Highly Efficient Regulation Strategy of Fluorescence Emission Wavelength via Designing the Structure of Carbon Dots

Abstract Multicolor carbon dots (CDs) possess tremendous potential applications, especially in optoelectronic devices. However, further applications of multi-color LED have been constrained due to the very limited researches concerning the wavelength control mechanism of multi-color CDs. In this work, through theoretical calculation and experimental verification, the regulatory effects of sp 2 conjugated domain on the fluorescence wavelength of CDs were explored. Firstly, through a regulation on the structure size and the introduction of amide bonds, four kinds of structures were designed in DFT theoretical calculation to explore the influence of sp 2 conjugated domain on the fluorescence wavelength of CDs theoretically. Then, using thiourea and p -phenylenediamine as the precursors and by regulating the reaction solvents, multicolor CDs with blue, green and red fluorescence emission were prepared to experimentally verify the emission mechanism. It was confirmed that the increasing structure size and the introduction of amide bond would induce an increasing size of the sp 2 conjugated domain, leading to the red shift of the CDs fluorescence wavelength. Finally, in order to suppress the self-quenching performance, the CDs@PVP fluorescent film possessing bright solid-state fluorescence was constructed for a better application in light-emitting diodes. The approach provided an effective strategy to realize the programmed regulation on the fluorescence wavelength of CDs, offering us full of potentials for the applications of CDs in the photoelectric device fields.