At present, the actual mechanism of the photoluminescence （PL） of fluorescent carbon dots （CDs） is still an open debate among researchers. Because of the variety of CDs, it is highly important to summarize the PL ...At present, the actual mechanism of the photoluminescence （PL） of fluorescent carbon dots （CDs） is still an open debate among researchers. Because of the variety of CDs, it is highly important to summarize the PL mechanism for these kinds of carbon materials; doing so can guide the development of effective synthesis routes and novel applications. This review will focus on the PL mechanism of CDs. Three types of fluorescent CDs were involved： graphene quantum dots （GQDs）, carbon nanodots （CNDs）, and polymer dots （PDs）. Four reasonable PL mechanisms have been confirmed： the quantum confinement effect or conjugated 7x-domains, which are determined by the carbon core; the surface state, which is determined by hybridization of the carbon backbone and the connected chemical groups; the molecule state, which is determined solely by the fluorescent molecules connected on the surface or interior of the CDs; and the crosslink- enhanced emission （CEE） effect. To give a thorough summary, the category and synthesis routes, as well as the chemical/physical properties for the CDs, are briefly introduced in advance.展开更多
Thanks to their remarkable mechanical, electrical, thermal, and barrier properties, graphene-based nanocomposites have been a hot area of research in the past decade. Because of their simple top-down synthesis, graphe...Thanks to their remarkable mechanical, electrical, thermal, and barrier properties, graphene-based nanocomposites have been a hot area of research in the past decade. Because of their simple top-down synthesis, graphene oxide (GO) and reduced graphene oxide (rGO) have opened new possibilities for gas barrier, membrane separation, and stimuli-response characteristics in nanocomposites. Herein, we review the synthesis techniques most commonly used to produce these graphene derivatives, discuss how synthesis affects their key material properties, and highlight some examples of nanocomposites with unique and impressive properties. We specifically highlight their performances in separation applications, stimuli-responsive materials, anti-corrosion coatings, and energy storage. Finally, we discuss the outlook and remaining challenges in the field of practical industrial-scale production and use of graphene-derivative-based polymer nanocomposites.展开更多
Carbon dots(CDs) are potentially useful in many areas such as bioimaging, light-emitting diodes, and sensing because of their excellent optical properties, high biocompatibility, and low toxicity.Knowledge of their ph...Carbon dots(CDs) are potentially useful in many areas such as bioimaging, light-emitting diodes, and sensing because of their excellent optical properties, high biocompatibility, and low toxicity.Knowledge of their photoluminescence(PL) mechanisms, which have been widely studied, is of significance in guiding the synthesis and promoting applications of CDs with tunable PL emissions. However,the intrinsic mechanism of PL emission remains unclear, and a unified mechanism has not been found because of differences in particle structures. This review generalizes the categories of CDs, noting their structural diversity. Three types of PL mechanism pertaining to structural differences are outlined: internal factors dominated emission(including the conjugation effect, the surface state, and the synergistic effect), external factors dominated emission(including the molecular state and the environment effect),and crosslink-enhanced emission. Optical applications of CDs are also briefly mentioned. Finally, the prospects for research into PL mechanisms are discussed, noting the remaining challenges and directions for future work.展开更多
Carbon dots (CDs) with average diameter of 3.1 ± 0.5 nm were facilely synthesized with candle soot through hydrothermal reaction in sodium hydroxide aqueous solution. The as-prepared CDs were covered with a lot o...Carbon dots (CDs) with average diameter of 3.1 ± 0.5 nm were facilely synthesized with candle soot through hydrothermal reaction in sodium hydroxide aqueous solution. The as-prepared CDs were covered with a lot of hydroxyls, possessed properties of good water-solubility, anti-photobleaching, salt tolerance, and low cytotoxicity, and had a fluorescence quantum yield (QY) of about 5.5%. The fluorescence of the hydroxyls-coated CDs could be selectively quenched by metal ions such as Cr3+, Al3+ and Fe3+, which is because these metals can easily combine with the hydroxyl groups on the surface of CDs and induce aggregation of hydroxyls-coated CDs. Experiments showed that the quenching of Cr3+ had a Sterm-Volmer constant of 1.03 × 107 M-1 with a liner range of 1.0-25.0 μM and detection limit of 60 nM (3σ).展开更多
Unlike inorganic quantum dots,fluorescent graphene quantum dots(GQDs)display excitation-dependent multiple color emission.In this study,we report N-doped GQDs(N-GQDs)with tailored single color emission by tuning p-con...Unlike inorganic quantum dots,fluorescent graphene quantum dots(GQDs)display excitation-dependent multiple color emission.In this study,we report N-doped GQDs(N-GQDs)with tailored single color emission by tuning p-conjugation degree,which is comparable to the inorganic quantum dot.Starting from citric acid and diethylenetriamine,as prepared N-GQDs display blue,green,and yellow light emission by changing the reaction solvent from water,dimethylformamide(DMF),and solvent free.The X-ray photoelectron spectroscopy,ultraviolet-visible spectra results clearly show the N-GQDs with blue emission(N-GQDs-B)have relatively short effective conjugation length and more carboxyl group because H_(2)O is a polar protic solvent,which tends to donate proton to the reagent to depress the H_(2)O elimination reaction.On the other hand,the polar aprotic solvent(DMF)cannot donate hydrogen,the elimination of H_(2)O is promoted and more nitrogen units enter GQD framework.With the increase of effective p-conjugation length and N content,the emission band of N-GQDS red-shifts to green and yellow.We also demonstrate that N-GQDs could be a potential great biomarker for fluorescent bioimaging.展开更多
Carbon dots(CDs) have received much attention due to their superior properties including water solubility, low toxicity, biocompatibility, small size,fluorescence, and ease of modification. The use of a more environme...Carbon dots(CDs) have received much attention due to their superior properties including water solubility, low toxicity, biocompatibility, small size,fluorescence, and ease of modification. The use of a more environmentally friendly method to prepare high-quality CDs is still an urgent question waiting for solve. The use of renewable, inexpensive, and green biomass resources not only meets the urgent need for large-scale synthesis biomass CDs(BCDs), but also promotes the development of sustainable applications.In this article, we summarize the representative methods for synthesizing BCDs in green and simple ways using biomass as a carbon source, including hydrothermal carbonization, and microwave, pyrolysis. The prepared BCDs have a uniform particle size distribution and a relatively high throughput,which provide a method to scale up industrial production. Moreover, the integration of specific optical properties, that is, tunable photoluminescence and up-photoluminescence, has led to remarkable use in bioimaging, sensing,and drug delivery. But the current review is not particularly comprehensive for BCDs. Therefore, we now provide a review focusing on the synthesis,properties, and recent advances in BCDs in biosensing, bioimaging,optoelectronics, and catalytic applications.展开更多
The development of low cost, metal free semiconductor photocatalysts for CO2 reduction to fuels and valuable chemical feedstocks is a practically imperative for reducing anthropogenic CO2 emissions. In this work, blac...The development of low cost, metal free semiconductor photocatalysts for CO2 reduction to fuels and valuable chemical feedstocks is a practically imperative for reducing anthropogenic CO2 emissions. In this work, black phosphorus quantum dots（BPQDs） were successfully dispersed on a graphitic carbon nitride（g-C3N4） support via a simple electrostatic attraction approach, and the activities of BP@g-C3N4 composites were evaluated for photocatalytic CO2 reduction. The BP@g-C3N4 composites displayed improved carrier separation efficiency and higher activities for photocatalytic CO2 reduction to CO（6.54 μmol g^-1h^-1 at the optimum BPQDs loading of 1 wt%） compared with pure g-C3N4（2.65 μmol g^-1h^-1）. This work thus identifies a novel approach towards metal free photocatalysts for CO2 photoreduction.展开更多
A new calibration method of detectors can be realized by using correlated photons generated in spontaneous parametric down-conversion （SPDC） effect of nonlinear crystal. An absolute calibration system of detector qu...A new calibration method of detectors can be realized by using correlated photons generated in spontaneous parametric down-conversion （SPDC） effect of nonlinear crystal. An absolute calibration system of detector quantum efficiency is performed. And its principle and experimental setup are introduced. A continuouswave （CW） ultraviolet （351 nm）, diode-pumped, frequency-doubled, and solid-state laser is used to pump BBO crystal. The quantum efficiencies of the photomultiplier at 633, 702, and 789 nm are measured respectively. The coincidence peaks are observed using coincidence circuit. Some measurement factors including the filter bandwidth of trigger channel, the detector position alignment and polarization of the pump light are analyzed. The uncertainties of this calibration method are also analyzed, and the relative uncertainties of total calibration are less than 5.8%. The accuracy of this method could be improved in the future.展开更多
Near-infrared emissive carbon dots(CDs) were synthesized by hydrothermal method. The as-prepared CDs exhibited a relatively high quantum yield(QY) of 33.96% in an aqueous solution, and the peak toward the near-infrare...Near-infrared emissive carbon dots(CDs) were synthesized by hydrothermal method. The as-prepared CDs exhibited a relatively high quantum yield(QY) of 33.96% in an aqueous solution, and the peak toward the near-infrared fluorescence reached 685 nm. The CDs exhibited pH-sensitive characteristics under strong acidic conditions. Even at pH = 0, the as-prepared CDs retained a high fluorescence intensity,which proved that they possessed good acid resistance. More importantly, the CDs were sensitive to the Fe3+changes in living cells. In addition, they could also be used for white and red emissive LEDs.This discovery will expand the use of aqueous-phase high QY CDs in the field of living cell sensing and imaging.展开更多
High-performance white light-emitting diodes (WLEDs) hold great potential for the next-generation backlight display applications.However,achieving highly efficient and stable WLEDs with wide-color-gamut has remained a...High-performance white light-emitting diodes (WLEDs) hold great potential for the next-generation backlight display applications.However,achieving highly efficient and stable WLEDs with wide-color-gamut has remained a formidable goal.Reported here is the first example of pure red narrow bandwidth emission triangular CQDs (PR-NBE-T-CQDs) with photoluminescence peaking at 610 nm.The PR-NBE-T-CQDs synthesized from resorcinol show high quantum yield (QY) of 72% with small full width at half maximum of 33 nm.By simply controlling the reaction time,pure green (PG-) NBE-T-CQDs with high QY of 75% were also obtained.Highly efficient and stable WLEDs with wide-color-gamut based on PR- and PG-NBE-T-CQDs was achieved.This WLED showed a remarkable wide-color gamut of 110% NTSC and high power efficiency of 86.5 lumens per Watt.Furthermore,such WLEDs demonstrate outstanding stability.This work will set the stage for developing highly efficient,low cost and environment-friendly WLEDs based on CQDs for the next-generation wide-color gamut backlight displays.展开更多
Carbon dots(CDs), as a new member of carbon nanomaterial family, have aroused great interest since their discovery in 2004. Because of their outstanding water solubility, high sensitivity and selectivity to target ana...Carbon dots(CDs), as a new member of carbon nanomaterial family, have aroused great interest since their discovery in 2004. Because of their outstanding water solubility, high sensitivity and selectivity to target analytes, low toxicity, favorable biocompatibility, and excellent photostability, researchers from diverse disciplines have come together to further develop the fundamental properties of CDs. Many methods for the production of CDs have been reported, therein, hydrothermal and solvothermal technology needs simple equipments, and microwave synthesis needs less reaction time, hence these methods become current common synthesis methods, in which many precursors have been applied to produce CDs. Due to their excellent fluorescence, CDs have made impressive strides in sensitivity and selectivity to a diverse array of salt ions,organic/biological molecules and target gases. The development of CDs as nanoprobes is still in its infancy, but continued progress may lead to their integration into environmental and biological applications. Hydrothermal,solvothermal, and microwave synthesis of fluorescent carbon dots and their detection applications as nanoprobes in salt ions, organic/biological molecules, and target gases will be reviewed.展开更多
A facile one-pot microwave irradiation reduction route has been developed for the synthesis of highly luminescent CdTe quantum dots using Na_(2)TeO_(3) as the Te source in an aqueous environment.The synthesis paramete...A facile one-pot microwave irradiation reduction route has been developed for the synthesis of highly luminescent CdTe quantum dots using Na_(2)TeO_(3) as the Te source in an aqueous environment.The synthesis parameters of this simple and rapid approach,including the reaction temperature and time,the pH of the reaction solution and the molar ratio of the 3-mercaptopropionic acid(MPA)stabilizer to Cd^(2+),have considerable influence on the particle size and photoluminescence quantum yield of the CdTe quantum dots.The photoluminescence quantum yield of CdTe quantum dots prepared using relatively short reaction times(1040 min)reached 40%60%(emission peaks at 550640 nm).Furthermore,the resulting products could be used as fl uorescent probes to detect Hg^(2+)ions in aqueous media.The response was linearly proportional to the concentration of Hg^(2+)ion in the range 8.0×10^(9)mol/L to 2.0×10^(6)mol/L with a detection limit of 2.7×10^(9)mol/L.展开更多
MXenes,a new family of two-dimensional(2D)materials with excellent electronic conductivity and hydrophilicity,have shown distinctive advantages as a highly conductive matrix material for lithium-ion battery anodes.Her...MXenes,a new family of two-dimensional(2D)materials with excellent electronic conductivity and hydrophilicity,have shown distinctive advantages as a highly conductive matrix material for lithium-ion battery anodes.Herein,a facile electrostatic self-assembly of SnO2 quantum dots(QDs)on Ti3C2Tx MXene sheets is proposed.The as-prepared SnO2/MXene hybrids have a unique 0D-2D structure,in which the 0D SnO2 QDs(~4.7 nm)are uniformly distributed over 2D Ti3C2Tx MXene sheets with controllable loading amount.The SnO2 QDs serve as a high capacity provider and the“spacer”to prevent the MXene sheets from restacking;the highly conductive Ti3C2Tx MXene can not only provide efficient pathways for fast transport of electrons and Li ions,but also buffer the volume change of SnO2 during lithiation/delithiation by confining SnO2 QDs between the MXene nanosheets.Therefore,the 0D-2D SnO2 QDs/MXene hybrids deliver superior lithium storage properties with high capacity(887.4 mAh g?1 at 50 mA g?1),stable cycle performance(659.8 mAh g?1 at 100 mA g?1 after 100 cycles with a capacity retention of 91%)and excellent rate performance(364 mAh g?1 at 3 A g?1),making it a promising anode material for lithium-ion batteries.展开更多
The development of large-scale synthetic methods for high quality carbon quantum dots(CQDs) is fundamental to their applications.However,the macroscopic preparation and scale up synthetic of CQDs is still in its infan...The development of large-scale synthetic methods for high quality carbon quantum dots(CQDs) is fundamental to their applications.However,the macroscopic preparation and scale up synthetic of CQDs is still in its infancy.Here,we report a facile,green,kilogram-scale synthesis of high quality fluorescent CQDs derived from poplar leaves via a one-step hydrothermal method.Notably,the throughput of CQDs can reach a level up to as high as 1.4975 kg in one pot.The structure and properties of the as-prepared CQDs were assessed through TEM,XRD,XPS and various spectroscopic methods.The obtained high quality CQD s with a photoluminescent quantum yield of 10.64% showed remarkable stability in aqueous media,rich functional groups,high photostability,consistent photoluminescence within biological pH range and low cytotoxicity.On account of these good properties,we demonstrated the multifunctional application to electrocatalytic water splitting,Fe^3+ sensing and bioimaging.It showed remarkable electrocatalytic activity,Fe^3+ sensitivity and good biocompatibility.This study provides a green,facile,inexpensive and large-scale method for producing high quality CQDs,which provides application value for large-scale production of CQDs.展开更多
文摘At present, the actual mechanism of the photoluminescence （PL） of fluorescent carbon dots （CDs） is still an open debate among researchers. Because of the variety of CDs, it is highly important to summarize the PL mechanism for these kinds of carbon materials; doing so can guide the development of effective synthesis routes and novel applications. This review will focus on the PL mechanism of CDs. Three types of fluorescent CDs were involved： graphene quantum dots （GQDs）, carbon nanodots （CNDs）, and polymer dots （PDs）. Four reasonable PL mechanisms have been confirmed： the quantum confinement effect or conjugated 7x-domains, which are determined by the carbon core; the surface state, which is determined by hybridization of the carbon backbone and the connected chemical groups; the molecule state, which is determined solely by the fluorescent molecules connected on the surface or interior of the CDs; and the crosslink- enhanced emission （CEE） effect. To give a thorough summary, the category and synthesis routes, as well as the chemical/physical properties for the CDs, are briefly introduced in advance.
基金sponsored by the National Science Foundation (NSF, CMMI-1562907)the GAANN Fellowship for financial support (No. P200A150330)the Navy STEM Fellowship and the GAANN Fellowship for financial support
文摘Thanks to their remarkable mechanical, electrical, thermal, and barrier properties, graphene-based nanocomposites have been a hot area of research in the past decade. Because of their simple top-down synthesis, graphene oxide (GO) and reduced graphene oxide (rGO) have opened new possibilities for gas barrier, membrane separation, and stimuli-response characteristics in nanocomposites. Herein, we review the synthesis techniques most commonly used to produce these graphene derivatives, discuss how synthesis affects their key material properties, and highlight some examples of nanocomposites with unique and impressive properties. We specifically highlight their performances in separation applications, stimuli-responsive materials, anti-corrosion coatings, and energy storage. Finally, we discuss the outlook and remaining challenges in the field of practical industrial-scale production and use of graphene-derivative-based polymer nanocomposites.
基金financially supported by the National Natural Science Foundation of China(21905253,51973200)the China Postdoctoral Science Foundation(2018M640681,2019T120632)。
文摘Carbon dots(CDs) are potentially useful in many areas such as bioimaging, light-emitting diodes, and sensing because of their excellent optical properties, high biocompatibility, and low toxicity.Knowledge of their photoluminescence(PL) mechanisms, which have been widely studied, is of significance in guiding the synthesis and promoting applications of CDs with tunable PL emissions. However,the intrinsic mechanism of PL emission remains unclear, and a unified mechanism has not been found because of differences in particle structures. This review generalizes the categories of CDs, noting their structural diversity. Three types of PL mechanism pertaining to structural differences are outlined: internal factors dominated emission(including the conjugation effect, the surface state, and the synergistic effect), external factors dominated emission(including the molecular state and the environment effect),and crosslink-enhanced emission. Optical applications of CDs are also briefly mentioned. Finally, the prospects for research into PL mechanisms are discussed, noting the remaining challenges and directions for future work.
基金financially supported by the National Natural Science Foundation of China (21035005)
文摘Carbon dots (CDs) with average diameter of 3.1 ± 0.5 nm were facilely synthesized with candle soot through hydrothermal reaction in sodium hydroxide aqueous solution. The as-prepared CDs were covered with a lot of hydroxyls, possessed properties of good water-solubility, anti-photobleaching, salt tolerance, and low cytotoxicity, and had a fluorescence quantum yield (QY) of about 5.5%. The fluorescence of the hydroxyls-coated CDs could be selectively quenched by metal ions such as Cr3+, Al3+ and Fe3+, which is because these metals can easily combine with the hydroxyl groups on the surface of CDs and induce aggregation of hydroxyls-coated CDs. Experiments showed that the quenching of Cr3+ had a Sterm-Volmer constant of 1.03 × 107 M-1 with a liner range of 1.0-25.0 μM and detection limit of 60 nM (3σ).
基金The authors thank the National Natural Science Foundation of China(No.21301166,21201159,61306081,and 61176016)Science and Technology Department of Jilin Province(No.20130522127JH)are gratefully acknowledged+1 种基金ZS thanks the support of the‘Hundred Talent Program’of CAS and Innovation and Entrepreneurship Program of JilinThe project was supported by Open Research Fund of State Key Laboratory of Polymer Physics and Chemistry and the open research fund program of the State Key Laboratory of Luminescence and Applications.
文摘Unlike inorganic quantum dots,fluorescent graphene quantum dots(GQDs)display excitation-dependent multiple color emission.In this study,we report N-doped GQDs(N-GQDs)with tailored single color emission by tuning p-conjugation degree,which is comparable to the inorganic quantum dot.Starting from citric acid and diethylenetriamine,as prepared N-GQDs display blue,green,and yellow light emission by changing the reaction solvent from water,dimethylformamide(DMF),and solvent free.The X-ray photoelectron spectroscopy,ultraviolet-visible spectra results clearly show the N-GQDs with blue emission(N-GQDs-B)have relatively short effective conjugation length and more carboxyl group because H_(2)O is a polar protic solvent,which tends to donate proton to the reagent to depress the H_(2)O elimination reaction.On the other hand,the polar aprotic solvent(DMF)cannot donate hydrogen,the elimination of H_(2)O is promoted and more nitrogen units enter GQD framework.With the increase of effective p-conjugation length and N content,the emission band of N-GQDS red-shifts to green and yellow.We also demonstrate that N-GQDs could be a potential great biomarker for fluorescent bioimaging.
基金financially supported by Project funded by China postdoctoral Science Foundation(No.2018M640681)the National Science Foundation of China(NSFC)under Grant Nos.51433003 and 21774041
文摘Carbon dots(CDs) have received much attention due to their superior properties including water solubility, low toxicity, biocompatibility, small size,fluorescence, and ease of modification. The use of a more environmentally friendly method to prepare high-quality CDs is still an urgent question waiting for solve. The use of renewable, inexpensive, and green biomass resources not only meets the urgent need for large-scale synthesis biomass CDs(BCDs), but also promotes the development of sustainable applications.In this article, we summarize the representative methods for synthesizing BCDs in green and simple ways using biomass as a carbon source, including hydrothermal carbonization, and microwave, pyrolysis. The prepared BCDs have a uniform particle size distribution and a relatively high throughput,which provide a method to scale up industrial production. Moreover, the integration of specific optical properties, that is, tunable photoluminescence and up-photoluminescence, has led to remarkable use in bioimaging, sensing,and drug delivery. But the current review is not particularly comprehensive for BCDs. Therefore, we now provide a review focusing on the synthesis,properties, and recent advances in BCDs in biosensing, bioimaging,optoelectronics, and catalytic applications.
基金supported by the National Natural Science Foundation of China (51502146, U1404506, 21671113, 51772305, 51572270, and U1662118)the International Partnership Program of Chinese Academy of Sciences (GJHZ1819)+1 种基金the Royal Society-Newton Advanced Fellowship (NA170422)supported by Open Fund (PEBM201702) of Key Laboratory for Photonic and Electric Bandgap Materials, Ministry of Education (Harbin Normal University)
文摘The development of low cost, metal free semiconductor photocatalysts for CO2 reduction to fuels and valuable chemical feedstocks is a practically imperative for reducing anthropogenic CO2 emissions. In this work, black phosphorus quantum dots（BPQDs） were successfully dispersed on a graphitic carbon nitride（g-C3N4） support via a simple electrostatic attraction approach, and the activities of BP@g-C3N4 composites were evaluated for photocatalytic CO2 reduction. The BP@g-C3N4 composites displayed improved carrier separation efficiency and higher activities for photocatalytic CO2 reduction to CO（6.54 μmol g^-1h^-1 at the optimum BPQDs loading of 1 wt%） compared with pure g-C3N4（2.65 μmol g^-1h^-1）. This work thus identifies a novel approach towards metal free photocatalysts for CO2 photoreduction.
基金the National Natural Science Foundation of China under Grant No.60378027.
文摘A new calibration method of detectors can be realized by using correlated photons generated in spontaneous parametric down-conversion （SPDC） effect of nonlinear crystal. An absolute calibration system of detector quantum efficiency is performed. And its principle and experimental setup are introduced. A continuouswave （CW） ultraviolet （351 nm）, diode-pumped, frequency-doubled, and solid-state laser is used to pump BBO crystal. The quantum efficiencies of the photomultiplier at 633, 702, and 789 nm are measured respectively. The coincidence peaks are observed using coincidence circuit. Some measurement factors including the filter bandwidth of trigger channel, the detector position alignment and polarization of the pump light are analyzed. The uncertainties of this calibration method are also analyzed, and the relative uncertainties of total calibration are less than 5.8%. The accuracy of this method could be improved in the future.
基金financially supported by the China Postdoctoral Science Foundation (2018M640681, 2019T120632)the National Natural Science Foundation of China (21774041, 51433003)the National Key Research and Development Program of China (2016YFB0401701)
文摘Near-infrared emissive carbon dots(CDs) were synthesized by hydrothermal method. The as-prepared CDs exhibited a relatively high quantum yield(QY) of 33.96% in an aqueous solution, and the peak toward the near-infrared fluorescence reached 685 nm. The CDs exhibited pH-sensitive characteristics under strong acidic conditions. Even at pH = 0, the as-prepared CDs retained a high fluorescence intensity,which proved that they possessed good acid resistance. More importantly, the CDs were sensitive to the Fe3+changes in living cells. In addition, they could also be used for white and red emissive LEDs.This discovery will expand the use of aqueous-phase high QY CDs in the field of living cell sensing and imaging.
基金supported by the National Natural Science Foundation of China (NSFC)(Nos.21573019 and 21872010)the Major Research Plan of the National Natural Science Foundation of China (No.21233003)the Fundamental Research Funds for the Central Universities.
文摘High-performance white light-emitting diodes (WLEDs) hold great potential for the next-generation backlight display applications.However,achieving highly efficient and stable WLEDs with wide-color-gamut has remained a formidable goal.Reported here is the first example of pure red narrow bandwidth emission triangular CQDs (PR-NBE-T-CQDs) with photoluminescence peaking at 610 nm.The PR-NBE-T-CQDs synthesized from resorcinol show high quantum yield (QY) of 72% with small full width at half maximum of 33 nm.By simply controlling the reaction time,pure green (PG-) NBE-T-CQDs with high QY of 75% were also obtained.Highly efficient and stable WLEDs with wide-color-gamut based on PR- and PG-NBE-T-CQDs was achieved.This WLED showed a remarkable wide-color gamut of 110% NTSC and high power efficiency of 86.5 lumens per Watt.Furthermore,such WLEDs demonstrate outstanding stability.This work will set the stage for developing highly efficient,low cost and environment-friendly WLEDs based on CQDs for the next-generation wide-color gamut backlight displays.
基金supported by the National HighTech R&D Program of China (863 program, 2011AA050504)National Natural Science Foundation of China (21171117 and 61376003)+4 种基金Program for New Century Excellent Talents in University (NCET-12-0356)Shanghai Natural Science Foundation (13ZR1456600)Shanghai Science and Technology Grant (12JC1405700)Shanghai Pujiang Program (11PJD011)the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning, and Medical-Engineering Crossover Fund (YG2012MS40 and YG2012MS32) of Shanghai Jiao Tong University
文摘Carbon dots(CDs), as a new member of carbon nanomaterial family, have aroused great interest since their discovery in 2004. Because of their outstanding water solubility, high sensitivity and selectivity to target analytes, low toxicity, favorable biocompatibility, and excellent photostability, researchers from diverse disciplines have come together to further develop the fundamental properties of CDs. Many methods for the production of CDs have been reported, therein, hydrothermal and solvothermal technology needs simple equipments, and microwave synthesis needs less reaction time, hence these methods become current common synthesis methods, in which many precursors have been applied to produce CDs. Due to their excellent fluorescence, CDs have made impressive strides in sensitivity and selectivity to a diverse array of salt ions,organic/biological molecules and target gases. The development of CDs as nanoprobes is still in its infancy, but continued progress may lead to their integration into environmental and biological applications. Hydrothermal,solvothermal, and microwave synthesis of fluorescent carbon dots and their detection applications as nanoprobes in salt ions, organic/biological molecules, and target gases will be reviewed.
基金Helpful discussion with Prof.Yitai Qian and financial support from the National Natural Science Foundation of China(NSFC,20501014)Program for New Century Excellent Talents in University(NCET)National Basic Research Program of China(973 Program,2005CB623601,2007CB936602)is gratefully acknowledged.
文摘A facile one-pot microwave irradiation reduction route has been developed for the synthesis of highly luminescent CdTe quantum dots using Na_(2)TeO_(3) as the Te source in an aqueous environment.The synthesis parameters of this simple and rapid approach,including the reaction temperature and time,the pH of the reaction solution and the molar ratio of the 3-mercaptopropionic acid(MPA)stabilizer to Cd^(2+),have considerable influence on the particle size and photoluminescence quantum yield of the CdTe quantum dots.The photoluminescence quantum yield of CdTe quantum dots prepared using relatively short reaction times(1040 min)reached 40%60%(emission peaks at 550640 nm).Furthermore,the resulting products could be used as fl uorescent probes to detect Hg^(2+)ions in aqueous media.The response was linearly proportional to the concentration of Hg^(2+)ion in the range 8.0×10^(9)mol/L to 2.0×10^(6)mol/L with a detection limit of 2.7×10^(9)mol/L.
基金supported by the National Key Research and Development Program of China“New Energy Project for Electric Vehicle”(2016YFB0100204)the National Natural Science Foundation of China(Nos.51772030,21805011,51572011,51802012)+2 种基金the Joint Funds of the National Natural Science Foundation of China(U1564206)Beijing Key Research and Development Plan(Z181100004518001)China Postdoctoral Science Foundation(Nos.2017M620637,2018M643697,2019T120930).
文摘MXenes,a new family of two-dimensional(2D)materials with excellent electronic conductivity and hydrophilicity,have shown distinctive advantages as a highly conductive matrix material for lithium-ion battery anodes.Herein,a facile electrostatic self-assembly of SnO2 quantum dots(QDs)on Ti3C2Tx MXene sheets is proposed.The as-prepared SnO2/MXene hybrids have a unique 0D-2D structure,in which the 0D SnO2 QDs(~4.7 nm)are uniformly distributed over 2D Ti3C2Tx MXene sheets with controllable loading amount.The SnO2 QDs serve as a high capacity provider and the“spacer”to prevent the MXene sheets from restacking;the highly conductive Ti3C2Tx MXene can not only provide efficient pathways for fast transport of electrons and Li ions,but also buffer the volume change of SnO2 during lithiation/delithiation by confining SnO2 QDs between the MXene nanosheets.Therefore,the 0D-2D SnO2 QDs/MXene hybrids deliver superior lithium storage properties with high capacity(887.4 mAh g?1 at 50 mA g?1),stable cycle performance(659.8 mAh g?1 at 100 mA g?1 after 100 cycles with a capacity retention of 91%)and excellent rate performance(364 mAh g?1 at 3 A g?1),making it a promising anode material for lithium-ion batteries.
基金financial support from Project funded by China postdoctoral Science Foundation (No. 2018M640681)
文摘The development of large-scale synthetic methods for high quality carbon quantum dots(CQDs) is fundamental to their applications.However,the macroscopic preparation and scale up synthetic of CQDs is still in its infancy.Here,we report a facile,green,kilogram-scale synthesis of high quality fluorescent CQDs derived from poplar leaves via a one-step hydrothermal method.Notably,the throughput of CQDs can reach a level up to as high as 1.4975 kg in one pot.The structure and properties of the as-prepared CQDs were assessed through TEM,XRD,XPS and various spectroscopic methods.The obtained high quality CQD s with a photoluminescent quantum yield of 10.64% showed remarkable stability in aqueous media,rich functional groups,high photostability,consistent photoluminescence within biological pH range and low cytotoxicity.On account of these good properties,we demonstrated the multifunctional application to electrocatalytic water splitting,Fe^3+ sensing and bioimaging.It showed remarkable electrocatalytic activity,Fe^3+ sensitivity and good biocompatibility.This study provides a green,facile,inexpensive and large-scale method for producing high quality CQDs,which provides application value for large-scale production of CQDs.
