Semiconducting metal oxide nanowires represent a class of novel materials that are of superior
properties to naoparticles currently used in dye sensitized solar cell and polymer hybrid solar cells.
The quasi one-dimensional nanostructure and surface states of nanowires improve carrier mobility
and charge transfer through interface interactions of theses nanocomposite materials. Raman
spectroscopy, especially resonant Raman spectroscopy, is used to correlate nanomaterial synthesis
condition to the structural, optical and electric transport properties that are important to
photocatalysis, exciton transport and recombination and hydrogen storage mechanism. For example,
highly orientated ZnO nanowires studied with Raman and photoluminescence spectroscopy
demonstrated the high efficiency of the phonon and electron coupling. These results are compared
with that of other ZnO forms such as thin film, polycrystalline powder and solid. The Raman
bandwidths and shifts of nanowires revealed the phonon confinement in the quasi one-dimensional
nanostructures, which is further demonstrated with In2O3 nanowires at 5, 10, 20, 30 nm in diameters.
Room temperature photoluminescence results also show band gap shifts with nanowire dimensions.
Nanowire sizes, defects and strains, controlled by synthesis conditions, have shown to determine
band structure and optical phonon properties. We also discuss characterization and synthesis of
carbon nanotube based composite materials including polymer electropolymerization and
infiltration. Combining significantly enhanced mechanical compressive strength and excellent
electric conductivity, these composite materials offer potentials to fuel cell anode materials as
multifunctional hydrogen storage media.