[en] Despite their advantageous attributes, such as a narrow bandgap and reduced toxicity, tin-lead halide perovskites (TLHPs) have received limited attention due to their lower power conversion efficiency (PCE) relative to lead-only variants. In this study, a transformative approach is introduced that leverages perovskite quantum dots (PQDs) to optimize TLHP solar cells. While conventional oleyl-capped PQDs enhance the open circuit voltage (V${}_{OC}$), the long-chain ligands hinder charge transport. To overcome this limitation, a post-treatment with isopropyl alcohol effectively dissociates these ligands and PQD crystals, resulting in reduced defect density, improved charge transfer, and elevated quasi-Fermi level splitting in the TLHP device. Consequently, the PCE of the device is notably increased from 19.0% to 23.74% and elevated the V${}_{OC}$ from 0.78 to 0.87 V, without compromising the photocurrent or fill factor. The findings highlight PQD modification as a compelling avenue for TLHP solar cell enhancement, particularly in boosting V${}_{OC}$. (© 2024 Wiley‐VCH GmbH)