RGO@In2O3 based flexible gas sensor: Efficient monitoring of trace NO2 gas at room temperature

Abstract

In the realm of modern reinforced concrete, the harmful gases released during industrial production pose a significant threat to human health, thus the demand for wearable gas sensors is increasing day by day. However, creating a portable flexible sensor for detecting nitrogen dioxide under room temperature conditions and ensuring outstanding gas sensing performance remains a challenge. To address this issue, this study synthesized rGO@In₂O₃ composite nanofibers using coaxial electrospinning and calcination methods. Compared to pure In₂O₃, the rGO@In₂O₃ composite nanofibers exhibit superior gas sensing performance. At room temperature (25 °C), the response value of the rGO@In₂O₃ sensor to 1 ppm nitrogen dioxide gas is 14.18 (with a theoretical detection limit as low as 2.58 ppb). Its excellent performance can be attributed to a relatively complete depletion layer that enhances the high carrier density in the p-n heterojunction, consistent with the shell depletion theory in semiconductor physics. Furthermore, the rGO@In₂O₃ sensor also demonstrates outstanding stability, selectivity and flexibility, offering a new direction for the development of wearable gas sensors at room temperature.