Simple ITO Surface Treatments Induced Better Performance for Low Cost Organic Solar Cells

Abstract

The objective of this research is to study effects of different indium tin oxide (ITO) surface treatments on the performances of organic solar cells. The organic solar cells (ITO/PEDOT:PSS/PCDTBT:PC70BM/TiOx/Al) was fabricated using a cost-effective method called Rapid Deposition Convective (RDC)technique, whichuses small amount of solution to create uniform thin film on a substrate. The film thickness can easily be controlled by deposition speed and volume. Two surface treatment methods, UV radiation method and oxygen plasma method, were compared. The efficiency of solar cells under UV radiation treatment and oxygen plasma treatment are 6.30 and 7.24%, respectively, while the efficiency of untreated surface is 4.93%. AFM topography images also revealed that the surface prepared by oxygen plasma is smoother than the surface prepared by UV radiation. Both surface treatment methods not only effectively increase the work function of ITO substrate but also can improve the conductivity and the hydrophilic properties for the compatible of ITO and PEDOT:PSS layer.