Abstract:
Dye-sensitized solar cells (DSSCs) have gained a great attention because they deliver good
efficiency in power conversion, ease of manufacturing and lower costs, making them the
most promising alternatives to traditional photovoltaic systems. DSSC photo-anodes were
manufactured using nanostructures of undoped Titanium dioxide (TiO2) and Copper (Cu)
doped TiO2 (CTO) in this study (2% and 4% concentration by wt. of Cu). The sol-gel
process was utilized to synthesize these nanostructures. For materials analysis, Raman
Spectroscopy, FTIR, UV-Visible (UV-Vis) spectrophotometer, EDS analysis, and
scanning electron microscopy (SEM) were used to evaluate the material's properties, such
as structural, optical, and morphological properties of prepared nanostructures. The FTIR
spectra of three samples showed that intensity varied as we change the Cu concentration
with TiO2. The peak intensity decreases in case of 2% and and 4% CTO. The Raman
spectra of bare TiO2 and Cu doped TiO2 showed the shift in peaks, more intense peak is
observed at 606cm-1 corresponding to A1g mode in TiO2. The lower peak is at 413cm-1
in
case of 2% while in 4% CTO it is shifted to 404cm-1
. SEM analysis revealed that doping
of Cu with TiO2 increase the surface area of TiO2 nanoparticles and hence increase the
conversion efficiency of cells. The average particle size of doped titania was observed
about 60 nm. EDS analysis of the samples is done along with the SEM analysis to study
the elemental composition of the samples. The EDS analysis of the bare and Cu doped titania
confirmed the synthesis of titania nanostructures and Cu doping. In UV-Visible analysis,
the absorption improves with increasing Cu doping concentration, whereas the band gap
decreases from 3.25 eV to 3.02 eV. The band gap value of undoped TiO2 is measured to
be 3.25 eV, which was calculated using tauc plot. The band gap of 2% CTO was 3.17 eV,
and of 4% CTO was measured as 3.02 eV. The solar cell device was fabricated, and solar
simulations (J-V measurements) were performed, the photovoltaic parameters such as open
circuit voltage (Voc), short circuit current density (Jsc), fill factor (FF) and efficiency (𝜂)
were calculated. Simultaneous improvements in photovoltaic performance were achieved
by Cu doping. In comparison with bare titania and 2% CTO, the 4% Cu doped TiO2 exhibits
the higher efficiency (𝜂) of 1.76%.
