Fabrication of Ag nanoparticles embedded in TiO2 nanotubes: using electrospun nanofibers for controlling plasmonic effects.

Composites of electrospun poly(ethylene oxide) (PEO) fibers and silver nanoparticles (Ag NPs) were used as a soft template for coating with TiO2 by atomic layer deposition (ALD). Whereas the as-deposited TiO2 layers on PEO fibers and Ag NPs were completely amorphous, the TiO2 layers were transformed into polycrystalline TiO2 nanotubes (NTs) with embedded Ag NPs after calcination. Their plasmonic effect can be controlled by varying the thickness of the dielectric Al2 O3 spacer between Ag NPs and dye molecules by means of the ALD process. Electronic and spectroscopic analyses demonstrated enhanced photocurrent generation and solar-cell performance due to the intense electromagnetic field of the dye resulting from the surface plasmon effect of the Ag NPs.