Langmuir-Blodgett assembly of nanometric WO3 thin film for electrochromic performance: A new way

In the present investigation, a nanometric Tungsten oxide (WO3) thin film has been fabricated via a Langmuir-Blodgett (LB) technique through the thermal decomposition of a multilayer film of octadecylamine (ODA)-tungsten complex. ODA forms a stable complex with tungstate ion at the air-water interface and ODA-tungstate complex was subsequently deposited on ITO substrate by LB technique. The synthesised WO3 film was characterized for optical, structural and electrochromic properties. The film shows a large optical modulation of 30% at λ630 nm at a potential of ±1.2 V, faster switching speed, the time of coloration (tc) is 3.18 s and time of bleaching (tb) is 2.93 s, and a high coloration efficiency of 73.12 cm2 C−1. The high coloration efficiency is attributed to well organized nanomatric WO3 on the substrate without any seed layer. After all, colored and bleached state of film was presented on CIE 1931 Lab estimated at 2° observer using D-65 illumination.