Van Der Waals Hybrid Perovskite of High Optical Quality by Chemical Vapor Deposition

Abstract 2D hybrid perovksite (RNH₃)₂PbX₄ materials not only serve as ideal platforms to study fundamental physics such as polariton dynamics but also show promise for optoelectronic and electro‐optic applications. However, for the preparation of high optical quality crystals, mechanical exfoliation has to be applied in the past. In this work, the vapor phase growth of single crystalline (C₄H₉NH₃)₂PbI₄ flakes with high optical quality is reported. Individual single crystalline domains show lateral size about 5–10 µm with defined rectangular shape. Spectroscopic studies show room temperature photoluminescence full width at half maximum of 70 meV and decay lifetime of several nanoseconds, indicating comparably high quality with mechanically exfoliated counterparts. Exciton binding energy 279 ± 46 meV and electron–phonon coupling strength around 20 meV are revealed. This vacuum‐based method may provide a solution for integrating layered perovskites into optoelectronic devices and systems.