Electrostatic-Force-Assisted Dispensing Printing of Electrochromic Gels for Low-Voltage Displays

In this study, low-voltage, printed, ion gel-based electrochromic devices (ECDs) were successfully fabricated. While conventional dispensing printing provides irregularly printed electrochromic (EC) gels, we improved the adhesion between the printed gel and the substrate by applying an external voltage. This is called electrostatic-force-assisted dispensing printing. As a result, we obtained well-defined, printed, EC gels on substrates such as indium tin oxide-coated glass. We fabricated a gel-based ECD by simply sandwiching the printed EC gel between two transparent electrodes. The resulting ECD, which required a low coloration voltage (∼0.6 V), exhibited a high coloration efficiency (η) of 161 cm/C and a large transmittance contrast (∼82%) between the bleached and colored states at -0.7 V. In addition, electrostatic-force-assisted dispensing printing was utilized to fabricate directly patterned ECDs.