荧光
共轭体系
碳纤维
吸收(声学)
可见光谱
甲酰胺
光催化
带隙
材料科学
光化学
化学
分析化学(期刊)
光电子学
有机化学
光学
聚合物
复合材料
催化作用
复合数
物理
作者
Siqi Wei,Xinghang Yin,Haoyi Li,Xiaoyu Du,Limei Zhang,Jing Wang,Rui Yang
标识
DOI:10.1002/chem.202000763
摘要
Abstract Four types of carbon dots (CDs) with various color (blue, green, yellow, and red) emissions have been synthesized under solvent‐free conditions from citric acid and different nitrogen sources (DMF, urea, ethanamide, and formamide). By detailed characterization and comparison, it is confirmed that the graphitized sp 2 conjugated domain and surface functional groups such as C−O and C=N play synergetic roles in adjusting the fluorescence properties. Notably, the size effect is not the dominant mechanism to achieve multi‐color fluorescence emissions in this work. The structural configuration of the carbon dots further influences the energy band structure, as demonstrated in simplified energy level diagrams. An absorption peak at approximately 560 nm appears in the visible light region for red‐emitting CDs, assigned to an n→π* transition of the aromatic structure, thus introducing a new surface state energy level, resulting in a reduction in the energy of electron transition and the expansion into the visible region of the UV/Vis spectrum. Taking advantage of the diverse absorption and emission properties, different CDs/TiO 2 binary composites are obtained for photocatalytic degradation of organic dyes, and it is found that the absorption range in terms of visible light and the band gap of the carbon dots make a difference to the photocatalytic performance of the composites.
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