Noise-induced quantum coherence drives photo-carrier generation dynamics at polymeric semiconductor heterojunctions.

Here we report on an exciton/lattice model of the electronic dynamics of primary photo excitations in a polymeric semiconductor heterojunction that includes both polymer π-stacking, energetic disorder and phonon relaxation. Our model indicates that that in polymer/fulerene heterojunction systems, resonant tunnelling processes brought about by environmental fluctuations couple photo excitations directly to photocurrent producing charge-transfer states on <100 fs time scales. Moreover, we find this process to be independent of the location of energetic disorder in the system, and hence we expect exciton fission via resonant tunnelling to polarons to be a ubiquitous feature of these systems.