title: Photoexcited State Properties of Carbon Dots from Thermally Induced Functionalization of Carbon Nanoparticles.
abstract: Carbon dots are small carbon nanoparticles with various surface passivation schemes, in which more effective has been the deliberate chemical functionalization of the nanoparticles for brighter fluorescence emissions, though the synthesis method is more tedious and subject to some limitations in the selection of functionalization molecules. Another more popular synthesis method has been the carbonization of organic species, with the method being more efficient and versatile, but less controllable in the synthesis and for the desired dot structure and performance. In this work, a hybrid approach combining the advantageous characteristics of the two synthesis methods was applied to the preparation of carbon dots with polyethyleneimine (PEI) for surface passivation, where pre-processed and selected small carbon nanoparticles were functionalized with PEI in microwave-induced thermal reactions. The optical absorption and fluorescence emission properties were evaluated, and the results suggested that the carbon dots thus prepared shared the same photoexcited state characteristics with those from the deliberate chemical functionalization, including comparable fluorescence colors and other properties. A further demonstration on the similarity in photoexcited state properties was based on the same visible light-activated bactericidal functions of the PEI-carbon dots as those found in carbon dots from the deliberate chemical functionalization. The advantages and potential limitations of the hybrid approach for more controllable yet versatile and efficient syntheses of carbon dots are highlighted and discussed.
authors.affiliation: Department of Chemistry and Laboratory for Emerging Materials and Technology, Clemson University, Clemson, South Carolina 29634, USA.
authors.forename: Yin
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Pharmaceutical Sciences, Biomanufacturing Research Institute and Technology Enterprise, North Carolina Central University, Durham, NC 27707, USA.
authors.forename: Mohamad M
authors.initials: MM
authors.lastname: Al Awak
authors.affiliation: Department of Chemistry and Laboratory for Emerging Materials and Technology, Clemson University, Clemson, South Carolina 29634, USA.
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.affiliation: Department of Chemistry and Laboratory for Emerging Materials and Technology, Clemson University, Clemson, South Carolina 29634, USA.
authors.forename: Sijia
authors.initials: S
authors.lastname: Yan
authors.affiliation: Department of Chemistry and Laboratory for Emerging Materials and Technology, Clemson University, Clemson, South Carolina 29634, USA.
authors.forename: Qingwu
authors.initials: Q
authors.lastname: Xiong
authors.affiliation: Department of Chemistry and Laboratory for Emerging Materials and Technology, Clemson University, Clemson, South Carolina 29634, USA.
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.affiliation: Department of Mathematics and Physics, North Carolina Central University, Durham, NC 27707, USA.
authors.forename: Yongan
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Department of Pharmaceutical Sciences, Biomanufacturing Research Institute and Technology Enterprise, North Carolina Central University, Durham, NC 27707, USA.
authors.forename: Liju
authors.initials: L
authors.lastname: Yang
authors.affiliation: Department of Chemistry and Laboratory for Emerging Materials and Technology, Clemson University, Clemson, South Carolina 29634, USA.
authors.forename: Gregory E
authors.initials: GE
authors.lastname: LeCroy
authors.affiliation: Department of Chemistry and Laboratory for Emerging Materials and Technology, Clemson University, Clemson, South Carolina 29634, USA.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Hou
authors.affiliation: Air Force Research Laboratory, Propulsion Directorate, Wright-Patterson Air Force Base, Ohio 45433, USA.
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Bunker
authors.affiliation: Department of Chemistry and Laboratory for Emerging Materials and Technology, Clemson University, Clemson, South Carolina 29634, USA.
authors.forename: Linxi
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Chemistry and Laboratory for Emerging Materials and Technology, Clemson University, Clemson, South Carolina 29634, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Tomlinson
authors.affiliation: Department of Chemistry and Laboratory for Emerging Materials and Technology, Clemson University, Clemson, South Carolina 29634, USA.
authors.forename: Ya-Ping
authors.initials: YP
authors.lastname: Sun