@article{Liu2024, 
author = {Jia Liu and Hailong Yu and Guan Wang and Shuang Yang and Meichen Li and Xin Zhang and Yang Jia and Yachen Gao},
title = {Photophysical properties of nitrogen-doped carbon quantum dots synthesized by graphite},
year = {2024},
journal = {Journal of Materiomics},
volume = {10},
number = {4},
pages = {828-836},
keywords = {Carbon quantum dots, Nitrogen-doped, Photoluminescence, Temperature-dependent, Non-radiative transition},
url = {https://www.sciopen.com/article/10.1016/j.jmat.2023.10.003},
doi = {10.1016/j.jmat.2023.10.003},
abstract = {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.}
}