ZnO纳米结构与半导体量子点的叠层复合及其可见-红外光电转换的特性研究

Film solar cells are promising photovoltaic devices for high efficiency and low cost solar energy conversion. Making best use of solar radiation through improving conversion efficiency is one of the ongoing tasks. Even though laminated cells have a wide spectroscopic response range, the complex processing technique and high price limit its application. In this project, on the basis of the dye-sensitized solar cell, composite nanostructured films made up of oriented crystalline ZnO nanostructures and semiconductor quantum dots is introduced to replace the dye in order to achieve high efficiency and low cost for solar cell by two kinds of quantum dots, which takes advantage of direct carrier transport pathways of ZnO nanostructures and PbS and CdSe quantum dots with controllable spectrum. Many processing methods for preparing nanostructures and quantum dots will be investigated and optimized. The composite of the quantum dots on the surface of ZnO nanostructures will be explored in details. Spectroscopic response of ZnO nanostructures, quantum dots and their composite structures will be measured experimentally and analyzed. The mechanisms for improving photoelectric conversion efficiency of the composite ZnO nanostructures assembling two kinds of quantum dots will be revealed. The implementation of this project will not only help understanding the composite rules of the quantum dots and nanostructures, but also help extending applications of nano assembly structure in the solar cells, and also help to form the core of intellectual property rights series in photoelectric convert the source of basic research.

高效低成本薄膜太阳能电池是未来光伏技术的主流，充分利用太阳辐射提高电池效率是人们努力的方向之一。虽然叠层电池具有较大的光谱响应范围，但复杂的制作工艺和昂贵的价格限制了其应用。本项目以染料敏化电池为原型器件，利用叠层电池的概念；引入半导体纳米结构和量子点，利用ZnO纳米结构优异的电子传输性能、PbS和CdSe量子点的可调控光谱吸收特性，实现双量子点共敏化高效低成本新型太阳能薄膜电池；重点研究纳米结构和量子点的制备并优化工艺条件；探索量子点在ZnO纳米结构中复合行为；深入分析纳米结构、量子点及其复合结构的光谱响应过程；着重复合两种量子点的ZnO纳米结构电池,研究提高电池光电转换效率的主要机制，并对电池的性能进行细致评价与分析。项目的实施有助于了解量子点与氧化物纳米结构的相互作用规律，有助于把握纳米组装结构在光电转换过程中的作用与内在联系，也有助于在光电转换基础研究的源头形成系列核心知识产权。

充分利用太阳辐射提高电池效率是光伏技术需要解决的技术途径之一，也是未来高效、低成本薄膜光伏技术重要研究方向。半导体量子可通过结构、尺寸与组分等参数，有效的调节其在可见-近红外波段的光学性质。这为优化薄膜光伏结构的光吸收和光电转换提供了技术途径。本课题从优化非硅光伏结构的光吸收出发，首先通过调节量子点（CdSe和PbS量子点）尺寸与组分，获得了第一吸收峰在520 nm-0nm和830 nm-1700 nm可调的量子点材料。其次，在不同ZnO纳米材料制备的基础上，进一步研究了量子点和ZnO纳米材料形成的复合结构及其光学特性。最后，利用制备的CdSe和PbS量子点材料制备了太阳能电池，通过研究量子点太阳能电池的制备和特性，探索了量子点与氧化物纳米结构的相互作用规律及其纳米复合结构在光电转换过程中的作用与内在联系。