Peng Zhang

Name: 张鹏

Organization: Southwest University , China

Department: The School of Chemistry and Chemical Engineering

Title: Associate Professor(PhD)

Chemicals
References

Synthesis, photophysics, ion detection and DFT investigation of novel cyano-substituted red-light chromophores with a triphenylamine donor

Co-reporter:Na Sun, Peng Zhang and Yanling Hou

RSC Advances 2016 vol. 6(Issue 15) pp:12205-12214

Publication Date(Web):15 Jan 2016

DOI:10.1039/C5RA24341F

A series of novel triphenylamine-based red-light chromophores with multiple electron-withdrawing cyano substituents were synthesized by the Knoevenagel condensation reaction and characterized in detail. Compounds 3–5 showed bright green-yellow emission in dichloromethane solution and red-light emission in the solid state, respectively. The interesting solvatochromic behavior in different polar solvents was observed, varying from positive solvatochromism for compound 3 to negative solvatochromism for compound 5. In addition, the notable optical response of metal ions in DMF solution for the cyano-substituted chromophores was investigated. Especially, with the addition of Hg2+ ions, the blue shift in the absorption spectra and the decrease in the emission spectra suggested that the new metal complexes possibly formed between the cyano substituents and metal ions or metal ion-induced optical quenching happened. Density functional theory calculations were used to further understand the effect of the cyano substituents on the photoelectron properties of the donor–acceptor molecules.

Resistivity-temperature behavior and morphology of low density polyethylene/graphite powder/graphene composites

Co-reporter:Peng Zhang;Dongliang Cao ;Shaonan Cui

Polymer Composites 2014 Volume 35( Issue 8) pp:1453-1459

Publication Date(Web):

DOI:10.1002/pc.22798

In this work, the positive-temperature-coefficient (PTC) effect of resistivity of low density polyethylene/graphite powder (45%) composites (LDPE/GP) in the presence of graphene before and after crosslinked was comparatively investigated by differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy, Raman spectrum, and resistivity-temperature test. The composites showed the repeatability of the PTC effect with heating cycles and a certain improvement in the room temperature resistivity. After crosslinked, the composites presented a higher PTC trip temperature at about 140°C than pure LDPE (T_m = 112°C), and stronger PTC intensity than room temperature resistivity (over 5 orders of magnitude). The results from DSC, XRD, and Raman spectrum indicated that the addition of graphene resulted in the gradual enhancement in the crystallization of LDPE matrix, which was the origin of the improvement of the PTC behavior of the composites. As a result, we could conclude that the additional conducting filler could improve the PTC effect of the conducting composite system. POLYM. COMPOS., 35:1453–1459, 2014. © 2013 Society of Plastics Engineers

New conjugated cruciform chromophores with D-π-A structure: Synthesis, characterization and theoretical calculation

Co-reporter:Dongliang Cao, Peng Zhang, Pei Liu, Shaonan Cui, Na Sun

Journal of Molecular Structure 2014 1076() pp: 396-402

Publication Date(Web):5 November 2014

DOI:10.1016/j.molstruc.2014.07.066

Synthesis and characterization of oligothiophene-functionalized phenanthroline chromophores with symmetrical or unsymmetrical configuration

Co-reporter:Peng Zhang, Pei Liu, Yong Zhao, Dongliang Cao

Journal of Molecular Structure 2013 Volume 1037() pp:122-129

Publication Date(Web):10 April 2013

DOI:10.1016/j.molstruc.2012.12.041

A series of promising symmetrical or unsymmetrical oligothiophene-functionalized phenanthroline chromophores was synthesized by cross-coupling reactions, and their photophysics, morphologic structure, thermal stability were characterized. All compounds which ranged from crystalline to amorphous character, provided with an excellent thermal stability. Bright blue–green emission and positive solvatochromism of these compounds were evaluated. Moreover, the redox behaviors of these compounds were performed by cyclic voltammetry. In a word, the chemical and physical properties of these compounds could be efficiently regulated by the symmetrical or unsymmetrical molecular configuration.Highlights► Oligothiophene-functionalized phenanthroline chromophores were synthesized. ► Their optoelectronic properties were regulated by symmetrical or unsymmetrical substituents. ► Their morphological structure ranged from crystalline to amorphous character. ► The effects of molecular structures on electronic structure were demonstrated.

Positive temperature coefficient effect and interaction based on low-density polyethylene/graphite powder composites

Co-reporter:P. Zhang;W.T. Xue;Y. Zhao ;P. Liu

Journal of Applied Polymer Science 2012 Volume 123( Issue 4) pp:2338-2343

Publication Date(Web):

DOI:10.1002/app.34747

Abstract

In this article, the positive temperature coefficient (PTC) and interaction based on low-density polyethylene (LDPE) filled with the loading of graphite (G) powder have been investigated. The dependence of the room temperature resistivity on filler content showed the significant decrease. The PTC behavior enhanced with increasing graphite content but this was not always the case. The maximum PTC effect was observed in LDPE/G composites (G, 45 wt %) with the relatively low room temperature resistivity. The thermal behavior was measured by differential scanning calorimetry (DSC). The structure characteristic for LDPE/G composites was examined by X-ray diffraction (XRD), field-emission scanning electron microscopy (SEM), and stress–strain test. The fact was revealed that the slight interaction between LDPE matrix and graphite may lead to change the thermal-electric properties of the PTC materials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Facile coordinating decoration of salophen Al on graphene nanosheet: Salophen Al complex functionalized graphene nanocomposite with electrochemical properties

Co-reporter:Wenting Xue, Peng Zhang, Yong Zhao, Pei Liu

Materials Chemistry and Physics 2012 Volume 133(Issue 1) pp:170-175

Publication Date(Web):15 March 2012

DOI:10.1016/j.matchemphys.2012.01.003

Salophen Al complex functionalized graphene (SCFG) nanocomposite was synthesized by simple coordination of phenol functionalized graphene (PFG) and as-prepared salophen Al complex. This process is facile, convenient and high efficient. We also investigated the structure, optical properties and electrochemical properties of the obtained SCFG composites. The results showed that salophen Al conjugated and incorporated onto the graphene sheet surface and the composites maintained the micro-structure of graphene sheets without agglomeration. The photoluminescence of salophen Al was completely quenched by graphene, due to the charge transfer between the salophen Al and the graphene nanosheets. Moreover, a significant electrochemical signal emerged on the SCFG modified electrodes compared with those of the graphene sheets or salophen Al complex. Owing to preliminary results of the excellent electrochemical property, SCFG nanocomposite is a promising electrochemical redox probe material.Graphical abstractSalophen Al complex functionalized graphene (SCFG) nanocomposite was synthesized by coordination of phenol functionalized graphene and salophen Al. Graphene quenched the photoluminescence of salophen Al and a significant electrochemical signal promised SCFG nanocomposite redox probe material.Highlights► The coordination reaction is a new and facile path to modify the graphene. ► Salophen Al is used to modify the graphene for its luminescent property. ► Salophen Al @ graphene nanocomposite is an excellent redox probe material.

Preparation, characterization and photodegradation of methylene blue based on TiO2 microparticles modified with thiophene substituents

Co-reporter:Pei Liu;DongLiang Cao;WenTing Xue

Science Bulletin 2012 Volume 57( Issue 33) pp:4381-4386

Publication Date(Web):2012 November

DOI:10.1007/s11434-012-5447-x

The new microparticles, 2-formylthiophene (FT)/TiO2 and (E)-1,2-bis(5-formyl-2-thienyl) ethylene (EBFTE)/TiO2 were synthesized with a silane coupling agent. The prepared TiO2 composites were characterized using Ultraviolet-Vis absorption (UV-Vis), X-ray diffraction (XRD), scanning electron microscope (SEM) and thermogravimetric analyzer (TGA). Methylene blue was used as a model material to examine the photocatalytic activities of the prepared catalysts under both Ultraviolet-Vis (UV) and visible (Vis) light. The enhanced photocatalytic activities were observed in the presence of (FT)/TiO2 and EBFTE/TiO2 under Vis light. It suggests that FT or EBFTE plays a block or active role in the photodegradation mechanisms under UV and Vis light irradiation, respectively.

Optical properties and electronic structure of terminal group-perturbed ethynyl-linked dendrimers

Co-reporter:Peng Zhang, Wenting Xue, Pei Liu, Lihua Gan

Synthetic Metals 2011 Volume 161(21–22) pp:2289-2294

Publication Date(Web):November–December 2011

DOI:10.1016/j.synthmet.2011.08.036

Three ethynyl-linked dendrimers with terminal carbazole, namely the electronic donor–acceptor compounds 1–3, the symmetric compound 9-(3-(2-(1-(2-(3-(9Hcarbazol-9-yl)-9-p-tolyl-9H-carbazol-6-yl)ethynyl)pyren-6-yl)ethynyl)-9-p-tolyl-9H-carbazol-6-yl)-9H-carbazole (1), the unsymmetric compounds 6-pyren-1-ylethynyl-9-p-tolyl-9H-[3,9′]bicarbazolyl (2) and 3,6-di-tert-butyl-9-(4-pyren-1-ylethynyl-phenyl)-9H-carbazole (3), respectively, were well investigated by experimental and theoretic methods. Good reversible oxidation and reduction processes of these compounds were observed, and the corresponding HOMO and LUMO levels could be well tuned by the different terminal group, which was proved by the theoretical calculation. In addition, they showed bright blue-green emission in dichloromethane solution and in the solid state, and exhibited efficient solvatochromism, suggesting that their electron transition may be considered as π–π* transition, charge–transfer transition and the coeffect of the former two, respectively.Highlights► We experimentally and theoretically investigate electronic structures which reflect the emitting principle. ► Electronic structures and photophysical properties are tuned by terminal group as donor. ► We reveal their emitting mechanism, π–π* transition, intramolecular charge transfer and both interaction.

The comparative investigation on the optical properties and electronic structures of the alkoxy-tuned 1,3,4-oxadiazole derivatives

Co-reporter:Peng Zhang, Benchen Tang, Wenjing Tian, Bing Yang, Min Li

Materials Chemistry and Physics 2010 Volume 119(1–2) pp:243-248

Publication Date(Web):15 January 2010

DOI:10.1016/j.matchemphys.2009.08.053

The optical properties and electronic structures of three series of 1,3,4-oxadiazole derivatives, 1,4-bis[(4-methylphenyl)-1,3,4-oxadiazolyl]phenylene (OXD1), 1,4-bis[(4-alkoxyphenyl)-1,3,4-oxadiazolyl]phenylene (OXD3–n+1) and 5,5′-di-(4-methyl)-2,2′-p-(2,5-bisalkoxyphenylene)-bis-1,3,4-oxadiazole (OXD2–n+1) were investigated theoretically by quantum calculation theory method as well as experimentally by UV/vis absorption, photoluminescence (PL), excitation spectra and differential pulse polarograph (DPP). The maximum absorption and emission for these oxadiazole derivatives were increasingly red-shifted with the electron-donating abilities of the different position substituents, which was in accordance with the results from time-dependent density functional theory (TD-DFT) calculations. The excitation spectra for these oxadiazole derivatives in CH2Cl2 solution were extended in wide region from 250 nm to 420 nm, and the broad excitation band was attributed to the increasing effect of alkoxy group. The HOMO level, the LUMO level and energy gap (Eg, LUMO–HOMO) for these oxadiazole derivatives were determined by the experimental method and by DFT method, and the results showed that only HOMO had been evidently influenced by changing the different position substituents. We used the DFT methods to generate the optimized structures of their model compounds, OXD1, OXD3-1 and OXD2-1. It was found that the slight difference in bond length and dihedral angle for the model compounds was generated. This strongly localized character of the electron density was illustrated by the frontier orbital contour plots as the effect of alkoxy substituents. The calculated results showed that LUMO mainly localized on the central benzene ring and two oxadiazole rings and HOMO delocalized along the whole conjugated chain except for OXD2-1. It suggested that the spectral properties of these oxadiazole derivatives were determined by the electronic structures with the different effect of alkoxy substituents on the HOMO.