Thumbnail image of graphical abstract

The image shows a highly flexible ITO-free polymer solar cell (PSC) module comprising 16 serially interconnected cells. The substrate is 60 μm thin PET foil. A hexagonal silver grid and PEDOT:PSS composite forms the transparent conductor for the front electrode. With P3HT:PCBM as the photoactive blend material, a power conversion efficiency of ∼2% on >100cm2 total area is achieved, as presented by Dechan Angmo and Frederik C. Krebs on page 1. All layers are processed in ambient conditions on a roll-to-roll machine using a combination of printing and coating methods. With the rapid progress in the use of thin layer outlines, low cost input materials, and high production speed, it will not be long before PSCs can competitively supplement conventional energy sources.