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dc.contributor.authorTeng, Chiao-Yien_US
dc.contributor.authorBa-Son Nguyenen_US
dc.contributor.authorYeh, Te-Fuen_US
dc.contributor.authorLee, Yuh-Langen_US
dc.contributor.authorChen, Shean-Jenen_US
dc.contributor.authorTeng, Hsishengen_US
dc.date.accessioned2018-08-21T05:54:13Z-
dc.date.available2018-08-21T05:54:13Z-
dc.date.issued2017-06-28en_US
dc.identifier.issn2040-3364en_US
dc.identifier.urihttp://dx.doi.org/10.1039/c7nr01037ken_US
dc.identifier.urihttp://hdl.handle.net/11536/145675-
dc.description.abstractFluorescent graphene oxide dots (GODs) are environmentally friendly and biocompatible materials for photoluminescence (PL) applications. In this study, we employed annealing and hydrothermal ammonia treatments at 500 and 140 degrees C, respectively, to introduce nitrogen functionalities into GODs for enhancing their green-color PL emissions. The hydrothermal treatment preferentially produces pyridinic and amino groups, whereas the annealing treatment produces pyrrolic and amide groups. The hydrothermally treated GODs (A-GODs) present a high conjugation of the nonbonding electrons of nitrogen in pyridinic and amino groups with the aromatic pi orbital. This conjugation introduces a nitrogen nonbonding (n(N 2p)) state 0.3 eV above the oxygen nonbonding state (n(O 2p) state; the valence band maximum of the GODs). The GODs exhibit excitation-independent green-PL emissions at 530 nm with a maximum quantum yield (QY) of 12% at 470 nm excitation, whereas the A-GODs exhibit a maximum QY of 63%. The transformation of the solvent relaxation-governed pi* -> n(O 2p) transition in the GODs to the direct pi* -> n(N 2p) transition in the A-GODs possibly accounts for the substantial QY enhancement in the PL emissions. This study elucidates the role of nitrogen functionalities in the PL emissions of graphitic materials and proposes a strategy for designing the electronic structure to promote the PL performance.en_US
dc.language.isoen_USen_US
dc.titleRoles of nitrogen functionalities in enhancing the excitation-independent green-color photoluminescence of graphene oxide dotsen_US
dc.typeArticleen_US
dc.identifier.doi10.1039/c7nr01037ken_US
dc.identifier.journalNANOSCALEen_US
dc.citation.volume9en_US
dc.citation.spage8256en_US
dc.citation.epage8265en_US
dc.contributor.department光電學院zh_TW
dc.contributor.departmentCollege of Photonicsen_US
dc.identifier.wosnumberWOS:000403943600025en_US
Appears in Collections:Articles