPA molecules did not improve the charge transfer process from CdSe quantum dots to ZnO nanocrystal films,it was indicated that the MPA molecules was not a good choice in CdSe quantum dot sensitized solar cell.The experimental result suggested that the direct adsorption of CdSe quantum dots on metal oxide nanocrystal films would obtain quantum dot sensitized solar cell with higher power conversion efficiency.