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首页> 外文期刊>Chemistry: A European journal >Chemical Functionalisation and Photoluminescence of Graphene Quantum Dots
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Chemical Functionalisation and Photoluminescence of Graphene Quantum Dots

机译：石墨烯量子点的化学功能化和光致发光

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Chemical modification of graphene quantum dots (GQDs) can influence their physical and chemical properties; hence, the investigation of the effect of organic functional groups on GQDs is of importance for developing GQD-organic hybrid materials. Three peripherally functionalised GQDs having a third-generation dendritic wedge (GQD-2), long alkyl chains (GQD-3) and a polyhedral oligomeric silsesquioxane group (GQD-4) were prepared by the Cu-I-catalysed Huisgen cycloaddition reaction of GQD-1 with organic azides. Cyclic voltammetry indicated that reduction occurred on the surfaces of GQD-1-4 and on the five-membered imide rings at the periphery, and this suggested that the functional groups distort the periphery by steric interactions between neighbouring functional groups. The HOMO-LUMO bandgaps of GQD-1-4 were estimated to be approximately 2 eV, and their low-lying LUMO levels (< - 3.9 eV) were lower than that of phenyl-C61-butyric acid methyl ester, an n-type organic semiconductor. The solubility of GQD-1-4 in organic solvents depends on the functional groups present. The functional groups likely cover the surfaces and periphery of the GQDs, and thus increase their affinity for solvent and avoid precipitation. Similar to GQD-2, both GQD-3 and GQD-4 emitted white light upon excitation at 360 nm. Size-exclusion chromatography demonstrated that white-light emission originates from the coexistence of differently sized GQDs that have different photoluminescence emission wavelengths.
机译：石墨烯量子点（GQD）的化学修饰会影响其物理和化学性质;因此，研究有机官能团对GQD的影响对于开发GQD-有机杂化材料非常重要。通过Cu-I催化的GQD的Huisgen环加成反应制备了具有第三代树枝状楔形物（GQD-2），长烷基链（GQD-3）和多面体低聚倍半硅氧烷基团（GQD-4）的三个外围功能化的GQD。 -1与有机叠氮化物。循环伏安法表明还原发生在GQD-1-4的表面和外围的五元酰亚胺环上，这表明官能团通过相邻官能团之间的空间相互作用使外围扭曲。据估计，GQD-1-4的HOMO-LUMO带隙约为2 eV，其低态LUMO水平（<-3.9 eV）低于n型苯基-C61-丁酸甲酯的水平有机半导体。 GQD-1-4在有机溶剂中的溶解度取决于存在的官能团。官能团可能覆盖了GQD的表面和外围，因此增加了它们对溶剂的亲和力并避免了沉淀。与GQD-2相似，GQD-3和GQD-4在360 nm激发时均发出白光。尺寸排阻色谱法表明，白光发射源自具有不同光致发光发射波长的大小不同的GQD的共存。

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