The Origin of Collected Charge and Open-Circuit Voltage in Blended Polyfluorene Photovoltaic Devices


  • This work was funded by the Engineering and Physical Sciences Research Council, (EPSRC). We thank Dr. Peter Ho for the optical modeling data and for valuable discussions. We also thank Dr. Carlos Silva for valuable discussions.


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Polymer blend photovoltaic devices (see Figure) are investigated and the characteristic electron and hole lengths estimated. It is found that for a polymer film exhibiting fine-scale phase separation, only charges generated close to the electrode can be collected. The open-circuit voltage for polymer blend devices is found to be lower than that for bilayer devices, a result of the direct paths from cathode to anode within each blend component.