Self‐Powered and Broadband Photodetectors Based on High‐performance Mixed Dimensional Sb₂O₃/PdTe₂/Si Heterojunction for Multiplex Environmental Monitoring

Abstract

Solar‐blind ultraviolet (SBUV) to near‐infrared (NIR) broadband photodetectors (BB‐PD) have important applications in environmental monitoring and other applications. However, it is challenging to prepare SBUV–IR photosensitive materials via simple steps and to construct SBUV–IR broadband devices for multiplex detection with high sensitivity at different wavelengths. Here, self‐powered and broadband photodetectors using a high‐performance mixed dimensional Sb2O3 nanorod 1‐dimension (1D)/monodisperse microdiamond‐like PdTe2 3‐dimension (3D)/Si (3D) heterojunction for multiplex detection of environmental pollutants with high sensitivity at broadband wavelength are developed. The 1D/3D mixed dimensional Sb2O3/PdTe2/Si structure combines the advantages of strong light absorption, high carrier transport efficiency of 1D Sb2O3 nanorods, and expansion of interface barrier caused by 3D microdiamond‐like PdTe2 interlayer to improve the photocurrent density and self‐powered ability. The efficient photogenerated charge separation enables anon/off ratio of more than 5 × 106. The device exhibits excellent photoelectric properties from 255 to 980 nm with the responsivity from 4.56 × 10−2 to 6.55 × 10−1 AW−1, the detectivity from 2.36 × 1012 to 3.39 × 1013 Jones, and the sensitivity from 3.90 × 107 to 1.10 × 1010 cm2 W−1 without external bias. Finally, the proposed device is applied for the multiplex monitoring of environmental pollution gases NO2 with the detection limit of 200 ppb and PM2.5 particles at mild pollution at broadband wavelength. The proposed BB‐PD has great potential for multiplex detection of environmental pollutants and other analytes at broadband wavelength.