溶剂对石墨烯量子点荧光性质的影响

摘要

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 eth-ylene 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.