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Updated: May 5, 2026

An Electrochemical Cholesteric Liquid Crystalline Device for Quick and Low-Voltage Color Modulation
Published on: February 27, 2019
Aerosol-jet-printed, 1 volt H-bridge drive circuit on plastic with integrated electrochromic pixel
Mingjing Ha1, Wei Zhang, Daniele Braga
1Department of Chemical Engineering and Materials Science, University of Minnesota , 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States.
Abstract:
In this report, we demonstrate a printed, flexible, and low-voltage circuit that successfully drives a polymer electrochromic (EC) pixel as large as 4 mm(2) that is printed on the same substrate. All of the key components of the drive circuitry, namely, resistors, capacitors, and transistors, were aerosol-jet-printed onto a plastic foil; metallic electrodes and interconnects were the only components prepatterned on the plastic by conventional photolithography. The large milliampere drive currents necessary to switch a 4 mm(2) EC pixel were controlled by printed electrolyte-gated transistors (EGTs) that incorporate printable ion gels for the gate insulator layers and poly(3-hexylthiophene) for the semiconductor channels. Upon application of a 1 V input pulse, the circuit switches the printed EC pixel ON (red) and OFF (blue) two times in approximately 4 s. The performance of the circuit and the behavior of the individual resistors, capacitors, EGTs, and the EC pixel are analyzed as functions of the printing parameters and operating conditions.

