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Harnessing Vis-NIR broad spectrum for photocatalytic CO2 reduction over carbon quantum dots-decorated ultrathin Bi2WO6 nanosheets

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Nano Research 2017年第5期10卷 1720-1731页

作者： Xin Ying Kong Wen Liang Tan Boon-Junn Ng Siang-Piao Chai Abdul Rahman Mohamed Multidisciplinary Platform of Advanced Engineering Chemical Engineering Discipline School of Engineering Monash University Jalan Lagoon Selatan 47S00 Bandar Sunway Selangor Malaysia Low carbon Economy (LCE) Group School of Chemical Engineering Engineering Campus Universiti Sains Malaysia Seri Ampangan 14300 Nibong Tebal Pulau Pinang Malaysia

The photocatalytic reduction of CO2 to energy-rich hydrocarbon fuels is a promising and sustainable method of addressing global warming and the imminent energy crisis concomitantly. However, a vast majority of the existing photocatalysts are only capable of harnessing ultraviolet （UV） or/and visible light （Vis）, whereas the near-infrared （NIR） region still remains unexplored. In this study, carbon quantum dots （CQDs）-decorated ultrathin BizWO6 nanosheets （UBW） were demonstrated to be an efficient photocatalyst for CO2 photoreduction over the Vis-NIR broad spectrum. It is noteworthy that the synthesis procedure of the CQDs/UBW hybrid nanocomposites was highly facile, involving a one-pot hexadecyltrimethylammonium bromide （CTAB）-assisted hydrothermal process. Under visible light irradiation, the optimized 1CQDsAJBW （1 wt.% CQD content） exhibited a remarkable 9.5-fold and 3.1-fold enhancement of CH4 production over pristine Bi2WO6 nanoplatelets （PBW） and bare UBW, respectively. More importantly, the photocatalytic responsiveness of CQDs/UBW was successfully extended to the NIR region, which was achieved without involving any rare earth or noble metals. The realization of NIR-driven CO2 reduction could be attributed to the synergistic effects of （i） the ultrathin nanostructures and highly exposed {001} active facets of UBW, （ii） the excellent spectral coupling of UBW and CQDs, where UBW could be excited by the up-converted photoluminescence of CQDs, and （iii） the electron-withdrawing nature of the CQDs to trap the photogenerated electrons and retard the recombination of charge carriers.

关键词： photocatalysis CO2 reduction near-infrared (NIR) light carbon quantum dots bismuth tungstate ultrathin nanosheets

The resistance switching performance of the memristor improved effectively by inserting carbon quantum dots(CQDs)for digital information processing

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Nano Research 2024年第9期17卷 8438-8446页

作者： Tianqi Yu Jie Li Wei Lei Suhaidi Shafe Mohd Nazim Mohtar Nattha Jindapetch Paphavee van Dommelen Zhiwei Zhao Joint International Research Laboratory of Information Display and Visualization School of Electronic Science and EngineeringSoutheast UniversityNanjing 210096China Institute of Nanoscience and Nanotechnology University Putra MalaysiaSerdangSelangor 43400Malaysia Department of Electrical Engineering Faculty of EngineeringPrince of Songkla UniversityHat YaiSongkhla 90112Thailand Division of Physical Science Faculty of SciencePrince of Songkla UniversityHat Yai Campus 15 KarnjanavanichHat YaiSongkhla 90110Thailand

As an emerging information device that adapts to development of the big data era,memristor has attracted much attention due to its advantage in processing massive ***,the nucleation and growth of conductive filaments often exhibit randomness and instability,which undoubtedly leads to a wide and discrete range of switching parameters,damaging the electrical performance of *** this work,a strategy of inserting carbon quantum dots(CQDs)into graphene oxide(GO)resistance layer is utilized to improve the stability of the switching parameters and the reliability of the device is *** with GO-based devices,GO/CQDs/GO-based devices exhibit a more stable resistance switching curve,low power,lower and more concentrated threshold voltage parameters with lower variation coefficient,faster switching speed,and more stable retention and *** cause-inducing performance improvement may be attributed to the local electric field generated by CQDs in resistance switching that effectively guides the formation and rupture of conductive filaments,which optimizes the effective migration distance of Ag^(+),thereby improving the uniformity of resistance ***,a convolutional neural network model is constructed to identify the CIFAR-10 data set,showing the high recognition accuracy of online and offline *** cross-kernel structure is used to further implement convolutional image processing through multiplication and accumulation *** work provides a solution to improve the performance of memristors,which can contribute to developing digital information processing.

关键词： carbon quantum dots memristor uniformity convolutional neural network convolutional image processing

Photoluminescence of carbon quantum dots:coarsely adjusted by quantum confinement effects and finely by surface trap states

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Science China Chemistry 2018年第4期61卷 490-496页

作者： Zexi Liu Hongyan Zou Ni Wang Tong Yang Zhewei Peng Jian Wang Na Li Chengzhi Huang Key Laboratory of Luminescent and Real-Time Analytical Chemistry(Southwest University) Ministry of EducationCollege of Pharmaceutical ScienceSouthwest UniversityChongqing 400715China Chongqing Key Laboratory of Biomedical Analysis(Southwest University) Chongqing Science&Technology CommissionCollege of Chemistry and Chemical EngineeringSouthwest UniversityChongqing 400715China Beijing National Laboratory for Molecular Sciences Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of EducationInstitute of Analytical ChemistryCollege of Chemistry and Molecular EngineeringPeking UniversityBeoing 100871China

Photoluminescence(PL) mechanism of carbon quantum dots(CQDs) remains controversial up to now even though a lot of approaches have been made. In order to do that, herein a PL color ladder from blue to near infrared of CQDs with the absolute quantum yields higher than 70% were prepared via a one-pot hydrothermal synthesis route and separated by silica gel ***-correlated single photon counting measurements suggest that the electron transition takes in effect in the PL progress of the crystalline core-shell structured CQDs, and the PL properties could be coarsely adjusted by tuning the size of the crystalline carbon core owing to quantum confinement effects, and finely adjusted by changing the surface functional groups consisted shell owing to surface trap states,respectively. Both coarse and fine adjustments of PL, as optical and photoelectrical characterizations and density-functional theory(DFT) calculations have demonstrated, make it possible for top-level design and precise synthesis of new CQDs with specific optical properties.

关键词： carbon quantum dots quantum confinement effects surface trap states electron transition

Green synthesis of fluorescent carbon quantum dots and carbon spheres from pericarp

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Science China Chemistry 2015年第5期58卷 863-870页

作者： Wei Du Xiaoqian Xu Han Hao Rongmei Liu Di Zhang Feng Gao Qingyi Lu State Key Laboratory of Coordination Chemistry Nanjing National Laboratory of Microstructures Coordination Chemistry Institute Nanjing University Department of Materials Science and Engineering Nanjing University College of Biological and Chemical Engineering Anhui Polytechnic University

An economical idea was developed to synthesize fluorescent carbon quantum dots （CQDs） directly fl-om the refluxing extraction of orange pericarp via a hydrothermal technique. Hydrothermal temperatures and times were adjusted to control the particle sizes and the quantum yields of the obtained CQDs. The as-prepared carbon quantum dots showed narrow particle size distribution, good water solubility, and acceptable fluorescence lifetimes. Due to their high stability, these obtained carbon quantum dots have great application potential in nano-biotechnology. Furthermore, carbon spheres with uniform morphology and size can be easily obtained as the reaction byproducts of this green synthesis process.

关键词： carbon quantum dots carbon sphere green synthesis fluorescence

Engineering carbon quantum dots for photomediated theranostics

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Nano Research 2018年第1期11卷 1-41页

作者： Mahbub Hassan Vincent G. Gomes Alireza Dehghani Sara M. Ardekani School of Chemical and Biomolecular Engineering The University of Sydney NSW 2006 Australia

carbon quantum dots （CQDs） have emerged as potential alternatives to classical metal-based semiconductor quantum dots （QDs） due to the abundance of their precursors, their ease of synthesis, high biocompatibility, low cost, and particularly their strong photoresponsiveness, tunability, and stability. Light is a versatile, tunable stimulus that can provide spatiotemporal control. Its interaction with CQDs elicits interesting responses such as wavelength-dependent optical emissions, charge/electron transfer, and heat generation, processes that are suitable for a range of photomediated bioapplications. The carbogenic core and surface characteristics of CQDs can be tuned through versatile engineering strategies to endow specific optical and physicochemical properties, while conjugation with specific moieties can enable the design of targeted probes. Fundamental approaches to tune the responses of CQDs to photo-interactions and the design of bionanoprobes are presented, which enable biomedical applications involving diagnostics and therapeutics. These strategies represent comprehensive platforms for engineering multifunctional probes for nanomedicine, and the design of QD probes with a range of metal-free and emer^in~ 2D materials.

关键词： carbon quantum dots nanobiophotonics therapeutics diagnostics nanomedicine

Photophysical properties of nitrogen-doped carbon quantum dots synthesized by graphite

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Journal of Materiomics 2024年第4期10卷 828-836页

作者： Jia Liu Hailong Yu Guan Wang Shuang Yang Meichen Li Xin Zhang Yang Jia Yachen Gao School of Electronic Engineering Heilongjiang UniversityHarbin150080HeilongjiangChina College of Communication and Electronic Engineering Qiqihar UniversityQiqihar161000HeilongjiangChina

Here,nitrogen-doped carbon quantum dots(N-CQDs)were successfully synthesized by the solvothermal method using graphite as the carbon source and N,N-dimethylformamide as the nitrogen *** characterized the structure and chemical constitution of N-CQDs using X-ray diffraction,Fourier transform infrared spectroscopy and X-ray photoelectron *** investigated the pump-and temperature-dependent photoluminescence(PL)properties and the dynamic exciton recombination processes of N-CQDs,using both steady-state and time-resolved PL *** spectral results show that the PL emission peak located at 518 nm at room temperature,mainly originates from the n-π∗transition on the surface of *** pump fluence and PL integral intensity were analyzed to demonstrate the existence of single-photon excitation under the 405 nm laser *** the temperature increases,the non-radiative transition gradually increases,which decreases the PL intensity,the full width at half maxima first narrows and then widens and the PL lifetime gradually ***,we combined the N-CQDs with chip to prepare light-emitting diode(LED).The resulting chromaticity coordinate was obtained to be(0.29,0.40).This study offers a comprehensive understanding of the luminescence mechanism in N-doped CQDs and introduces a novel approach for the quickly fabrication of full-color display LEDs.

关键词： carbon quantum dots Nitrogen-doped Photoluminescence Temperature-dependent Non-radiative transition

Incorporation of Fluorescent carbon quantum dots into Metal-Organic Frameworks with Peroxidase-Mimicking Activity for High-Performance Ratiometric Fluorescent Biosensing

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Journal of Analysis and Testing 2023年第1期7卷 16-24页

作者： Qiuyu Ye Tao Dai Jin Shen Qin Xu Xiaoya Hu Yun Shu School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225002China

A new ratiometric fluorescent sensor based on the bifunctional carbon quantum dots(CQDs)@metal-organic framework(MOF)nanocomposite possessing peroxidase-mimicking catalytic and luminescent characteristics was developed for hydrogen peroxide(H_(2)O_(2))and cholesterol *** incorporation of fluorescent CQDs into the cavities of MIL-101(Fe)MOF with peroxidase-like activities endows the nanocomposite with bifunctional *** CQDs@MOF can oxidize o-phenylene-diamine to 2,3-diaminophenolazine by H_(2)O_(2)with yellow fluorescence(556 nm).Meantime,the intrinsic fluorescence signal(455 nm)of CQDs@MOF is inhibited due to the inner filter ***,the ratio of the fluorescent intensity is employed as the signal output to construct the H_(2)O_(2)ratiometric *** addition,the cholesterol can be determined by the ratiometric sensor with high *** addition,the total cholesterol in human serum is determined with high accuracy using our ratiometric *** ratiometric fluorescent platform based on the bifunctional CQDs@MOF provides new insights in the field of bio-sensing.

关键词： carbon quantum dots Metal-organic framework Peroxidase-like activity Ratiometric fluorescent detection

Preparation of a Novel Green Fluorescent carbon quantum dots and Application in Fe^(3+)-Specific Detection in Biological System

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Journal of Analysis and Testing 2024年第1期8卷 40-51页

作者： Xianfen Zhang Wenxian Wang Lijiao Guan Huajie Chen Dai Li Lipeng Zhang Saipeng Huang School of Chemical Engineering Northwest UniversityXi'an 710069China Chemical Technology Academy of Shandong Province Qingdao University of Science and TechnologyJinan250014China

Trace ferric ion(Fe^(3+))detection has attracted increasing attention as an essential and indispensable role in many physiological and pathological *** green-emitting carbon quantum dots(Green-CQDs)were obtained through a green and facile one-step hydrothermal method for the specific recognition and trace detection of Fe^(3+)in this *** optimal excitation and emission wavelengths of the CQDs were 395 nm and 490 nm,*** stokes shift was up to 95 nm,which can effectively reduce the background fluorescence *** addition,it also exhibited good water solubility,stability,and high *** fluorescence intensity of Green-CQDs was linearly related to the concentration of Fe^(3+)(range of 0-80μmol/L),and the detection limit was as low as 59 nmol/*** good properties were favorable and successful for Fe^(3+)detection in tap water,human serum samples and living *** addition,a fluorescence visual test paper(FP@CQDs)was prepared utilizing filter paper as carrier,which can quickly identify Fe^(3+)in real time,and is suitable for the visualization analysis of Fe^(3+)in *** an efficient nanoprobe,the Green-CQDs held great promise and bright prospects in practical application in prevention and early clinical diagnosis of Fe^(3+)-associated diseases.

关键词： carbon quantum dots Fluorescent Hydrothermal Fe^(3+)-specific detection Cell imaging

Red-emissive carbon quantum dots minimize phototoxicity for rapid and long-term lipid droplet monitoring

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Chinese Chemical Letters 2024年第10期35卷 341-347页

作者： Fengkai Zou Borui Su Han Leng Nini Xin Shichao Jiang Dan Wei Mei Yang Youhua Wang Hongsong Fan Department of Orthopedics Affiliated Hospital of Nantong UniversityNantong 226001China Graduate School Dalian Medical UniversityDalian 116044China National Engineering Research Center for Biomaterials College of Biomedical EngineeringSichuan UniversityChengdu 610064China School of Chemistry and Chemical Engineering Liaoning Normal UniversityDalian 116029China

Long-term fluorescence monitoring of subcellular organelles is crucial for cellular physiology and pathology *** droplets(LDs)are increasingly recognized for their involvement in various biological processes,to influence disease development through diverse behaviors However,existing LD probes face challenges in achieving high targeting and long-term monitoring due to poor photostability and long-term *** quantum dots(CQDs)have gained prominence due to their exceptional fluorescence properties,but their prevalent blue excitation wavelength presents difficulties for long-term ***,we synthesized red-emissive carbon quantum dot(R-CQDs)with superior photobleaching resistance and red-emission,thus enabling harmlessly fluorescence monitoring of cells longer than3 *** addition,R-CQD exhibits suitable amphiphilicity and remarkable solvatochromic effect,allowing rapid targeting to LDs for immediate imaging without cumbersome washing ***,R-CQD shows high performance for extended observation of dynamic LD behavior in various biological processes,which is confirmed by documenting the course of LDs during starvation as well as *** to commercial probes,R-CQD extends live cell imaging time by at least 9-fold,facilitating the study of LD behavioral characteristics under diverse physiological or pathological *** work provides a reliable fluorescence tool for tracking intercellular microenvironment dynamically thus to understand the divers biological or disease mechanism.

关键词： carbon quantum dots Solvatochromism Lipid droplet probe Fluorescence imaging Wash-free