Effect of blocking layers prepared by the hydrolysis of TiCl4 solution on the photovoltaic performance of a dye-sensitized solar cell

Abstract

Blocking layer thin films were prepared on a conductive fluorine-doped tin oxide (FTO) substrate by the hydrolysis of TiCl4 solution with different concentrations. This blocked the recombination between photoelectrons and I3-. Blocking layer compositions were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The surface morphology and transmittance were determined by field emission scanning electron microscopy (FE-SEM) and UV-visible spectrophotometry. The photovoltaic performance of the dye-sensitized solar cells (DSSC) was measured under AM1.5 illumination and under dark conditions. We found that the blocking layers were composed of TiO2 particles. Increasing the concentration of TiCl4 in solution leads to an increase in the blocking layer thickness. Apart from the increase in thickness, the morphology develops as the concentration increases. The transmittance of FTO decreases after the blocking layers deposit on the surface and the blocking layers prepared using 0.04 mol · L-1 TiCl4 solution can suppress the dark current most efficiently and we thus obtained the highest power conversion efficiency of 7.84% under AM1.5 illumination conditions. © Editorial office of Acta Physico-Chimica Sinica.