Credit: Adapted with permission from Smerdon et al., Nano Letters 16, 2603 (2016). Copyright 2016 American Chemical Society.
Self-assembled structures, called heterojunctions, contain ordered pentacene molecules (purple) standing upright on buckyballs (red) ordered on a copper surface. The measured map (left) shows the rectification ratio, which is a measure of how much current flows in the forward and reverse directions. The heterojunction has a far better rectification ratio (blue insert – bent line I(V)) measure than the pentacene without the buckyball buffer (red inset left – straight line I(V))