A planar electrochromic device using WO3 nanoparticles and a modified paper-based electrolyte

Abstract

Electrochromic devices are increasing its interest in the last decades due to the wide range of applications, from smart windows to biosensors or from smart labels to super-capacitors. So, the development of simple and cost-effective production technologies based on solution process and mask less approach is of great interest. In this work, a new planar and flexible electrochromic device based on tungsten oxide (WO3) nanoparticles with a paper-based modified electrolyte was successfully produced, using a CO2 laser technology for electrodes patterning and hydrothermal synthesis for the nanoparticles production. The devices were fabricated with a paper pad inserted in the sensor area for hydration on time of usage, thus replacing the electrolyte material of a typical electrochromic structure with a multi-layer stack, eliminating leakage problems, easy integration with other devices and enhancing the shelf life of the devices to several months. The produced device presents a low power consumption of only 2.86 A·cm2, with a deep blue color and an initial charge modulation of 11.5.