Tailoring of Low Bandgap Polymer and its Performance Analysis in Organic Solar Cells

New conjugated, alternating ter-polyfluorene prepared by Suzuki reaction and a LUMO energy level of ―3.3 eV, which is sufficient for electron transfer to the PCBM is presented. A solar cell power conversion efficiency of 0.8% is reached for the composition P6: PCBM 1:4. From optical simulations were derived a maximum short circuit current density exceeding 16 mA · cm -2 at 500 nm thick films. Comparative measurements of the field effect hole mobility give an indication of two orders of magnitude lower charge carrier mobility of P6 in comparison to P3HT. The combined optical and electrical simulations of this system with a variation of the charge carrier mobilities support suspicion of a predominant limitation of the charge carrier mobility.