Boosting the kesterite Cu2ZnSnS4 solar cells performance by diode laser annealing

Abstract In this work, a novel diode laser annealing was performed as a post-sulfurization heat treatment on pure-sulfide Cu 2 ZnSnS 4 thin film solar cells fabricated by sputtering deposition. The effect on both film quality and device performance after annealing at various laser doses was investigated. After receiving an ultra-fast laser scan treatment, the crystallinity of the CZTS film can be improved and the Cu/Zn disordering is reduced. The power conversion efficiency of the laser annealed device was boosted to 7.33%, compared with the reference cell efficiency of 6.72%. The major increase in the short circuit current is driving force of such improvement, from 18 mA/cm 2 to 19.31 mA/cm 2 after laser treatment. These results indicate that the quality of CZTS thin films and the device performance can be effectively improved by the diode laser annealing.