交联剂改善羧基化石墨烯量子点荧光性能

Crosslinking Agents Enhancing Fluorescence Performance of Carboxylate Graphene Quantum Dots

1-(3-二甲氨基丙基)-3-乙基碳二亚胺盐酸盐(EDC)作为一种水溶性交联剂,目前广泛应用于纳米材料研究中。然而,其对石墨烯量子点(GQDs)的光学性质影响很少被关注。本工作以羧基化石墨烯量子点(CGQDs)为对象,研究EDC交联剂对C-GQDs光学性质的影响,改善了C-GQDs的荧光强度。实验中采用一步水相法得到C-GQDs与EDC复合物(C-GQDs/EDC)。实验结果表明,与EDC反应后,C-GQDs荧光显著增强约23倍。此外,也验证了溶液浓度、光辐照和反应时间等因素对荧光的影响。分析表明,C-GQDs的发光是本征态、表面态和缺陷态能级跃迁的多过程作用结果,而原C-GQDs中丰富的缺陷能级导致了发光性能的减弱。机理分析认为,EDC与羧基间发生的活化反应起到了表面缺陷钝化作用,提高了C-GQDs的表面态激子复合效率。该工作有效改善了C-GQDs发光强度低的问题,扩展了其在发光领域的应用前景,并为GQDs光学性质调控提供了参考方案。

1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride(EDC)as a water-soluble carbodiimide crosslinking agent,it is widely used in nanomaterial research.The utilization of EDC is as a key component in the de‐sign and functionalization of nanomaterials for diverse applications.This study focused on carboxyl-functionalized graphene quantum dots(C-GQDs)and investigated the impact of EDC on its optical properties which has received limited attention previously.This method can effectively enhance the fluorescence intensity of C-GQDs.In experi‐ments,C-GQDs and EDC were reacted to form C-GQDs/EDC complexes via a one-step aqueous method.Experimen‐tal results demonstrate that after reaction with EDC,the fluorescence of C-GQDs/EDC is significant enhanced by ap‐proximately 23 times.Additionally,the impact of factors such as solution concentration,light irradiation,and reac‐tion time on fluorescence were also validated.Fluorescence spectroscopy analysis indicates that the luminescence of C-GQDs is the result of a multi-process interplay involving intrinsic,surface,and defect-state energy level transi‐tions.Abundance of defect energy levels in original C-GQDs contributed to the weakened luminescent performance.The mechanistic analysis suggests that the activation reaction occurring between EDC and carboxyl groups plays a role in surface defect passivation,thereby improving the surface-state exciton recombination efficiency of C-GQDs.