Charge transport and recombination in organic solar cells
Conferences & Talks

description

Organic solar cells have reached about 8% efficiency, but need to be more efficient to compete with other materials. An understanding of the losses of organic bulk heterojunction solar cells requires knowledge of how the heterojunction interface influences the electronic transport and recombination mechanisms. We describe how transient photoconductivity measurements and the cell spectral response provide information about the carrier mobility, recombination mechanisms and the electronic structure. We find that geminate recombination is not a dominant recombination process in P3HT:PCBM or PCDTBT:PCBM cells. Instead, there is good evidence that recombination through interface traps is important. The measurements of the electronic structure show band tail effects attributed to the material disorder. The band tails contribute to suppressing geminate recombination and allowing trap recombination. The role of the interface on the electronic structure and the electronic properties will be discussed.