Wang Zengyao, Wu Hao, Wu Qingyun, Zhao Yi-Ming, Shen Lei
Engineering Science Programme, Faculty of Engineering, National University of Singapore, Singapore 117575, Singapore.
Department of Mechanical Engineering, National University of Singapore, Singapore 117575, Singapore.
Molecules. 2023 Jul 14;28(14):5402. doi: 10.3390/molecules28145402.
It is critical for gas sensors that sense greenhouse gas molecules to have both good sensitivity and selectivity for water molecules in the ambient environment. Here, we study the charge transfer, IV curves, and electric field tuning of vanadium-doped monolayer ϵ-phosphorene as a sensor for NO, NO, and HO gas molecules via first-principle and transport calculations. We find that the paramagnetic toxic molecules of NO and NO have a high adsorption energy on V-ϵ-phosphorene, which originates from a large amount of charge transfer driven by the hybridisation of the localised spin states of the host with the molecular frontier orbital. Using the non-equilibrium Green's function, we investigate the IV responses with respect to the adsorption of different molecules to study the performance of gas molecule sensors. Our IV curves show a larger amount of changes in resistance of the paramagnetic NO and NO than nonmagnetic HO gas molecules, suggesting both sensitivity and selectivity. Moreover, our calculations show that an applied external electric field (gate voltage) can effectively tune the amount of charge transfer. More charge transfer makes the sensor more sensitive to the molecule, while less charge transfer can reduce the adsorption energy and remove the adsorbed molecules, allowing for the repeated use of the sensor.
对于检测温室气体分子的气体传感器而言，在周围环境中对水分子同时具有良好的灵敏度和选择性至关重要。在此，我们通过第一性原理和输运计算，研究了钒掺杂单层ϵ-磷烯作为检测NO、NO和HO气体分子的传感器的电荷转移、IV曲线和电场调控。我们发现，NO和NO的顺磁性有毒分子在V-ϵ-磷烯上具有较高的吸附能，这源于主体的局域自旋态与分子前沿轨道杂化驱动的大量电荷转移。利用非平衡格林函数，我们研究了不同分子吸附时的IV响应，以研究气体分子传感器的性能。我们的IV曲线表明，顺磁性的NO和NO的电阻变化量比非磁性的HO气体分子大，这表明了其灵敏度和选择性。此外，我们的计算表明，施加的外部电场（栅极电压）可以有效地调控电荷转移量。更多的电荷转移使传感器对分子更敏感，而较少的电荷转移可以降低吸附能并去除吸附的分子，从而使传感器能够重复使用。
