TY  - JOUR
AU  - Liu, Jia
AU  - Yu, Hailong
AU  - Wang, Guan
AU  - Yang, Shuang
AU  - Li, Meichen
AU  - Zhang, Xin
AU  - Jia, Yang
AU  - Gao, Yachen
PY  - 2024
TI  - Photophysical properties of nitrogen-doped carbon quantum dots synthesized by graphite
JO  - Journal of Materiomics
SN  - 2352-8478
SP  - 828
EP  - 836
VL  - 10
IS  - 4
AB  - Here, nitrogen-doped carbon quantum dots (N-CQDs) were successfully synthesized by the solvothermal method using graphite as the carbon source and N,N-dimethylformamide as the nitrogen source. We characterized the structure and chemical constitution of N-CQDs using X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. We investigated the pump- and temperature-dependent photoluminescence (PL) properties and the dynamic exciton recombination processes of N-CQDs, using both steady-state and time-resolved PL techniques. The spectral results show that the PL emission peak located at 518 nm at room temperature, mainly originates from the n-π* transition on the surface of N-CQDs. The pump fluence and PL integral intensity were analyzed to demonstrate the existence of single-photon excitation under the 405 nm laser excitation. As the temperature increases, the non-radiative transition gradually increases, which decreases the PL intensity, the full width at half maxima first narrows and then widens and the PL lifetime gradually decreases. Furthermore, we combined the N-CQDs with chip to prepare light-emitting diode (LED). The resulting chromaticity coordinate was obtained to be (0.29, 0.40). This study offers a comprehensive understanding of the luminescence mechanism in N-doped CQDs and introduces a novel approach for the quickly fabrication of full-color display LEDs.
UR  - https://doi.org/10.1016/j.jmat.2023.10.003
DO  - 10.1016/j.jmat.2023.10.003