Dynamically Tuneable Reflective Structural Coloration with Electroactive Conducting Polymer Nanocavities

Abstract

Dynamic control of structural colors across the visible spectrum with high brightness has proven to be a difficult challenge. Here, this is addressed with a tuneable reflective nano‐optical cavity that uses an electroactive conducting polymer (poly(thieno[3,4‐b]thiophene)) as spacer layer. Electrochemical doping and dedoping of the polymer spacer layer provides reversible tuning of the cavity's structural color throughout the entire visible range and beyond. Furthermore, the cavity provides high peak reflectance that varies only slightly between the reduced and oxidized states of the polymer. The results indicate that the polymer undergoes large reversible thickness changes upon redox tuning, aided by changes in optical properties and low visible absorption. The electroactive cavity concept may find particular use in reflective displays, by opening for tuneable monopixels that eliminate limitations in brightness of traditional subpixel‐based systems.

Graphene-Based Tunable Coloration Film through Intercalation

“…Yang et al provided photochromic nanocomposite organohydrogels with high transparency, excellent strength, and 60 s response time . Meanwhile, structural color is another important approach to produce high-resolution colors with a physical structure. , By designing nanostructures such as nanowires, gratings, and disk-hole coupling with suitable geometrical parameters, the desired color can be acquired from reflecting or scattering light through periodic arrays or individual resonators. , By combining advantages of the structural color and smart materials such as electrochromic materials, many researchers have shown excellent works about color tuning. − For example, Arsenault et al reported an electrical control method to control photonic crystals to fabricate a full-color display with 1–2 s response time, and its cycling stability is excellent . Lee et al showed a novel dynamic structural color based on organic electrochromic materials.…”

A review of tunable photonics: Optically active materials and applications from visible to terahertz

“…Due to the different phase-transition temperature between tungsten-doped VO 2 (W-VO 2 ) and VO 2 , the resonance wavelength of cavity structure (VO 2 /SiO 2 /W-doped VO 2 ) shows multilevel color variation. Furthermore, based on the electrochemical reaction, the conductive polymer (poly-thieno[3,4-b]thiophene, pT34bT) offers a dynamic and full-colored Fabry-Perot cavity under low operating voltages ( Rossi et al., 2021 ). Even in low electrochemical potential (−1 to 0.7 V), distinct refractive index variation of pT34bT enhanced the color tunability, resulting in color modulation across the entire visible range.…”

Molecular Plasmonics with Metamaterials

“…The switching was completely reversible with possible modulation rates of 10s of Hz and energy consumption of just 9 fJ per pixel. Alternative electrochromic polymers, whose optical properties can be switched electrochemically or chemically between conductive and insulating states to obtain dynamic metamaterials, are poly­[3,4-ethylenedioxythiophene] (PEDOT) − and poly­(3,4-propylenedioxythiophene) (PProDOT) derivatives, poly­(thieno­[3,4- b ]­thiophene), polypyrrole (PPy), − and triphenylamine-based polyamide (TPA-PA) …”