Strategic Design of Graphenized Plasmonic/Nb2O5 Hybrid Nanocomposite for Highly Efficient Plasmonic Dye-Sensitized Solar Cells

Abstract

This study presents the strategic design of a graphenized plasmonic/Nb2O5 hybrid nanocomposite for high-efficiency dye-sensitized solar cells (DSSCs). The composite was synthesized via a hydrothermal method, integrating reduced graphene oxide and Cu nanoparticles with Nb2O5 to enhance light harvesting and charge transport. Structural characterization using XRD confirmed the orthorhombic phase of Nb2O5 and successful rGO incorporation, while SEM revealed a hierarchical 3D architecture with uniformly dispersed Nb2O5 nanoparticles (50-100 nm) anchored on rGO sheets. TGA demonstrated enhanced thermal stability, with only 25% weight loss up to 800°C, while UV-Vis spectroscopy identified a plasmonic absorption band (550-650 nm) from Cu nanoparticles. Electrochemical impedance spectroscopy (EIS) revealed a 55% reduction in charge transfer resistance (250 Ω vs. 550 Ω for pristine Nb2O5), attributed to rGO’s conductive network and Cu’s plasmonic effects. Photovoltaic testing under AM 1.5G illumination showed a champion power conversion efficiency (PCE) of 5.15% for the rGO/Cu/Nb2O5-based DSSC, a 23% improvement over Nb2O5 (4.19%). This performance boost stemmed from synergistic enhancements: a 29% increase in short-circuit current density (14.36 mA/cm2) due to improved light absorption and charge collection, while maintaining a high fill factor (~60%) and open-circuit voltage (~0.6 V). EQE spectra further validated these gains, with a peak efficiency of 68% at 530 nm. The study demonstrates the potential of plasmonic rGO/Cu/Nb2O5 nanocomposites as advanced photoanodes for high-performance DSSCs, combining efficient light harvesting, charge transport, and thermal stability.