Enhancing performance of tin-based perovskite solar cells by polyvinyl pyrrolidone doping strategy

The power conversion efficiency (PCE) of tin-based perovskite solar cells (TPSCs) was significantly improved when polyvinyl pyrrolidone (PVP) was doped into the formamidinium tin iodide (FASnI(3)) layer with an optimized doping mass. After doping, the FASnI(3) grain size, film smoothness and average carrier lifetime were largely enhanced, which demonstrate the crystallization quality improvement to FASnI(3). The champion PCE of the enhanced TPSC was improved to 7.83%, which is relatively 27% larger than that of the control, 6.15%. After continuous storage for 15 days, the PCE of the enhanced TPSC remained 74.4% of its original value. Using the finite difference time domain (FDTD) simulation method, we demonstrated that the light absorption ratio of the FASnI(3):PVP layer was larger than that of the FASnI(3) , and the photo-generated carrier density of the enhanced TPSC was approximately 2% similar to 3% larger than that of the control. The ultimate efficiency of the enhanced TPSC was calculated to be 26.23%. It is potential to dope PVP into FASnI(3) to further enhance the device performance of TPSCs.