Gallium and Germanium Doped Nanodiamonds for Methanol Detection: A Quantum Mechanical Investigation for Sensor Applications

Abstract

The detection of hazardous gases and vapours has recently become more crucial for monitoring pollution, manufacturing industrial products, and car exhaust. Researchers have recently focused a lot of work on developing new sensors for volatile organic compounds (VOCs). Methanol is one of these VOCs and is a common feedstock for many essential chemicals, but it is also extremely hazardous to humans, therefore sensors that can detect methanol are crucial to be manufactured. In the current study, calculations using the density functional theory have been done to explore the potential of doped Nanodiamonds as a gas sensor and to evaluate the adsorption of methanol on the surface of pristine and Ga and Ge-doped Nanodiamond clusters at different temperatures 298k and 323k. In this investigation, the double zeta (DZ) basis sets GGA:PW91 approach was utilised. The adsorption energy values and charge distributions of the structures demonstrate the methanol molecule is sensitive to Pristine ND, Ga-doped, and Ge-doped Nanodiamonds structures. When methanol was adsorbed on the Pristine ND, Ga-doped, and Ge-doped Nanodiamond structures, the HOMO-LUMO gap of each of these structures decreased. However, Pristine ND displayed a higher value of HOMO-LUMO gap, greater stability, and higher hardness in comparison to Ga and Ge doped Nanodiamond structures. Additionally, Ga and Ge doped NDs have higher electrical conductivity values than pristine Nanodiamonds, which have very little electrical conductivity. The results indicate that Ga and Ge doped Nanodiamonds can be utilised as a potential material for Methanol sensing. Furthermore, Ge doped ND exhibits a very low value of recovery time, which is inappropriate for efficient adsorption, but Ga doped ND exhibits an appropriate value of recovery time for methanol adsorption. Additionally, the Ga doped ND is more sensitive and effective at detecting methanol due to its higher sensitivity than the Ge-doped ND.