Electrochromic two-dimensional covalent organic framework with a reversible dark-to-transparent switch.

ABSTRACT: Electrochromic (EC) materials with a dark-to-transmissive switch have great applications in optical communications, infrared wavelength detectors for spacecraft, and infrared camouflage coatings. However, such electroactive materials with high stability and cyclability are rare. Considering the advantages of the donor-acceptor approach (wide-range tuneable band position) and porous two-dimensional (2D) covalent organic framework (COF, well-ordered crystalline framework with stable structure and high surface area), in this work we constructed an extended delocalised ?-electron layered dark purple EC-COF-1 by reacting the donor N,N,N',N'-tetrakis(p-aminophenyl)-p-benzenediamine (TPBD) with the acceptor 2,1,3-benzothiadiazole-4,7-dicarboxaldehyde (BTDD). A sandwiched device made of EC-COF-1 exhibits the two-band bleaching (370?nm and 574?nm) in the visible region and becomes transparent under the applied potential with an induced absorption centring at 1400?nm. This discovery of a stable dark-to-transmissive switch in COF might open another door for their application in many EC devices for various purposes.

SUBMITTER: Yu F 

PROVIDER: S-EPMC7608553 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature