Effect of pre-annealing on Cu2ZnSnSe4 thin-film solar cells prepared from stacked Zn/Cu/Sn metal precursors

The effects of pre-annealing the stacked metallic precursor (Zn/Cu/Sn/Mo/glass) on the structural and morphological properties of the resultant Cu2ZnSnSe4 (CZTSe) thin films and their device properties were investigated. The crystalline quality and morphology of the CZTSe thin films were enhanced by the pre-annealing treatment. The pre-annealed CZTSe solar cells showed an improved conversion efficiency η of 7.02% compared with those that were not pre-annealed (η=5.65%). This enhancement in solar cell performance was mainly attributed to an improvement in shunt resistance (Rsh) from 80 to 150 Ω cm2, which resulted in improvements in open-circuit voltage and fill factor.