Amy M. Ballantyne1, Lichun Chen1, J. Dane1, T. C. Hammant1, Felix Braun1, Martin Heeney2, Warren Duffy3, Iain McCulloch4, Donal D. C. Bradley1, Jenny Nelson1
1Department of Physics, Imperial College London, London SW7 2AZ, UK
2Department of Materials, Queen Mary, University of London, London E1 4NS, UK
3Merck Chemicals, Chilworth Science Park, University Parkway, Southampton SO16 7QD, UK
4Department of Chemistry, Imperial College London, London, UK
Tóm tắt
AbstractThe time‐of‐flight method has been used to study the effect of P3HT molecular weight (Mn = 13–121 kDa) on charge mobility in pristine and PCBM blend films using highly regioregular P3HT. Hole mobility was observed to remain constant at 10−4 cm2V−1s−1 as molecular weight was increased from 13–18 kDa, but then decreased by one order of magnitude as molecular weight was further increased from 34–121 kDa. The decrease in charge mobility observed in blend films is accompanied by a change in surface morphology, and leads to a decrease in the performance of photovoltaic devices made from these blend films.
