Enhanced optical modulation due to SPR in gold nanoparticles embedded WO3 thin films

Abstract Surface plasmon resonance (SPR) phenomenon of metal–dielectric composite thin films formed by embedding the noble metal nanoparticles in a dielectric matrix offers a high degree of flexibility and enables many applications such as surface enhanced spectroscopes, numerous biological and chemical sensing fields. A remarkable enhancement in optical modulation after embedding the gold nanoparticles in a reticulated mesh like matrix of WO 3 thin films was observed. WO 3 films were prepared onto the conducting ITO coated glass substrates by a novel pulsed spray pyrolysis technique (PSPT). A reticulated mesh like morphology of WO 3 was achieved by optimizing the deposition parameters of PSPT and the gold nanoparticles were embedded in the WO 3 matrix by a drop casting method. Enhancements in electrochromic properties of WO 3 in terms of optical modulation (ΔOD), coloration efficiency ( η ) and response times ( t c and t b ) were attributed to the assistance of SPR in gold nanoparticles during coloration and electric field induced quenching of SPR during bleaching.