Perovskite/La-BDC heterojunction enhances the performance of carbon-based perovskite solar cells

Carbon-based Perovskite Solar Cells (C-PSCs) present a promising avenue for enhancing the stability and commercialization of PSCs. However, the power conversion efficiency (PCE) of C-PSCs still lags behind that of metal-based PSCs. In this study, La-BDC (La-MOF prepared by La3+ and ligand H2BDC) has successfully synthesized using a simple hydrothermal method and then directly introduced into CH3NH3PbI3 (MAPbI3) perovskite precursor solution to prepare perovskite/La-BDC heterojunction structure with remarkable properties in light absorption, hydrophobicity, and crystallinity. By incorporating this structure, the PCE of C-PSCs with an FTO/SnO2/MAPbI3/La-BDC/Carbon architecture was effectively enhanced. The presence of CO functional group in La-BDC effectively reduced interface defects while improving carrier separation efficiency, and successfully passivated the free Pb2+ ions within the perovskite. Remarkably, the La-BDC-based device achieved a superior PCE of 14.95%, surpassing the pristine device's PCE by an impressive margin of 20.37%. Moreover, even after a 31 days period of air storage (temperature range of 15–25℃, humidity range of 15–30%), the La-BDC-based devices maintained over 90% of the initial performance, demonstrating excellent stability. This study provides a facile and effective strategy for improving the PCE and stability of C-PSCs through implementing a La-BDC heterojunction structure， and provides a new idea for MOF materials in the field of PSCs. •Hydrothermal synthesis was used to create La-BDC MOF nanocomposites.•Light absorption and hydrophobic qualities were improved by adding La-BDC.•CO group in La-BDC passivates free Pb2+ ions and reduces interface defects.•C-PSCs with La-BDC achieved an efficiency increase of over 20.37%.•The La-BDC-based device maintained more than 90% of its initial performance.