制备条件对PEI功能化石墨烯量子点荧光性能的影响

石墨烯量子点凭借其良好的水溶性、低生物毒性等特点,被不断尝试应用于生物成像领域,但其有限的荧光性能限制了其进一步应用。为改善石墨烯量子点的荧光性能以及进一步揭示石墨烯量子点的制备机理,本文对聚乙烯亚胺(PEI)功能化石墨烯量子点的制备条件进行了探索,讨论了不同反应时间、制备温度以及混悬液pH值对其荧光性能的影响。测试结果显示,当混悬液pH值为12时,在反应釜中经过200 ℃高温反应20 h,所制备的功能化石墨烯量子点能取得良好的紫外吸收峰和荧光性能,同时达到较高的量子产量。     

基于Cite Space的碳量子点研究热点及趋势可视化分析

利用Cite Space软件梳理了碳量子点领域1998～2021年期间3465篇文献的主要研究信息（国家、机构、作者）,归纳了该领域的研究主题及热点。碳量子点作为一种具有良好荧光性能的碳纳米材料,在荧光检测、传感器、光催化降解等方面得到广泛应用。2011～2021年,碳量子点领域研究呈现高速发展态势。中国科学院、苏州大学及江苏大学等机构的学者在该领域的学术研究十分活跃。该领域的研究主题及热点呈现阶段性特点,2003～2007年,研究主题是碳量子点合成,研究热点是碳量子点的反应活性和转化率;2008～2012年,研究主题是碳量子点合成及发光机理,研究热点是碳量子点的光致发光机理和光催化降解;2013～2017年,研究主题是碳量子点绿色合成和传感器应用,研究热点是碳量子点传感器和检测应用;2018年至今,研究主题是碳量子点传感器以及复合碳量子点材料对有机污染物的光催化降解性能,研究热点是碳量子点在生物传感器,生物检测等领域的应用开发。     

发光碳量子点的合成、性质和应用

基于碳量子点具有良好的水溶性、化学惰性、低毒性、易于功能化和抗光漂白性等优异性能,碳量子点和其它的碳纳米材料（如富勒烯、碳纳米管和石墨烯等）同样引起了研究者广泛的关注。 碳量子点可以通过很多较为廉价的一步法进行大规模的制备,包括化学氧化法、超声法、微波法和激光烧蚀法等。 本文主要介绍了不同碳量子点的合成方法,以及依赖于碳量子点尺寸和波长等性质的发光性能,并且讨论了碳量子点在生物成像、光催化、能量转换/储存、光电子、光限幅和传感器等方面的应用。     

绿色、低成本球磨-水热法制备石墨烯量子点及其应用研究

以绿色、简单、成本低的球磨方法制备的石墨烯为碳源,采用一步水热法成功制备了分散性好、尺寸分布均一、平均直径为(4.80 ± 0.20) nm、厚度为1~3层石墨烯烯量子点.分别采用高分辨透射电镜、原子力显微镜、傅里叶变换红外光谱、X射线光电子能谱、紫外-可见吸收光谱、荧光光谱等对石墨烯量子点进行形貌、结构以及荧光性能的表征. 合成的石墨烯量子点可用于Fe.3+的非标记、特异性检测,检测线性范围为2.0×10.-6~7.0×10.-4 mol/L,检出限为1.8×10.-6 mol/L(S/N=3),同时对检测机理进行了推断,证明此石墨烯量子点用于自来水中Fe.3+的检测的可行性;基于其低毒性和优良的生物相容性,所制备的石墨烯量子点可应用于细胞成像研究.本研究为碳纳米材料的制备提供了一种新途径,也为石墨烯量子点在生化分析、成像等方面的研究奠定了基础.     

石墨烯-量子点复合材料的制备与应用

石墨烯因其独特的物理化学性质以及潜在的巨大应用价值引起了越来越多的研究兴趣,但其特殊的零带隙结构却限制了它在光电领域的应用。半导体量子点因其特有的量子尺寸效应而表现出迷人的光学性能,已成功应用于生物标记及电化学等领域,但电子-空穴对易复合湮灭,导致电子迁移率较低,限制了其在光电转换方面的应用。石墨烯独特的结构和电子特性使其成为优秀的导电支架,可从量子点中捕获并输运电子,实现了电子空穴对的有效分离。石墨烯-量子点复合材料不仅具有石墨烯的高电子传输性能,而且具备量子点特殊结构产生的量子尺寸效应和边缘效应,二者复合后在纳米器件和光电器件等领域极具应用潜力。本文详细总结了近年来石墨烯-量子点复合材料的制备方法,包括相转移法、静电复合、水热和溶剂热法以及电化学法和微波辅助法等,并简要介绍了相关应用领域的研究进展,以期为石墨烯基纳米复合材料的发展研究提供相关的参考与依据。     

氨基功能化石墨烯量子点表面缺陷钝化及其发光增强

通过酸氧化法将氧化石墨烯进一步“切割”制备石墨烯量子点（GQDs）,在100℃水热条件下,用氨水处理石墨烯量子点制备得到氨基功能化石墨烯量子点（N-GQDs）。傅里叶变换红外光谱证明NH₃可以有效地进攻环氧基碳和羧基碳,形成羟胺和酰胺基。原子力显微镜结果表明NH₃不仅能够有助于产生更小的量子点,还对石墨烯纳米片有致孔作用。氨基功能化之后,由于C-O-C相关的n-π^*跃迁受到抑制,N-GQDs发光具有更弱的激发波长依赖性,并使其荧光量子产率从0.3%提高至9.6%。时间分辨发光光谱表明,相比含氧基团,含氮基团相关的局域电子激发态具有更长的荧光寿命和更弱的发射光谱依赖性。     

碳量子点荧光探针的设计及其在农残检测中的应用进展

农药的长期、大量、不合理使用,对我国生态环境和农畜产品的安全生产及人体生命与健康构成了严重威胁。发展灵敏、高效的探针监测农药原体及其代谢产物对食品安全预警有重要意义。因此科研工作者致力于开发简单、高效的农残检测新策略。碳量子点作为一种新型荧光碳纳米材料,无毒无害,具有良好的稳定性及优越的光学性能,易于实现功能化,因此碳量子点荧光探针在农残检测方面极具应用潜力。该文对碳量子点荧光探针的研究进展进行综述,简述了碳量子点的特性及合成,重点介绍了碳量子点作为荧光探针在农残检测中的最新应用进展,并对其发展过程中尚待解决的问题进行总结,对未来发展方向进行展望。     

石墨烯量子点的合成及其在气体传感中的应用进展

石墨烯量子点(Graphene quantum dots,GQDs)作为一种零维碳纳米材料,不仅具备石墨烯的优异性能,还具有量子限域效应和边界效应,在气体传感检测领域具有重要的应用价值.采用不同的制备方法可得到不同尺寸的GQDs.利用GQDs自身表面丰富的官能团,通过与其它材料复合使其表面进一步功能化,可以满足检测不同...     

基于纸基的荧光碳量子点传感器的可视化检测研究进展

碳量子点作为一种新型的纳米材料,其独特的荧光性能使其在物质检测领域得到了越来越多的关注。利用碳量子点与物质反应导致荧光强度发生变化的特性,可将其应用于可视化检测,检测方法分为荧光猝灭型和荧光恢复型。基于纸基的荧光传感器与基于液相反应的荧光检测相比,其快速、现场和可视化的特点更加突出,因此有着更为广泛的应用。本文针对碳量子点的荧光特性、可视化荧光检测、纸基传感器的研究现状,并结合本课题组相关研究进展进行论述,以期为今后纸基碳量子点荧光传感器的研究和应用提供参考。     

石墨烯/CdTe量子点复合物的合成及在克伦特罗检测方面的应用

成功地合成了石墨烯/CdTe量子点复合物,并采用透射电镜、紫外吸收光谱、荧光发射光谱、荧光衰减曲线和X射线光电子能谱对产物进行了表征。透射电镜结果显示CdTe量子点被修饰于石墨烯的表面;X射线光电子能谱结果表示石墨烯在合成过程中被还原,还表明在所合材料的表面具有羧基和羟基;荧光发射光谱和荧光衰减曲线的结果显示将CdTe量子点修饰于石墨烯表面显著提高了CdTe量子点的荧光性能。此外,基于克伦特罗和石墨烯/CdTe量子点复合物之间形成的氢键,所合成材料可用于定量分析克伦特罗。克伦特罗对石墨烯/CdTe量子点复合物具有显著的猝灭作用,荧光强度的降低（F₀/F）与克伦特罗之间存在良好的线性关系,线性范围为7.22~108.30 μmol·L^-1,检出限为4 μmol·L^-1。     

Electrochemiluminescence of Carbon-based Quantum Dots: Synthesis,Mechanism and Application in Heavy Metal Ions Detection

In recent years, carbon-based quantum dots as luminophores and co-reactants have aroused broad interest for their ability to function in electrochemiluminescence (ECL) sensors due to their unique features, including excellent biocompatibility, low toxicity, and water solubility. In this mini review, the synthesis methods of carbon-based quantum dots are firstly introduced. Then, the mechanism of carbon-based quantum dots as luminophores and co-reactants and their latest progress application in the detection of heavy metal ions are explored. Finally, the current challenges and potential future development directions of carbon-based quantum dots in ECL sensing filed for heavy metal ions analysis are summarized.     

Mn,B, N co-doped graphene quantum dots for fluorescence sensing and biological imaging

The fluorescent and quantum yield (QY) of graphene quantum dots has been improved in recent years by doped atoms, which have good application prospects in fluorescence sensors and biological imaging. Here, a one-step hydrothermal synthesis method was used to synthesize manganese ions bonded with boron and nitrogen-doped graphene quantum dots (Mn-BN-GQDs). Compared with the boron and nitrogen co-doping graphene quantum dots (BN-GQDs), the fluorescence properties and quantum yield of Mn-BN-GQDs are significantly improved. Meanwhile, Mn-BN-GQDs exhibit low toxicity and good fluorescence imaging in living cells and has high selectivity to Fe³⁺ ions. Therefore, this experiment design Mn-BN-GQDs as a fluorescence sensor to detect Fe³⁺ ions, providing strong evidence for the advanced high sensitivity, selectivity and wide detection range of the Mn-BN-GQDs as a fluorescence sensor. These results indicate a dual linear relationship with good linear relationships in the 10–100 μM and 100–800 μM ranges, and limit of detection are 0.78 μM and 9.08 μM, respectively. Cellular imaging results demonstrate that Mn-BN-GQDs can be used as fluorescence sensors in biological imaging. Mn-BN-GQDs can be used for fluorescence sensing in biological imaging in combination with low toxicity, QY and quantum dot lifetime.     

Preparation and formaldehyde sensitive properties of N-GQDs/SnO2 nanocomposite

Graphene quantum dots (GQDs) have both the properties of graphene and semiconductor quantum dots, and exhibit stronger quantum confinement effect and boundary effect than graphene. In addition, the band gap of GQDs will transform to non-zero from 0 eV of graphene by surface functionalization, which can be dispersed in common solvents and compounded with solid materials. In this work, the SnO₂ nanosheets were prepared by hydrothermal method. As the sensitizer, nitrogen-doped graphene quantum dots (N-GQDs) were prepared and composited with SnO₂ nanosheets. Sensing performance of pristine SnO₂ and N-GQDs/SnO₂ were investigated with HCHO as the target gas. The response (R_a/R_g) of 0.1% N-GQDs/SnO₂ was 256 for 100 ppm HCHO at 60 °C, which was about 2.2 times higher than pristine SnO₂ nanosheet. In addition, the material also had excellent selectivity and low operation temperature. The high sensitivity of N-GQDs/SnO₂ was attributed to the increase of active sites on materials surface and the electrical regulation of N-GQDs. This research is helpful to develop new HCHO gas sensor and expand the application field of GQDs.     

基于柠檬酸的石墨烯量子点的制备及其应用

石墨烯量子点（GQDs）是一种新型碳基准零维材料,不但具有石墨烯的独特平面结构,同时具备碳点的量子限制效应和边界效应。GQDs具有独特的光学性质、低毒性、高荧光稳定性和高生物相容性,被广泛应用于检测、传感、催化、细胞成像、药物递送和污染治理等领域。GQDs的合成分为自上而下法和自下而上法,前者将大尺寸的石墨烯、石墨、碳材料切割成纳米级的量子点,后者使用不同的前驱体,通过水热法、热裂解法等方法合成石墨烯量子点。柠檬酸（CA）是一种重要的有机酸,室温下是白色结晶状粉末,是自下而上法合成GQDs的一种常用前驱体,近年来有许多关于以CA为前驱体合成不同GQDs的研究,以CA为前驱体合成的GQDs（CA-GQDs）在生物医药、荧光检测、成像等领域均有应用,具有较好的应用前景。对近年来基于CA的合成方法和具体应用进行了总结和回顾,旨在将现有CA-GQDs的相关成果尽可能汇总和展现,以对相关领域研究工作者提供一定参考,并对未来CA-GQDs较有前景的研究方向进行了展望。     

Fluorescent determination of graphene quantum dots in water samples

This work presents a simple, fast and sensitive method for the preconcentration and quantification of graphene quantum dots (GQDs) in aqueous samples. GQDs are considered an object of analysis (analyte) not an analytical tool which is the most frequent situation in Analytical Nanoscience and Nanotechnology. This approach is based on the preconcentration of graphene quantum dots on an anion exchange sorbent by solid phase extraction and their subsequent elution prior fluorimetric analysis of the solution containing graphene quantum dots. Parameters of the extraction procedure such as sample volume, type of solvent, sample pH, sample flow rate and elution conditions were investigated in order to achieve extraction efficiency. The limits of detection and quantification were 7.5 μg L⁻¹ and 25 μg L⁻¹, respectively. The precision for 200 μg L⁻¹, expressed as %RSD, was 2.8%. Recoveries percentages between 86.9 and 103.9% were obtained for two different concentration levels. Interferences from other nanoparticles were studied and no significant changes were observed at the concentration levels tested. Consequently, the optimized procedure has great potential to be applied to the determination of graphene quantum dots at trace levels in drinking and environmental waters.     

氮掺杂石墨烯量子点/钯纳米复合材料的研究

铂基催化剂因具有高催化活性、高稳定性而成为极其重要的能源转化催化剂。本文采用水热法合成氮掺杂石墨烯量子点支撑的钯纳米复合材料(Pd@N-GQDs),并将其用于碱性介质中甲醇的电催化氧化反应。实验结果表明,相比同类型材料钯负载于石墨烯纳米片(Pd@GS)、钯负载于石墨烯量子点(Pd@GQDs)和商业钯黑催化剂(Pd@C),Pd@N-GQDs纳米材料具有很高的催化活性和稳定性,并可减少催化剂材料中贵金属的使用量。     

Chlorine Modulation Fluorescent Performance of Seaweed-Derived Graphene Quantum Dots for Long-Wavelength Excitation Cell-Imaging Application

Biological imaging is an essential means of disease diagnosis. However, semiconductor quantum dots that are used in bioimaging applications comprise toxic metal elements that are nonbiodegradable, causing serious environmental problems. Herein, we developed a novel ecofriendly solvothermal method that uses ethanol as a solvent and doping with chlorine atoms to prepare highly fluorescent graphene quantum dots (GQDs) from seaweed. The GQDs doped with chlorine atoms exhibit high-intensity white fluorescence. Thus, their preliminary application in bioimaging has been confirmed. In addition, clear cell imaging could be performed at an excitation wavelength of 633 nm.     

Improving singlet oxygen generating abilities of phthalocyanines: aluminum tetrasulfonated phthalocyanine in the presence of graphene quantum dots and folic acid

Glutathione-capped graphene quantum dots (GQDs@GSH) were covalently linked to folic acid (FA). Aluminum tetrasulfonated phthalocyanine (ClAlTSPc) was then adsorbed on the GQDs@GSH-FA conjugate to form GQDs@GSH-FA/ClAlTSPc or on GQDs@GSH and pristine GQDs alone to form GQDs@GSH/ClAlTSPc and GQDs/ClAlTSPc, respectively. We report for the first time on the photophysicochemical behavior of the resulting nanoconjugates. The fluorescence quantum yields of pristine GQDs, GQDS@GSH, or GQDs@GSH-FA conjugate were quenched upon non-covalent interaction (π–π) with ClAlTSPc. There was an increase in triplet quantum yields from 0.38 for ClAlTSPc alone to 0.60, 0.75, and 0.73 when ClAlTSPc was linked to pristine GQDs, GQDs@GSH, and GQDs@GSH-FA, respectively. The singlet oxygen quantum yields also increased from 0.37 for ClAlTSPc alone to 0.42 (for ClALTSPc with pristine GQDs), 0.52 (for ClAlTSPc with GQDs@GSH), and 0.54 (for ClAlTSPc with GQDs@GSH-FA). Thus, the present work may lead to a new generation of carbon-based nanomaterial photodynamic therapy agents with overall performance superior to conventional agents in terms of singlet oxygen generation, water dispersibility, and biocompatibility.