| The photovoltaic properties of polymer/inorganic hybrid systems havebeen investigated.1 Polymer/inorganic hybrid ultra violet (UV) photovoltaic device is fabricated byusing poly (N-Vinyl-carbazole) (PVK) and Zinc Sulfide (ZnS) with the structure ofITO/PEDOT:PS S/PVK/ZnS/Al.The device shows promising photovoltaic characteristics with a high open circuitvoltage of 1.65V, and a short-circuit current of 46.8μA/cm2 under the illumination of340um UV light with the intensity of 14mW/cm2.2 Photovoltaic properties of photodiodes based on the blends of poly[2-methoxy-5-(2'-ethylhexoxy-1,4-phenylenevinylene) (MEH-PPV) and fullerene (C60) areinvestigated.Concentration dependence. The experimental results show that the open-circuitvoltage (Foe) declines with the increasing concentration. It is indicated that theelectron affinity potential of C60 can strongly influence the resulting Voc.Modifying layer of LiE The changes of photovoltaic properties are attributed to thedipole layer between composite film and AI cathode due to the introduction of LiFlayer.Electric-field polarization of composite film. Due to the polarization causes theorientation of the MEH-PPV chains, the resulting thin-film devices show improvedphotovoltaic properties.Thermal annealing on composite film. Upon thermal annealing at 120℃,short-circuit current (Isc) and power conversion efficiency (n) are more than tripled,while a sharp rise by eight times in Isc and n is found for the device annealed at 200℃. It is concluded that the improved phase separation between MEH-PPV and C60leads to the enhancement of Isc and n at 120℃, while thermodynamic moleculearrangement at the higher temperature of～200℃induces to a significant increasein all photovoltaic parameters of composite devices except the open-circuit voltage(Voc).EXcited states in composite film,- It is proposed that at low concentration, doping C60 increases self-absorptionrate of composite films, and charge trapping on C60 molecules induces to the loss of efficiency. At high concentration, the large scale of aggregations in compositefilms builds pathways for charge carriers to transport to respective electrodes,which inhibits the self-absorption effect and the charge recombination on C60.- The results in electric field-induced quenching of photoluminescence (EFIQP)show that EFIQP in the composite film is much easier compared to that in theundoped MEH-PPV film. It is attributed to a facilitation of exciton dissociation dueto the photoinduced charge transfer from MEH-PPV to C60.3 Photovoltaic cells based on MEH-PPV/CuS nanopartieles composites film havebeen fabricated.By comparing composite devices with different weight ratios of MEH-PPV:CuS as1:1, 1:1.25, 1:2.5 and 1:5, it was found that the device with the ratio of 1:2.5 exhibitedthe best performance: the short-circuit current density of 17μA/cm2 with the lightintensity of 16.7mW/cm2, the highest open-circuit voltage of 0.83V, and the photogain,at reverse bias of-IV, of 132, which was improved by a factor of 5 compared with thatof the undoped MEH-PPV device.4 A planar configuration is applied to polymer thin-film photovoltaic devices.With a planar configuration, a completely symmetric device can be realized, whichenables the device operating mechanism to be dueidated more effectively. Anothergreat benefit of the planar configuration is its large interelectrode spacing which, on theorder of 1mm, allows partly illuminating the device so as to investigate the dynamics ofphotogenerated carriers in the polymer film.
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