TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The first electrode is comprised of indium tin oxide. The second electrode is comprised of Ag.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Device: The mixture of the organic acceptor material and the organic donor material in first organic layer occurs in a ratio of 10:1 - 1:10 respectively. Each of the first and second organic layers contributes at least 5 (preferably at least 10)% of the total energy output of the photoactive device. Each of the first and second organic layers absorbs at least 5 (preferably at least 10) % of the energy absorbed by the photoactive region. The device further comprises a first non-photoactive layer disposed between the first electrode and the second organic layer. The first non-photoactive layer is an exciton blocking layer. The photoactive region further comprises a third organic layer disposed between the first electrode and the second electrode. The third organic layer is in direct contact with the first organic layer and comprises an unmixed layer of the organic donor material of the first organic layer. The third organic layer has a thickness of not less than 0.1 optical absorption lengths. When the device is a solar cell, the cell comprises two electrodes; and an organic photoactive region disposed between the electrodes and the photoactive region is comprised of a mixture of two organic materials where the series resistance between the electrodes is 0.25plus minus 0.15 omegacm2. For the solar cell, photons absorbed by the first organic layer contribute at least 5 (preferably at least 10)% of the photocurrent generated by the device, and photons absorbed by the second organic layer contribute at least 5 (preferably at least 10)% of the photocurrent generated by the device.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The organic acceptor material is fullerene; perylene; catacondensed conjugated molecular system (preferably linear polyacenes (including anthracene, naphthalene, tetracene, or pentacene), pyrene, coronene, and their functionalized variants. The organic donor material is metal containing porphyrin, metal-free porphyrin, rubrene, metal containing phthalocyanine, metal-free phthalocyanine, diamine (such as NPD), or their functionalized variants including naphthalocyanines. The first organic layer consists of a mixture of CuPc and 60C. The first non-photoactive layer comprises 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP). The second organic layer comprises the organic acceptor material or the organic donor material of the first organic layer.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The first electrode is comprised of indium tin oxide. The second electrode is comprised of Ag.