Enhancing the thermal stability of polythiophene:fullerene solar cells by decreasing effective polymer regioregularity.
Regioregularity has been shown to be an important aspect for the properties of poly(3-hexylthiophene) both in the pristine material and in bulk heterojunction photovoltaics with the fullerene derivative PCBM. Here we present a straightforward method to adjust the effective regioregularity of poly(3-hexylthiophene) by introducing 3,4-dihexylthiophene into the polymer chain. By investigating bulk heterojunction morphology and photovoltaic performance upon annealing, we observe that polythiophene with 91% regioregularity maintains equivalent electronic properties but forms a more thermally stable interpenetrating network with PCBM than polythiophene with regioregularity >96%.
Sivula
Kevin
K
Departments of Chemistry and Chemical Engineering, University of California-Berkeley, 718 Latimer Hall, Berkeley, CA 94720-1460, USA.
Luscombe
Christine K
CK
Thompson
Barry C
BC
Fréchet
Jean M J
JM