Flexible polymer solar cells with power conversion efficiency of 8.7%

Here we demonstrate flexible polymer solar cells with a record high power conversion efficiency of 8.7% and a very high specific power of 400 W kg(-1), by depositing a physical blend of a conjugated semi-conducting polymer and a fullerene derivative on a highly flexible polyethylene terephthalate (PET) substrate. The flexible device reported here performs basically as well as those based on rigid glass/ITO substrates with regard to most of the device parameters, however has a relatively lower fill factor, which can be further improved via interface engineering between the photoactive layer and electrodes or by the development of novel flexible substrates. The processing method for the flexible polymer solar cells is solution-based and all of the film deposition processes are completed at room temperature, thus this simplicity of preparing flexible polymer solar cells can offer easy-processability over a large area with fast deposition on an industrial scale at room temperature.