PEI/PEG functionalized Black Phosphorus prepared by a One-Pot method for a wide detection range CO2 gas sensor

Abstract

Black Phosphorus (BP) has attracted considerable attention in gas detection fields attributing to layer-dependent direct bandgap, and high carrier mobility. Currently, many researchers use blended polyethyleneimine/polyethylene-glycol (PEI/PEG) functionalized two-dimensional (2D) material to detect carbon dioxide (CO2). However, the detection rage of CO2 sensor based blended PEI/PEG functionalized 2D materials still need further with widen to realize more application. In this paper, a RT (25 °C) CO2 sensor prepared by a One-Pot method based on a PEI/PEG functionalized BP composite material is developed, in which the existence of PEI/PEG onto BP was confirmed by SEM, EDS, etc. The gas-sensing experiment results show that the low limit of detection of PEI/PEG-BP gas sensor is 200 ppm CO2 under air conditions and a high limit of detection of 250,000 ppm CO2 under N2 conditions. Moreover, the PEI/PEG-BP sensor shows high selectivity, and excellent repeatability. The excellent gas-sensing properties of the PEI/PEG-BP sensor can be attributed to the meso-macropores structure, the recognition function of amino groups, and the formation of P-N heterojunction between BP and PEI. The reported results of PEI/PEG-BP sensor can provide a foundation for PEI/PEG functionalized 2D material and understand the sensing mechanism for compositing the 2D materials with polymer semiconductors.