Improved conductive atomic force microscopy measurements on organic photovoltaic materials via mitigation of contact area uncertainty



Physical processes that lead to conversion of light into electrical energy inside photovoltaic devices happen at the nanoscale. Therefore, understanding of electrical properties of photovoltaic materials at this length scale is of paramount importance for improvement of device performance. In this paper, we describe and validate a new framework for high-resolution quantitative measurements of electrical and mechanical properties of compliant materials with sub-100-nm resolution. Previous approaches have generally suffered from uncertainty in the quantitative level of contact between the probe and the material being measured; the methodology presented here overcomes this obstacle. We use the broadly studied ITO/PEDOT:PSS/P3HT:PC61BM system as an example to illustrate variability of chemical composition and electrical properties of the active layer at hundred-nanometers and micrometer length scales. Copyright © 2012 John Wiley & Sons, Ltd.