Since its isolation in 2004, graphene has become one of the most promising materials of the twenty-first century, particularly for next-generation electronics. Because conventional silicon-based electronics face fundamental limitations at the nanoscale, preparing and modifying graphene for use in next-generation carbon-based nanoelectronics has been the focus of intense research. One of the most powerful and feasible methods of tailoring the properties of graphene is by doping with foreign atoms. Nitrogen, with a similar size to carbon but with one more electron, is expected to form donor states in graphene as a substitutional dopant; however, experimental measurements of N-doped graphene reveal the existence of several nitrogen configurations with distinct electronic properties. In particular, one can tune the electron and hole carrier concentrations by controlling these dopant bonding configurations to chemically transform graphene into a p-type or n-type semiconductor.<br/><br/>While there have been previous experimental and theoretical results for nitrogen-doped graphene at extremely small sizes, there has not been a systematic study of these materials for larger sizes, where optoelectronic properties will be heavily governed by doping density and quantum confinement effects. To this end, we have carried out a theoretical investigation of nitrogen-doped graphene nanoflakes via a new real-time time-dependent density functional tight binding (RT-TDDFTB) code that runs on massively-parallelized GPUs. This GPU-enhanced capability allows us to efficiently and accurately calculate the electron dynamics of these systems (~1400 atoms) at a quantum mechanical level, whereas conventional approaches are computationally limited to only hundreds of atoms. Most importantly, the use of high-performance GPUs permits an efficient approach for calculating and understanding the effects of graphene dopants to rationally guide experimental efforts in harnessing these novel materials.

GPU-enabled real-time electron dynamics of nitrogen-doped graphene nanoflakes

254th National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.