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Colorless-to-Black Electrochromism from Binary Electrochromes toward Multifunctional Displays.
Xuewen Yu1, Meijuan Chang1, Weinan Chen1
1Laboratory of Advanced Materials, State Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai 200438, P. R. China.
ACS Applied Materials & Interfaces
|August 19, 2020
Summary
This study introduces a new colorless electrochromic polymer, PTPA-HDI, and a viologen derivative, HVCN, for advanced displays. Combining these creates high-contrast, fast-switching electrochromic devices with applications in encryption and smart windows.
Area of Science:
- Materials Science
- Electrochemistry
- Polymer Chemistry
Background:
- Conventional electrochromic polymers often lack sufficient color contrast or transparency.
- Developing new materials for advanced electrochromic devices (ECDs) is crucial for next-generation displays.
Purpose of the Study:
- To synthesize and characterize a novel electrochromic polymer, poly(bis(N,N-diphenyl-4-aminophenyl)cyclohexane-1,2,4,5-tetracarboxylic diimide) (PTPA-HDI).
- To design and synthesize a viologen derivative (HVCN) for colorless-to-black electrochromism.
- To fabricate and evaluate supporting electrolyte-free ECDs using PTPA-HDI and HVCN for multifunctional display applications.
Main Methods:
- Electropolymerization of PTPA-HDI on ITO-coated glass.
- Spectroelectrochemical analysis of PTPA-HDI films.
- Synthesis of an asymmetric viologen derivative (HVCN).
- Fabrication of asymmetric electrochromic devices (ECDs) with PTPA-HDI and HVCN.
Main Results:
- PTPA-HDI exhibits hypsochromic shift and good electrochromic properties with optimal performance at 15 scan cycles.
- The synthesized HVCN derivative shows colorless-to-green electrochromism.
- Combined PTPA-HDI and HVCN in an ECD achieve fast, high-contrast, reversible colorless-to-black electrochromism.
- Demonstrated applications include an encryption ECD and an autodigital display integrated into a smart window.
Conclusions:
- The study presents a novel approach to achieving colorless-to-black electrochromism using binary electrochromes.
- The developed ECDs offer fast switching, high contrast, and excellent reversibility.
- These findings pave the way for designing multifunctional displays and advanced smart window applications.
