POST-DEPOSITION ANNEALING IN Cu_2ZnSnS_4 THIN FILM SOLAR CELLS and its impact on device PERFORMANCE - (PPT)

摘要

In this work we present an optimization of the post-deposition annealing, in Cu_2ZnSnS_4 (CZTS) thin film solar cells, applied at different stages of the solar cell preparation, namely, bare CZTS absorber, CZTS/CdS heterojunction and CZTS/CdS/i-ZnO/ITO complete solar cell. The optimum post-deposition annealing for CZTS is at 300°C for 15 mins and at atmospheric pressure. The highest efficiency gain was obtained when the absorber layer composition is close to the ideal one and when a single annealing step is performed on complete solar cells, where, we obtained efficiency improvements from below 1% to 6.6%. Despite the observed improvement in device performance for annealing at intermediate stages it is, however, less pronounced than for full cell annealing. In this process we demonstrate cell performance improvements by a factor of 47.