Modulation of the electronic properties of pristine and AIP-codoped stanene monolayers by the adsorption of CH2O and CH4 molecules: a DFT study

The adsorption of formaldehyde (CH2O) and methane (CH4) on the pristine and AlP-codoped stanene monolayers were investigated using the density functional theory calculations in order to search for potential sensors for detection of CH2O and CH4 molecules. The effects of CH2O and CH4 adsorption on the structural and electronic properties of stanene monolayers were systematically studied. The results indicated that both CH2O and CH4 molecules were physisorbed on the stanene sheets with small adsorption energy and large adsorption distance. The adsorption of CH2O and CH4 on the AlP-codoped stanene is more energetically favorable than that on the pristine one. Band structure calculations indicate that CH2O and CH4 adsorbed pristine and AlP-codoped stanene show semiconductor characteristics. The charge density difference calculations represent the significant charge accumulation on the adsorbed gas molecules. The considerable changes in the electronic properties of stanene induced by gas adsorption suggest the potential application of these group-IV buckled nanomaterials for CH2O and CH4 detection.