Enhanced stability and optoelectronic properties of MAPbI3 films by a cationic surface-active agent for perovskite solar cells

The insufficient stability of perovskite solar cells (PSCs) has considerably restrained their development and applications. Herein, we demonstrate an approach to prepare PSCs with high stability and efficiency by adding n-octyltrimethylammonium bromide (OTAB) to the precursor solution. In the resultant films, the charge trap density exhibits a significant reduction, and the long-term stability shows a remarkable enhancement. Upon adding 0.5 mg mL−1 OTAB, the power conversion efficiency (PCE) of PSCs reaches 18.32% under simulated AM 1.5G solar illumination, which represents an increase of 16% compared to the pristine devices. Moreover, the OTAB-modified devices demonstrate excellent performances both in high-temperature (70 °C, 40 ± 5% relative humidity) and high-humidity (25 °C, 75 ± 5% relative humidity) environments. These results indicate a very promising approach to improve the comprehensive performance of PSCs.