Highly Stable Perovskite Solar Cells with Protective Layers Obtained via Interfacial Modification

Currently, achieving both high efficiency and long-term stability is crucial for the successful application of perovskite solar cells (PSCs). Grain boundary (GB) defects significantly impact the stability of PSCs, and passivating these GBs remains a major challenge. Herein, the surfactant dodecyltrimethylammonium chloride (DTAC) is dissolved in low-polarity chlorobenzene (CB) at 58 °C to modify the interface of MAPbI 3 film, and DTAC reacts with MAPbI 3 film surface to generate a protective layer that can be covered on the perovskite grains, effectively reducing the expose GBs. Additionally, the hydrophobic alkyl chains of DTA + and the strong chemical bond between the Cl − and Pb 2+ ions further enhance the resistance of the perovskite surface layer to heat, moisture, and oxidation. Due to the passivation of iodine vacancy defects, the photo-stability of unencapsulated DTAC devices is significantly improved. By passivating surface and GBs defects of the MAPbI 3 perovskite crystals, the power conversion efficiency of the low-temperature carbon-based PSCs treated by DTAC is 15.03% compared to 13.97% for the control device. This study offers another referable strategy for enhancing the thermal, moisture, light, and oxygen stability of perovskite materials while considering the photovoltaic performance of devices.