Quasi-Two-Dimensional Halide Perovskite Single Crystal Photodetector

The robust material stability of the quasi-two-dimensional (quasi-2D) metal halide perovskites has opened the possibility for their usage instead of three-dimensional (3D) perovskites. Further, devices based on large area single crystal membranes have shown increasing promise for photoelectronic applications. However, growing inch-scale quasi-2D perovskite single crystal membranes (quasi-2D PSCMs) has been fundamentally challenging. Here we report a fast synthetic method for synthesizing inch-scale quasi-2D PSCMs, namely (C4H9NH3)n(CH3NH3)n−1PbnI3n+1 (index n = 1, 2, 3, 4, and ∞), and demonstrate their application in a single-crystal photodetector. A quasi-2D PSCM has been grown at the water–air interface where spontaneous alignment of alkylammonium cations and high chemical potentials enable uniform orientation and fast in-plane growth. Structural, optical, and electrical characterizations have been conducted as a function of quantum well thickness, which is determined by the index n. It is shown that th...