keywords BULK HETEROJUNCTION POLYMER CHARGE INJECTION EFFICIENCY ENERGY-LEVEL ALIGNMENT Engineering Engineering, Electrical & Electronic HOLE-TRANSPORTING MATERIALS INDIUM-TIN-OXIDE INTERFACIAL ELECTRONIC-STRUCTURES LIGHT-EMITTING-DIODES Materials Science Materials Science, Multidisciplinary Optics POLYMER SOLAR-CELLS Physical Sciences SELF-ASSEMBLED MONOLAYER Science & Technology THIN-FILMS Technology