Inkjet Printing Bio‐Inspired Electrochromic Pixels

Abstract

In this report the design, fabrication, and testing of inkjet‐printed electrochromic pixels (ECPs) incorporating the biochrome, xanthommatin (Xa) as programmable display units is described. As a redox sensitive chromophore, Xa is present in some species as a physiological indicator with red (reduced) or yellow (oxidized) colors associated with different behavioral or developmental stages. These features have been recently leveraged in some materials applications, illustrating a bio‐inspired design solution to color‐changing sensors and displays. This paper describes an extension of these applications to print individually addressable ECPs that can be processed in a mild annealing step to introduce localized conductivity on initially nonconductive substrates. When formulated together with a poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) carrier ink, an addition of 0.19 wt% Xa is enough to generate dynamic ECPs which can be batch printed as lateral electrodes on any substrate to serve as both conductors and display units across electrically isolated boundaries. Application of low potentials triggers reversible color changes that span the red/yellow color space and can cycle for days. These results represent an important step towards the incorporation of alternative active materials like Xa to manufacture and scale low‐power, color‐changing pixels and patterns.

Cephalopods as a Natural Sensor-Display Feedback System Inspiring Adaptive Technologies

“…51,52 Alternatively, an electrical or magnetic field can be used to rotate or align particles embedded within a material, thereby revealing a pattern or transforming a colored/opaque material into a transparent one, or vice versa. 53 A third approach to color change can be achieved through chromophore manipulation, such as through redox chemistry 54,55 or mechanochromism (Fig. 3c).…”

“…As the applied electric field continues to increase (63.1 kV mm −1 ), the patterned wrinkles become circular craters, highlighting a stimuli-responsive mode to generate color and textural changes. 48 Other approaches to replicate adaptive coloration in cephalopods include variations of light, 62,63 thermal, 49,50,64 mechanical, 51,52,65 chemical, [66][67][68] electrochemical, 54,55,69 or magnetic 53 control strategies in response to passive and/or active stimuli. The creation of more complex, multi-material design schemes for dual mode (both structural and pigmentary) color changes have also been explored.…”

Adaptive coloration enabled by the reversible osmotic annealing of chromatophore-like microcapsules

“…While many color-changing technologies have been developed using pigments as active components, including approaches based on translocation of colored solutions 11 or electrochromism, 12,13 these actuation strategies (e.g., pressure, electricity) are not entirely compatible with the stimuli used to specifically target patterned features of tunable structural materials, which can include humidity, 14 organic vapors, 15 pH, 16 temperature, 17 and mechanical force. 18 To develop engineered systems capable of actuation across diverse coloration mechanisms, similar to the performance exemplified by cephalopods, a strategic selection of materials must be made that can respond to common or compatible stimuli.…”

“…While many color-changing technologies have been developed using pigments as active components, including approaches based on translocation of colored solutions 11 or electrochromism, 12,13 these actuation strategies ( e.g. , pressure, electricity) are not entirely compatible with the stimuli used to specifically target patterned features of tunable structural materials, which can include humidity, 14 organic vapors, 15 pH, 16 temperature, 17 and mechanical force.…”

C-Rich Carbon Nitride Conjugated Polymer Enabling Ion-Migration-Induced Precise Electrochromic Display

“…Until now, PEDOT:PSS has been the most commonly used material to manufacture ink for printing techniques. Despite the good EC performances of PEDOT:PSS and various strategies, such as piezoelectric inkjet printing and in situ polymerization, , to improve the printing process, the expected high-quality precise display has still not been achieved. It is quite urgent to explore new EC materials and device-manufacturing strategies for EC displays.…”