Gas sensing response of transition metal (Ag, Au) modified monolayer InP to agricultural greenhouse gases (C2H4, CO2, H2O, H2S, NH3, NO2, SO2): From a DFT perspective

Amidst global climate change and resource scarcity, conventional agricultural practices are encountering significant challenges. The adoption of greenhouses for cultivating crops can mitigate adverse climatic conditions, enhance both the output and caliber of crops, lower the incidence of pests and diseases, reduce reliance on chemical pesticides, and support environmental sustainability. However, issues such as inadequate air circulation, thermal retention, and fertilizer management within greenhouses may lead to the generation of several gases (C2H4, CO2, H2O, H2S, NH3, NO2, SO2). Among these, C2H4, CO2, and H2O pose minimal risk to human safety but notably influence crop development, whereas H2S, NH3, NO2, and SO2 substantially affect both human health and plant growth. InP, as a representative III–V compound semiconductor, exhibits outstanding semiconductor characteristics, rendering it a promising material for gas sensing applications. Modification with transition metals like Au and Ag may improve its gas-sensitive performance. Employing density functional theory (DFT), this work comprehensively investigates the sensing mechanisms of Ag- and Au-modified InP toward typical greenhouse gases (C2H4, CO2, H2O, H2S, NH3, NO2, SO2). By evaluating adsorption energies, the most favorable adsorption configurations of these gases on the modified InP surfaces are identified. Examination of band structures, density of states, and charge density differences elucidates the nature of interactions between gas molecules and the functionalized substrates. Furthermore, variations in work function and charge transfer before and after adsorption are analyzed to assess the gas permeation behavior of each system. These findings offer theoretical insights useful for designing and advancing sensors aimed at monitoring hazardous gases in agricultural greenhouse environments.