Low-temperature solution-based processing to 7.24% efficient superstrate CuInS2 solar cells

The fabrication of high performance, solution-processed CIGS family solar cells is based on high-temperature crystallization processes in chalcogen-containing atmosphere and/or using dangerous solvents like hydrazine. The non-hydrazine sulfurization- and selenization-free reports typically suffer from poor grain structures. We report a facile strategy to overcome grain growth limitations at very low temperature processing (250 °C). Selenium free Superstrate configuration CuInS2 (CIS) solar cells are fabricated using a nanocrystals ink which avoiding from high temperature selenization or/and sulfurization is targeted. We investigated the effect of intentional M doping (M = Sb, Zn, Cd and Sn) on structural, morphological and photovoltaic response of the fabricated CIS films. It is found that inserting of Sb and Zn leads to improve the CIS crystal growth and surface morphology. Compared with the performance of the non-doped CIS cell, the Sb-doped and Zn-doped CIS solar cell displayed a remarkable efficiency enhancement of 15% and 38%, respectively. The champion device showed promising PCE of 7.24% without any anti-reflection coating. To the best of our knowledge, the obtained eeficiency is the highest efficiency for any non-vacuum deposited CuIn(S,Se)2 superstrate solar cell to date.