First-principles study of 2D V-V binary materialα-AsN for VOCs-sensing applications

Increased emissions of volatile organic compounds (VOCs) are prone to cause health issues like cancer and central nervous system disorders, making the development of efficient VOCs-sensing materials crucial. Monolayerα-AsN, a two-dimensional (2D) V-V binary material with a wrinkled honeycomb structure, features better environmental stability (higher cohesive energy than black phosphorus, BP) and tunable electrical properties (unlike single-target VOC-sensing TMDs). It overcomes flaws of existing 2D sensors (BP's poor stability, TMDs' narrow selectivity) while retaining high surface-to-volume ratio, and shows superior adsorption efficiency and selectivity for alcohol VOCs versus BP and acetone-specialized Janus TMDs. However, its VOCs-sensing performance remains uninvestigated. This study employed density functional theory and nonequilibrium Green's function to systematically investigate the adsorption and sensing behaviors of monolayerα-AsN toward the five VOCs. Electronic localization function analysis confirmed physical adsorption (no chemical bonding) betweenα-AsN and all VOCs. Among the tested VOCs, methanol and ethanol exhibited the highest adsorption energy and density (ethanol slightly higher), with ultra-low detection limits (7.69 × 10^-⁴ p.p.b. for methanol and 4.88 × 10^-⁵ p.p.b. for ethanol). Critically, methanol adsorption reducedα-AsN's current by 30%, while ethanol increased it by 100%. These findings demonstrate that monolayerα-AsN holds great application potential for the selective detection of methanol and ethanol.