A photosensitive cell includes an anode and a cathode; a donor-type organic material and an acceptor-type organic material forming a donor-acceptor junction connected between the anode and the cathode; and an exciton blocking layer connected between the acceptor-type organic material of the donor-acceptor junction and the cathode, the blocking layer consisting essentially of a material that has a hole mobility of at least 10.sup.-7 cm.sup.2/V-sec or higher, where a HOMO of the blocking layer is higher than or equal to a HOMO of the acceptor-type material.
UNITED STATES GOVERNMENT RIGHTS
 This invention was made with U.S. Government support under Contract No. 339-4012 awarded by U.S. Department of Energy, National Renewable Energy Laboratory. The government has certain rights in this invention.