n-ZnO:Al/i-ZnO/n-CdS/p-Cu2ZnSnS4太阳能电池光伏特性的分析

具有高光吸收系数的半导体Cu₂ZnSnS₄ (CZTS)薄膜是一种新型太阳能电池材料. 本文对n-ZnO:Al/i-ZnO/n-CdS/p-CZTS结构的CZTS薄膜太阳能电池进行分析, 讨论CZTS薄膜的掺杂浓度、厚度、缺陷态和CdS薄膜的掺杂浓度、 厚度对太阳能电池转换效率的影响以及太阳能电池的温度特性. 分析表明, CZTS薄膜作为太阳能电池的主要光吸收层, CZTS薄膜的掺杂浓度和厚度的取值对太阳能电池的转换效率有显著影响, CZTS薄膜结构缺陷态的存在会导致太阳能电池性能的下降. CdS缓冲层的掺杂浓度、厚度对太阳能电池光伏特性的影响较小. 经结构参数优化得到的n-ZnO:Al/i-ZnO/n-CdS/p-CZTS薄膜太阳能电池的最佳光 伏特性为开路电压1.127 V、短路电流密度27.39 mA/cm²、填充因子87.5%、 转换效率27.02%,转换效率温度系数为-0.14%/K.

Investigation of the photovoltaic performance of n-ZnO:Al/i-ZnO/n-CdS/p-Cu2ZnSnS4 solar cell

The semiconducting Cu₂ZnSnS₄ (CZTS) thin film with high absorption coefficient has long been recognized as a novel solar cell material. In this work, the performances of n-ZnO:Al/i-ZnO/n-CdS/p-CZTS solar cells are analyzed by using semiconductor theory. The influences of doping concentration, thickness, and defect states of CZTS layer and the doping concentration and thickness of CdS layer on the performances of the solar cells and the temperature characteristics are investigated. The calculated results show that the CZTS layer is a main absorption layer in the solar cell. The changes in doping concentration and thickness of CZTS layer have significant influence on the conversion efficiency of the solar cell. The density of defect states in CZTS can sharply degrade the photovoltaic performances. The influences of the doping concentration and thickness of CdS layer can be neglected. The calculated results show that the optimal n-ZnO:Al/i-ZnO/n-CdS/p-CZTS structure has open-circuit voltage of 1.127 V, short circuit current density of 27.39 mA/cm², fill factor of 87.5%, and conversion efficiency of 27.02%. In addition, the temperature gradient of conversion efficiency is -0.14%/K. These results reveal the promising photovoltaic characteristics of CZTS thin film serving as a solar cell absorber.