Applied Physics Letters · 2011 · 145 citations · 17 references
Natural SciencesMaterials EngineeringMaterials ScienceElectronic MaterialsPolymer ChemistrySemiconductor MaterialsConducting PolymersConductive PolymersOrganic SemiconductorsPhotovoltaic MaterialsSolar Cell MaterialsSolar CellsBulk Heterojunction Solar CellsEnergy Conversion EfficiencyMorphology ControlOrganic Photovoltaic CellsOrganic Solar CellsPolymer-solvent InteractionsPower ConversionPower Conversion Efficiency
Incremental increase in dimethyl sulfoxide (or dimethyl formamide) in ortho-dichlorobenzene solution of poly[N-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT) gradually reduces the polymer-solvent interaction, the attraction forces between polymer chains become more dominant, and the polymer chains adopt a tight and contracted conformation with more interchain interactions, resulting in a progressive aggregation in both solutions and films. This was used to fine tune the morphology of PCDTBT/PC71BM based solar cells, leading to improved domain structure and hole mobility in the active layer, and significantly improved photovoltaic performance. The power conversion efficiency increased from 6.0% to 7.1% on devices with an active area of 1.0 cm2.
17