Anatase (TiO2) thin layers for solar energy conversion

Abstract

This paper describes the possibilities of obtaining nanostructured TiO₂ using Spray Pyrolysis Deposition and its application in a solid state solar cell (FTO/ TiO₂ In₂S₃/ CuSbS₂/ graphite). Nanostructured TiO₂ films are deposited from ethanolic solution of titanium (IV) isopropoxid, (TTIP, 99.99%, Sigma-AIdrich), and acetilacetonate, (AcAc, 99+%, Aldrich); two parameters are proposed for investigation: the annealing duration in air at 500degC, t_TT (h), and the number of sprayed sequences, No._p.c.. The layers are characterised by XRD, AFM, Raman Spectroscopy, UV-VIS Spectroscopy and the cells by current-voltage measurement in dark and under illumination. It was found that annealing and the spraying time structure can be o a method of tailoring the TiO₂ thin films properties and can influence the photovoltaic response of the cells. The best response was obtained for the cell obtained with TiO₂ thin films deposited with 20 number of sprayed sequences and 6 h of annealing in air at 500degC, for which the open circuit voltage is V_oc = 210 mV, the short circuit current is I_Ic = 8.13-10^-2 mA, the values of the maximal power is defined by V_max = 117 mV and I_max = 4.64O₂ldr10² mA, corresponding to a fill factor FF = 0.318.