Optimizing the window layer for achieving over 10% efficient Cu2ZnSn(S,Se)4 solar cells
Indium tin oxide (ITO) and intrinsic ZnO (i-ZnO) are usually used as the window layer of Cu 2 ZnSn(S,Se) 4 (CZTSSe) solar cells within a typical structure. The optoelectronic properties of the window layer play a crucial role in determining the efficiency of solar cells. In this work, two types of CZTSSe solar cells with and without i-ZnO layers were fabricated using dimethyl sulfoxide (DMSO) and dimethylformamide (DMF) as solvents, respectively. The impact of the window layer on the performance of CZTSSe solar cells was investigated. The results suggest that the device without i-ZnO still exhibits a high power conversion efficiency (PCE) compared to conventional bilayer i-ZnO/ITO structures. By removing i-ZnO and optimizing the thickness of ITO, the highest power conversion efficiency (PCE) of DMSO and DMF-based CZTSSe solar cells has been up to 10.17% and 10.27%, respectively, with an increase in open-circuit voltage (V OC ) of 15 mV (in DMSO system) and 10 mV (in DMF system), as well as an enhancement in fill factor (FF) by ∼5 percentage points. These performance improvements are mainly attributed to the reduction of series resistance (R s ) of the window layer due to the removal of i-ZnO layer. Further analysis shows that the generation and collection of photon-generated carriers in CZTSSe solar cells can be affected by the optimized window layer due to optical interference effects and its resistance. Our research may provide insights for the preparation of high efficient CZTSSe solar cells with new structures of the i-ZnO free window layer.
危险品化学品经营许可证（带存储）