Tailoring tungsten trioxide (WO3): pH-dependent synthesis, structural insights, and exceptional electrochromic performance
Ayesha Khan, Suchitra N. Sapakal, Anamika V. Kadam
Abstract
In the current investigation, WO 3 thin films are prepared via simple hydrothermal method at different pH values (1, 7 and 11). In this study, XRD, SEM, FTIR, UV–visible, and electrochemical techniques were used to study pH effects on the preparation of WO 3 and their structural, morphological, and electrochromic variations. The XRD analysis revealed that the pH of the precursor solution significantly influences crystallinity, with acidic conditions favouring high crystallinity and efficient electrochromic (EC) performance, while more alkaline conditions result in reduced crystallinity and amorphous film formation. The SEM analysis demonstrates that pH significantly influences the morphology of WO 3 films. FTIR spectroscopy exhibited characteristic peaks associated with WO 3 , affirming the successful synthesis of WO 3 thin films. The electrochemical investigations demonstrated that WO 3 films prepared at a pH of 1 exhibited exceptional EC activity, characterized by the highest optical modulation density of 0.3 and a colouration efficiency (CE) of approximately 122.2 cm 2 /C at 633 nm. These findings underscore the promising potential of pH-controlled hydrothermal method for tailoring the electrochromic behavior of WO 3 thin films, with implications in energy efficient smart windows. • pH of the precursor solution plays a significant role in determining the crystallinity of WO 3 thin films. • The study underscores the influence of pH on the morphology of WO 3 films. • WO 3 films prepared at pH 1 exhibited exceptional electrochromic activity. • WO 3 films of pH 1 shows highest optical modulation density of 0.3 and coloration efficiency (CE) 122.2 cm 2 /C at 633 nm. • Electrochromic properties of WO 3 by hydrothermal method tailor promising approach for energy-efficient smart windows.