Thickness dependent optical and eosin-Y sensitized solar cells characteristics of nc-a TiO2 films

• Modified sol–gel dip coating method is versatile technique.
• Nanocrystalline anatase TiO2 is limited by annealing treatment.
• Optical properties depend on thickness and nanocrystalline anatase TiO2.
• Photovoltaic properties depend on thickness and eosin-Y dye.
• Conversion efficiency for sample (IM510) TiO2 film using eosin-Y dye is 1.10%.

Herein, we report the thickness dependent optical and eosin-Y dye sensitized solar cell (DSSC) characteristics of nanocrystalline anatase (nc-a) TiO2 films deposited on indium tin oxide (ITO) substrates by using sol–gel dip-coating method with C12H28O4Ti (TTIP) (0.05 and 0.10 M) as Ti-precursor. The as-deposited films were heated at 400 °C/2 h in air. The XRD and Raman spectroscopy characterization studies revealed the formation of pure single anatase TiO2 phase in resultant films. The HRTEM studies reflected uniform size distribution of spherical TiO2 nanoparticles (average size ∼20 nm) with crystalline grains of diameters = 15–20 nm in a structured matrix. This is consistent with XRD results of crystallite size = 10–25 nm. A profound effect of variation of film thickness on optical and eosin-Y sensitized photovoltaic characteristics of nc-a TiO2 films is observed. With increasing the film thickness, the % optical transmission (T), absorption coefficient (α), refractive index (n) and optical conductivity (σopt) are found to be decreasing whereas, porosity ratio (% P) and photoconversion efficiency (η) are found to be increasing. The optical indirect band gap is found to be between 3.20 and 3.21 eV. The better photovoltaic performance: open-circuit voltage of 0.554 V, short circuit current of 1.291 mA, fill factor of 41.57% and conversion efficiency (η) of 1.10% is obtained for eosin-Y DSSC using redox polyiodide (1 M KOH + 1 M KI + 0.5 M iodine) electrolyte in actonitrile.

The nanocrystalline N doped TiO2 has been prepared using modified sol–gel dip coating method. The photovoltaic properties of dye sensitized solar cell based on the thickness and eosin-Y dye TiO2 thin film was demonstrated.Figure optionsDownload as PowerPoint slide