The photovoltaic performance of zinc phthalocyanine (ZnPc)∕C60 heterojunctions is improved by alternately depositing ultrathin active layers between the two bulk layers. Using a proper multilayer structure, a 60% improvement in conversion efficiency under AM1.5 illumination is obtained, in comparison with that of flat heterojunctions. Transmission electron microscope investigations reveal an effective phase separation of ZnPc and C60 and a high degree of crystalline ordering of C60 in this system. The authors propose that an interpenetrating interface is formed, which facilitates both exciton separation and charge transport, and enhances the photocurrent from ZnPc due to an extended photoactive region.

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In this work we report effi ciency measurements on light-emitting diodes with electrochemically synthesized sulfonated polyaniline as hole transport layer. The anode used in our devices is fluorine-doped tin oxide, the blocking layer is electrochemically synthesized poly(9,9-dioctyl-1,4-fluorenylenevinylene) and the electron transporting material and emitter is tris-(8-hydroxyquinoline) aluminum. Sulfonated polyaniline based devices presented effi ciency of 0.79 cd/A.

Seven-segment displays are used to show numerical quantities in electronic equipment, being present in most of the low-end electronics. In this work we describe a novel organic light emitting display made with poly(1,10 decanedioxy 2 methoxy - 1,2 phenylene - 1,2 ethenylene - 3,6 dimethoxy - 1,4 phenylene - 1,2 ethenylene 3 methoxy - 1,4 - phenylene) (OPPVDBC), tris(8-hydroxyquinoline)aluminum salt (Alq3) and a hole injection layer (PEDOT:PSS: poly(3,4 - ethylenedioxythiophene) : poly(styrenesulfonate)). The general device structure is FTO/PEDOT:PSS/OPPVDBC/Ca/Al or FTO/PEDOT:PSS/OPPVDBC/Alq3/Ca/Al. The FTO (fluorine-doped tin oxide) thin films are transparent (transmittance > 80 % in the visible region of the spectrum), conductive (< 15 omega/º for 200 nm thick films), and present high chemical stability