Ag nanoparticles embedded defective tungsten oxide hydrate thin films for the enhanced electrochromic performance: Insights on the physico-chemical properties and localized surface plasmon resonance mechanism

Abstract Electrochromic materials have attracted tremendous attention for high colour efficiency, reflection, transparency with lower-power consumption and potential optoelectronic applications. The current work reports the investigation of the Physico-chemical and localized surface plasmon resonance effect (LSPR) of Ag nanoparticles on the overall properties of WO3·0.33H2O thin films and their collective performance towards the enhancement of electrochromic activity. The hexagonal-snowflakes like WO3·0.33H2O/ Ag(x%) nanohybrids were synthesized by hydrothermal method, and their thin films were successively fabricated by drop cast come spin coating method. The obtained nanohybrids were characterized by several analytical techniques to study their structural, optical, morphological features and their impact on electrochromic performance. The electrochromic activity of the WO3·0.33H2O/Ag(2.5%) thin-film showed significant improvement and observed a large optical modulation of 67.11% at 633 nm with rapid colouration-bleaching time, which is far better compared to WO3·0.33H2O/Ag(x%) films. This improvement is credited to enhanced electrical conductivity, quick double insertion/extraction of electrons/ions after the surface modification, large surface area and improved overall properties. Notably, the LSPR effect of Ag nanoparticles supported the intercalation-deintercalation pathways by virtue of accessible ion transport channels at WO3·0.33H2O/Ag interface. Different correlation study revealed the importance and co-catalytic impact of Ag nanoparticles in the WO3·0.33H2O/Ag(x%) nanohybrids. Overall the improvement in the electrochromic performance of the WO3·0.33H2O/Ag(x%) thin films are credited to LSPR effect, tuned physical, chemical and structural properties.