High‐Efficiency Solar Cell Enabled by MAPbI ₃ Perovskite–PbS Nanostructure Stack: A Theoretical Design

This study proposes a perovskite solar cell architecture integrating quantum dots (QDs) to harness additional sub‐bandgap photons. A thin low‐bandgap (1.35 eV) PbS‐QD layer is embedded within a wide‐bandgap (1.6 eV) MAPbI 3 absorber, forming a quantum well (QW) structure. Acting as a broadband multi‐bandgap absorber, this design enables additional absorption of sub‐bandgap photons (1.35–1.6 eV), with carrier transport occurring via thermionic emission across the QW barrier. The standard p–i–n MAPbI 3 device achieved a simulated efficiency of 25.6%, while the QW‐integrated device reached 28.1%. These results highlight the potential of quantum well architectures to advance next‐generation high‐efficiency perovskite photovoltaics.