Two New Bithiophenes Derivatives Multielectrochromic Copolymer Based on Triphenylamine Unit and Their Application for Electrochromic Devices

An Efficient Electrochromic Supercapacitor Based on Solution-Processable Nanoporous Poly{tris[4-(3,4-ethylenedioxythiophene)phenyl]amine}

A new green synthetic route to tris[4-(3,4-ethylenedioxythiophene)phenyl]amine (TEPA) monomer has been developed and the molecular structure of TEPA has been determined by using single-crystal XRD. Solution-processable nanoporous poly{tris[4-(3,4-ethylenedioxythiophene)phenyl]amine} (PTEPA) is prepared by a chemical oxidative polymerization in a microemulsion. Based on the distorted structure of TEPA in the solid state, it is proposed that dendritic PTEPA has a distorted 3 D conformation with multiple twisted channels and pores that are narrowed and blocked by bifurcation and distortion of PTEPA, which is consistent with the observed hierarchical pore structure. As a cathode material, PTEPA exhibits a discharge capacity of 89.5 mAh g-1 in the initial cycle with a highly sloping two-stage discharge curve and relatively stable cycling performance. Beyond its excellent energy storage properties, PTEPA also shows relatively good electrochromic performance. Furthermore, an efficient all-solid-state electrochromic supercapacitor (ECSC) with good electrochromic performance and high energy storage capacity (13.3 mF cm-2 ) is assembled from PTEPA and nanoporous graphene films. During charge-discharge processes, the color of the ECSC changes between yellow-green and steel blue. Thus, the energy storage level of the ECSC can be monitored by the corresponding color changes. The fabricated ECSC may have practical applications, for example, in self-powered electrochromic smart windows.