Abstract
Electrochromic coatings are promising for applications in smart windows or energy-efficient optical displays. However, classical inorganic electrochromic materials such as WO3 suffer from low coloration efficiency and slow switching speed. We have developed highly efficient and fast-switching electrochromic thin films based on fully organic, porous covalent organic frameworks (COFs). The low band gap COFs have strong vis-NIR absorption bands in the neutral state, which shift significantly upon electrochemical oxidation. Fully reversible absorption changes by close to 3 OD can be triggered at low operating voltages and low charge per unit area. Our champion material reaches an electrochromic coloration efficiency of 858 cm(2) C-1 at 880 nm and retains >95% of its electrochromic response over 100 oxidation/reduction cycles. Furthermore, the electrochromic switching is extremely fast with response times below 0.4 s for the oxidation and around 0.2 s for the reduction, outperforming previous COFs by at least an order of magnitude and rendering these materials some of the fastest-switching frameworks to date. This combination of high coloration efficiency and very fast switching reveals intriguing opportunities for applications of porous organic electrochromic materials.
| Item Type: | Journal article |
|---|---|
| Faculties: | Chemistry and Pharmacy > Department of Chemistry |
| Research Centers: | Center for NanoScience (CENS) |
| Subjects: | 500 Science > 540 Chemistry 500 Science > 500 Science |
| ISSN: | 0002-7863 |
| Language: | English |
| Item ID: | 96986 |
| Date Deposited: | 05. Jun 2023 15:24 |
| Last Modified: | 05. Jun 2023 15:24 |
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