Search

In this work, poly(N-methyl-3,4-dihydrothieno[3,4-b][1,4]oxazine) (PMDTO), a new nitrogen poly(3,4-ethylendioxythiophene) (PEDOT) analogue, was synthesized by an electrochemical deposition method, and the capacitive properties of PMDTO were investigated and compared with those of PEDOT. The structure and morphology of PMDTO were characterized by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, and thermal analysis. The pseudocapacitive properties of the as-prepared PMDTO electrodes have been examined by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) measurements and electrochemical impedance spectroscopy (EIS) in 0.1 mol L−1 CH3CN–Bu4NBF4 electrolyte solution. The as-prepared PMDTO electrode showed a high specific capacitance of 154.3 F g−1 at a discharge current density of 3 A g−1 and exhibited cycling stability with the maximal capacitance retention of nearly 71% after 500 cycles at a high current density of 10 A g−1. Additionally, the asymmetrical supercapacitor based on PMDTO and PEDOT electrodes exhibited a maximum specific capacitance of 63.5 F g−1 and an energy density of 12.7 W h kg−1 at a power density of 0.59 kW kg−1. These results implied that the PMDTO electrode can be used as a potential electrode material for supercapacitors. [ABSTRACT FROM AUTHOR]

Two novel EDOT end-capped monomers, namely, 2,8-di-2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl-dibenzothiophene (DBT-EDOT), and 2,8-di-2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl-dibenzofuran (DBF-EDOT), were synthesised via Stille coupling and electropolymerised to form conjugated polymers P(DBT-EDOT) and P(DBF-EDOT). The monomers exhibited blue-light-emitting characteristics, and DFT calculations revealed band gap values of 4.20 eV for DBT-EDOT and 4.34 eV for DBF-EDOT, while those of the corresponding polymers were brought down to 2.46 eV for P(DBT-EDOT) and 2.58 eV for P(DBF-EDOT), respectively. Moreover, both of the polymers displayed good electrochromic properties with colour switching between yellow in the reduced state and purple in the oxidised state. Structure characterisation and properties of monomers and as-formed polymers using FTIR spectroscopy, UV-vis spectroscopy, surface morphology, fluorescence spectroscopy, electrochemistry, and spectroelectrochemistry, together with structure–property relationships, were systematically investigated and comprehensively discussed. [ABSTRACT FROM AUTHOR]