Polyiodide-assisted fabrication of hybrid perovskite thin films from lead nanolayers on flexible substrates

Abstract Despite remarkable progress in solvent-assisted processing of hybrid perovskite thin films, the scalable fabrication of their uniform and pin-hole free layers remains a difficult task, especially on flexible substrates. In contrast, we have demonstrated that the polyiodide-assisted conversion of Pb nanolayers into MAPbI 3 results in the formation of crystalline MAPbI 3 thin films on large flexible substrates already at room temperature. The exposure of stoichiometric Pb/MAI bilayers to iodine vapor leads to the formation of highly reactive polyiodide melts MAI 3(L) , which instantly react with the Pb nanolayers converting them into pure MAPbI 3 films without byproducts or unreacted components.