Tailoring the electronic structure of graphene via molecular adsorption

Graphene demonstrates many exceptional properties that makes it a promising candidate in various applications, such as electronics, energy-related and biomedical. However, there are still many challenges remaining to realize graphene's fullest extent possible. In recent years, graphene functionalization has become the primary driving force for enhancing the performance of graphene-based devices. Among the various approaches of graphene functionalization, molecular adsorption has received growing attention due to its low cost, flexibility and effectiveness in controlling the properties of graphene. Here, density functional calculations are employed to investigate three specific graphene-molecule systems used for electronic, catalytic and sensing applications, focusing on the interplay between graphene and adsorbed molecules. Major challenges facing functionalized graphene are thoroughly examined and discussed, such as identifying novel adsorbates, refining surface conditions, and strengthening electronic signals arising from graphene-molecule interactions. The work presented in this thesis aims to provide critical theoretical insights into the electronic structure of graphene modified by molecular adsorption, and help the design and development of future graphene-based devices.