Abstract
Understanding the luminescence mechanisms and regulating the emission centers of carbon dots(CDs)are important for advancing their related applications.In this work,we systematically investigate the formation processes of multi-emission centers in CDs synthesized through a bottom-up approach by con-trolling the solvothermal reaction temperature.CDs synthesized at a lower temperature(140 ℃,140-CDs)exhibit smaller particle sizes(3-4 nm)with dominant green-yellow emission,while CDs synthesized at a higher temperature(180 ℃,180-CDs)exhibit larger particle sizes(8-9 nm)with enhanced red emis-sion and emerging near-infrared(NIR)emission.The green-yellow emission and red emission originate from the core state and the surface-related state,respectively,and the emissions could be regulated by temperature-controlled dehydration and carbonization processes.The clear NIR emission center in 180-CDs is attributable to the increased content of radical defects in the cores during the increased dehydra-tion and carbonization processes during higher-temperature solvothermal treatment.
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