New Dication-Based Lead-Deficient 3D MAPbI3 and FAPbI3 “d-HPs” Perovskites with Enhanced Stability

Toxicity induced by the presence of lead and the rather poor stability of halide perovskite semiconductors represent the major issues for their large-scale application. We previously reported a new family of lead- and iodide-deficient MAPbI₃ and FAPbI₃ perovskites called d-HPs (for lead- and iodide-deficient halide perovskites) based on two organic cations: hydroxyethylammonium HO-(CH₂)₂-NH₃⁺ (HEA⁺) and thioethylammonium HS-(CH₂)₂-NH₃⁺ (TEA⁺). In this article, we report the use of an organic dication, 2-hydroxypropane-1,3-diaminium (2-propanol 1,3 diammonium), named PDA²⁺, to create new 3D d-HPs based on the MAPbI₃ and FAPbI₃ network with general formulations of (PDA)_0,88x(MA)_1-0,76x[Pb_1-xI_3-x] and (PDA)_1,11x(FA)_1-1,22x[Pb_1-xI_3-x], respectively. These d-HPs have been successfully synthesized as crystals, powders, and thin films and exhibit improved air stability compared to their reference MAPbI₃ and FAPbI₃ perovskite counterparts. PDA²⁺-based deficient MAPbI₃ was also tested in operational perovskite solar cells and exhibited an efficiency of 13.0% with enhanced stability.