Efficiency of exciton dissociation at the interface between a conjugated polymer and an electron acceptor with consideration for a two-dimensional arrangement of interfacial dipoles

Exciton dissociation at the interface between a conjugated polymer as an electron donor (D) and a fullerene derivative as an acceptor (A) is often considered in the dipole model that suggests existence of the dipolar layer between D and A materials. In the current article, we calculate the dissociation probability of excitons in the dipole model assuming a two-dimensional arrangement of the interfacial dipoles at a D-A interface. We find that the dipolar layer between D-A materials can radically alter the energy of the Coulomb attraction between an optically generated electron and its geminate hole. We show that the calculated dissociation probability of electron-hole pairs is in agreement with experimental field dependences of photocurrents reported previously for a bilayer solar cell consisting of C-60 as an electron acceptor and a well ordered conjugated polymer as an electron donor.