宽谱吸收的表面等离激元双异质结太阳能电池中热载流子机理及其界面调控研究

High-efficiency solar cell requires the maximum absorption of solar energy.The key problem of solar cell is the relatively narrow absorption spectrum range compared with that of solar radiation. In this project, we focused on the efficient absorption of the broad-spectrum light by using a novel solar cell structure with double-heterojunction. This type of solar cell is constructed by both an organic polymer-semiconductor heterostructure and a metal-semiconductor heterostructure. Taking the advantage of the light-induced surface plasmon hot carriers, the optical absorption beyond the limit of bandgap of the traditional semiconductors can be realized. By further designing the parallel electric channel with separated carriers, the highly efficient light absorption and conversion ranging from visible to infrared spectrum can be achieved. This project is aiming at studying the mechanisms of hot carrier effect and interface regulation characteristics, unveiling the scientific problems of efficient light coupling of double heterojunction, barrier control of heterojunction and trapping states regulation at the interface. The main tasks are as follows, the study on the generation, regulation and transportation of hot carriers with high efficiency, experimental fabrication and in-situ characterization via near field equipment, contact design and band regulating of heterostructure interface characteristics, fabrication and electrical measurement of double heterojunction solar cells. The research achievements are of significance for developing efficient broad-spectrum photovoltaic conversion technique in the future.

高效率太阳能电池需要最大限度地利用太阳光谱，目前太阳能电池的关键技术难题之一是光谱吸收范围窄。本项目以太阳能电池对宽谱太阳光高效利用问题为牵引，提出一种全新的双异质结电池结构，由有机-半导体异质结及金属-半导体异质结集成，通过表面等离激元光致热载流子突破传统半导体吸收波长极限的光学通道设计，以及并联式载流子分离的电学通道设计，在可见光到红外宽谱范围内实现光的高效吸收与转换。本项目旨在研究表面等离激元双异质结太阳能电池中热载流子机理及界面调控物理机制，揭示光的宽谱高效耦合、界面势垒调控和缺陷态控制等关键科学问题。研究内容包括：研究表面等离激元半导体异质结中高效热载流子产生、调控和输运机理，实验制备异质结并进行多物理场表征，研究双异质结接触及能带调控特性，以及实验制备宽谱增效双异质结电池并测试。本项目的研究成果对于发展高效的宽光谱响应光电转换技术具有重要意义。

表面等离激元异质结构中的热载流子机理和界面调控研究为高效宽谱吸收的太阳能电池提供了新的机遇。本项目通过自主搭建的微区光电研究系统，从单个纳米颗粒的尺度，研究了金属表面等离激元-半导体构成的电池中的光局域、热电子产生和输运的机理，实现了研究了表面等离激元双异质结太阳能电池中热载流子机理及界面调控物理机制，揭示等离激元对热载流子、光子和激子的高效耦合机制，阐明了等离激元异质结构实现半导体带隙外吸收、界面及晶体质量对于载流子输运的关键作用。通过纳米尺度的界面功能层调控，实现了表面等离激元双异质结器件的能带设计，从而有效提高了载流子的输运和收集效率。通过本项目的研究，为纳米尺度器件功能层设计、加工和调控提供了一系列新方法，为高效光电能源和探测器件的设计提供了新思路。项目执行期间发表SCI论文19篇，其中包括Nano Letters 1 篇，Applied Catalysis B: Environmental 1篇, Solar Energy Materials and Solar Cells 1篇, Optics Express 1篇, Journal of Materials Chemistry C 1篇。申请国家发明专利17项，美国专利6项。