Electrochromic Polymers

Abstract

Shi report the synthesis of two heterocycle-fluorene-heterocycle monomers using Stille coupling and electropolymerization to form corresponding polymers with good electro-chemical behavior. In particular, P(EDOT-F-EDOT) revealed favorable electrochromic performance, showing fast response time and high coloration efficiency. These electro-chromic materials provide a wider variety of colors and hold promise for display applications. STRUCTURE-PROPERTY RELATIONSHIPS OF ELECTROCHROMIC POLYMERS The structure-property relationships of P(Th-F-Th) and P(EDOT-F-EDOT), including optical properties, surface morphologies, and electrochemical and electrochromic performances , were investigated on page 325. The two heterocycle-fluorene-heterocycle mono-mers, synthesized using Stille coupling and electropolymerization, exhibited excellent redox activity and electrochromic performance. SOLUTION-PROCESSABLE ELECTROCHROMIC POLYMERS Solution-processable electrochromic polymers that can switch from one distinct color to another highly transmissive state are required for electrochromic applications. In Volume 53 Issue 19 on page 2285 demonstrate a promising candidate based on copolymer complex P(EOTT-co-EDOT)/PSS by optimizing the optical properties, stability, and processability to replace PEDOT as the electro-chromic polymer. The studied complex exhibited superior coloration efficiencies, low switching voltages, and decent contrast ratios. From these results, the complex would be a processable candidate material for the mass production of electrochromic-related organic electronics.

Electrochromic Thin Films Based on NiAl Layered Double Hydroxide Nanoclusters for Smart Windows and Low-Power Displays

“…As already observed by Villemure and co-workers, 32 the bleaching of the film occurs in two steps, the first one corresponding to the direct reduction of Ni sites in the LDH and the second to the mediated reduction by Fe(CN) 6 , which remains an efficient mediator for the reduction in basic medium. The same tendency was clearly observed in DPA experiments ( Figure 5), highlighting the intrinsic advantage of using Fe(CN) 6 4− as a redox mediator. These data can be advantageously compared with the values reported in the literature for other NiAl-LDH EC devices (Table S1), in particular with those analyzed in situ during CV (≈15−20 scans) in borate buffer in the presence of Fe(CN) 6 4− .…”

“…In all cases, the same minimal transmittance value was reached (∼30%); this value depends on the optimum film thickness. In the presence of ABTS, the peaks in the CV are slightly shifted toward less anodic potentials, but there is no significant change in electrochromic contrast, similar to Ru(CN) 6 4− . However, with Fe(CN) 6 4− , the transmittance of the reduced film returns to nearly 90%, leading to an enhancement of the electrochromic contrast.…”

“…In the presence of ABTS, the peaks in the CV are slightly shifted toward less anodic potentials, but there is no significant change in electrochromic contrast, similar to Ru(CN) 6 4− . However, with Fe(CN) 6 4− , the transmittance of the reduced film returns to nearly 90%, leading to an enhancement of the electrochromic contrast. As already observed by Villemure and co-workers, 32 the bleaching of the film occurs in two steps, the first one corresponding to the direct reduction of Ni sites in the LDH and the second to the mediated reduction by Fe(CN) 6 , which remains an efficient mediator for the reduction in basic medium.…”

“…, and Ru(CN) 6 4− , may improve the contrast between the bleaching and the colored states of the NiAl-LDH transparent electrodes, 32−34 the electroactive anions playing the role of electron mediators in the electrochemical process. Figure S6 shows the transmittance of NiAl-LDH NC as a function of applied potential recorded in situ during the 25 th potential scan in 0.1 M LiOH containing different electroactive ions (0.1 mM Fe(CN) 6 4− , Ru(CN) 6 4− , and ABTS). With Ru(CN) 6 4− , there is no significant modification of the transmittance transient from that obtained in the blank electrolyte.…”

“…Figure S6 shows the transmittance of NiAl-LDH NC as a function of applied potential recorded in situ during the 25 th potential scan in 0.1 M LiOH containing different electroactive ions (0.1 mM Fe(CN) 6 4− , Ru(CN) 6 4− , and ABTS). With Ru(CN) 6 4− , there is no significant modification of the transmittance transient from that obtained in the blank electrolyte. The transmittance of the film drops rapidly when the potential reaches the foot of the oxidation peak at ∼0.6 V and remains stable until the potential returns to ∼0.4 V where the electrochemical reduction process begins.…”