Light intensity effects on the performance of In2O3 gas sensors: Insights into adsorption and desorption dynamics

Abstract

This study delves into the effects of light intensity on In₂O₃ gas sensors, offering a detailed analysis of how light impacts the adsorption and desorption dynamics at the sensor surface. Light activation has been widely employed in chemiresistive gas sensing, but little exploration of the light intensity effect on molecular kinetics can be found. A low-temperature direct growth of In₂O₃ microflowers on the patterned substrate has been acquired via a facile hydrothermal approach, and the growth mechanism has been proposed. Various UV light intensities (0.4, 0.8, 2, and 3.2 mW cm⁻²) have been employed. The sensor with a light intensity of 2 mW cm⁻² shows the highest response of 1224% toward 500 ppb NO₂. The outstanding performance is attributed to its porous surface, high specific surface area and additional active edge sites. The relationship between photon flux and sensor response has been analyzed, leading to the derivation of a second-order quadratic equation that describes the kinetic constant as a function of varying light intensity. This study provides valuable insights into optimizing light-driven gas sensors, which could enhance the sensitivity and efficiency of semiconductor-based sensor technologies in the industry.