基于多激子效应，窄带隙量子点太阳能电池具有更高的理论光电转换效率。但量子点表面缺陷态密度高，且界面电荷传输不均衡导致严重的界面电荷复合，这是电池光电转换效率远低于理论值的重要原因。为此，本项目提出双功能界面修饰量子点的研究思想。拟在三元绿色CuInSe QDs敏化光阳极的表面原位生长P型半导体CuxSe界面修饰层，P型半导体CuxSe不仅作为空穴传输层，促进空穴传输，还有效钝化量子点表面缺陷。该修饰层兼具平衡界面电荷传输和抑制界面电荷复合的双重作用，将显著提高电池的电荷收集效率。为实现这一思想，本项目将重点研究：量子点界面P型半导体CuxSe原位生长及调控机理；CuxSe的化学组成、厚度、能级结构等对量子点表面缺陷和电荷传输的作用机制；深层次理解多界面下电荷输运和复合动力学过程；高电荷收集效率量子点太阳能电池的制备。该研究将为构建新型高效的太阳能电池结构提供理论支撑和技术指导。

Quantum dot solar cells (QDSCs) show high theoretical power conversion efficiency (44%) in view of the multiple generation effect of quantum dots (QDs). However, the power conversion efficiency of QDSCs lags much far behind the theoretical value, primarily attributable to the fact that lots of surface defects in quantum dots and the imbalanced hole and electron transfer leads to high charge recombination and low electron collection. To improve the power conversion efficiency, it is imperative to overcome kinetic barriers for charge transfer at semiconductor interfaces and repair the surface defects. Based on our research and other relative investigations, we propose to in-situ deposit a P-type double functional surface decoration layer of CuxSe on the surface of the “green” quantum dot CuInSe. Such a decoration layer would not only reduce and repair the surface defects of the quantum dots, but also accelerate the hole extraction from QDs to the electrolyte. It is anticipated that the charge collection efficiency of QDSCs will be significantly enhanced, consequently resulting in a much higher power conversion efficiency. Our research will focus on the controllable deposition of CuxSe coating layer on the interface of the QDs. And to understand the electron and hole transfer dynamics as well as the charge trapping as a function of the chemical composition, shell thickness, energy level structure of the surface decoration layer. As well as the fabrication and optimization of quantum dot sensitized solar cells with high charge collection. This research will provide theoretical support and technical guidance for the construction of next generation solar cells.