Long Yang

Sichuan University, Hua-yang, Sichuan, China

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Publications (18)44.55 Total impact

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    ABSTRACT: Conjugated polymer/TiO2 photocatalysts hold great promise for solar chemical conversion processes by combining the advantages from both the conjugated polymer and the inorganic semiconductor, overcoming the serious drawbacks of fast charge recombination and the limited visible light absorption of inorganic semiconductor through interfacial electron transfer. To address the crucial way to promote the visible light photocatalytic activity of conjugated polymers/TiO2 photocatalysts, P3HT/TiO2 composites with strong interfacial interaction between P3HT and TiO2, which was demonstrated by the results of X-ray photoelectron spectroscopy and dissolution tests, were prepared by binding cyanoacrylic acid end-groups functionalized P3HT to the surface of TiO2. The pseudo-first-order kinetic constants of photocatalytic degradation of model pollutant methyl orange (MO) under visible light with P3HT/TiO2 composites of monofunctionalized and difunctionalized polymers were 7.06 and 20.18 times as great as that of unfunctionalized polymer, respectively, indicating a remarkably enhanced visible light photocatalytic activities by an order of magnitude with the incorporation of cyanoarrylic acid end-groups. In consideration of their similar morphology, specific surface area, ability of harvesting visible light and adsorption capacities toward MO independent of end-group functionalization, the dramatically enhanced photocatalytic activity arises from the facilitated electron injection and separation of photogenerated carriers owing to strong interfacial interaction between TiO2 and end-group functionalized P3HT, which was proved to be crucial for photocatalytic capability of conjugated polymer/TiO2 photocatalysts, providing a new effective direction for the improvement of their visible light photocatalytic activity.
    Applied Catalysis B Environmental 09/2015; 174. DOI:10.1016/j.apcatb.2015.02.034 · 7.44 Impact Factor
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    ABSTRACT: A series of new asymmetric chromophores containing aromatic substituents and possessing the excellent π-extension in space were prepared through multi-steps routes. One-photon and two-photon spectral properties of these new chromophores could be tuned by these substituents finely and simultaneously. The linear correlation of the wave numbers of the one-photon absorption and emission maxima to Hammett parameters of these substituents was presented. Near infrared two-photon absorption emission integrated areas of the target chromophores were correlated linearly to Hammett constants of these substituted groups.
    Journal of Fluorescence 09/2015; DOI:10.1007/s10895-015-1637-7 · 1.93 Impact Factor
  • Feijie Ge · Yanyun Ding · Long Yang · Yun Huang · Long Jiang · Yi Dan
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    ABSTRACT: Introduction of UV absorbing group onto polymer chain through covalent bonding greatly reduced the UV light transmittance of resulting polylactide (PLA) film and reserved the high transparency to visible light. Compared to simple blending UV absorber with PLA matrix, covalent bonding of UV absorbing group with polylactide enabled the prepared films to have better dispersion of UV absorbing group, stable solvent resistance, better protection effect against UV damage and slower rate of UV irradiated degradation while the distribution of the UV absorbing group made no difference in the aformentioned properties. The degradation of both PLA film covalently bonded with UV absorbing group and PLA/UV-absorber blending film followed the same mechanism as pure PLA films did that the alkyl-oxygen bond broke first to produce acyl-oxygen and secondary carbon radicals, then they captured hydrogen to form carboxyl group and alkyl group at the end of fractured polymer chain. More UV absorbing group at the chain end was more favorable for reducing UV transmittance, providing better protection effect on packaged probe, and slowing UV irradiated degradation of PLA film. The thermal stability was dependant on molecular weight of polylactide and hardly affected by introduction of UV absorber or UV absorbing group.
    RSC Advances 08/2015; 5(86). DOI:10.1039/C5RA13285A · 3.84 Impact Factor
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    ABSTRACT: Conjugated polymer/TiO2 composites are promising visible light photocatalysts for solar chemical conversion processes in the field of environmental chemistry for decomposition of organic compounds in water and air. In consideration of the fact that conjugated polymers are also organic substances, particular attention must be focused on the stability of conjugated polymer/TiO2 composites, which has not been laid enough emphasis upon so far. Poly(3-hexylthiophene)/titanium dioxide (P3HT/TiO2) composites, as a representative of conjugated polymer/TiO2 photocatalysts, were prepared by combining chemical oxidative polymerization method and physical blending technique. The stability of the composites was systematically studied by comparative analysis of the physical and chemical structure of P3HT/TiO2 composites before and after the photocatalytic reaction. As confirmed by the results of high-resolution transmission electron microscopy (HRTEM), scanning electron microscope (SEM), ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS), fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), the P3HT/TiO2 composites were quite stable to 10 h of photodegradation of methyl orange (MO) under visible light, maintaining both their physical and chemical structure.
    Applied Surface Science 05/2015; 349. DOI:10.1016/j.apsusc.2015.04.192 · 2.71 Impact Factor
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    ABSTRACT: Heavy aggregation-caused quenching perylene diimides (PDI) are changed successfully by simply chemical modification with two quinoline moieties through C=C at the bay positions to obtain aggregation-induced enhanced emission (AIEE) of a perylene derivative (Cya-PDI) with large π-conjugation system. Cya-PDI is weakly luminescent in the well-dispersed CH3CN or THF solutions and exhibits evident time-dependent AIEE and absorption spectra broadening in the aggregating state. In addition, morphological inspection demonstrates that Cya-PDI molecules exhibit the aggregating form of organized microstructures changing from plate-shaped to rod-like aggregates under the co-effect of time and water. An edge-to-face arrangement was proposed and discussed. Prospectively, the Cya-PDI aggregates show broad absorption covering the whole visible-light range and strong intermolecular action through π-π stacking in the solid state which makes them promising materials in the opto-electric aspects. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    Chemistry - An Asian Journal 02/2015; 10(5). DOI:10.1002/asia.201500056 · 4.59 Impact Factor
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    ABSTRACT: To obtain broadly absorbing perylene derivatives with the synchronous impact of intrinsic π-π* transition of large conjugated system and intra-molecular charge transfer (ICT), we report here the facile synthesis and physical characterization of new type N-(n-octylaminyl)-3,4,9,10-perylene tetracarboxylic acid diimides (PDI) bearing benzyl substituted quinoline-4( 1H )-ylidene-methyl unit as effective donors on the 1,7-position (C1) and 1-position (C2). Compared to unsubstituted PDI, C1 and C2 both show a pronounced bathochromic shift to the near infra-red region, high molar extinction coefficient, concentration-dependent π-π stacking induced fluorescence and low LUMO energy level. The investigation of spectroscopic properties and molecular simulation reveals effective ICT character in compounds C1 and C2. All the properties and analysis indicate that the derivatives are efficient solar-harvesting and potential candidate materials for the use in photovoltaic devices and photo-catalyst.
    RSC Advances 08/2014; 4(82). DOI:10.1039/C4RA07288J · 3.84 Impact Factor
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    ABSTRACT: o-hydroxyphenyl-triazine derivatives with formyl substituents were surveyed for the excited state intramolecular proton transfer (ESIPT). The occurrence of ESIPT was confirmed by well-separated emission bands for the derivatives. A low energy change from enol to keto in the excited state explains ESIPT for the derivatives.
    Chinese Science Bulletin 05/2011; 56(14):1457-1460. DOI:10.1007/s11434-011-4473-4 · 1.58 Impact Factor
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    ABSTRACT: This paper presents a variety of conjugated derivatives with different number of arms (4-styryl-triphenylamine: C1, 4,4'-di-styryltriphenylamine: C2, 4,4',4″-tri-styryltriphenylamine: C3). The linear absorption and fluorescence maxima and the molar extinction coefficients are in the order of C1<C2<C3 in various solvents. Two-photon absorption (TPA) up-converted emission of the derivatives were determined with Ti:sapphire femtosecond laser. The maximal TPA emission wavelength and the two-photon absorption cross section of the derivatives are also in the order of C1<C2<C3 in various solvents. The dipole moment changes of the derivatives between the excited state and the ground state were estimated from experiment, and they are in the order of C1<C2<C3, which is confirmed further by the molecular geometry optimization of the derivatives. The electron density distribution and the energy levels of the frontier orbital of the derivatives were analyzed. The cyclic voltammograms of the derivatives were performed and discussed.
    Journal of Fluorescence 10/2010; 21(2):545-54. DOI:10.1007/s10895-010-0741-y · 1.93 Impact Factor
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    ABSTRACT: This paper presents a range of novel new branched conjugated dyes containing benzophenone moiety. As compared with those of 4-(p-benzoyl-styrene)yl-4'-(styrene)yl-triphenylamine (C1) and 4-(p-benzoyl-styrene)yl-4'-3,4,5-trimethoxyl-styrene)yl-triphenylamine (C2), the maximal linear absorption and emission wavelength of 4-(p-benzoyl-styrene)yl-4'-(p'-nitro-styrene)yl-triphenylamine (C3) displays red-shifted remarkably, While the fluorescence quantum yields of C3 are lower than those of C1 and C2 in various solvents. The fluorescence lifetimes of the derivatives were measured, and radiative and non-radiative transition constants of the derivatives were calculated. Two-photon absorption (TPA) optical data of the derivatives were measured by Ti:sapphire femtosecond laser tuning from 720 to 880 nm at intervals of 20 nm. TPA induced fluorescence emission of C3 is red-shifted with respected to that of C1 and C2. TPA cross sections of C3 are larger than those of C1 and C2 in various excited laser frequencies. TPA cross section of C2 and C3 are much larger than those of 3,4,5-(trimethoxylstyrene)yl-triphenylamine (C4) and 4-(p-nitrostyrene)yl-triphenylamine (C5) respectively under various near-IR Ti:sapphire femtosecond laser wavelength. C1 and C2 show similar one- and two- photon optical nature. Geometry optimization with ab initio method confirms that C3 has different electron density distribution, the energy levels in frontier orbitals, the dipole moment changes, the absorption and emission spectroscopy from those of C1 and C2. The cyclic voltammograms of the derivatives were detected in methylene chloride at various scan rates, and the energy of frontier orbials were estimated further from the redox potentials.
    Journal of Fluorescence 10/2010; 21(1):393-407. DOI:10.1007/s10895-010-0728-8 · 1.93 Impact Factor
  • Fang Gao · Jian Liu · Long Yang · Qi Wang · Hongru Li · Shengtao Zhang
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    ABSTRACT: This paper presents the investigation of tuning the color and photoluminescence of a range of triphenylamine- based derivatives with various substituent groups. The ultraviolet/visible absorption and fluorescence spectroscopy of the derivatives showed remarkable difference. The molecular geometry optimization demonstrated that the properties of the ground state and the excited state of the compounds have a close relationship with the substituent groups. Therefore, it is possible to tune the color and photoluminescence of the derivatives at molecular level. The cyclic voltammograms of these compounds were detected in methylene chloride at various scan rates. The thermal stabilities of the compounds were analyzed with the different scanning calorimetry and the thermogravimetry.
    Chinese Journal of Chemistry 06/2010; 28(6):950-960. DOI:10.1002/cjoc.201090177 · 1.58 Impact Factor
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    ABSTRACT: A variety of new conjugated dyes bearing a benzophenone unit were synthesized, and the linear absorption and emission were determined. Two-photon absorption properties of the derivatives have been measured by a Ti:sapphire femtosecond laser tuning from 720 to 880 nm at intervals of 20 nm. One- and two-photon optical properties of the derivatives were found to be significantly dependent on their chemical structures.
    Chemistry Letters 04/2010; 39(4):324-325. DOI:10.1246/cl.2010.324 · 1.23 Impact Factor
  • Chemistry Letters 01/2010; 39(6):582-583. DOI:10.1246/cl.2010.582 · 1.23 Impact Factor
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    ABSTRACT: Suitable chemical strategy is a useful approach on the tuning color and photoluminescence of organic dyes. This paper presented tuning novel branched p-nitro-stilbene derivatives efficiently with a new chemical strategy through variation of chemical bridged bond. Linking bonds played significant effects on the absorption and fluorescence spectroscopy of the branched p-nitro-stilbene derivatives. A change from "D-pi-A" to "A-pi-A" chemical structural characteristics occurred for the branched p-nitro-stilbene derivatives as ester bond was attached. This led to not only large hypsochromic shift of the maximal absorption wavelength of the branched p-nitro-stilbene derivatives, but considerable reduction of the fluorescence intensity. While in contrast, the branched p-nitro-stilbene derivatives with ether bond exhibited longer wavelength absorption and much stronger fluorescence emission in modest polar solvent. The cyclic voltammograms of these branched p-nitro-stilbene derivatives were determined. Different electrochemistry processes were observed for the branched p-nitro-stilbene derivatives with various linking bonds. The energies of frontier orbital of the branched p-nitro-stilbene derivatives were estimated from their corresponding redox potentials. Molecular geometry optimization of the branched p-nitro-stilbene derivatives was performed, and the electron density distribution of frontier orbital was analyzed. Thermal stabilities of these branched nitro-stilbene derivatives were investigated via the analysis of the differential scanning calorimetry (DSC) and thermograving (TGA) curves. This paper presented strong evidences that the absorption and fluorescence spectroscopy of the branched stilbene derivatives could be mediated efficiently by chemical strategy.
    Journal of Fluorescence 12/2009; 20(1):353-64. DOI:10.1007/s10895-009-0564-x · 1.93 Impact Factor
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    ABSTRACT: In this paper, we presented four novel visible light photoinitiating systems, which employed nitro-stilbenzene derivatives as photoinitiators. Visible light photopolymerization of these systems was studied completely. The results showed that the chemical structures of the photoinitiators, photoinduced electron transfer approach, solvent polarity, and monomers played significant effects on the visible light photopolymerization. The electrochemistry of nitro-stilbenzene was dramatically influenced by the linking benzophenone moiety. The cyclic voltammograms of four photoinitiators were determined and discussed. We further estimated the thermodriving force for electron transfer between nitro-stilbenzene and benzophenone. Thermal stabilities of new photoinitators were determined by the analysis of differential scanning calorimetry (DSC) and thermogravimetry (TG) in this paper. Copyright © 2009 John Wiley & Sons, Ltd.
    Polymers for Advanced Technologies 12/2009; 20(12):1010 - 1016. DOI:10.1002/pat.1357 · 1.76 Impact Factor
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    ABSTRACT: We discuss the synthesis and characterization of 3',4'-bis(p-benzoylphenylmethoxy)yl-4-nitrostilbene (C1). Ultraviolet and fluorescence spectroscopy was used to investigate its behavior in various solvents. Results showed that the visible absorption of C1 could be assigned to the chromophore and that the attached benzophenone made major contribution to the ultraviolet absorption of C1. This compound exhibited strong fluorescence in modest polar solvents.Acomprehensive investigation of the two-photon properties and electrochemistry of C1 and 2',4'-bis(p-benzoylphenylmethoxy)yl-4-nitrostilbene (C2) was undertaken. Results suggested that at 800 nm femtosecond laser excitation, C1 and C2 showed strong two-photon induced upconversion fluorescence. The two-photon absorption cross-section of the compound was shown to be related to the substitution position of benzophenone. Molecular geometry optimization and electrochemistry suggested that the energies of the frontier orbitals and electron densities of C1 and C2 could be correlated to the position of benzophenone substitution as well.
    ACTA PHYSICO-CHIMICA SINICA 07/2009; 25(7). DOI:10.3866/PKU.WHXB20090718 · 0.85 Impact Factor
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    ABSTRACT: Novel nitro-azobenzene dyes bearing one or two benzophenone branches were proposed and synthesized to improve their photophysical and photochemical properties. The new dyes exhibited double UV/visible bands, and they displayed weak fluorescence emission as excited at 350 nm. Single crystal X-ray diffraction data showed that two phenyl rings of azobenzene was almost coplanar, and the benzophenone part was neither coplanar nor linear connection with azobenzene via ether bridged bond, which have good fit with molecular geometry optimization calculation results. The cyclic voltammeric results of nitro-azobenzene dyes were firstly reported in this paper, which demonstrated that the electrochemical properties of nitro-azobenzene dyes was altered by the substitution of benzophenone part. Thermal stabilities of the new dyes were studied by the analysis of differential scanning calorimetry (DSC) and thermograving (TG) in this paper. Efficient visible-light photoinitiating polymerization of methyl methacrylate (MMA) by the novel nitro-azobenzene dyes was presented and discussed.
    Journal of Fluorescence 12/2008; 19(3):533-44. DOI:10.1007/s10895-008-0442-y · 1.93 Impact Factor
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    ABSTRACT: In this paper, we have presented a range of new nitro-stilbene derivatives with benzophenones via ether or ester bridged bond. These nitro-stilbene derivatives with benzophenones have been conveniently obtained by condensation reaction. The linked benzophenones were efficiently introduced to nitro-stilbene dyes. The structures of these compounds have been characterized with NMR and element analysis. The single crystals of two target compounds (11 and 12) have been obtained, and their X-ray crystallographic data have been determined and discussed. Remarkably different absorption and fluorescence spectroscopy was observed for nitro-stilbene derivatives with benzophenones via different linked bonds. The results show that electron-donating or electron withdrawing bridged bonds have significant influence on the absorption and fluorescence spectroscopy, which makes it possible for the development of ideal nitro-stilbene dyes with benzophenones through chemical strategy.
    Journal of Fluorescence 07/2008; 18(5):787-99. DOI:10.1007/s10895-008-0391-5 · 1.93 Impact Factor
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    ABSTRACT: "A-B" type photosensitive compounds including two-photon chromophore and benzophenone moiety have been designed, synthesized and characterized. The UV-vis absorption and fluorescence emission of the compounds have been extensively studied in various solvents. The results show that the absorption of "A-B" type compounds displays obvious double absorption bands, one of which at short-wavelength is related to the benzophenone moiety, the other at long-wavelength is mainly contributed by chromophore. The emission of "A-B" type compounds at 500-700 nm shows an "unexpected" blue-shift comparing with that of the sole chromophore. The photosensitive compounds with amino group display strong emission in apolar solvents and have a low fluorescence quantum yields in polar solvents. In contrast, the compounds without amino group exhibit strong fluorescence emission in polar solvents, and low fluorescence quantum yields in apolar solvents. The fluorescence quantum yields of "A-B" type compounds are higher than those of the sole chromophore. The discoveries suggest that charge redistribution induced by the introduction of benzophenone moiety plays a key role on the absorption and emission spectroscopy.
    Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy 11/2007; 70(5):1006-12. DOI:10.1016/j.saa.2007.07.064 · 2.35 Impact Factor

Publication Stats

26 Citations
44.55 Total Impact Points


  • 2014–2015
    • Sichuan University
      • • State Key Laboratory of Polymer Material Engineering
      • • Polymer Research Institute
      Hua-yang, Sichuan, China
  • 2007–2011
    • Chongqing University
      • Department of Chemical Engineering
      Ch’ung-ch’ing-shih, Chongqing Shi, China