Method to enhance the kesterite solar cell performance

A method for obtaining a photovoltaic kesterite thin-film solar cell including:

• arranging a kesterite film,
• preparing a substrate,
• depositing said kesterite film on said substrate,
• adding a doping cadmium chloride solution dropwise, after the deposition of said kesterite film on said substrate, wherein the step of adding the doping cadmium chloride solution dropwise introduces impurities into the kesterite film, and
• depositing a buffer layer, wherein the buffer layer comprises a CdS buffer layer deposited by chemical bath deposition after said step of adding said doping cadmium chloride solution,
• wherein the step of depositing the CdS buffer layer comprises providing 10 to 30 ml of cadmium acetate dihydrate (Cd(CH3COO)2 2H2O), 5 to 20 ml of thiourea, 10 to 30 ml of ammonia solution (NH4OH, 20%) and 100 to 300 ml of distilled water to form a combined solution.