Synthesis and Characterization of Organic−Inorganic Perovskite Thin Films Prepared Using a Versatile Two-Step Dipping Technique

Abstract

A convenient two-step technique for preparing thin films of the organic−inorganic perovskites (RNH3)2(CH3NH3)n-1MnI3n+1 (R = butyl, phenethyl; M = Pb, Sn; n = 1, 2, ∞) has been achieved. Films of the metal halide, MI2, were first deposited onto ash glass or quartz disks using vacuum evaporation or spin-coating. By dipping these inorganic films, at room temperature, into an organic ammonium iodide solution for a short period of time (1−5 min for the layered perovskites), single-phase samples of the corresponding organic−inorganic perovskite thin films were formed. While a variety of solvents can be used for the dipping process, toluene/2-propanol mixtures have been shown to work well for many of the present compounds. The layered organic−inorganic perovskite films exhibited uniform surfaces and strong photoluminescence at wavelengths that were consistent with the corresponding materials made by single-crystal growth from solution. However, dipped organic−inorganic films made from evaporated PbI2 exhibited ...