Enhancement reversibility and electrochromic efficiency of porous WO<inf>3</inf> films by sparking method under electric/magnetic field

Abstract

This article reports on the morphological design to enhance reversibility and electrochromic performance of porous WO3 films synthesized by sparking method using electric field (E = 6 kV/cm) and magnetic field (B = 500 mT). The excellent H+ ion exchange between liquid electrolyte and the WO3 films was influenced by extremely fluffy morphology as observed by sparking under an electric field— WO3 with E sample. The morphology of the films becomes denser when sparked under a combination of electric and magnetic fields—WO3 with (E + B) sample—which reduces the diffusion pathway and improves electron transfer within the films. Finally, we designed and fabricated dense/porous double-layer WO3 films (WO3 with (E + B)/E sample) to integrate their advantages to enhance 7-fold optical modulation and 9-fold coloration efficiency. Furthermore, the reversible efficiency increased from 16.1 % to 83.7 % compared to WO3 with E sample.