Fabrication of plasmonic gold-nanoparticle-transition metal oxides thin films for optoelectronic applications

A simple, cost-effective, and one-step procedure for fabrication of gold-nanoparticle-transition metal oxide (Au-TMO) thin films with tuned optical and structural properties is described. In this approach, a homogeneous mixed precursor solution was used to fabricate Au-MoO₃ and Au-WO₃ thin films via a spray pyrolysis technique. The in-situ grown Au nanoparticles in the host matrices exhibited a characteristic surface plasmon resonance absorption in the visible-NIR region with peak positions at λ_max ≈ 600 nm, ≈550 nm, and ≈575 nm for Au-MoO₃, Au-a-WO₃ (amorphous), and Au-h-WO₃ (hexagonal) films, respectively. The structural and morphological characterization measurements confirmed that the high purity in-situ grown Au nanoparticles were 10–100 nm in size, and individual particles were embedded into the host matrices. These films were applied as plasmon-induced photoelectric conversion devices with ITO/NiO_x/Au-WO₃/Ag structures as a prototype device. The device exhibited a short-circuit current of 0.1 mA with an open-circuit voltage of ∼1.4 V under one-sun illumination. Our one-step fabrication approach is highly promising for fabricating other Au-TMOs thin films with tuned optical properties on a large area and can be applied for various optoelectronic applications.