Patent ID: 8586967

Claim:
A device for generating photocurrent by absorbing photons, comprising: a first electrode; a second electrode; a photoactive region disposed between the first electrode and the second electrode, the photoactive region further comprising: a first photoactive organic layer for generating excitons by absorbing photons comprising a mixture of a small molecule organic acceptor material and a small molecule organic donor material, wherein the first organic layer has a thickness not greater than 0.8 characteristic charge transport lengths; and a second photoactive organic layer for generating excitons by absorbing photons in direct contact with the first photoactive organic layer, wherein: the second photoactive organic layer comprises an unmixed layer of the small molecule organic acceptor material of the first photoactive organic layer, and the second photoactive organic layer has a thickness not less than about 0.1 optical absorption lengths, wherein excitons generated by absorption of photons by the first and second photoactive organic layers dissociate into electrons and holes that contribute to the photocurrent.