Stabilizing Hybrid Electrochromic Devices through Pairing Electrochromic Polymers with Minimally Color-Changing Ion-Storage Materials Having Closely Matched Electroactive Voltage Windows

Abstract

Conjugated electrochromic polymers hold great promises for next-generation color-changing windows and displays. One of the major roadblocks in their solid-state electrochromic devices is the relatively poor cycling stability. Finding ion-storage materials as a charge-balancing component is critical in improving their electrochemical cycling stability. A key criterion for the selection of ion-storage materials is to match their electroactive voltage windows with the paired electrochromic polymers. Thus, we developed a nanostructured, amorphous vanadium oxide (VO x ) ion-storage material that exhibits high transmissivity, minimal color interference, and excellent charge-balancing capability in a closely matched electroactive window with the paired electrochromic polymers. High-performance magenta-to-transmissive hybrid electrochromic devices constructed from pairing the polymer with the VO x can be reversibly switched for 50 000 cycles with an optical loss less than 5%.

Post-Synthetic Color Tuning of the Ultra-Effective and Highly Stable Surface-Confined Electrochromic Monolayer: Shades of Green for Camouflage Materials

“…This winning combination results in an incredible boost in the stability of the resulting device (up to 50,000 cycles with less than 5% loss of the optical density). 31 Despite the significant progress in the area of polymer-based EC materials, still, not many literature examples of inorganicbased green EC materials have been reported. To name a few, the inorganic hybrid SnO 2 /V 2 O 5 core/shell rough composite EC with a large transmittance modulation (47%) and a good in its class coloration efficiency of 118 cm 2 C −1 was reported for applications to adaptive camouflage materials.…”

“…To overcome this limitation, interesting hybrid architectures were created by using a combination of the EC polymers with the proper transparent charge-balancing ion-storage material [nanostructured, amorphous vanadium oxide (VO x )]. This winning combination results in an incredible boost in the stability of the resulting device (up to 50,000 cycles with less than 5% loss of the optical density) …”

Emerging Electrochromic Materials and Devices for Future Displays

“…The ion storage layer (ISL) is used to balance charges via doped active materials; it undergoes reversible electrochemical oxidation (reduction) to match with the reduction (oxidation) of EC materials in the electrochromic layer (ECL). Thus, related materials for ISL must maintain good electrochemical reversibility, stability, capacity, and compatibility with EC materials. − The ion transport layer (ITL) has the function of transferring ions inside the device. The candidates for related ion-transport materials include electrolytes (e.g., lithium salt, ammonium salt, and ionic liquid)-doped gels/solutions/films, − polymers with ionic conductivity − such as poly­(ionic liquid) and Nafion, (ionic) liquid crystals, , etc.…”

Toward Durably Flexible Nickel Oxide Electrochromic Film by Covering an 18 nm Zinc Tin Oxide Buffer Layer

“…Therefore, it is essential to develop some new technologies to reduce energy consumption in buildings. In this case, a smart window using electrochromic (EC) technology is an effective method to reduce energy consumption in buildings which can create a comfortable indoor environment according to the season. − The electrochromic device (ECD) can modulate the optical transmittance in the visible-light region through ion insertion and extraction in response to the switch of an externally applied potential . A conventional electrochromic device consists of five layers, i.e., bottom transparent conducting layer, anodic electrochromic layer, ion-conducting layer, cathodic electrochromic layer, and top transparent conducting layer .…”