Improving gas sensing properties of graphene by introducing dopants and defects: a first-principles study

TLDR

Graphene’s gas‑sensing performance depends on its structure and the adsorption configuration, with interactions altering its electronic properties. The study employed density‑functional calculations to examine interactions between pristine, B‑ or N‑doped, and defective graphenes with CO, NO, NO₂, and NH₃ to assess sensor potential. Doped or defective graphenes exhibit markedly stronger adsorption and, for example, B‑doped graphene yields a two‑order‑of‑magnitude higher sensor sensitivity, demonstrating that appropriate dopants or defects can drastically enhance graphene‑based gas‑sensor performance.

Abstract

The interactions between four different graphenes (including pristine, B- or N-doped and defective graphenes) and small gas molecules (CO, NO, NO2 and NH3) were investigated by using density functional computations to exploit their potential applications as gas sensors. The structural and electronic properties of the graphene–molecule adsorption adducts are strongly dependent on the graphene structure and the molecular adsorption configuration. All four gas molecules show much stronger adsorption on the doped or defective graphenes than that on the pristine graphene. The defective graphene shows the highest adsorption energy with CO, NO and NO2 molecules, while the B-doped graphene gives the tightest binding with NH3. Meanwhile, the strong interactions between the adsorbed molecules and the modified graphenes induce dramatic changes to graphene's electronic properties. The transport behavior of a gas sensor using B-doped graphene shows a sensitivity two orders of magnitude higher than that of pristine graphene. This work reveals that the sensitivity of graphene-based chemical gas sensors could be drastically improved by introducing the appropriate dopant or defect.