铜铟硒与铜铟硫太阳能电池中有序缺陷化合物的性质及对能带偏移的影响

摘要

The crystal structure of the ordered defect compound (ODC) CuIn5S8 was established and its properties were studied and compared with CuInS2. Further, ZnSe and CuI were chosen as the buffer layers of CuInSe2 and CuInS2 solar cells respectively. The valence band offset (VBO) was calculated based on the first principle calculation. On the ZnSe/CIS interface, the valence band maximum (VBM) of CIS was higher than that of ZnS with a VBO by about 0. 52 eV due to a larger p-d repulsion in CIS. On the CuI/CuInS2 interface, VBM of CuI was lower than that of CuInS2 with a VBO of about 0.37 eV. The p-d repulsion was much weaker in ODC compared with CuInSe2 and CuInS2, resulting in a lower VBM.%利用第一性原理模拟计算铜铟硒(CIS)太阳能电池CIS吸收层,及CIS中普遍存在的有序缺陷化合物(ordered defect compound,ODC) CuIn5 Se8的性质.依据CuIn5Se8形成的方式,结合对称性越高、能量越低的原则,建立CuInS2中的ODC-CuIn5S8结构,并从态密度角度讨论CuInS2与CuIn5S8的差异.分别选用ZnSe和CuI半导体作为CIS和CuInS2电池的缓冲层,利用第一性原理计算得到价带偏移(valence band offset,VBO).在ZnSe/CIS界面处,CIS的价带顶(valence band maximum,VBM)比ZnSe高0.52 eV；在CuI/CuInS2界面处,CuI的价带顶比CuInS2低0.37 eV,表明CuI非常适合应用于CuInS2电池缓冲层.ODC中由于Cu的缺失,其d轨道电子和阴离子p轨道电子的p-d排斥力减小,使ODC材料的价带顶相对于自身本征材料有所下降.