Solid‐State Ligand‐Exchange Fabrication of CH₃NH₃PbI₃ Capped PbS Quantum Dot Solar Cells

CH3NH3PbI3 capped PbS colloidal quantum dots have been successfully fabricated by solid-state ligand exchange from oleate and oleylamine capped PbS. The optimal solar cells made by layer-by-layer solution deposition give a high power conversion efficiency of 4.25% with an impressive short-circuit photocurrent density of 24.83 mA cm−2.