Naphthylmethylamine post-treatment of MAPbI3 perovskite solar cells with simultaneous defect passivation and stability improvement

Abstract The surfaces of perovskite films are vulnerable to the moisture in the surroundings, and surface passivation is a widely accessible technique to solve this problem. Here, we report an effective strategy to improve the stability and photovoltaic performance of MAPbI3 perovskite solar cells by surface passivation with Naphthylmethylamine (NMA). The solar cell devices without NMA showed a highest power conversion efficiency (PCE) of 18.4%, while the devices with NMA achieved a highest PCE of 19.4% under the same conditions. The reduced trap density and enhanced recombination resistance are thought to be the main reasons for the improved photovoltaic performance. Moreover, the long-term stability of the passivated solar cell devices was also greatly enhanced. The NMA-treated device maintained 90% of its original PCE after 90 days storage at a relative humidity of 60% and 25 °C, while the device without NMA only maintained 72% of its original PCE under the same conditions.