title: Elucidating Quantum Confinement in Graphene Oxide Dots Based On Excitation-Wavelength-Independent Photoluminescence.
abstract: Investigating quantum confinement in graphene under ambient conditions remains a challenge. In this study, we present graphene oxide quantum dots (GOQDs) that show excitation-wavelength-independent photoluminescence. The luminescence color varies from orange-red to blue as the GOQD size is reduced from 8 to 1 nm. The photoluminescence of each GOQD specimen is associated with electron transitions from the antibonding π (π*) to oxygen nonbonding (n-state) orbitals. The observed quantum confinement is ascribed to a size change in the sp(2) domains, which leads to a change in the π*-π gap; the n-state levels remain unaffected by the size change. The electronic properties and mechanisms involved in quantum-confined photoluminescence can serve as the foundation for the application of oxygenated graphene in electronics, photonics, and biology.
authors.affiliation: Department of Chemical Engineering and Research Center for Energy Technology and Strategy, National Cheng Kung University , Tainan 70101, Taiwan.
authors.forename: Te-Fu
authors.initials: TF
authors.lastname: Yeh
authors.affiliation: Department of Internal Medicine, College of Medicine and Hospital, National Cheng Kung University , Tainan 70101, Taiwan.
authors.forename: Wei-Lun
authors.initials: WL
authors.lastname: Huang
authors.affiliation: Center for Micro/Nano Science and Technology, National Cheng Kung University , Tainan 70101, Taiwan.
authors.forename: Chung-Jen
authors.initials: CJ
authors.lastname: Chung
authors.affiliation: Department of Internal Medicine, College of Medicine and Hospital, National Cheng Kung University , Tainan 70101, Taiwan.
authors.forename: I-Ting
authors.initials: IT
authors.lastname: Chiang
authors.affiliation: Department of Chemical Engineering and Research Center for Energy Technology and Strategy, National Cheng Kung University , Tainan 70101, Taiwan.
authors.forename: Liang-Che
authors.initials: LC
authors.lastname: Chen
authors.affiliation: Department of Engineering Science, National Cheng Kung University , Tainan 70101, Taiwan.
authors.forename: Hsin-Yu
authors.initials: HY
authors.lastname: Chang
authors.affiliation: Department of Internal Medicine, College of Medicine and Hospital, National Cheng Kung University , Tainan 70101, Taiwan.
authors.forename: Wu-Chou
authors.initials: WC
authors.lastname: Su
authors.affiliation: Department of Physics, National Cheng Kung University , Tainan 70101, Taiwan.
authors.forename: Ching
authors.initials: C
authors.lastname: Cheng
authors.affiliation: Center for Micro/Nano Science and Technology, National Cheng Kung University , Tainan 70101, Taiwan.|Department of Engineering Science, National Cheng Kung University , Tainan 70101, Taiwan.
authors.forename: Shean-Jen
authors.initials: SJ
authors.lastname: Chen
authors.affiliation: Department of Chemical Engineering and Research Center for Energy Technology and Strategy, National Cheng Kung University , Tainan 70101, Taiwan.|Center for Micro/Nano Science and Technology, National Cheng Kung University , Tainan 70101, Taiwan.
authors.forename: Hsisheng
authors.initials: H
authors.lastname: Teng
mesh_terms: D006108:Graphite / Q000737:chemistry*; D049449:Luminescence; D010087:Oxides / Q000737:chemistry*; D045663:Quantum Dots / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D010087:Oxides; D006108:Graphite