Theoretical analysis of doping of perovskite light-absorbing layer for highly efficient perovskite solar cells

The physical properties of perovskites—the central components of perovskite solar cells (PSCs)—are crucial for photovoltaic (PV) performance. Suitable doping of perovskites can improve the electric-field distribution within them, thus enhancing their PV performance. In this study, the effects of the three doping strategies on PV performance of MAPbI3 based PSCs were explored. First, uniform acceptor doping of perovskite was performed. With increasing uniform acceptor doping concentration (NA), the open-circuit voltage (VOC) gradually increased, but the short-circuit current density (JSC) decreased. As the decline in JSC limited further PCE increase, non-uniform acceptor doping of perovskite was performed, which increased the width of the space-charge region near the MAPbI3/SnO2 interface, promoting the flow of holes from MAPbI3 to the carbon electrode. The JSC increased from 19.05 to 22.30 mA cm−2, and the power conversion efficiency (PCE) increased from 19.74 % to 22.72 % when the doping concentration curve for non-uniform acceptor doping was a line passing through 3×1018 and 3×1014. In order to further enhance the PCE, simultaneous non-uniform acceptor doping and uniform donor doping of perovskite was adopted, which further improved the JSC and fill factor (FF), and the PCE increased from 22.72 % to 23.92 % when the uniform donor doping concentration was 1×1018 cm−3. This work provides a strategy of doping of perovskite for highly efficient PSCs.