TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Layer: The electron blocking layer comprises metal oxide chosen from copper, aluminum, tin, nickel, tungsten, titanium, magnesium, indium, molybdenum, zinc and their mixture. The electron blocking layer comprises silicon, II-VI group semiconductor material and/or III-V group semiconductor material. The hole blocking layer comprises at least one inorganic material chosen from titania, gallium nitride, zinc sulfide, zinc oxide, zinc selenide, strontium titanate, potassium titanate, barium titanate, manganese titanate, lead oxide, tungsten oxide and tin oxide. The electron blocking layer is in contact with the donor region. The hole blocking layer is in contact with the acceptor region. The device has both an electron blocking layer and a hole blocking layer.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The electron blocking layer comprises at least one organic semiconducting material chosen from tris(8-hydroxyquinolinato)aluminum(III), N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4'-diamine, 4,4'-bis(N-(naphthyl)-N-phenyl-amino)biphenyl, subphthalocyanine, pentacene, squaraine, copper phthalocyanine, zinc phthalocyanine, chloroaluminum phthalocyanine, or tris(2-phenylpyridine). The hole blocking layer comprises organic semiconducting material chosen from naphthalene tetracarboxylic anhydride, p-bis(triphenylsilyl)benzene, 3,4,9,10-perylenetetracarboxylic dianhydride, and 7,7,8,8-tetracyanoquinodimethane. The donor region comprises at least one material chosen from copper phthalocyanine, tin phthalocyanine and squaraine, preferably copper phthalocyanine or tin phthalocyanine. The acceptor region comprises at least one material chosen from C60 fullerene and 3,4,9,10-perylene tetracarboxylic bis(benzimidazole), preferably C60 fullerene. The device has primary photoconductive organic semiconductor material and second photoconductive organic semiconductor material having spectral sensitivity in the visible spectrum. The primary photoconductive organic semiconductor material and secondary photoconductive organic semiconductor materials are partially mixed. The photo-active region forms at least one of a mixed heterojunction, planar heterojunction, bulk heterojunction, nanocrystalline-bulk heterojunction, and hybrid planar-mixed heterojunction. The electron blocking layer comprises subphthalocyanine, copper phthalocyanine, or molybdenum oxide, preferably molybdenum oxide, and has thickness of 30-100 Angstrom . The hole blocking layer has thickness of 20-500 Angstrom .