Influence of sintering temperature on energy conversion efficiency in dye-sensitized solar cell
The dye-sensitized nanocrystalline TiO2 film solar cells were fabricated here. The TiO2 electrodes were prepared by a sol-gel process and were sensitized by the nature dye extracted from a paper mulberry tree. When the sintering temperature of TiO2 films rises from 90 to 500 °C, the energy conversion efficiency of the solar cell improves considerably and up to an optimum value at 470 °C. To investigate this, the nano-TiO2 films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-Vis spectrum, and the current-voltage (I-V) characteristic of the heteroj unction between the nano-TiO2 and the indium tin oxide (ITO) was measured. The results show the size, crystal phase and band gap of TiO2 nanoparticles undergo changes at the various sintering temperatures. Besides, the resistance of the heteroj unction decreases with increasing the sintering temperature. As the temperature going up and beyond 450 °C, the heterojunction begins to develop into a Schottky junction, and its potential barrier decreases.