Encryptable Electrochromic Smart Windows: Uniaxially Oriented and Polymerized Hierarchical Nanostructures Constructed by Self-Assembly of Tetrathiafulvalene-Based Reactive Mesogens.

Abstract

Tetrathiafulvalene (TTF)-based reactive mesogens (TTF-E and TTF-T) are synthesized, self-assembled, uniaxially oriented, and polymerized for the development of encryptable electrochromic smart windows. Electrochemical and spectroscopic experiments prove that the self-assembled TTF mixture (TTFM, TTF-E:TTF-T = 1:1) can reversibly switch the absorption wavelength of the TTF chromophore according to the redox reactions. Based on the identification of the phase transition and crystallographic structure, uniaxially oriented hierarchical nanostructures are easily constructed on the macroscopic area by simple coating and a self-assembly process. Subsequent polymerization of hierarchical nanostructures of TTFM significantly enhances thermal and mechanical stabilities and makes it possible for them to be fabricated as an electrochromic device. The angularly dependent correlation between the anisotropy of mesogens and the linearly polarized light allow us to demonstrate TTFM as smart windows capable of various optical security applications, including privacy protection and information encryption.