Multinary alloys, such as Cu2ZnSnS4 and recently discovered ABX3, are  the most promising absorber materials for thin-film solar cells, since it is a low-cost material with the optimal band gap 1.5 eV for single-junction solar cells and a high adsorption coefficient.  Although the synthesize of such compound could be long time ago, due to the complicity of these multinary compound, the properties are not well understood, which are crucial for improving the solar cell performance.  In this talk, I will focus on the defect properties of Cu2ZnSnS4 and ABX3, the intrinsic point defects and also complex defects. The dominant defect in CZTS will be p-type CuZn antisite, which has an acceptor level deeper than the Cu vacancy. We proposed that CuZn+SnZn and 2CuZn+SnZn defect complex could be detrimental to efficiency, with a small Voc. We predicted the possible reconstruction configurations of the frequently observed cation-terminated (112) and anion-terminated () surfaces, and found that the polar surfaces are stabilized by the charge-compensating defects, such as vacancies (VCu, VZn), antisites (ZnCu, ZnSn, SnZn) and defect clusters (CuZn+CuSn, VZn+2VCu). I will also show the defect properties of the ABX3, which is important to understand its high efficiencyThe work is collaborated with Shiyou Chen, Peng Xu, Hongjun Xiang and Suhuai Wei

Defect and surface properties of of multinary alloys for solar energy absorber

248th National Meeting (2014)

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