TECHNOLOGY FOCUS - ELECTRONICS - Preferred Arrangement: An exciton blocking layer is situated between the electron acceptor layer and the cathode.An anode smoothing layer is situated between the electron donor layer and the anode.The electron-hole recombination zone is a semi-transparent metal layer.The recombination zone is less than about 20 Angstrom.The metal layer is composed of nanoparticles.The recombination zone comprises a region of electronically active defects.The external power conversion efficiency of the device is at least 1%, preferably 3.6%, at one sun illumination.The hole transport layer is formed of a photoconductive organic semiconductor material.The electron transport layer, the hole transport layer and exciton blocking layer are disposed between two parallel planar reflective surfaces which form a waveguide. One of the two reflective surfaces has an aperture to admit light incident upon the device.The device has a transparent opening between the reflective surfaces so that light is admitted to the device from a direction parallel to the planes of the reflective surfaces.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Compounds: The exciton blocking layer contains bathocuproine (BCP) or bis(2-methyl-8-hydroxyquinolinoato)-aluminum (III) phenolate (Alq2OPH).The anode smoothing layer comprises polyethylene dioxythiophene:polystyrene sulfonate (PEDOT:PSS).The electron donor layer comprises a phthalocyanine or a porphyrin.The electron acceptor layer comprises perylene, naphthalene, fullerene chosen from 60-96C, or nanotube.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Compounds: The anode is chosen from transparent conductive oxides, preferably indium tin oxide.    TECHNOLOGY FOCUS - METALLURGY - Preferred Metals: The recombination zone contains silver, lithium, lithium fluoride, aluminum, titanium and/or tin, preferably silver. EXAMPLE - An organic photosensitive optoelectronic device was fabricated on pre-cleaned indium tin oxide (ITO) glass substrate, spin-coated with a 300 Angstrom thick layer of polyethylene dioxythiophene:polystyrene sulfonate (PEDOT). The organic materials were purified by train sublimation. The photovoltaic cells were formed by thermal evaporation of organic materials on the ITO/PEDOT glass in the following sequence: donor-acceptor-metal-donor-acceptor-metal. Copper phthalocyanine was used as the donor and perylene tetracarboxylic bis-benzimidazole was used as the acceptor.