Electrochromic capacitive windows based on all conjugated polymers for a dual function smart window

Myoung

2019

Adv Funct Materials

118

Electrochromic materials reversibly change colors by redox reactions depending on the oxidation states. To utilize electrochromic materials for active-matrix display applications, an electrochromic display (ECD) requires simultaneous implementation of various colors and a fine-pixelation process. Herein, flexible and transparent ECDs with simultaneously implementable subpixelated EC gels by sequential multiple patterning are successfully demonstrated. Ionic liquid-based EC gels of monoheptyl-viologen, diheptylviologen (DHV), and diphenyl-viologen (DPV) are used to create the colors of ECDs: magenta, blue, and green, respectively. Especially, to realize an improved green color, DHV-DPV composite gels are synthesized. Three EC gels exhibit stable properties without degradation during repetitive operation. Moreover, a transmittance greater than 90% is maintained in a bleached state, which is sufficient for application as a transparent display. The subpixelation process for multicolored-flexible ECDs is designed to facilitate both easy fabrication and rapid operation with various patterns at low cost. The subpixelated EC gels using a film mask can be implemented to a minimum size of 200 µm. Furthermore, the subpixelated flexible ECDs exhibit high durability even after 1000 cycles of mechanical bending tests at a bending radius of 10 mm. Therefore, these EC materials can be used directly for flexible and transparent active-matrix displays.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Flexible and Transparent Electrochromic Displays with Simultaneously Implementable Subpixelated Ion Gel‐Based Viologens by Multiple Patterning

Myoung

2019

Adv Funct Materials

118

“…In this way, one can precisely control overvoltage for EC reaction and achieve high color contrast. [ 81 ] In this context, high color contrast blue and red‐colored EC polymers, poly(3,3‐bis(bromomethyl)‐3,4‐dihydro‐2H‐thieno[3,4‐b][1,4]dioxepine) (PR‐Br) and poly(3,4‐di(2‐ethylhexyloxy)thiophene‐ co ‐3,4‐di(methoxy)thiophene) (Th‐OR), respectively, were introduced into an EC window containing polyaniline (PANI) film as transparent capacitive layer. [ 81 ] A nonaqueous electrolyte (SPAn) was developed using acetonitrile solution containing NaClO 4 (0.3 m ) and HClO 4 (0.1 m ) for the ECCAP.…”

Section: Multifunctional Smart Windows With Integrative Functionalitiesmentioning

confidence: 99%

Electrochromic Conjugated Polymers for Multifunctional Smart Windows with Integrative Functionalities

Rémond

Adv Materials Technologies

et al. 2020

Self Cite

121

In the advent of next‐generation smart windows, materials play a multifunctional role, providing not only a pleasant environment for humans but also energy‐efficient buildings and transportation. To this ends, smart windows tend to integrate multiple functions with the purpose of controlling external or sunlight input, self‐power functionality, and display functionality. Among the several chromogenic mechanisms, electrochromic methods are fast and simple to control. Here, the recent electrochromic research on the integration of different functionalities is reviewed. Efforts toward the combination of functionalities have led to synergetic and technical breakthroughs over the years. These include development of new electrochromic polymers by main chain, as well as, side chain engineering, morphology and assembly control, and nanostructurization. In this context, electrochemical principles for smart windows offer easier integration of functionalities due to the integrative principles in common working mechanisms for color, energy, and information carrier controls. Some examples of multifunction devices are electrochromic capacitive windows, self‐powered smart windows, and electrochromic‐luminescent windows. Herein, discussed are the electrochromism from polymers and the electrochemically driven smart windows with two or more functionalities, which give rise to an innovative material with cooperative functions, featuring energy storage, energy generation, or light emission.

“…Electrochromic (EC) materials have attracted considerable attention due to their electric responsive behaviors that change optical absorbance or transmittance. 1-3 EC devices (ECDs) have found relatively new applications such as functional energy storage devices (referred to as EC capacitors; ECSs), [4][5][6] and electronic skins (e-skins). 7,8 Nonetheless, most applications are in smart windows [9][10][11][12][13][14] for buildings, cars, sunglasses, and reective displays.…”

Section: Introductionmentioning

confidence: 99%

Tetrathiafulvalene: effective organic anodic materials for WO₃-based electrochromic devices

et al. 2019

RSC Adv.

Finding a new, effective anodic species is a challenge for achieving simpler low-voltage tungsten trioxide (WO 3 )based electrochromic devices (ECDs). In this work, we utilize tetrathiafulvalene (TTF) and demonstrate its reversible redox behaviors as an electrolyte-soluble anodic species. The concentration of TTF in the electrolyte is varied to optimize device performance. When the TTF concentration is low (0.01 M), a smaller maximum transmittance difference (DT max $ 34.2%) and coloration efficiency (h $ 59.6 cm 2 C À1 ) are measured.Although a better performance of DT max $ 93.7% and h $ 74.5 cm 2 C À1 is achieved at 0.05 M TTF, the colored state could no longer return to its original form. We conclude that 0.03 M of TTF is the appropriate concentration for high-performance WO 3 ECDs with high optical contrast and reversible EC behaviors. The irreversible EC transition at high concentrations of TTF is attributed to the agglomeration of TTF molecules.