A Functional Biological Molecule Restores the PbI₂ Residue-Induced Defects in Two-Step Fabricated Perovskites

Coating the perovskite layer via a two-step method is an adaptable solution for industries compared to the anti-solvent process. But what about the impact of unreacted PbI₂? Usually, it is generated during perovskite conversion in a two-step method and considered beneficial within the grain boundaries, while also being accused of enhancing the interface defects and nonradiative recombination. Several additives are mixed in PbI₂ precursors for the purpose of improving the perovskite crystallinity and hindering the Pb²⁺ defects. Herein, in lieu of adding additives to the PbI₂, the effects of the PbI₂ residue via the electron transport layer/perovskite interface modification are explored. Consequently, by introducing artemisinin decorated with hydrophobic alkyl units and a ketone group, it reduces the residual PbI₂ and improves the perovskites' crystallinity by coordinating with Pb²⁺. In addition, artemisinin-deposited perovskite enhances both the stability and efficiency of perovskite solar cells by suppressing nonradiative recombination.