Surface Engineering of Halide Perovskites with 2D Covalent Organic Framework Nanoparticles for Surface-Enhanced Gas Capture with Ultra-sensitive Sensing Properties

Abstract Halide perovskites exhibit excellent semiconductor properties, defect insensitivity, and easy processability, making them promising candidates for detecting ultralow-concentration gases. However, as bipolar semiconductors, perovskites can respond to gases with different properties, which has inhibited their applicability in gas sensing. Here, we propose a novel approach to enhance the gas selectivity and sensitivity of halide perovskites by effectively assembling covalent organic framework nanoparticles with large specific surface areas and abundant active sites on their surfaces. This modification enhances the gas-carrying capacity of the sensing material, thereby significantly improving the selectivity and sensitivity of the sensor. Using TAPB-PDA and TAPA-PDA covalent organic framework nanoparticles to adsorb low concentrations of NO2 present in the environment, we observed a substantial increase in the sensing signal intensity. This allows the direct discrimination of ultra-low concentrations (10 ppb) of NO2 while limiting the detection of other gases.