Imaging the Electric Potential within Organic Solar Cells

• Published in: Advanced functional materials Vol. 23; no. 47; pp. 5854 - 5860
• Main Authors: Saive, Rebecca, Scherer, Michael, Mueller, Christian, Daume, Dominik, Schinke, Janusz, Kroeger, Michael, Kowalsky, Wolfgang
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 17.12.2013; WILEY‐VCH Verlag
• Subjects: bulk heterojunction; Charge transport; focused ion beam; organic electronics; solar cells
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201301315

The charge transport in organic solar cells is investigated by surface potential measurements via scanning Kelvin probe microscopy. Access to the solar cell's cross‐section is gained by milling holes with a focused ion beam which enables the direct scan along the charge transport path. In a study of poly(3‐hexylthiophene):1‐(3‐methoxycarbonyl)propyl‐1‐phenyl[6,6]C61 (P3HT:PCBM) bulk heterojunction solar cells, the open circuit voltage is built up at the top contact. A comparison of the potential distribution within normal and inverted solar cells under operation exhibits strongly different behaviors, which can be assigned to a difference in interface properties. The charge transport in P3HT:PCBM bulk heterojunction solar cells in conventional and inverted device structures is investigated by surface potential measurements via scanning Kelvin probe microscopy. The cross‐section of solar cells is accessed by milling holes with a focused ion beam, which enables the direct scan along the charge transport path.