Efficient ternary polymer solar cells with dihydronaphthyl-based C60 bisadduct as an third component material

A dihydronaphthyl-based C60 bisadduct (NCBA) acceptor is introduce as a third component to typical PTB7: PC71BM binary polymer solar cells (PSCs). NCBA play bridging role between the lowest unoccupied molecular orbital (LUMO) of PTB7 and PC71BM and provides more routes for charge carrier transfer at the interface between PTB7 and PC71BM, a higher open-circuit voltage (VOC) realize upon addition of NCBA can be achieve relative to the neat PC71BM as an electron acceptor. The strong visible light absorption in the range from 350 to 700 nm of NCBA molecule compared with PC71BM molecule, it has the effect of apparently complementary visible light absorption compare with the binary PTB7:PC71BM thin films. The current density-voltage (J-V) characteristics dependent on incident light intensity were employed and to analyze the effect of NCBA concentration on the charge carrier recombination process of ternary PSCs. The crystallinity and surface morphology of the ternary PTB7:NCBA:PC71BM thin films with NCBA concentration is 15% of blend acceptor is similar to that of the binary PTB7:PC71BM thin films, which guarantees suitable efficient exciton dissociation and charge carrier transport. The transient photovoltage (TPV) and transient photocurrent (TPC) were measured, and the results illustrate the effect of NCBA as the third component materials in terms of higher charge carrier density and long charge carrier lifetime and weaken charge carrier recombination.