National Physical Laboratory, Dr. K. S. Krishnan road, New Delhi-110012, India.
ChemSusChem. 2010;3(1):97-105. doi: 10.1002/cssc.200900202.
An electrochromic zwitterionic viologen, N,N'-bis(3-sulfonatopropyl)-4-4'-bipyridinium, has been used for the first time for doping poly (3,4-ethylenedioxythiopene) (PEDOT) films during electropolymerization. Slow and fast diffusional rates for the monomer at deposition potentials of +1.2 and +1.8 V, respectively yielded the viologen-doped PEDOT films with granular morphology and with dendrite-like shapes. The dual electrochrome formed at +1.8 V, showed enhanced coloration efficiency, larger electrochemical charge storage capacity, and superior redox activity in comparison to its analogue grown at +1.2 V, thus demonstrating the role of dendritic shapes in amplifying electrochromism. Flexible electrochromic devices fabricated with the viologen-doped PEDOT film grown at +1.8 V and Prussian blue with an ionic liquid-based gel electrolyte film showed reversible coloration between pale and dark purple with maximum coloration efficiency of 187 cm2C(-1) at lambda=693 nm. The diffusional impedance parameters and switching kinetics of the device showed the suitability of this dual electrochrome formed as a single layer for practical electrochromic cells.
一种电致变色两性离子紫罗碱，N，N'-双（3-磺丙基）-4-4'-联吡啶鎓，首次用于掺杂聚（3,4-亚乙基二氧噻吩）（PEDOT）薄膜在电聚合过程中。单体在沉积电位为+1.2 和+1.8 V 时的扩散速率较慢和较快，分别得到了具有粒状形貌和树枝状形状的紫罗碱掺杂 PEDOT 薄膜。在+1.8 V 下形成的双电致变色，与在+1.2 V 下生长的类似物相比，显示出更高的着色效率、更大的电化学电荷存储容量和更好的氧化还原活性，从而证明了树枝状形状在放大电致变色中的作用。用在+1.8 V 下生长的紫罗碱掺杂 PEDOT 薄膜和普鲁士蓝与基于离子液体的凝胶电解质膜制造的柔性电致变色器件在淡紫色和深紫色之间表现出可逆着色，在 lambda=693 nm 时最大着色效率为 187 cm2C(-1)。器件的扩散阻抗参数和开关动力学表明，这种作为单层形成的双电致变色适用于实际的电致变色电池。
