Study on the properties and charge generation in dye-sensitized n-TiO 2|dye|p-CuI solid state photovoltaic solar cells

Abstract

Transparent semiconducting copper iodide (CuI) films were prepared by XeCl Excimer laser and their characteristics are investigated. These films exhibited optical transmittance over 80% in the wavelength range from 400 to 900 nm and minimum resistivity of about 2 kΩ cm −1. The optical absorption of the these films shows a remarkable blue shift compared to that of polycrystalline of CuI, which can be explained from the viewpoint formation of ultra fine of CuI grains. The titanium dioxide (TiO 2) films have been prepared by sol–gel method. The properties of pulsed laser deposited CuI and TiO 2 films in power output of n-TiO 2|dye|p-CuI cells is studied. An efficient charge generation is observed through the illumination of TiO 2 layer of the fabricated n-TiO 2|dye|p-CuI solid state photovoltaic solar cells. From the current–voltage characteristics, the fill factor and power conversion efficiency were about of 45 and 3%, respectively. The maximum photo-current of about 12.5 mA/cm 2 and photo-voltage of 475 mV under AM 1.5 conditions were obtained for the n-TiO 2|dye|p-CuI solid states photovoltaic solar cells with good reproducibility. Adsorbed dye molecules to the TiO 2 surface act as a relay, especially under illumination through TiO 2 layer in the wave range region of 300–400 nm.