Molecular doping has been proven to be an effective approach to adjusting the electronic structure of polymeric carbon nitride(PCN)and thus improving its optical properties and photocatalytic activity.Herein,theobromi...Molecular doping has been proven to be an effective approach to adjusting the electronic structure of polymeric carbon nitride(PCN)and thus improving its optical properties and photocatalytic activity.Herein,theobromine,a compound composed of an imidazole ring and a pyrimidine ring,was first copolymerized with urea to prepared doped PCN.Experimental investigations and theoretical calculations indicate that,a narrowing in band gap and a positive shift in valence band positon happened to the theobromine doped PCN,owing to the synergistic effect between the pyrimidine ring and the imidazole ring in the theobromine molecule.Moreover,it is shown that the doping with theobromine at a suitable mass fraction makes the obtained sample exhibit decreased photoluminescent emission,enhanced photocurrent density,and reduced charge-transport resistance.Consequently,an enhancement in the photocatalytic activity for water oxidation is found for the sample,which oxygen evolution rate is 4.43 times higher than that of the undoped PCN.This work sheds light on the choice of the molecular dopants for PCN to improve its photocatalytic performance.展开更多
Fluorescent nanoparticles (NPs), including quantum dots (QDs), dye-doped NPs, and rare earth-based NPs, etc., have been a major focus of research and development during the past decade. The impetus behind such endeavo...Fluorescent nanoparticles (NPs), including quantum dots (QDs), dye-doped NPs, and rare earth-based NPs, etc., have been a major focus of research and development during the past decade. The impetus behind such endeavors can be attributed to their unique chemical and optical properties, such as bright fluorescence, high photostability, large Stocks shift and flexible processability. The introduction of fluorescent NPs into analytical chemistry has opened up new venues for fluorescent analysis. In this review, we focus on the developments and analytical applications of fluorescent NPs in the chemical and biological sensing of pH, ions, organic compounds, small biological molecules, nucleic acids, proteins, virus and bacteria. The review also points out the in vitro and in vivo imaging application of fluorescent NPs at the cell and body levels. Meanwhile, the ad- vantages of NPs brought field of sensing and signal transductions are also discussed.展开更多
Efficient white-polymer-light-emitting devices (WPLEDs) have been fabricated with a single emitting layer containing a hole-transporting host polymer,poly(N-vinylcarbzole),and an electron-transporting auxiliary,1,3-bi...Efficient white-polymer-light-emitting devices (WPLEDs) have been fabricated with a single emitting layer containing a hole-transporting host polymer,poly(N-vinylcarbzole),and an electron-transporting auxiliary,1,3-bis[(4-tert-butylphenyl)-1,3,4-oxadiazolyl]-phenylene,codoped with two phosphorescent dyes:Iridium(III)bis (2-(4,6-difluorophenyl)-pyridinato-N,C2') picolinate (FIrpic) and home-made Ir-G2 for blue and red emission,respectively.With the structure of ITO/PEDOT:PSS 4083(40 nm)/emission layer(80 nm)/Ba(4 nm)/Al(120 nm),the device showed a maximal luminous efficiency (LE) of 13.5 cd A-1(corresponding to an external quantum efficiency (EQE) of 6.8%),and a peak power efficiency (PE) of 6.5 lm W-1 at 6.0 V.Meanwhile,the device exhibited pure white emission with Commission Internationale de l'Eclairage (CIE) coordinates of (0.34,0.35) at a current density of 12 mA cm-2,which is very close to the equi-energy white point with CIE coordinates of (0.33,0.33).The device performance can be further optimized when more balanced hole/electron injection is achieved by incorporating a lower conducting type anode buffer layer (PEDOT:PSS) and incorporating poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorenene)-alt-2,7-(9,9-dioctyfluorene)] (PFN) as an electron injection layer at the cathode.The optimized device showed an LE of 24.6 cd A-1 (with an EQE of 14.1%),while the peak power efficiency reached 12.66 lm W-1.Moreover,the WPLEDs showed good electroluminescence (EL) stability over a wide range of operating current density and luminance.展开更多
The energy crisis and environmental pollution are serious challenges that humanity will face for the long-term. Despite tremendous efforts, the development of environmentally friendly methods to fabricate new energy m...The energy crisis and environmental pollution are serious challenges that humanity will face for the long-term. Despite tremendous efforts, the development of environmentally friendly methods to fabricate new energy materials is still challenging. Here we report, for the first time, a new strategy to fabricate various doped carbon nanofiber (CNF) aerogels by pyrolysis of bacterial cellulose (BC) pellicles which had adsorbed or were dyed with different toxic organic dyes. The proposed strategy makes it possible to remove the toxic dyes from waste-water and then synthesize doped CNF aerogels using the dyed BC pellicles as precursors. Compared with other reported processes for preparing heteroatom doped carbon (HDC) nanomaterials, the present synthetic method has some significant advantages, such as being green, general, low-cost and easily scalable. Moreover, the as-prepared doped CNF aerogels exhibit great potential as electrocatalysts for the oxygen reduction reaction (ORR) and as electrode materials for supercapacitors.展开更多
Rare-earth doped titania single-crystalline hollow nanoparticles of 20 nm are constructed via a simple sol-gel process. Amphiphilic ABA tri-block copolymers played a key role in assisting the formation of hollow struc...Rare-earth doped titania single-crystalline hollow nanoparticles of 20 nm are constructed via a simple sol-gel process. Amphiphilic ABA tri-block copolymers played a key role in assisting the formation of hollow structure, for which a hollow nanostructure growth mechanism is proposed. By introducing rare earth into the synthesis process, the as-prepared nanoparticles exhibit near-infrared light absorption properties. Photo-decomposition efficiency of Orange II azo dye can be successfully evaluated when using Yb3+-doped Ti O2 hollow nanoparticles as photocatalysts; it is more than two times higher than the pure Ti O2 hollow nanoparticles. The hollow nanostructured Yb3+-doped Ti O2 samples are exploited as photoanodes in N719- sensitized solar cells and prove able to improve the photoelectric conversion efficiency by measuring the solar cell parameters of dye-sensitized solar cells(DSSCs) under simulative sunlight.展开更多
Al-doped ZnO (AZO) nanocrystalline aggregates (NCAs) were prepared by a low cost colloid chemistry method and effects of the Al-doped concentration on the morphological and structural properties of the AZO NCAs were s...Al-doped ZnO (AZO) nanocrystalline aggregates (NCAs) were prepared by a low cost colloid chemistry method and effects of the Al-doped concentration on the morphological and structural properties of the AZO NCAs were studied. The dye adsorption ability of the AZO NCAs with various Al-doped concentrations was also investigated. Results indicate that the doping of the Al ions not only does not change the wurtzite structure of the ZnO crystal but also can reduce the crystallite grain size and the particle size distribution of the NCAs, which gives them a higher specific surface area and dye adsorption ability than that of the ZnO NCAs. The as-prepared AZO NCAs would be a promising material to be applied in the dye sensitized solar cells and water treatment.展开更多
基金National Natural Science Foundation of China(91122034,51125006,61376056,61204072)Science and Technology Commission of Shanghai(13JC1405700,14520722000)
基金supported by the National Natural Science Foundation of China(21276088,U1507201)Natural Science Foundation of Guangdong Province(2014A030312009)China Postdoctoral Science Foundation(2018M640784)~~
文摘Molecular doping has been proven to be an effective approach to adjusting the electronic structure of polymeric carbon nitride(PCN)and thus improving its optical properties and photocatalytic activity.Herein,theobromine,a compound composed of an imidazole ring and a pyrimidine ring,was first copolymerized with urea to prepared doped PCN.Experimental investigations and theoretical calculations indicate that,a narrowing in band gap and a positive shift in valence band positon happened to the theobromine doped PCN,owing to the synergistic effect between the pyrimidine ring and the imidazole ring in the theobromine molecule.Moreover,it is shown that the doping with theobromine at a suitable mass fraction makes the obtained sample exhibit decreased photoluminescent emission,enhanced photocurrent density,and reduced charge-transport resistance.Consequently,an enhancement in the photocatalytic activity for water oxidation is found for the sample,which oxygen evolution rate is 4.43 times higher than that of the undoped PCN.This work sheds light on the choice of the molecular dopants for PCN to improve its photocatalytic performance.
基金supported by the National Natural Science Foundation of China (90606003 & 20775021)International Science & Technology Cooperation Program of China (2010DFB30300)+2 种基金Program for Changjiang Scholar and Innovative Research Team in UniversityProgram for New Century Excellent Talents in University (NCET-09-0338)Hunan Natural Science Foundation (10JJ7002 & 08JJ1002)
文摘Fluorescent nanoparticles (NPs), including quantum dots (QDs), dye-doped NPs, and rare earth-based NPs, etc., have been a major focus of research and development during the past decade. The impetus behind such endeavors can be attributed to their unique chemical and optical properties, such as bright fluorescence, high photostability, large Stocks shift and flexible processability. The introduction of fluorescent NPs into analytical chemistry has opened up new venues for fluorescent analysis. In this review, we focus on the developments and analytical applications of fluorescent NPs in the chemical and biological sensing of pH, ions, organic compounds, small biological molecules, nucleic acids, proteins, virus and bacteria. The review also points out the in vitro and in vivo imaging application of fluorescent NPs at the cell and body levels. Meanwhile, the ad- vantages of NPs brought field of sensing and signal transductions are also discussed.
基金Fund of Ministry of Education of China (20090172120012)the National Basic Research Program of Chima (2009CB623602)+4 种基金the National Natural Science Foundation of China (60906032)the Fundamental Research Funds for the Central Universities for the financial support. Wong W.-Y. thanks the Hong Kong Research Grants Council (HKBU202709)the University Grants Committee of HKSAR,China (AoE/P-03/08)Hong Kong Baptist University (FRG2/08-09/111)the Croucher Foundation for the Croucher Senior Research Fellowship
文摘Efficient white-polymer-light-emitting devices (WPLEDs) have been fabricated with a single emitting layer containing a hole-transporting host polymer,poly(N-vinylcarbzole),and an electron-transporting auxiliary,1,3-bis[(4-tert-butylphenyl)-1,3,4-oxadiazolyl]-phenylene,codoped with two phosphorescent dyes:Iridium(III)bis (2-(4,6-difluorophenyl)-pyridinato-N,C2') picolinate (FIrpic) and home-made Ir-G2 for blue and red emission,respectively.With the structure of ITO/PEDOT:PSS 4083(40 nm)/emission layer(80 nm)/Ba(4 nm)/Al(120 nm),the device showed a maximal luminous efficiency (LE) of 13.5 cd A-1(corresponding to an external quantum efficiency (EQE) of 6.8%),and a peak power efficiency (PE) of 6.5 lm W-1 at 6.0 V.Meanwhile,the device exhibited pure white emission with Commission Internationale de l'Eclairage (CIE) coordinates of (0.34,0.35) at a current density of 12 mA cm-2,which is very close to the equi-energy white point with CIE coordinates of (0.33,0.33).The device performance can be further optimized when more balanced hole/electron injection is achieved by incorporating a lower conducting type anode buffer layer (PEDOT:PSS) and incorporating poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorenene)-alt-2,7-(9,9-dioctyfluorene)] (PFN) as an electron injection layer at the cathode.The optimized device showed an LE of 24.6 cd A-1 (with an EQE of 14.1%),while the peak power efficiency reached 12.66 lm W-1.Moreover,the WPLEDs showed good electroluminescence (EL) stability over a wide range of operating current density and luminance.
基金This work is supported by the Ministry of Science and Technology of China (Grants 2010CB934700, 2013CB933900, 2014CB931800), the National Natural Science Foundation of China (Grants 21431006, 91022032, 91227103, 21061160492, J1030412), the Chinese Academy of Sciences (Grant KJZD-EW- M01-1), and Hainan Province Science and Technology Department (CXY20130046) for financial support. We thank Ms. C. Y. Zhong for kindly providing purified bacterial cellulose pellicles.
文摘The energy crisis and environmental pollution are serious challenges that humanity will face for the long-term. Despite tremendous efforts, the development of environmentally friendly methods to fabricate new energy materials is still challenging. Here we report, for the first time, a new strategy to fabricate various doped carbon nanofiber (CNF) aerogels by pyrolysis of bacterial cellulose (BC) pellicles which had adsorbed or were dyed with different toxic organic dyes. The proposed strategy makes it possible to remove the toxic dyes from waste-water and then synthesize doped CNF aerogels using the dyed BC pellicles as precursors. Compared with other reported processes for preparing heteroatom doped carbon (HDC) nanomaterials, the present synthetic method has some significant advantages, such as being green, general, low-cost and easily scalable. Moreover, the as-prepared doped CNF aerogels exhibit great potential as electrocatalysts for the oxygen reduction reaction (ORR) and as electrode materials for supercapacitors.
基金financially supported by the National Natural Science Foundation of China(21201133,51272186)
文摘Rare-earth doped titania single-crystalline hollow nanoparticles of 20 nm are constructed via a simple sol-gel process. Amphiphilic ABA tri-block copolymers played a key role in assisting the formation of hollow structure, for which a hollow nanostructure growth mechanism is proposed. By introducing rare earth into the synthesis process, the as-prepared nanoparticles exhibit near-infrared light absorption properties. Photo-decomposition efficiency of Orange II azo dye can be successfully evaluated when using Yb3+-doped Ti O2 hollow nanoparticles as photocatalysts; it is more than two times higher than the pure Ti O2 hollow nanoparticles. The hollow nanostructured Yb3+-doped Ti O2 samples are exploited as photoanodes in N719- sensitized solar cells and prove able to improve the photoelectric conversion efficiency by measuring the solar cell parameters of dye-sensitized solar cells(DSSCs) under simulative sunlight.
基金supported by the National High Technology Research and Development Program of China (Grant No. 2009AA03Z218)the National Natural Science Foundation of China (Grant No. 90923012)
文摘Al-doped ZnO (AZO) nanocrystalline aggregates (NCAs) were prepared by a low cost colloid chemistry method and effects of the Al-doped concentration on the morphological and structural properties of the AZO NCAs were studied. The dye adsorption ability of the AZO NCAs with various Al-doped concentrations was also investigated. Results indicate that the doping of the Al ions not only does not change the wurtzite structure of the ZnO crystal but also can reduce the crystallite grain size and the particle size distribution of the NCAs, which gives them a higher specific surface area and dye adsorption ability than that of the ZnO NCAs. The as-prepared AZO NCAs would be a promising material to be applied in the dye sensitized solar cells and water treatment.