Organic photovoltaics (OPVs) are typically deposited on transparent conducting oxides, such as Indium-Tin Oxide (ITO). These are complex oxides with surfaces known to be heterogeneous in composition and electrical properties on a nanometer length scale. The electrical properties of the surface can be modified by various surface treatments, most commonly detergent/solvent cleaning, oxygen plasma treatment and UV-ozone treatment. These treatments may alter the electronic properties of the surface, but may not address the issue of heterogeneity, which can seriously affect the power conversion efficiency of these devices. This presentation focuses on the use of Conducting-Tip Atomic Force Microscopy (C-AFM) to explore the relation between electrical heterogeneity of the ITO surface and the performance of OPV devices. C-AFM can be used to obtain current-voltage curves on ca. 20nm² areas across ITO/organic thin films. In this study one of three surface treatments (detergent cleaning, oxygen plasma treatment or acid etch) was applied to ITO, followed by vacuum deposition of copper phthalocyanine, the first organic layer of our OPV devices (ITO/Copper Phthalocyanine/C₆₀/Aluminum Quinolate/Aluminum). In general the current density varies by several orders of magnitude for different points on a given ITO/Pc film, except for the films on acid-etched ITO that are constant within a factor of ca. 5. The OPV made on the acid-etched ITO exhibits a diode quality factor of 2, as predicted for an interface recombination-limited diode. The other ITO surface treatments exhibit significantly higher diode quality factors in OPV devices, and as a result have lower fill factors and decreased power conversion efficiency. The addition of a heavily doped conducting polymer (PEDOT:PSS) layer on top of the ITO also results in spatially uniform injection into the phthalocyanine film, at the cost of a small additional energy barrier that appears in the CAFM and OPV device current voltage curves.