SnO 2 films elaborated by radio frequency (RF)magnetron sputtering as a potential TCOs alternative for organic solar cells

International audienceTransparent conducting oxides (TCOs) are crucial component of solar cells. Tin doped indium oxide (ITO) is the most employed TCO, but the scarcity and high price of indium induce a search for lower cost TCOs with equivalent properties as substitute. Tin dioxide (SnO2) films have many advantages, such as rich sources of material, low prices, and non-toxicity. SnO2 films present a high visible light transmittance, near-infrared light reflectivity, and excellent electrical properties. They also have a higher chemical and mechanical stability compared to ITO. The aim of this work is to elaborate SnO2 films by RF-magnetron sputtering in order to use them as electrodes for Organic Solar Cells (OSCs). The SnO2 films were deposited on glass, SiO2 and quartz substrates in a mixed environment of Ar and O2. XRD measurements show that the as-deposited SnO2 films are polycrystalline with cassiterite tetragonal structure. SEM analysis showed that the films are homogeneous, continuous, and nanostructured. The electrical resistivity and average optical transmittance of the samples are about 10 −3 Ω.cm and over 80%, respectively. The estimated optical band gap (Eg) is around 4.0 eV while the work function of the films is around 5.0 eV. The SnO2 films are used as electrodes for inverted OSCs, using poly(3-hexylthiophene-2,5-diyl): [6,6]phenyl-C60-butryric acid methyl ester (P3HT:PC60BM) as active layer. The device's open circuit voltage (VOC) and short circuit current density (JSC) are similar to those obtained for the inverted OSCs employing ITO as the same electrode. Even if the achieved power conversion efficiency is lower compared to the value for the reference OSC with an ITO electrode, these results are promising and place SnO2 TCO as a potential candidate to replace ITO