Two-dimensional (PEA)2PbBr4 perovskite single crystals for a high performance UV-detector

Abstract

Two-dimensional (2D) metal halide perovskites have shown great potential in high performance optoelectronic applications due to their intrinsic quantum well structure, enhanced moisture- and photo-stability. Unfortunately, there is still no effective method to produce large-size 2D hybrid perovskite single crystals, and consequently there is lack of research on its optoelectronic applications. Herein, we report the utilization of a controlled evaporation process to grow well-defined large-size (>200 mm²) 2D (PEA)₂PbBr₄ (C₆H₅CH₂CH₂NH₃⁺, PEA⁺) single crystals. Upon careful examination of the crystal growth kinetics, it was found that the optimum temperature for the growth of (PEA)₂PbBr₄ single crystal wafer was 23 ± 0.5 °C. The wafers that were harvested showed high mu-tau (μτ) product, superior environmental stability and irradiation resistance. Furthermore, an array of planar-type UV photodetectors were designed and fabricated with extremely low dark current (∼10⁻¹³ A), large ON/OFF current ratio (∼10⁵), very high specific detectivity (∼10¹³ cm Hz^1/2 W⁻¹) and fast response rate (∼0.4 ms). All the above performance data are among the best achieved compared to those of the state-of-the-art materials including ZnO, TiO₂ and GaN in the field. It makes us believe that the availability of these materials may pave the way for ultrafast optical computing and optical communications.