Direct photocurrent mapping of organic solar cells using a near-field scanning optical microscope

Direct photocurrent mapping of organic solar cells (OSCs) using a novel implementation of a near-field scanning optical microscope (NSOM) is described. By rastering the light output from the NSOM through a semitransparent electrode across the OSC surface, it is possible to collect height and photocurrent images simultaneously with a lateral resolution that is governed by the NSOM aperture. The photocurrent images demonstrate that film inhomogeneities and segregation effects strongly influence OSC device performance.