... Fluorene-based low band-gap copolymers for high performance photovoltaic devices. Applied Physics Letters, Vol.84, No .10, (March 2004), pp. 1653, ISSN 107 7-3118 Solar Cells – New Aspects and Solutions ... Reviews, Vol .107 , No.4, (April 2007), pp. 1324-1338, ISSN 1520-6890 Solar Cells – New Aspects and Solutions 462 Chart 4. 3-substituted thiophene dimer isomers, regioregular P3HT and regioirregular ... properties. Polyfluorene, however, has a band gap of ~3.0eV, which limits its application in Solar Cells – New Aspects and Solutions 478 M Zn(CH2COO) and 0.1 M Na2S aqueous solution for...