At present, the actual mechanism of the photoluminescence （PL） of fluorescent carbon dots （CDs） is still an open debate among researchers. Because of the variety of CDs, it is highly important to summarize the PL ...At present, the actual mechanism of the photoluminescence （PL） of fluorescent carbon dots （CDs） is still an open debate among researchers. Because of the variety of CDs, it is highly important to summarize the PL mechanism for these kinds of carbon materials; doing so can guide the development of effective synthesis routes and novel applications. This review will focus on the PL mechanism of CDs. Three types of fluorescent CDs were involved： graphene quantum dots （GQDs）, carbon nanodots （CNDs）, and polymer dots （PDs）. Four reasonable PL mechanisms have been confirmed： the quantum confinement effect or conjugated 7x-domains, which are determined by the carbon core; the surface state, which is determined by hybridization of the carbon backbone and the connected chemical groups; the molecule state, which is determined solely by the fluorescent molecules connected on the surface or interior of the CDs; and the crosslink- enhanced emission （CEE） effect. To give a thorough summary, the category and synthesis routes, as well as the chemical/physical properties for the CDs, are briefly introduced in advance.展开更多
Two-dimensional graphene offers interesting electronic,thermal,and mechanical properties that are currently being explored for advanced electronics,membranes,and composites.Here we synthesize and explore the biologica...Two-dimensional graphene offers interesting electronic,thermal,and mechanical properties that are currently being explored for advanced electronics,membranes,and composites.Here we synthesize and explore the biological applications of nano-graphene oxide(NGO),i.e.,single-layer graphene oxide sheets down to a few nanometers in lateral width.We develop functionalization chemistry in order to impart solubility and compatibility of NGO in biological environments.We obtain size separated pegylated NGO sheets that are soluble in buffers and serum without agglomeration.The NGO sheets are found to be photoluminescent in the visible and infrared regions.The intrinsic photoluminescence(PL)of NGO is used for live cell imaging in the near-infrared(NIR)with little background.We found that simple physisorption viaπ-stacking can be used for loading doxorubicin,a widely used cancer drug onto NGO functionalized with antibody for selective killing of cancer cells in vitro.Owing to its small size,intrinsic optical properties,large specifi c surface area,low cost,and useful non-covalent interactions with aromatic drug molecules,NGO is a promising new material for biological and medical applications.展开更多
评述了近3年来在石墨烯(graphene)制备化学、石墨烯化学改性、石墨烯表面化学和催化等方面取得的重要进展.阐述了通过化学方法实现非支撑(freestan ding)或准非支撑(quasifree-standing)石墨烯结构的可控和规模制备;通过表面反应对石墨...评述了近3年来在石墨烯(graphene)制备化学、石墨烯化学改性、石墨烯表面化学和催化等方面取得的重要进展.阐述了通过化学方法实现非支撑(freestan ding)或准非支撑(quasifree-standing)石墨烯结构的可控和规模制备;通过表面反应对石墨烯进行掺杂和官能化,制备了石墨烷、石墨烯氧化物等具有特殊结构和性质的石墨烯相关化合物;这些石墨烯及石墨烯相关材料(graphene and related materials)在催化、储氢等领域展现出非常重要的应用前景.展开更多
Graphene （G） was dispersed uniformly in water and used as an inhibitor in waterborne epoxy coatings. The effect of dispersed G on anticorrosion performance of epoxy coatings was evaluated. The composite coatings dis...Graphene （G） was dispersed uniformly in water and used as an inhibitor in waterborne epoxy coatings. The effect of dispersed G on anticorrosion performance of epoxy coatings was evaluated. The composite coatings displayed outstanding barrier properties against H20 molecule compared to the neat epoxy coating. Open circuit potential （OCP）, Tafel and electrochemical impedance spectroscopy （EIS） analysis confirmed that the corrosion rate exhibited by composite coatings with 0.5 wt% G was an order of magnitude lower than that of neat epoxy coating. Salt spray test results revealed superior corrosion resistance offered by the composite coating.展开更多
文摘At present, the actual mechanism of the photoluminescence （PL） of fluorescent carbon dots （CDs） is still an open debate among researchers. Because of the variety of CDs, it is highly important to summarize the PL mechanism for these kinds of carbon materials; doing so can guide the development of effective synthesis routes and novel applications. This review will focus on the PL mechanism of CDs. Three types of fluorescent CDs were involved： graphene quantum dots （GQDs）, carbon nanodots （CNDs）, and polymer dots （PDs）. Four reasonable PL mechanisms have been confirmed： the quantum confinement effect or conjugated 7x-domains, which are determined by the carbon core; the surface state, which is determined by hybridization of the carbon backbone and the connected chemical groups; the molecule state, which is determined solely by the fluorescent molecules connected on the surface or interior of the CDs; and the crosslink- enhanced emission （CEE） effect. To give a thorough summary, the category and synthesis routes, as well as the chemical/physical properties for the CDs, are briefly introduced in advance.
基金by NIH-NCI funded CCNE TR at Stanford University.We are grateful to Drs.Alice Fan and Dean Felsher for providing the antibodies used in this work.
文摘Two-dimensional graphene offers interesting electronic,thermal,and mechanical properties that are currently being explored for advanced electronics,membranes,and composites.Here we synthesize and explore the biological applications of nano-graphene oxide(NGO),i.e.,single-layer graphene oxide sheets down to a few nanometers in lateral width.We develop functionalization chemistry in order to impart solubility and compatibility of NGO in biological environments.We obtain size separated pegylated NGO sheets that are soluble in buffers and serum without agglomeration.The NGO sheets are found to be photoluminescent in the visible and infrared regions.The intrinsic photoluminescence(PL)of NGO is used for live cell imaging in the near-infrared(NIR)with little background.We found that simple physisorption viaπ-stacking can be used for loading doxorubicin,a widely used cancer drug onto NGO functionalized with antibody for selective killing of cancer cells in vitro.Owing to its small size,intrinsic optical properties,large specifi c surface area,low cost,and useful non-covalent interactions with aromatic drug molecules,NGO is a promising new material for biological and medical applications.
文摘评述了近3年来在石墨烯(graphene)制备化学、石墨烯化学改性、石墨烯表面化学和催化等方面取得的重要进展.阐述了通过化学方法实现非支撑(freestan ding)或准非支撑(quasifree-standing)石墨烯结构的可控和规模制备;通过表面反应对石墨烯进行掺杂和官能化,制备了石墨烷、石墨烯氧化物等具有特殊结构和性质的石墨烯相关化合物;这些石墨烯及石墨烯相关材料(graphene and related materials)在催化、储氢等领域展现出非常重要的应用前景.
基金supported by the National Natural Science Foundation of China (No.41506098)the China Postdoctoral Science Foundation (No.2015M580528)the Open Fund Project of Key Laboratory of Marine Materials and Related Technologies (No.LMMTKFKT-2014-008) in the Chinese Academy of Sciences
文摘Graphene （G） was dispersed uniformly in water and used as an inhibitor in waterborne epoxy coatings. The effect of dispersed G on anticorrosion performance of epoxy coatings was evaluated. The composite coatings displayed outstanding barrier properties against H20 molecule compared to the neat epoxy coating. Open circuit potential （OCP）, Tafel and electrochemical impedance spectroscopy （EIS） analysis confirmed that the corrosion rate exhibited by composite coatings with 0.5 wt% G was an order of magnitude lower than that of neat epoxy coating. Salt spray test results revealed superior corrosion resistance offered by the composite coating.
