Abstract:
During the past few decades, the dye sensitized solar cells (DSSCs) have intensively been focused as
an alternative energy source due to their low cost, easy fabrication and environment friendly operation.
However, relaxation and recombination processes connected to the charge carriers hinder the
performance of DSSCs. One of the alternatives extensively studied to improve the mobility of charge
carriers in DSSCs is the use of doped TiO2 electrode. In this study, Ruthenium (Ru) was selected as the
dopant as Ru-based dyes have been reported to give better photovoltaic performance. TiO2 was doped
with RuCl3 and the performance of the DSSC using Ru- doped TiO2 electrode was investigated
systematically varying the Ru content (0.002 to 0.04 wt%). The synthesised Ru-doped TiO2 nanomaterials
were characterised by X-ray diffraction (XRD), UV–Visible spectroscopy (UV–Vis), Fourier-transform
infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) techniques. The XRD pattern
confirms the presence of mixed anatase and rutile phases of TiO2; the optical absorption spectra of
undoped and Ru doped TiO2 revealed red shift in the absorption peak with Ru doping. The undoped and
Ru-doped TiO2 thin films were separately deposited on dense TiO2 coated FTO using doctor-blading method
and subsequently liquid state DSSCs were fabricated with commercially available N719 dye, I− / I3
−
electrolyte and FTO/Pt electrodes and photovoltaic performance of the devices were studied using
Keithley-2420 source meter under simulated irradiation of intensity 100 mWcm-2 with AM 1.5 filter. The
0.004 wt% Ru-doped TiO2 electrode showed the best power conversion efficiency (PCE) of 7.34% with a
25% enhancement in the PCE relative to undoped TiO2 based DSSC (PCE= 5.88%) mainly due to the
increment of short circuit current density.
