First-principles study of the atomistic origins of codoping-induced type conversion in nitrogen doped graphene

Abstract

It was recently established that nitrogen-doped graphene (NG) can exhibit both p- and n-type characters depending on the C-N bonding nature, which represents a significant bottleneck for the development of graphene-based electronics. Based on first-principles calculations, we herein scrutinize the correlation between atomistic details in NGs and their electronic structure, and particularly explore the feasibility of converting p-type pyridinic, pyrrolic, and nitrilic NGs into n- or bipolar type by introducing an additional dopant atom in a post-synthetic manner. Out of nine candidates, B, C, O, F, Al, Si, P, S, and Cl, we conclude that B, Al, and P codopant atoms can structurally anneal the vacancy defects in p-type NGs and concurrently achieve robust n-type NGs. The atomistic origin of such type conversion is analyzed based on the Mulliken and crystal orbital Hamiltonian population analyses, which provide us with a framework to connect the local bonding chemistry with macroscopic electronic structure. Moreover, we will show that, because the proposed codoping scheme is based on the annealing of vacancy defects, it can recover the excellent charge transport properties of pristine graphene. Our findings should have significant implications for the graphene-based electronics as well as energy device applications such as fuel cell electrodes.