面向硅基叠层电池应用的硒化镉(CdSe)太阳能电池研究

构建多结叠层太阳能电池是突破Shockley-Queisser效率极限最可行的途径。双结硅基太阳能电池的理论效率高达45%，其顶层太阳能电池的光吸收材料最佳带隙为1.7eV。现有1.7eV带隙的光伏材料存在成本昂贵或稳定性不足等问题，难以满足低价、长期稳定的商业化需求。硒化镉（CdSe）禁带宽度合适（1.72eV），材料吸光系数大（>105 cm-1）、迁移率高（500 cm2 V-1 s-1），单结电池理论效率可达28%。同时，其储量丰富、组分简单、稳定性高，且能兼容碲化镉太阳能制备技术，非常适合制备太阳能电池并与晶硅叠层应用，但薄膜缺陷和器件界面复合导致的转换效率低的难题亟待解决。申请人前期已经取得了效率4%的CdSe太阳能电池，本项目拟阐明CdSe缺陷调控的微观机理，结合薄膜缺陷钝化和器件协同优化，获得效率>10%的CdSe太阳能电池，为叠层太阳能电池的研究提供备选方案。

Constructing a multi-junction solar cell is a feasible way to surpass the Shockley-Queisser efficiency limit. Theoretically, silicon-based tandem solar cells can achieve 45% efficiency in conjunction with a top cell that has an optimal bandgap of 1.7 eV. The existing photovoltaic materials with a 1.7 eV bandgap have problems such as high-cost or poor-stability, making it difficult to meet the demand for low-cost, long-term stable photovoltaic power. Cadmium selenide (CdSe) is such a very promising absorber material for Si-based solar cells due to its suitable bandgap (1.72 eV, theoretical efficiency of up to 28%), high absorption coefficient (>105 cm-1), high mobility (500 cm2 V-1 s-1) and high stability. Moreover, CdSe is relatively earth-abundant and compatible with the preparation technology of CdTe solar cells. However, the low efficiency caused by film defects and interface recombination is urgent to be addressed. Previously, the applicant has obtained an efficiency of 4% in CdSe solar cells. This project aims to elucidate the microscopic mechanism of CdSe defect passivation based on the defect theory. We will focus on defect passivation and device optimization to achieve an efficiency of >10% in CdSe thin-film solar cells, providing alternatives for tandem solar cells.