Carbon quantum dots（CQDs） have emerged as a new generation of photoluminescent nanomaterials with wide applications.Among the various synthetic routes for CQDs,the acid-refluxing method,which belongs to the group of...Carbon quantum dots（CQDs） have emerged as a new generation of photoluminescent nanomaterials with wide applications.Among the various synthetic routes for CQDs,the acid-refluxing method,which belongs to the group of ＂top-down＂ methods,offers the advantage of large-scale production of CQDs and uses cheap and abundantly available starting materials.In this study,we evaluated the potential of fullerene carbon soot（FCS）,a by-product obtained during the synthesis of fullerene,as the starting material for CQD production.It was found that FCS can be successfully converted to CQDs in high production yield in mixed acids,i.e.,concentrated HNO_3 and H_2SO_4,under mild conditions.The fluorescence quantum yield（0） of the as-produced CQDs is in the range of 3%-5%,which is the highest value for CQDs obtained from ＂top-down＂ methods.Importantly,the CQDs prepared by this method show emission in the yellow range of the visible light,which is advantageous for their various potential applications.Further investigations reveal that the CQDs are highly photostable over a wide pH range and show good resistance against ionic strength and long-term UV irradiation.This further expands their potential use under harsh conditions.展开更多
Large-scale production of graphene and sub- sequent sample engineering is the key for fully-realizing the potential applications proposed to this intriguing two-dimensional nanomaterial. Herein, smart graphene dispers...Large-scale production of graphene and sub- sequent sample engineering is the key for fully-realizing the potential applications proposed to this intriguing two-dimensional nanomaterial. Herein, smart graphene dispersions with low defects and thermo-responsive properties can be obtained by liquid phase exfoliation of graphite using an alkylated Percec monodendron （3,4,5-trioctadecy- loxybenzaldehyde, 1） as the stabilizing reagent. By simply changing the temperature, the dispersed graphene and 1 can be detached, leading to the recovery of both components. Besides noncovalent wrapping, the stabilizing reagent 1 can be also covalently attached to graphene through [3＋2] cycloaddition. The covalently functionalized graphene sheets show improved dispersibility in organic solvents compared to the pristine graphene, which opens the door for their applications in various polymer matrixes. The strategy demonstrated here provides a new methodology to get smart graphene dispersions with multiple functions.展开更多
基金supported by the National Natural Science Foundation of China(21402215 and 61474124)the Hundred Talents Program of the Chinese Academy of Sciences(Y20245YBR1)
文摘Carbon quantum dots（CQDs） have emerged as a new generation of photoluminescent nanomaterials with wide applications.Among the various synthetic routes for CQDs,the acid-refluxing method,which belongs to the group of ＂top-down＂ methods,offers the advantage of large-scale production of CQDs and uses cheap and abundantly available starting materials.In this study,we evaluated the potential of fullerene carbon soot（FCS）,a by-product obtained during the synthesis of fullerene,as the starting material for CQD production.It was found that FCS can be successfully converted to CQDs in high production yield in mixed acids,i.e.,concentrated HNO_3 and H_2SO_4,under mild conditions.The fluorescence quantum yield（0） of the as-produced CQDs is in the range of 3%-5%,which is the highest value for CQDs obtained from ＂top-down＂ methods.Importantly,the CQDs prepared by this method show emission in the yellow range of the visible light,which is advantageous for their various potential applications.Further investigations reveal that the CQDs are highly photostable over a wide pH range and show good resistance against ionic strength and long-term UV irradiation.This further expands their potential use under harsh conditions.
基金supported by the Hundred Talents Program of Chinese Academy of Sciences(Y20245YBR1)the National Natural Science Foundation of China(21402215 and 61474124)the financial support from Shandong Province Higher Education Science and Technology Program(J16LA01)
文摘Large-scale production of graphene and sub- sequent sample engineering is the key for fully-realizing the potential applications proposed to this intriguing two-dimensional nanomaterial. Herein, smart graphene dispersions with low defects and thermo-responsive properties can be obtained by liquid phase exfoliation of graphite using an alkylated Percec monodendron （3,4,5-trioctadecy- loxybenzaldehyde, 1） as the stabilizing reagent. By simply changing the temperature, the dispersed graphene and 1 can be detached, leading to the recovery of both components. Besides noncovalent wrapping, the stabilizing reagent 1 can be also covalently attached to graphene through [3＋2] cycloaddition. The covalently functionalized graphene sheets show improved dispersibility in organic solvents compared to the pristine graphene, which opens the door for their applications in various polymer matrixes. The strategy demonstrated here provides a new methodology to get smart graphene dispersions with multiple functions.
