溶剂对石墨烯量子点荧光性质的影响

Effects of Solvent on Luminescent Properties of GQDs

采用柠檬酸热解法制备了石墨烯量子点（GQDs）,研究了非极性溶剂戊烷,极性溶剂乙醇、丙酮、乙二醇对GQDs荧光性质的影响。透射电子显微镜（TEM）和原子力显微镜（AFM）图像表明,制备的GQDs尺寸分布在2~12 nm（平均尺寸为4.9 nm）,分散均匀,高度分布在0.5~2 nm。吸收光谱表明,GQDs具有明显的紫外吸收特性,吸收峰位于259 nm和274 nm。光致发光谱表明,GQDs的发光具有明显的溶剂依赖性。GQDs在极性溶剂乙醇、丙酮、乙二醇中,发光峰的位置依赖于激发波长,发射波长在可见光区。而在非极性溶剂戊烷中,GQDs表现出对激发波长不依赖的荧光性能,且发射波长在近紫外。

The graphene quantum dots（ GQDs） were prepared by pyrolyzing citric acid and dissolved with different organic solvents. The influence of solvent on luminescence properties is investigated.Transmission electron microscope（ TEM）,along with atomic force microscope（ AFM） was employed for the morphology and structure analysis of the as-prepared samples. The results show that GQDs＇ diameters are distributed in the range of 2- 12 nm（ 4. 9 nm average diameter）. Optical properties of the as-prepared samples were characterized by ultraviolet-visible spectra（ UV-Vis） and fluorescence spectrophotometer. The photoluminescence spectra depict that the GQDs exhibited solvent-dependent behaviors. The position of the peak fluorescence of GQDs in polar solvent ethanol,acetone and ethylene glycol is dependent on excitation wavelength,emission wavelength is in a visible light area.The fluorescence of GQDs in a nonpolar solvent pentane is independent of excitation wavelength,the strong emission appeared in the near-UV region.