Gas adsorption, stabilities and electronic properties of graphene monolayers and bilayers doped with B and N

Graphene has received much interest as sensor device materials because of its high carrier mobility as well as high sensitivity to adsorbates. Substitutional doping with heteroatoms can modify the electronic properties and often enhance the chemical reactivity of graphene. Here, we report polluting or toxic gas molecule adsorption effects on the stabilities and the electronic properties of graphene monolayers and bilayers doped with boron and nitrogen atoms based on our first-principles density-functional calculations [1,2]. We find that, while abundant molecules in air (O₂, N₂ etc.) do not bind strongly, the single NO (NO₂) as well as the double NO (NO₂) molecules can bind on the B-doped monolayer graphene with chemical bonds. Furthermore, we also show that a pair of NO and NO₂ molecules can bind chemically on the B-doped graphene. Owing to the formation of the chemical bonds, the charge transfers are shown to take place between the gas molecules and the graphene layers, and give rise to the change of the workfunction of the system. We also discuss the possibilities of designing sensors to detect only NO_x molecules in air. [1] Y. Fujimoto and S. Saito, Chem. Phys. 478 (2016) 55. [2] Y. Fujimoto and S. Saito, submitted.