Zhao-yang Zhang

National University of Defense Technology, Ch’ang-sha-shih, Hunan, China

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Publications (6)17.2 Total impact

  • Xiao-qian Xu · Wen-wei Zheng · Yi-jie Tao · Hai-feng Cheng · Zhao-yang Zhang
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    ABSTRACT: A copolymer based on selenophene and 3,4-ethylenedioxythiophene was successfully synthesized by electrochemical polymerization in boron trifluoride diethyl etherate (BFEE). The resultant copolymer was characterized by cyclic voltammetry, FTIR, XPS, SEM and spectroelectrochemistry. The copolymer presented tricolor electrochromism, which was dark green-yellow (in the neutral state), blue-green (in the intermediate state) and blue (in the oxidized state). Furthermore, the optical contrast and switching time of the copolymer was found to be 19.8% and 3.2 s at 728 nm, respectively, which remained 75.1% of its original electroactivity after 200 cycles.
    No preview · Article · Dec 2012 · Synthetic Metals
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    ABSTRACT: A copolymer based on thiophene and anthracene was prepared on indium tin oxide (ITO) glass electrode via electrochemical copolymerization in boron trifluoride diethyl etherate (BFEE). The resultant copolymer is characterized by cyclic voltammetry, FT-IR, XPS, SEM and spectroelectrochemical analysis. The copolymer film presents multicolor electrochromism and can exhibit six colors (yellowish red, yellow, yellow green, blue green, light blue and dark blue) under various applied potentials. The optical contrasts of the copolymer film at 491, 767 and 1100 nm are 21%, 38% and 37%, respectively, and the corresponding switching rates are 1.9, 1.3 and 2.3 s. The film has superior coloration efficiency which is calculated to be 327 cm2 C−1 (491 nm), 240 cm2 C−1 (767 nm) and 296 cm2 C−1 (1100 nm). Furthermore, the film presents reasonable electrochemical and optical stability which retains 73% of its original electroactivity after 500 cycles and 73.6% of its optical contrast after 800 steps. All of these indicate the satisfactory electrochromic properties of the copolymer film.
    No preview · Article · Sep 2012 · Electrochimica Acta
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    ABSTRACT: Copolymers based on anthracene and 3,4-ethylenedioxythiophene (EDOT) are successfully electrodeposited on ITO electrodes in boron trifluoride diethyl etherate (BFEE). The resultant copolymers are characterized by cyclic voltammetry (CV), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and spectroelectrochemical analysis. The copolymer films can present multicolor electrochromism under various applied potentials and the color change can be tuned through controlling the feed ratio of anthracene/EDOT. With the feed ratio of anthracene/EDOT at 1/4, the prepared copolymer shows a maximum optical contrast of 82% at 503 nm which is much near to the highest optical contrast of electrochromic materials. The switching time and coloration efficiency at 507 nm are 2.3 s and 278 cm C−1, respectively. Furthermore, the copolymer exhibits excellent electrochemical stability which retains 89.8% of its original electroactivity after 2000 cycles.
    No preview · Article · Aug 2012 · Electrochimica Acta
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    ABSTRACT: We report the facile and economical synthesis of an electrochromic copolymer for black based on electrochemical copolymerization of thiophene and 3, 4-ethylenedioxythiophene in boron trifluoride diethyl etherate. The resultant copolymer presents multicolor electrochromism with reversible color change between drab color and blue black. Furthermore, in the polar state the resultant copolymer shows strong and broad absorption in the whole visible region and then exhibits black color. The copolymer presents a transmittance variation of 25% at 522 nm, and corresponding response times for bleaching and coloration are 4.2 and 3.3 s, respectively. Good electrochemical stability can be achieved by the copolymer film, which retains 87% of its original electroactivity after 2000 cycles.
    Preview · Article · Jul 2012 · Optics Express
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    ABSTRACT: Copolymers based on pyrrole and 3,4-ethylenedioxythiophene (EDOT) are electrodeposited on indium tin oxide (ITO) electrode with various feed ratio of pyrrole/EDOT in aqueous micellar solution. The structures of the resultant copolymers are characterized via cycle voltammograms, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and spectroelectrochemical analysis. Different electrochromic properties can be achieved by the copolymers prepared with various pyrrole/EDOT ratios. The π-π* transition absorption peak (λmax) of the deposited copolymer with the pyrrole/EDOT ratio of 1/10 at the neutral state is located at 542 nm and the calculated energy gap (Eg) is 1.82 eV. Moreover, successive CVs indicate the copolymer film has a better electrochemical stability, retaining 80% of the original electroactivity after 1000 cycles, which mainly results from the incorporation of EDOT units into the Ppy.
    No preview · Article · May 2012 · Synthetic Metals
  • Zhao-Yang Zhang · Hai-Feng Cheng · Zhao-Hui Chen · Wen-Wei Zheng
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    ABSTRACT: The performance of camouflage targets recognition using visible and infrared images is limited by the low contrast in intensity for complex backgrounds. We are developing a polarization imaging technique where, in each image pixel, the polarization data is used to recognize camouflage targets. In the paper, the rationale of detection equipment is demonstrated and we analysis, using polarization images will significantly improve the performance of camouflage targets detection. Images are generated by using polarization degree and polarization angle of scattered light from the surface of camouflage targets. By using Multispectral CCD Polarization Camera, polarimetric characteristics of camouflaged targets and clutter background are measured and images of polarization degree and polarization angle are taken. Results indicate that polarimetric characteristics of scattering light from camouflaged targets are very different from that of natural backgrounds. Polarimetric imaging can eliminate the influence of backgrounds and enhance the efficiency of reconnaissance. Compared with reflectance images, polarization images have advantages in camouflage targets detection.
    No preview · Article · May 2009 · Proceedings of SPIE - The International Society for Optical Engineering