High contrast all-solid-state electrochromic device with 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), heptyl viologen, and succinonitrile

A WO3–poly(butyl viologen) layer-by-layer film/ruthenium purple film based electrochromic device switching by 1 volt application

“…In another study, for an all-solid-state electrochromic device with 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO), heptyl viologen, and succinonitrile, a high coloration efficiency of 342.2 cm 2 C À 1 was obtained at 610 nm [50]. In yet another report on a star-shaped viologen, a coloration efficiency of 279 cm 2 C À 1 was registered at 530 nm for a switch between light blue and violet blue states [51].…”

A fast electrochromic polymer based on TEMPO substituted polytriphenylamine

“…As a transparent organic radical provider that undergoes a stable and reversible redox reaction in organic solvents, TEMPO usually does not exhibit electrochromic behaviors. Even though, there are a few studies using TEMPO or TEMPO-based polymers as electroactive materials for the counter-electrode in electrochromic devices 26 27 28 . For example, Takahashi et al prepared an electrochromic cell using a TEMPO-based polymer film as the counter-electrode, allowing the device working at a remarkably low cell voltage 29 .…”

All-in-One Gel-Based Electrochromic Devices: Strengths and Recent Developments

“…In this regard, unlike alkyl-substituted viologens, which have been widely reported over the years [ 65 , 91 , 96 , 142 , 143 , 144 ], aryl-substituted ones have been used less even though they were first synthesized and evaluated more than three decades ago [ 145 , 146 ]. The main reason was the insolubility of their radical-cationic form, detected during the first investigations [ 147 , 148 ], which is more likely to occur in rod-like linear viologens such as aryl-substituted ones when using all-in-one configurations [ 63 ].…”

“…The term “all-in-one” has been used in the literature [ 63 , 64 ] to describe the symmetric device architecture where the EC material and the redox mediator are dissolved in liquid [ 28 , 29 , 30 ], solid, or semisolid electrolyte [ 65 , 66 ], and the resulting EC mixture (single layer) is sandwiched between two electrode substrates in a very simple configuration (glass/TCO/EC mixture/TCO/glass). This design, although restricted to EC materials that are soluble in the electrolytic media (e.g., viologens), may offer high levels of coloration and ease the fabrication process, making them more interesting from the industrialization point of view.…”