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

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 WO3 thin films was observed. WO3 films were prepared onto the conducting ITO coated glass substrates by a novel pulsed spray pyrolysis technique (PSPT). A reticulated mesh like morphology of WO3 was achieved by optimizing the deposition parameters of PSPT and the gold nanoparticles were embedded in the WO3 matrix by a drop casting method. Enhancements in electrochromic properties of WO3 in terms of optical modulation (ΔOD), coloration efficiency (η) and response times (tc and tb) were attributed to the assistance of SPR in gold nanoparticles during coloration and electric field induced quenching of SPR during bleaching.

Research highlights▶ Au nanoparticles were embedded in reticulated mesh like matrix of WO3 films prepared by a novel pulsed spray pyrolysis technique (PSPT). ▶ Surface plasmon resonance (SPR) was evidenced in Au-anchored WO3 films by enhancement in their electrochromic properties such as optical modulation (ΔOD), coloration efficiency (η) and response times (tc and tb).