Electrochemically polymerized nanostructured poly(3.4-ethylenedioxythiophene)-poly(styrenesulfonate) buffer layer for a high performance polymer solar cell

An electrochemically polymerized uniform column-like poly(3.4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT:Pss) nanostructure synthesized on indium tin oxide substrate has been used as the buffer layer to construct a polymer bulk heterojunction solar cell, demonstrating 50% higher power conversion efficiency (from 2.56 to 3.86%) than that of using the spin-coated PEDOT: Pss as the buffer layer. The enhanced device performance is ascribed to the improved carrier transport from the highly dense, uniform column-like PEDOT: Pss nanostructure, which penetrates into the polymer blend film to improve the connection of the active layer with the anode while providing a large conducting area for charge transport. This approach is compatible with the state-of-the-art bulk heterojunction solar cells, thus offering a high throughput, low cost manufacturing process for a high performance device.