Four Shades of Brown: Tuning of Electrochromic Polymer Blends Toward High-Contrast Eyewear

Abstract

We report a straightforward strategy of accessing a wide variety of colors through simple predictive color mixing of electrochromic polymers (ECPs). We have created a set of brown ECP blends that can be incorporated as the active material in user-controlled electrochromic eyewear. Color mixing of ECPs proceeds in a subtractive fashion, and we acquire various hues of brown through the mixing of cyan and yellow primaries in combination with orange and periwinkle-blue secondary colors. Upon oxidation, all of the created blends exhibit a change in transmittance from ca. 10 to 70% in a few seconds. We demonstrate the attractiveness of these ECP blends as active materials in electrochromic eyewear by assembling user-controlled, high-contrast, fast-switching, and fully solution-processable electrochromic lenses with colorless transmissive states and colored states that correspond to commercially available sunglasses. The lenses were fabricated using a combination of inkjet printing and blade-coating to illustrate the feasibility of using soluble ECPs for high-throughput and large-scale processing.

High-Performance Electrochromic Devices Based on Poly[Ni(salen)]-Type Polymer Films

“…2,3,4 Currently, EC materials are mainly applied in smart windows for green architecture 5 and in anti-glare rear view mirrors. 6 Other proposed applications are in displays of portable and flexible electronic devices, including smart cards, re-usable price labels and electronic papers, 7,8,9 protective eyewear 10 and in textiles for adaptative camouflage or simply for fashion.…”

New Roll‐to‐Roll Processable PEDOT‐Based Polymer with Colorless Bleached State for Flexible Electrochromic Devices

“…[12][13][14][15][16][17] Furthermore, ECPs feature a wide range of vivid colors, response times in the range of seconds, and light transmittance change over 60%. [3,6,7,[27][28][29][30][31][32][33][34] Other materials, such as multichromophoric polymers, can actually offer suitable bleached and colored states, but require elaborate synthesis routes and have an electrochemical operating window, which poses serious stability problems. The bandgap between the highest occupied π-electron band and the lowest unoccupied band determines the EC properties like color and color change.…”

Printed Multi-color Devices using Oxidative Electrochromic Materials

“…Gadgets that utilize changes in the optical properties of EC materials are called "electrochromic devices" (ECDs). Many applications for ECDs have been proposed such as antiglare rear-view mirrors [2], sunglasses [3,4], eyewear [3,4], and smart windows for airplanes and buildings [5][6][7][8][9].…”

“…Well known oxidative EC materials include triphenylamine (2) and tetraphenylbenzidine (3) that are used in hole-transport layers of organic photoconductors (OPCs) and organic light emitting diodes (OLEDs) (Fig. 1).…”