CuInSe量子点双功能界面修饰及电荷传输动力学研究

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.

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。

CuInSe2胶体量子点是一种窄带隙半导体纳米晶，具有带隙可调节、消光系数高、响应光谱宽（300-1100 nm波长）和环境友好等优点，在光电应用领域表现出巨大的发展潜力。但是， CuInSe2胶体量子点表面的长链有机配体影响量子点薄膜电荷的传输、载流子传输不平衡、表面缺陷态密度高等问题导致严重，因此，CuInSe2胶体量子点的光电转换性能偏低。针对上述问题，本项目提出配体交换、构建P型半导体双功能界面修饰层、锰离子掺杂等方法分别提升量子点导电性、减少量子点缺陷态密度和促进空穴迁移等，进而提高了CuInSe2胶体量子点的光电性能，并进一步采用超快动力学手段等验证了上述方法对光生载流子动力学的影响机制。本项目研究丰富了光电转换相关理论，为量子点光电转化效率的提升建立了有效途径。.在本项目支持下，发表学术论文9篇，包括SCI论文8篇，EI论文1篇（邀请论文），其中第一作者论文5篇，通讯作者论文3篇。申请发明专利2项。在本项目支持下，申请人获得香江学者计划支持，并晋升副教授。

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