Programme

P.59 -- Poster, VCTP-46

Date: Wednesday, 6 October 2021

Time: 08:30 - 10:00

Ab-initio Calculations of Water Adsorption on Graphene: The role of the Substrate Materials

Viet Bac T. Phung1, Van An Dinh2

1. Institute of Sustainability Science, VNU Vietnam Japan University, Luu Huu Phuoc street, My Dinh, Nam Tu Lien, Hanoi, Vietnam 2. Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan

Humidity sensors have attracted much attentions due to their various applications in environment monitoring and health care. Graphene has been found as a promising humidity sensing material because of its good hydrophilicity and high sensitivity. In this study, the adsorption characteristics of H2O onto the surface of the pristine graphene and onto graphene supported on different substrates such as h-BN, SnO2, GaAs are investigated using density functional calculations. The bonding of H2O to graphene has been characterized as physisorption. We use the band structure calculations and density of states analysis to study the influence of substrates in the electronic structure of graphene and the water adsorption properties of the graphene. Our calculations reveal that H2O acts as a weak acceptor, it receives electrons from graphene. The charge transfer between H2O and the graphene/substrates leads to the shift in the Fermi energy and should modify the electronic structures of the graphene surface. The introduction of considered substrates effects to the charge transfer between graphene and H2O and the workfunction. The presence of different substrates such as h-BN, SnO2, GaAs increases the adsorption energy of H2O on graphene up to 20%. This study could potentially be useful in developing graphene-based flexible humidity sensors . Keywords: graphene supported substrates, H2O adsorption, first-principle calculations, charge transfer

Presenter: Phung T. V. Bac