Xu Xiaofen, Guo Jun, Han Lu, Fan Huimin, Tong Fei
School of Electronic Engineering, Huainan Normal University, Huainan 232038, China.
School of Materials Science and Engineering, Anhui University, Hefei 230601, China.
Materials (Basel). 2025 May 2;18(9):2094. doi: 10.3390/ma18092094.
Nitrogen-doped graphene quantum dots (NGQDs) are made by heating a mixture of GQDs and ammonia using a thermochemical method. The optical properties of the samples were studied. Here, the role of the temperature used in the annealing process is investigated. It is found that with the increase in heating temperature, the sp fraction content continuously increases, and the photoluminescence (PL) blue shift continuously increases. The 550 nm peak of GQDs shifts from 550 nm to 513 nm NGQDs synthesized at 300 °C. The normalized PL intensity shows a significant blue shift in the emission peak of the NGQD samples compared to the GQDs. The peak position of the GQDs is 555 nm, while the peak positions of the NGQDs are 511 nm for NGQDs-250, 488 nm for NGQDs-300, and 480 nm for NGQDs-350. Using a simple thermochemical method, we can effectively dope N into GQDs, and it is evident from the electron energy loss spectra that N doping induces the emergence of a new energy level in the electronic structure, which alters the optical properties of NGQDs.
氮掺杂石墨烯量子点（NGQDs）是通过热化学方法加热石墨烯量子点（GQDs）和氨的混合物制成的。研究了样品的光学性质。在此，研究了退火过程中所用温度的作用。发现随着加热温度的升高，sp杂化分数含量不断增加，光致发光（PL）蓝移不断增大。GQDs的550nm峰在300℃合成的NGQDs中从550nm移至513nm。与GQDs相比，归一化PL强度显示NGQD样品的发射峰有明显蓝移。GQDs的峰位置为555nm，而NGQDs-250的NGQDs峰位置为511nm，NGQDs-300为488nm，NGQDs-350为480nm。使用简单的热化学方法，我们可以有效地将N掺杂到GQDs中，并且从电子能量损失谱可以明显看出，N掺杂在电子结构中诱导出一个新的能级，这改变了NGQDs的光学性质。
