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Yang Liu - One of the best experts on this subject based on the ideXlab platform.

  • Facile synthesis and characterization of Carbon Quantum Dots and photovoltaic applications
    Thin Solid Films, 2018
    Co-Authors: Hwain Lim, Yang Liu, Hak Yong Kim, Dong Ick Son
    Abstract:

    Abstract In this paper, we report the synthesis and characterization of Carbon Quantum Dots that were easily obtained from citric acid and ethanediamine. The synthesized Carbon Quantum Dots (QDs) had various wavelengths and improved electron extraction. We fabricated photovoltaic cells based on these QDs-integrated in polymer nanocomposite used as an interlayer (electron extraction layer) consisting of Carbon QDs dispersed by spin coating on an ethoxylated polyethylenimine. In addition, we investigated the photovoltaic performance of the photovoltaic cells.

  • One-step synthesis of chiral Carbon Quantum Dots and their enantioselective recognition
    RSC Advances, 2016
    Co-Authors: Yalin Zhang, Yue Sun, Cheng Zhu, Naiyun Liu, Hui Huang, Yang Liu, Cheng Zhi Huang, Zhenhui Kang
    Abstract:

    Chiral Carbon Quantum Dots (L-Carbon Quantum Dots, L-CQDs; and D-Carbon Quantum Dots, D-CQDs) were synthesized through the facile hydrothermal treatment of Carbonated citric acid and L-cysteine (or D-cysteine). The chirality in L-CQDs and D-CQDs was demonstrated by circular dichroism. Both L-Carbon Quantum Dots and D-Carbon Quantum Dots could exhibit good enantioselective recognition ability.

  • Silver modified Carbon Quantum Dots for solvent-free selective oxidation of cyclohexane
    New Journal of Chemistry, 2015
    Co-Authors: Yanmei Yang, Naiyun Liu, Hui Huang, Shi Qiao, Ruihua Liu, Yang Liu
    Abstract:

    Despite tremendous efforts devoted to the study of new nanocatalysts, obtaining effective nanocatalysts for the oxidation of cyclohexane under mild conditions is still a great challenge. The silver modified Carbon Quantum Dots were synthesized by a simple chemistry method and demonstrated to exhibit excellent catalytic ability for cyclohexane oxidation (conversion based on cyclohexane reached about 58.9% and selectivity to cyclohexanone reached about 84.6%) under visible light, which can be attributed to the synergistic catalysis of Ag nanoparticles and Carbon Quantum Dots. Besides, the Carbon Quantum Dots can stabilize Ag nanoparticles for the prevention of aggregation. Moreover, the silver modified Carbon Quantum Dots showed good reusability, being reused after ten consecutive runs. Based on a series of experiments, it can be concluded that the silver modified Carbon Quantum Dots are green and efficient nanocatalysts for the oxidation of cyclohexane.

  • Carbon Quantum Dots enhance the photocatalytic performance of BiVO4 with different exposed facets.
    Dalton transactions (Cambridge England : 2003), 2013
    Co-Authors: Di Tang, Hui Huang, Yang Liu, Ruihua Liu, Hengchao Zhang, Yuzhi Han, Cuiyan Tong, Zhenhui Kang
    Abstract:

    Carbon Quantum Dots (CQDs) were demonstrated to have the ability to enhance the photocatalytic performance of monoclinic BiVO4 with different exposed facets under visible light.

  • Highly sensitive humidity sensing properties of Carbon Quantum Dots films
    Materials Research Bulletin, 2013
    Co-Authors: Xing Zhang, Yang Liu, Zhenhui Kang, Ruihua Liu, Hai Ming, Xiao Han, Yonglai Zhang
    Abstract:

    Graphical abstract: Display Omitted Highlights: ► A humidity sensing device was fabricated based on Carbon Quantum Dots (CQDs) films. ► The conductivity of the CQDs films shows a linear and rapid response to atmosphere humidity. ► The humidity sensing property was due to the hydrogen bonds between the functional groups on CQDs. -- Abstract: We reported the fabrication of a humidity sensing device based on Carbon Quantum Dots (CQDs) film. The conductivity of the CQDs film has a linear and rapid response to relative humidity, providing the opportunity for the fabrication of humidity sensing devices. The mechanism of our humidity sensor was proposed to be the formation of hydrogen bonds between Carbon Quantum Dots and water molecules in the humidity environment, which significantly promote the electrons migration. In a control experiment, this hypothesis was confirmed by comparing the humidity sensitivity of candle soot (i.e. Carbon nanoparticles) with and without oxygen containing groups on the surfaces.

Hui Feng - One of the best experts on this subject based on the ideXlab platform.

  • Functional Carbon Quantum Dots: A Versatile Platform for Chemosensing and Biosensing.
    Chemical record (New York N.Y.), 2017
    Co-Authors: Hui Feng, Zhaosheng Qian
    Abstract:

    Carbon Quantum dot has emerged as a new promising fluorescent nanomaterial due to its excellent optical properties, outstanding biocompatibility and accessible fabrication methods, and has shown huge application perspective in a variety of areas, especially in chemosensing and biosensing applications. In this personal account, we give a brief overview of Carbon Quantum Dots from its origin and preparation methods, present some advance on fluorescence origin of Carbon Quantum Dots, and focus on development of chemosensors and biosensors based on functional Carbon Quantum Dots. Comprehensive advances on functional Carbon Quantum Dots as a versatile platform for sensing from our group are included and summarized as well as some typical examples from the other groups. The biosensing applications of functional Carbon Quantum Dots are highlighted from selective assays of enzyme activity to fluorescent identification of cancer cells and bacteria.

  • reversible fluorescent nanoswitch based on Carbon Quantum Dots nanoassembly for real time acid phosphatase activity monitoring
    Analytical Chemistry, 2015
    Co-Authors: Zhaosheng Qian, Lujing Chai, Jianrong Chen, Qian Zhou, Yuanyuan Huang, Cong Tang, Hui Feng
    Abstract:

    A reversible fluorescence nanoswitch by integrating Carbon Quantum Dots nanoassembly and pyrophosphate ion is developed, and a reliable real-time fluorescent assay for acid phosphatase (ACP) activity is established on the basis of the fluorescence nanoswitch. Carbon Quantum Dots (CQDs) abundant in carboxyl groups on the surface, nickel(II) ion and pyrophosphate ion comprise the fluorescent nanoswitch, which operates in the following way: the nanoassembly consisting of CQDs and nickel ions can be triggered by pyrophosphate ion serving as an external stimulus. At the same time, the fluorescence nanoswitch switches between two fluorescence states (OFF and ON) accompanying shifts in their physical states aggregation and disaggregation. Based on the nanoswitch, the introduction of ACP leads to breakdown of pyrophosphate ions into phosphate ions and resultant fluorescence quenching due to catalytic hydrolysis of ACP toward pyrophosphate ions (PPi). Quantitative evaluation of ACP activity in a broad range from 1...

  • si doped Carbon Quantum Dots a facile and general preparation strategy bioimaging application and multifunctional sensor
    ACS Applied Materials & Interfaces, 2014
    Co-Authors: Zhaosheng Qian, Xiaoyue Shan, Lujing Chai, Jianrong Chen, Hui Feng
    Abstract:

    Heteroatom doping of Carbon Quantum Dots not only enables great improvement of fluorescence efficiency and tunability of fluorescence emission, but also provides active sites in Carbon Dots to broaden their application in sensor. Silicon as a biocompatible element offers a promising direction for doping of Carbon Quantum Dots. Si-doped Carbon Quantum Dots (SiCQDs) were synthesized through a facile and effective approach. The as-prepared Si-doped Carbon Quantum Dots possess visible fluorescence with high Quantum yield up to 19.2%, owing to fluorescence enhancement effect of introduced silicon atoms into Carbon Dots. The toxicity test on human Hela cells showed that SiCQDs have lower cellular toxicity than common CQDs, and bioimaging experiments clearly demonstrated their excellent biolabelling ability and outstanding performance in resistance to photobleaching. Strong fluorescence quenching effect of Fe(III) on SiCQDs can be used for its selective detection among general metal ions. Specific electron trans...

  • b doped Carbon Quantum Dots as a sensitive fluorescence probe for hydrogen peroxide and glucose detection
    Analyst, 2014
    Co-Authors: Xiaoyue Shan, Zhaosheng Qian, Lujing Chai, Jianrong Chen, Hui Feng
    Abstract:

    Fluorescent B-doped Carbon Quantum Dots (BCQDs) were prepared by a facile one-pot solvothermal route. The BCQDs can be used as a novel fluorescence sensing system for hydrogen peroxide and glucose detection.

  • highly luminescent n doped Carbon Quantum Dots as an effective multifunctional fluorescence sensing platform
    Chemistry: A European Journal, 2014
    Co-Authors: Zhaosheng Qian, Hui Feng, Xiaoyue Shan, Linxiang Shao, Jianrong Chen
    Abstract:

    The doping of Carbon Quantum Dots with nitrogen provides a promising direction to improve fluorescence performance and broaden their applications in sensing systems. Herein we report a one-pot solvothermal synthesis of N-doped Carbon Quantum Dots (NCQDs) and the synthesis of a series of NCQDs with different nitrogen contents. The as-prepared NCQDs were compared with Carbon Quantum Dots (CQDs); the introduction of nitrogen atoms largely increased the Quantum yield of NCQDs and highest emission efficiency is up to 36.3 %. The fluorescence enhancement may originate from more polyaromatic structures induced by incorporated nitrogen atoms and protonation of nitrogen atoms on Dots. It was found that NCQDs can act as a multifunctional fluorescence sensing platform because they can be used to detect pH values, Ag(I), and Fe(III) in aqueous solution. The fluorescence intensity of NCQDs is inversely proportional to pH values across a broad range from 5.0 to 13.5, which indicates that NCQDs can be devised as an effective pH indicator. Selective detection of Ag(I) and Fe(III) was achieved based on their distinctive fluorescence influence because Ag(I) can significantly enhance the fluorescence whereas Fe(III) can greatly quench the fluorescence. The quantitative determination of Ag(I) can be accomplished with NCQDs by using the linear relationship between fluorescence intensity of NCQDs and concentration of Ag(I). The sensitive detection of H2O2 was developed by taking advantage of the distinct quenching ability of Fe(III) and Fe(II) toward the fluorescence of NCQDs. Cellular toxicity test showed NCQDs still retain low toxicity to cells despite the introduction of a great deal of nitrogen atoms. Moreover, bioimaging experiments demonstrated that NCQDs have stronger resistance to photobleaching than CQDs and more excellent fluorescence labeling performance.

Plinio Innocenzi - One of the best experts on this subject based on the ideXlab platform.

  • Energy Transfer Induced by Carbon Quantum Dots in Porous Zinc Oxide Nanocomposite Films
    The Journal of Physical Chemistry C, 2015
    Co-Authors: Kazumasa Suzuki, Luca Malfatti, Davide Carboni, Danilo Loche, Maria Francesca Casula, Alessandro Moretto, Michele Maggini, Masahide Takahashi, Plinio Innocenzi
    Abstract:

    A one-pot approach making use of a zinc oxide sol precursor and Carbon Quantum Dots, together with a partially fluorinated block copolymer as templating agent, has been used to synthesize a porous matrix characterized by interesting energy transfer properties. The choice of the fluorinated surfactant for inducing the porosity into the inorganic matrix has allowed an easy removal of the templating agent at low temperature, preserving at the same time the functional properties of the Carbon Quantum Dots. The resulting nanocomposite films have been characterized by steady-state 3D mapping that has evidenced a complex behavior as a function of the Carbon Quantum Dots concentration. In particular, the luminescence bands of the zinc oxide matrix appear to be modulated by the broad emission of the Carbon Quantum Dots, which depends on their aggregation state. These results can be thus considered as a step further toward the fine-tuning of the luminescence properties provided by zinc oxide-based nanocomposites as a result of a doping effect due to the presence of Carbon Quantum Dots.

Arunava Goswami - One of the best experts on this subject based on the ideXlab platform.

  • Room temperature and solvothermal green synthesis of self passivated Carbon Quantum Dots
    RSC Advances, 2013
    Co-Authors: Shouvik Mitra, Panchanan Pramanik, Sourov Chandra, Shaheen H. Pathan, Narattam Sikdar, Arunava Goswami
    Abstract:

    Highly fluorescent, self passivated Carbon Quantum Dots (CQDs) have been synthesized using PEG-200 at room temperature for the first time followed by solvothermal modification to increase the Quantum yield of these nano Carbons. At elevated temperature and pressure good surface passivation has been observed. No sophisticated instrument nor passivating agent is required to fabricate these CQDs, making the procedure unique and novel with respect to all the existing protocols. Solvothermally synthesized Carbon Quantum Dots (ST-CQDs) exhibited minimum toxicity and can be used easily for bioimaging.

  • Novel fluorescent matrix embedded Carbon Quantum Dots for the production of stable gold and silver hydrosols
    Journal of Materials Chemistry, 2011
    Co-Authors: Shouvik Mitra, Panchanan Pramanik, Sourov Chandra, Prasun Patra, Arunava Goswami
    Abstract:

    A facile one step route has been developed for the synthesis of highly fluorescent matrix embedded Carbon Quantum Dots (MCQDs) by the assistance of microwave irradiation. The material shows a homogeneous distribution of Carbon Quantum Dots throughout the surfaces of the Carbon matrices with an average size of 1 to 3 nm. The synthetic MCQDs can be employed as excellent catalysts during the synthesis of gold and silver nanoparticles.

Yang Jiao - One of the best experts on this subject based on the ideXlab platform.

  • Selenium‐Doped Carbon Quantum Dots for Free‐Radical Scavenging
    Angewandte Chemie (International ed. in English), 2017
    Co-Authors: Chenxing Sun, Jiahao Xia, Yang Jiao
    Abstract:

    Heteroatom doping is an effective way to adjust the fluorescent properties of Carbon Quantum Dots. However, selenium-doped Carbon Dots have rarely been reported, even though selenium has unique chemical properties such as redox-responsive properties owing to its special electronegativity. Herein, a facile and high-output strategy to fabricate selenium-doped Carbon Quantum Dots (Se-CQDs) with green fluorescence (Quantum yield 7.6 %) is developed through the hydrothermal treatment of selenocystine under mild conditions. Selenium heteroatoms endow the Se-CQDs with redox-dependent reversible fluorescence. Furthermore, free radicals such as . OH can be effectively scavenged by the Se-CQDs. Once Se-CQDs are internalized into cells, harmful high levels of reactive oxygen species (ROS) in the cells are decreased. This property makes the Se-CQDs capable of protecting biosystems from oxidative stress.

  • Selenium-Doped Carbon Quantum Dots (Se-CQDs) for Free Radical Scavenging
    Angewandte Chemie, 2017
    Co-Authors: Chenxing Sun, Jiahao Xia, Yang Jiao
    Abstract:

    Heteroatom doping is an effective way to adjust the fluorescent properties of Carbon Quantum Dots. However, selenium-doped Carbon Dots have rarely been reported even though selenium has unique chemical properties like redox-responsive properties owing to its special electronegativity. Herein, a facile and high-output strategy to fabricate selenium-doped Carbon Quantum Dots (Se-CQDs) with green fluorescence (Quantum yield 7.6 %) is developed through the hydrothermal treatment of selenocystine under mild conditions. Selenium heteroatoms endow the Se-CQDs with redox-dependent reversible fluorescence. In addition, free radicals such as *OH can be effectively scavenged by the Se-CQDs. Once Se-CQDs are internalized into cells, harmful high levels of reactive oxygen species (ROS) in the cells are reduced. This property makes the Se-CQDs capable of protecting the biosystems from oxidative stress.