Reduced Recombination Losses with Enhanced Dielectric Permittivity of Donor Polymers in Polymer Solar Cells

Abstract

In this work, we have demonstrated that the electric field assisted poling of the donor polymer possessing conformationally labile nitrile groups increases dipolar polarization and dielectric permittivity. We find that the enhanced dielectric permittivity of the donor polymer reduces non-geminate recombination losses in bulk-heterojunction (BHJ) solar cells (SCs), resulting in increased open circuit voltage (V-oc) compared with unpoled devices. This result reveals the importance of dielectric permittivity of polymers and also signifies the promising applicability of electric field assisted poling for high dielectric polymers in BHJ SCs.