碳化聚合物点：一种新型的单颗粒有机无机杂化体系

碳化聚合物点(CPDs)指通过自下而上法,经聚合、交联、碳化而形成的一种具有特殊的碳核和聚合物壳杂化结构.这种特殊的杂化结构赋予了CPDs独特的光学、电学等物理化学性质,作为一种新兴的零维碳纳米材料受到了广泛的研究关注.本文通过系统地总结与分析,强调了CPDs聚合-碳化的本质,把CPDs看作是一种新型的单颗粒有机无机杂化体系,并从CPDs的结构特点、制备、光电性质及其在光学和催化领域的应用4个角度总结了CPDs的研究进展.重点介绍了郑州大学碳点研究中心在CPDs的可控制备、发光机理、光学和催化领域的应用相关的研究工作,论述了CPDs未来发展所面临的问题与方向.     

碳化聚合物点发光主体的探究

以聚丙烯酸和乙二胺为原料, 通过水热法合成了碳化聚合物点(CPDs), 利用荧光光谱、 X射线光电子能谱和时间相关单光子计数等手段对3种不同碳化温度下形成的CPDs进行表征; 采用375 nm的紫外光对200 ℃下合成的CPDs进行光漂白, 分析了CPDs漂白前后的荧光寿命以及基团的变化, 探究了该CPDs的发光机理, 确定该CPDs具有碳核态和分子态共同控制的双发光中心.     

碳化聚合物点的核壳结构与功能

碳化聚合物点作为一类新型的荧光碳纳米点,其高量子产率、独特的碳核和聚合物壳的杂化结构和功能在近些年引起了广泛关注.本文通过系统总结、分析相关文献,揭示了碳化聚合物点不仅具有碳点的典型性质,也具有聚合物的性质.强调了碳化聚合物点的聚合-碳化的本质,并详细讨论了碳化聚合物点的结构特点、制备方法方面的普适性和规律性以及光致发光的机制.最后,基于碳化聚合物点的结构和性能调控,综述了其在传感、光电器件、催化和生物医学等不同领域的应用,并对碳化聚合物点的发展前景进行了展望.     

从量子点的角度审视碳点的研究进展

碳点不仅具有类似于传统量子点的强发光和小尺寸特性,还表现出传统量子点无法比拟的水相分散性和生物相容性等优势.作为量子点领域的一个新兴分支,碳点的结构、合成化学和光电性质与传统量子点显著不同,也为量子点的发展提供了新的机遇和挑战.随着碳点领域的迅速发展和不断深化,越来越有必要在一些基本概念上与传统量子点比较,并从传统量子点的角度澄清碳点的独特特征和关键挑战.本综述主要聚焦于基本结构、合成化学、光学性质和应用研究等四个方面,从传统量子点基础概念的角度来重新审视碳点领域的研究进展和挑战.     

荧光量子点的水相合成及其在化学和生物分析中的应用

荧光量子点(又称为半导体纳米晶体)是一种新兴的无机发光材料, 由于其具有独特的结构和光电性能, 在发光二极管、太阳能电池及生命科学等领域有广泛的应用. 目前, 有机相合成法和水相合成法已被成功地用于荧光量子点的合成. 与有机相合成法相比, 水相合成量子点方法简单、绿色且廉价, 合成的量子点水溶性好, 在生物医学等领域具有很好的应用前景. 本文主要介绍荧光量子点的水相合成方法及其在化学和生物分析中的应用, 并对其发展趋势进行了展望.     

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。     

纳米碳点的制备与应用研究进展

纳米碳点是碳纳米材料家族的新成员,近年来在国内外受到广泛关注。与传统的荧光染料和半导体量子点发光材料相比,碳点不仅具有优异的光学性能及尺寸效应,且具有制备成本低廉、生物相容性好、易于官能化、能带结构可调等优势。本文在理清有关碳点概念的基础之上,介绍了碳点结构特征和制备策略,着重综述了纳米碳点在生物成像与诊疗、传感器件、催化、光电器件和能量存储领域的最新研究进展,探讨了碳点研究目前存在的问题及未来的发展方向。     

碳点的制备及电化学能源应用进展

碳点是零维纳米碳材料的一种典型代表,由碳原子sp²/sp³杂化构成且尺寸通常小于10 nm.碳点独特的尺寸效应赋予其丰富的边缘活性位点和易于功能化调控等特性,在电催化、能源存储与转化等领域表现出广阔的应用前景.基于此,揭示碳点的形成机制及阐明其结构与性能的基本规律,以指导碳点的合成并获得优异的催化性能具有重要意义.本文在介绍碳点制备及调控策略的基础上,结合理论研究分析了碳点类催化材料活性的来源,并着重评述了碳点在电化学领域的最新应用进展,探讨了功能碳点材料未来发展的机遇与挑战.     

碳化聚合物点的核壳结构与功能

碳化聚合物点作为一类新型的荧光碳纳米点，其高量子产率、独特的碳核和聚合物壳的杂化结构和功能在近些年引起了广泛关注.本文通过系统总结、分析相关文献，揭示了碳化聚合物点不仅具有碳点的典型性质，也具有聚合物的性质.强调了碳化聚合物点的聚合-碳化的本质，并详细讨论了碳化聚合物点的结构特点、制备方法方面的普适性和规律性以及光致发光的机制.最后，基于碳化聚合物点的结构和性能调控，综述了其在传感、光电器件、催化和生物医学等不同领域的应用，并对碳化聚合物点的发展前景进行了展望.     

碳量子点上转换材料的制备及其应用研究进展

碳量子点(CQD)具有化学惰性,生物相容性和低毒性等优势,可能在能源、生物医药等领域得到广泛的应用. CQD可通过表面被聚合物(例如PEG)钝化而表现出很强的光致发光特性.在生物成像,疾病检测和药物输送中使用表面钝化后的功能化生物分子更为有效.并且碳材料由于其优异的电化学性能还展现出在催化、电子器件等许多领域广泛的应用前景.我们将对近年来碳量子点发光材料的研究进行总结,并讨论碳量子点在能源、环境和其他一些领域的应用.     

Polymerization-Driven Photoluminescence in Alkanolamine-Based C-Dots

Carbonized polymer dots (CPDs), a peculiar type of carbon dots, show extremely high quantum yields, making them very attractive nanostructures for application in optics and biophotonics. The origin of the strong photoluminescence of CPDs resides in a complicated interplay of several radiative mechanisms. To understand the correlation between CPD processing and properties, the early stage formation of carbonized polymer dots has been studied. In the synthesis, citric acid monohydrate and 2-amino-2-(hydroxymethyl)propane-1,3-diol have been thermally degraded at 180 °C. The use of an oil bath instead of a more traditional hydrothermal reactor has allowed the CPD properties to be monitored at different reactions times. Transmission electron microscopy, time-resolved photoluminescence, nuclear magnetic resonance, infrared, and Raman spectroscopy have revealed the formation of polymeric species with amide and ester bonds. Quantum chemistry calculations have been employed to investigate the origin of CPD electronic transitions. At short reaction times, amorphous C-dots with 80 % quantum yield, have been obtained.     

Controllable Photoelectric Properties of Carbon Dots and Their Application in Organic Solar Cells

Organic solar cells are a current research hotspot in the energy field because of their advantages of lightness,translucency,roll to roll printing and building integration.With the rapid development of small molecule acceptor materials with high-performance,the efficiency of organic solar cells has been greatly improved.Further improving the device efficiency and stability and reducing the cost of active layer materials will contribute to the industrial development of organic solar cells.As a novel type of carbon nanomaterials,carbon dots gradually show great application potential in the field of organic solar cells due to their advantages of low preparation cost,non-toxicity and excellent photoelectric performance.Firstly,the synthesis and classification of carbon dots are briefly introduced.Secondly,the photoelectric properties of carbon dots and their adjusting,including adjustable surface energy level structure,good film-forming performance and up/down conversion characteristics are summarized.Thirdly,based on these intrinsic properties,the feasibility and advantages of carbon dots used in organic solar cells are discussed.Fourthly,the application progress of carbon dots in the active layer,hole transport layer,electron transport layer,interface modification layer and down-conversion materials of organic solar cells is also reviewed.Finally,the application progress of carbon dots in organic solar cells is prospected.Several further research directions,including in-depth exploration of the controllable preparation of carbon dots and their application in the fields of interface layer and up/down conversion for improving efficiency and stability of device are pointed out.     

Polymer types regulation strategy toward the synthesis of carbonized polymer dots with excitation-wavelength dependent or independent fluorescence

Three kinds of carbonized polymer dots (CPDs) synthesized via a one-pot process from o-phenylenediamine (OPD), m-phenylenediamine (MPD) and p-phenylenediamine (PPD) exhibit excitation-wavelength independent yellow, green and red emissions, respectively. In sharp contrast, two kinds of CPDs prepared via a hydrothermal process from citric acid (CA) and diethylenetriamine (DETA) exhibit obvious excitation-wavelength dependent emissions. Through the characterization and comparison of the two types of CPDs, it is concretely revealed that the polymer structure types during the formation of CPDs can effectively control the fluorescence excitation-wavelength independence/dependence. The homogeneous polymer structures contained in CPDs contribute to excitation-wavelength independence, whereas random copolymer structures contribute to excitation-wavelength dependence. These studies are of great significance for further understanding the polymer structures and designing unique optical properties of CPDs.     

Quantum Dots Arrangement and Energy Transfer Control via Charge‐Transfer Complex Achieved on Poly(Phenylene Ethynylene)/Schizophyllan Nanowires

Assemblies of organic and inorganic compounds in the nanoscale region have contributed to the development of novel functional materials toward future applications, including sensors and opto‐electronics. We succeed in fabricating hybrid nanowires composed of a conjugated polymer and semiconductor quantum dots (QDs) by a supramolecular assembly technique. The 1‐D fashion of the nanowire structure is obtained by the polymer wrapping of cationic poly(phenylene ethynylene) (PPE) with helix‐forming polysaccharide schizophyllan (SPG). The electrostatic interaction between cationic PPE and anionic QDs affords the nanowires decorated with QDs. Upon addition of an acceptor molecule, tetranitrofluorenone (TNF), the charge‐transfer (CT) complex between PPE and TNF is formed, resulting in energy transfer from the QDs to PPE arising from the induced spectral overlap. Furthermore, the employment of the conjugated polymer allows highly sensitive quenching of the QD’s emission by raising the transmission efficiency to the CT complexed electron deficient sites along the polymer backbone.     

The necessity of structural irregularities for the chemical applications of graphene

Graphene is a fashionable material in the realm of nanotechnology, but its potentials are somehow misunderstood. Although a defect-free flat graphene looks perfect with exceptional mechanical properties, this perfectly ordered hexagonal structure is chemically less active, and not of practical interest in the applications involving chemical reactions. In most applications (e.g., in sensors, energy storage, electrochemical systems, catalysis, etc.) of graphene, the superior properties are usually because of the reactivity of intrinsic defects and dangling bonds. Unfortunately, the ordered structure of graphene mistakenly gets all the credits, and then, all attentions and even market supplies are shifted towards ideal graphene (i.e., chemically inert). There is a gradual shift to using graphene nanoribbons and quantum dots instead of ideal seamless graphene because the results are better. Understanding the roles of possible irregularities can pave the path for subtly designing graphene for the practical applications. Reducing the reactive sites may make graphene more well-defined structure-wise but practically less useful. While briefly describing common approaches for manipulating the classic structure of graphene, we summarize their successful utilization for various applications, e.g., in electrochemistry, luminescence, and catalysis.     

Achieving blue water-dispersed room-temperature phosphorescence of carbonized polymer dots through nano-compositing with mesoporous silica

Stabilizing triplet excited states is important for room temperature phosphorescence (RTP) materials to achieve multifunctional applications in humid environment. However, due to the lack of preparation strategies, the realization of RTP materials in water still faces challenges. Herein, a new design strategy was presented to achieve RTP in water by confining carbonized polymer dots (CPDs) in amino functional mesoporous silica (MSNs-NH₂). The as-prepared MSNs-CPDs aqueous dispersion exhibited blue afterglow, lasting more than 3 s to naked eyes. The triplet excited states were protected from non-radiative deactivation by the double-confinement effect including covalent bonding fixation and mesoporous structure confinement. The MSNs-CPDs inherited the structure of MSNs-NH₂, so the stability of morphology and properties were superior to CPDs and even most of silica-based CPDs RTP materials. A water-related encryption technique demonstrated the promising application of MSNs-CPDs as smart materials in the field of information security. Besides, the possibility of potential application in ion detection was also explored.     

Unraveling the Structure Transition and Peroxidase Mimic Activity of Copper Sites over Atomically Dispersed Copper-Doped Carbonized Polymer Dots

The lack of systematic structural resolution makes it difficult to build specific transition-metal-atom-doped carbonized polymer dots (TMA-doped CPDs). Herein, the structure-activity relationship between Cu atoms and CPDs was evaluated by studying the peroxidase-like properties of Glu−Cu−CPDs prepared by using copper glutamate (Glu) with a Cu−N₂O₂ initial structure. The results showed that the Cu atoms bound to Glu−Cu−CPDs in the form of Cu−N₂C₂, indicating that Cu−O bonds changed into Cu−C bonds under hydrothermal conditions. This phenomenon was also observed in other copper-doped CPDs. Moreover, the carboxyl and amino groups content decreased after copper-atom doping. Theoretical calculations revealed a dual-site catalytic mechanism for catalyzing H₂O₂. The detection of intracellular H₂O₂ suggested their application prospects. Our study provides an in-depth understanding of the formation and catalytic mechanism of TMA-doped-CPDs, allowing for the generation specific TMA-doped-CPDs.     

Photophysical Properties of Au‐CdTe Hybrid Nanostructures of Varying Sizes and Shapes

We design well‐defined metal‐semiconductor nanostructures using thiol‐functionalized CdTe quantum dots (QDs)/quantum rods (QRs) with bovine serum albumin (BSA) protein‐conjugated Au nanoparticles (NPs)/nanorods (NRs) in aqueous solution. The main focus of this article is to address the impacts of size and shape on the photophysical properties, including radiative and nonradiative decay processes and energy transfers, of Au‐CdTe hybrid nanostructures. The red shifting of the plasmonic band and the strong photoluminescence (PL) quenching reveal a strong interaction between plasmons and excitons in these Au‐CdTe hybrid nanostructures. The PL quenching of CdTe QDs varies from 40 to 86 % by changing the size and shape of the Au NPs. The radiative as well as the nonradiative decay rates of the CdTe QDs/QRs are found to be affected in the presence of both Au NPs and NRs. A significant change in the nonradiative decay rate from 4.72×10⁶ to 3.92×10¹⁰ s^?1 is obtained for Au NR‐conjugated CdTe QDs. It is seen that the sizes and shapes of the Au NPs have a pronounced effect on the distance‐dependent energy transfer. Such metal‐semiconductor hybrid nanostructures should have great potentials for nonlinear optical properties, photovoltaic devices, and chemical sensors.     

The fabrication strategies and enhanced performances of metal-organic frameworks and carbon dots composites: State of the art review

Metal-organic frameworks (MOFs) with large specific surface area, considerable pore volume, controllable structure, and high concentration of active metal sites have been applied widely in researches like catalysis and sensing. However, potential applications of MOFs in both photocatalysis and luminescence sensors are facing major challenges arising from their severe charge recombination, low utilization of solar energy, low quantum yield, limited charge transfer between the metal ions/clusters and the ligand. Recent studies revealed that rational introduction of carbon dots (CDs) with excellent optical properties, unique quantum confinement and high conductivity can greatly enhance the functions of MOFs. In this paper, typical synthesis methods of these CD-MOF composites as well as their potential applications in photocatalysis and sensing are reviewed with emphasis. Representative examples of these CD-MOF composites are discussed, and key features and advantages of CD-MOF composites that will facilitate future applications are highlighted.