Solvothermal synthesis of cesium lead halide perovskite nanowires with ultra-high aspect ratios for high-performance photodetectors

Abstract

One-dimensional (1D) inorganic perovskite nanowires (NWs) have attracted promising attention for application in the fields of photodetection, lasers and lighting due to their outstanding optoelectronic properties. However the direct synthesis of highly pure all-inorganic perovskite NWs with well-defined morphologies and compositions still remains challenging. Here we report the controllable synthesis of brightly emitting cesium lead halide CsPbX₃ (X = Cl, Br) NWs and their assembly into high-performance photodetector nanodevices. High quality CsPbX₃ NWs have been directly synthesized via a solvothermal method without using post-synthetic anion-exchange reactions. The NWs are single-crystalline, with uniform diameters of ∼10 nm and lengths of up to tens of microns, showing ultra-high aspect ratios. Both CsPbCl₃ and CsPbBr₃ NWs show excellent photoluminescence (PL) characteristics with narrow emission spectra and high PL quantum yields (PLQYs). The photodetectors constructed on the CsPbX₃ NWs and interdigital electrodes (with interdigitation widths up to 100 μm) exhibit promising photoelectric properties, achieving high switching ratios (5.8 × 10³ for CsPbCl₃ NW devices and 1.1 × 10³ for CsPbBr₃ NW devices) and fast response time. The present solvothermal approach is controllable, convenient, and is easily realized for quantifiable preparation, and can further promote the application of the all-inorganic perovskite NWs in the optoelectronic field.