Ruoyu Wu, Peng Han, Tobias Dittmann, Fuhe Wang, Yan Zhang and Gabriel Bester
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引用次数: 0
Abstract
We used a computational method based on ab initio (constrained) density functional theory to obtain the photoluminescence spectrum of graphene quantum dots with up to 240 carbon atoms, including the effect of multiphonons. We found that only a few phonon modes couple effectively to the excitons, namely one size- and shape-dependent global mode and two high frequency local modes. The exciton–phonon coupling decreases with increasing size for all structures and has a magnitude in the mid-range, leading to only relatively small multiphonon effects. We suggest that the photoluminescence sidebands can be used as fingerprints for the determination of the size and shape of graphene quantum dots. Our results are in very good agreement with the results from a recent experiment and reveal that a two-phonon replica (with n = 2) is clearly visible in the spectrum.
期刊介绍:
Nanoscale is a high-impact international journal, publishing high-quality research across nanoscience and nanotechnology. Nanoscale publishes a full mix of research articles on experimental and theoretical work, including reviews, communications, and full papers.Highly interdisciplinary, this journal appeals to scientists, researchers and professionals interested in nanoscience and nanotechnology, quantum materials and quantum technology, including the areas of physics, chemistry, biology, medicine, materials, energy/environment, information technology, detection science, healthcare and drug discovery, and electronics.