Flexible Solar Cells: Impact of Na Doping on the Carrier Transport Path in Polycrystalline Flexible Cu 2 ZnSn(S,Se) 4 Solar Cells (Adv. Sci. 21/2020)

In article number 1903085, Woo‐Lim Jeong, Kyung‐Pil Kim, Dong‐Seon Lee, and co‐workers analyze the effects of Na doping on polycrystalline flexible CZTSSe solar cells. When doping is excessive, a device shows low contact potential difference and fill factor and selects a worse carrier transport path even though the built‐in potential becomes stronger. On the other hand, the optimized CZTSSe solar cell clearly showed the enhancing effect of Na doping. [Image: see text]