Enhanced Performance of Perovskite Solar Cells via Reactive Post-treatment Process Utilizing Guanidine Acetate as Interface Modifier

摘要

Organic–inorganic lead halide perovskites (OIHPs) have emerged as promisingmaterials for next-generation photovoltaics. However, performance improvementsin the perovskite-based device are still limited due to defects that existmore intensively on the surface as well as grain boundaries (GBs) and mismatchingenergy levels at the interface. Herein, a reactive post-treatment process(RPP) using guanidine acetate (GA) is adopted to address defects and interfacialenergy level matching at the perovskite surface. The RPP with GA (GA-RPP)results in the formation of an improved perovskite layer with large grain size andlow GB density, leading to the formation of secondary phases on the perovskitesurface with appropriate energy levels, resulting in reduced defect density andcharge recombination. Furthermore, density functional theory analysis revealsthat the Pb-rich secondary phase could improve the conduction of electrons atthe perovskite interface. Therefore, the GA-RPP-based perovskite-based solar cell(PSC) shows enhanced performance with 20.4% efficiency and long-termstability.