Bimetallic MOFs derivative LaFeO3@C for efficient and stable carbon-based perovskite solar cells

Carbon-based MAPbI3 perovskite solar cells (C-PSCs) have attracted significant attention due to their low cost and stable performance. However, due to inherent structural defects and an energy level mismatch between the perovskite layer and the carbon electrode, C-PSCs still show a poorer power conversion efficiency (PCE) than traditional perovskite solar cells (PSCs). In this study, LaFeO3@C nanocomposite particles were successfully synthesized via pyrolysis of La-containing MIL-100(Fe) MOF gel. By introducing these pre-synthesized LaFeO3@C bimetallic composite oxide nanoparticles into the carbon electrode, the device featuring a FTO/SnO2/CH3NH3PbI3/LaFeO3@C/C architecture achieved an impressive maximum PCE of 16.35%, surpassing that of the pristine device by 9.36%. The enhanced optoelectronic performance can be primarily attributed to enhanced interfacial contacts, superior interfacial charge extraction ability, and better electrical conductivity. The LaFeO3@C-based device maintained more than 90% of the initial PCE after being stored for 31 days at room temperature and ambient humidity. This study provides a novel strategy for the preparation of efficient and stable C-PSCs from the perspective of spatial structure regulation of bimetallic MOF-based composites.