Silver nanoparticle-embedded titania nanobelts with tunable electronic band structures and plasmonic resonance for photovoltaic application

Metallic silver nanoparticle (NP)-embedded single-crystalline titania (Ag@TiO2) nanobelts have been prepared by a new process with use of sodium titanates sequentially from ion exchange, thermal hydrogenation to post-calcination. The structural transformation involved and their morphology were characterized. This work explored photovoltaic efficiency of these composite nanobelts as anode materials in dye-sensitized solar cells and their electronic and energy band properties, which correlate with the Ag content. Optical absorption and photoluminescence analyses reveal core Ag NP-induced localized surface plasmon resonance (LSPR) and mediated electron transfer within the titania shell. According to Mott-Schottky analysis, the Ag addition causes an increase in the donor density and an upshift in the flat-band potential of the oxide host. The investigated Ag@TiO2 cells produced higher photocurrents and open-circuit voltages than the bare TiO2 one, and the best performance was attained with a marked enhancement by 72% in the photovoltaic efficiency. As indicated by electrochemical impedance analysis, the Ag-added nanobelts are beneficial to rapid electron diffusion and electron lifetime, so that they promote charge collection efficiency. Synergistic combination of plasmonic resonance, electronic conduction and Fermi-level upshift is a plausible strategy to functionalize the one-dimensional core-shell Ag@TiO2 nanostructures for optoelectronic applications.

Automated summary

Metallic silver nanoparticle-embedded single-crystalline titania nanobelts were synthesized and investigated for their photovoltaic efficiency and electronic properties. The addition of silver resulted in enhanced photocurrents, open-circuit voltages, and a significant improvement of 72% in the photovoltaic efficiency. Electrochemical impedance analysis showed that the addition of silver improved electron diffusion and electron lifetime, thus promoting charge collection efficiency. The combination of plasmonic resonance, electronic conduction, and Fermi-level upshift is a promising strategy for functionalizing one-dimensional core-shell Ag@TiO2 nanostructures for optoelectronic applications.