Abstract:
Titanium dioxide (TiO2) is a commonly used semiconductor in Dye-Sensitized Solar cells (DSSCs) as it
is inexpensive, abundant and innocuous to the environment. However, lack of response to the visible light
and slow electron mobility limit its performance. Doping TiO2 with a non-metal such as Nitrogen has
been found to improve light absorption in the visible region of the solar spectrum and also enhance the
charge transport in the DSSCs[1],[2].This study reports a facile method to fabricate the nitrogen-doped
TiO2 photoanode. A series of nitrogen-doped TiO2 films were prepared by grinding TiO2 with various
amount of NH4OH and followed by calcination at 500°C. These films were characterized by X-ray
diffraction (XRD) and UV-Visible spectroscopy, which confirmed an increase in particle size and red
shift in the spectrum by nitrogen-doping respectively. Finally, the photovoltaic devices were fabricated
using N719 dye,
/
electrolyte and Pt counter electrode and device performance was tested under
simulated irradiation of intensity 100 mW/cm2 with AM 1.5 filter. 20% enhancement in Power
Conversion Efficiency (PCE) was observed for the optimized Nitrogen-doped TiO2 based device
compared to the control device. Moreover, doping TiO2 using Nitrogen enhanced the short circuit current
density (JSC) from 11.9 to 13.7 mA/cm2
. The improvement in JSC is attributed to the reduced charge
transport resistance which was confirmed by the Electrochemical Impedance Spectroscopy (EIS).
