DMF溶液法制备高效铜铟镓硒薄膜太阳能电池：富铜吸光材料的碱金属离子掺杂和表面后处理研究

低成本高效光伏技术是实现能源结构向低碳方向转型的关键。铜铟镓硒（CIGS）薄膜太阳能电池稳定性好、效率高、可柔性，是有望实现大规模应用的薄膜太阳能技术之一。然而目前商业化的CIGS电池的吸光层材料皆由真空法制备，无法充分发挥薄膜太阳能电池低成本优势；同时，理论研究表明富铜条件下制备的CIGS结晶度高，缺陷浓度低，具有更优异的光伏性能，这一点通过真空法还未能实现。本项目拟通过溶液法制备富铜CIGS薄膜实现低成本高效CIGS电池。将以二甲基甲酰胺（DMF）为溶剂、简单金属盐为前驱体化合物制备溶液和富铜CIGS薄膜，系统研究碱金属（Li, Na, K, Rb, Cs）离子掺杂和表面后处理（PDT）对富铜CIGS的组成、结晶性、缺陷态、晶界、表面性质和电池性能的影响及其作用机制。这些新策略有望将溶液法制备的CIGS电池效率提高到新的水平。

Low-cost and highly efficient photovoltaic is the key to realize the transition from fossil energy to clean energy. Copper indium gallium selenium thin film solar cells (CIGS) are one of the most promising technology to this goal due to their stability, high efficiency and flexibility. However, the current commercial CIGS solar cells are all fabricated from vacuum based methods, which cannot take full advantages of the thin film technology. In addition, theoretical calculation shows that Cu-rich CIGS contains less defects and has greatly potential to achieve better device efficiency than Cu-poor absorber, which has not been realized in vacuum based absorbers. In this project, we propose to explore new strategies to realize low-cost and highly efficient CIGS thin film solar cell by using solution processing to fabricate Cu-rich CIGS absorbers. We will systematically investigate the effect of alkali metal (Li, Na, K, Rb, Cs) doping and post-deposition treatment (PDT) on the composition, crystallinity, defects, grain boundaries, surface and junction property of Cu-rich absorber and the mechanism how the doping and PDT affect the device photovoltaic performance. These new strategies are expected to push the efficiency of solution processed CIGS solar cell to a new stage.