Abstract:
TiO2
films made by the pressing method and then nitrogen-doped by heat-treatment in
nitrogen, oxygen and argon gas mixture have been studied and the effects of structural characteristics,
optical and electrical properties on the efficiency of a cell reported. Nitrogen gas ratio (Φ ) in the
doping procedure was varied from 0 to 0.024. HigherΦ resulted in decrease in film porosity, and
XRD analysis of the TiO2 films showed that nitrogen doping induced a rutile-to-anatase phase
transitions. SEM shows that the particle sizes of nitrogen doped films reduced with increase of Φ
from an average of 36nm to 18nm. Optical measurements revealed that film transmittance improved
and reflectance reduced in the visible light spectrum with nitrogen doping. Nitrogen doped TiO2
photoelectrodes have been found to be more sensitive to visible light spectrum and has a narrower
band gap. Photoelectrochemical measurements showed a large anodic shift of the onset potential for
the cathodic scans of the order of 0.24V. The overall energy conversion efficiency, short circuit
current and open circuit voltages of the solar cell fabricated with nitrogen doped TiO2
photoelectrode
were found to depend onΦ . The cell fabricated with nitrogen doped TiO2
photoelectrode had an
overall efficiency of 0.70 % while the undoped had efficiency of 0.96 %.
