Quantum Dot Strategies Toward Performance Improvement of Perovskite Solar Cells

Perovskite solar cells (PSCs) have reached certified efficiencies exceeding 26%, yet the gap to the Shockley-Queisser limit and insufficient operational stability remain key obstacles to commercialization. Quantum dots (QDs) offer a versatile platform to address both challenges through their size-tunable bandgaps, high photoluminescence yields, and solution processability. This review systematically examines four QD integration strategies in PSCs: transport layer modification, active layer doping, UV conversion layers, and tandem sub-cells. The underlying mechanisms-including defect passivation, energy-level engineering, crystallization control, and ion migration suppression-are critically compared across these approaches. Despite significant advances, challenges persist, including the ligand-charge transport trade-off, the environmental toxicity of Pb/Cd-containing QDs, poor reproducibility, and the absence of standardized stability testing protocols. By providing a mechanism-oriented assessment across all device components, this review offers a clear framework for selecting appropriate QD strategies and identifies priority research directions. The perspective of QD strategies in this review provides a useful and significant reference for approaching the theoretical PCE limits of single-junction PSCs by reducing non-radiative recombination and improving light utilization, while QD-based tandem architectures offer a viable route toward surpassing the single-junction Shockley-Queisser limit.