Enhancement of Conversion Efficiency of Cu2ZnSnS4 Thin Film Solar Cells by Improvement of Sulfurization Conditions

To enhance the conversion efficiency of Cu2ZnSnS4 (CZTS) thin film solar cells prepared by the sulfurization method, we investigated the formation process of the CZTS thin film. The holding temperature of the sulfurization was 580 degrees C. This study showed that the spreading resistance (SR) of the CZTS layer strongly depends on the holding time of the sulfurization. At the intermediate holding time (similar to 30 min), the SR of the CZTS layer came to a minimum, and the efficiency of the CZTS solar cell came to a maximum. A 7.6% efficiency CZTS solar cell without a high-resistance buffer layer and an antireflection coating was fabricated. (C) 2013 The Japan Society of Applied Physics