Improved performance and stability of perovskite solar cells by incorporating silicon quantum dots within the FAPbI3 active layer

Embedding inorganic quantum dots (iQDs) within the perovskite absorber offers a promising route to improve both efficiency and stability in perovskite solar cells (PSCs). Due to the defect-tolerant nature of lead halide perovskites, iQDs can be incorporated within crystal grains without degrading performance, while contributing their unique optoelectronic properties. In this study, silicon quantum dots (SiQDs) are embedded into perovskite films to form high-quality hybrid thin films. Prior to forming the hybrid film, a femtosecond laser-based surface engineering (SE) technique is used to fragment SiQDs into highly dispersed, stable, ultrasmall particles (≈2 nm). Incorporation of SE-treated SiQDs (SE-SiQDs) into the perovskite layer reduces the density of shallow traps and improves carrier transport. A substantial decrease in residual lead iodide (PbI2) is observed at the film surface, and modulation of the Fermi level is achieved through SiQD incorporation. PSCs incorporating SE-SiQDs exhibit a fill factor exceeding 80% and a power conversion efficiency above 20% (active area: 0.23 cm2), along with enhanced long-term operational stability.