碳量子点是一类有发展和应用前景的新型荧光纳米材料,与半导体量子点等其他荧光纳米颗粒相比有其独特的优点。首先利用化学气相沉积法以乙炔为碳源制备碳微球(CMSs),然后用壳聚糖(CS)和SiO2两种不同性质的材料对CMSs进行了化学修饰的研究,得到CS/CMSs和SiO2/CMSs复合物,最后考察CMSs及其复合物在254nm紫外灯激发下的荧光性,讨论不同溶剂和不同浓度对CMSs及其复合物荧光性能的影响。采用场发射扫描电子显微镜、傅里叶变换红外光谱分析仪和荧光光谱仪对产物进行了表征和分析。结果表明:不同浓度的原始CMSs、氧化CMSs、CS/CMSs和SiO2/CMSs在有机溶剂(乙醇和CCl4)和水中发出不同颜色的荧光,随着溶剂极性的增加,荧光颜色向长波方向移动(紫色-黄色),且随着浓度的增加,颜色逐渐加深,浓度太大时发生荧光猝灭。
Carbon dots (C-Dots), an advanced fluorescent nanomaterial, have good prospects for development and application. Based on their advantages over quantum dots (QDs) and other fluorescent nanoparticles, C-dots could replace QDs in the scientific fields such as solar cells, lu minescent device and optical biomarkers. Carbon microspheres (CMSs) were prepared by chemi- cal vapor deposition using acetylene as carbon resource; then, CMSs were modified by chitosan (CS) and SiO2 ; finally, the fluorescence of CMSs and their composites were studied under ultra- violet irradiation (excited at 254 nm), in which the effects of solvent and concentration of suspen- sion were considered. Field emission scanning electron microscopy, Fourier transformation infra- red spectrometry and fluorescence spectrometry were employed to characterize the morphology and structure of the samples. The results show that as-synthesized CMSs, oxidized CMSs, CS/ CMSs and SiO2/CMSs with different suspension concentrations emitted different fluorescence in organic solvents (ethanol and tetrachloromethane) and water. With increasing solvent polarity, the fluorescence orescence color tion. color changed from purple to yellow, and with increasing concentration, the flu gradually deepened and finally led to fluorescence quenching at high concentra