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The use of vapor phase polymerized poly(3,4‐ethylenedioxythiophene) (VPP‐PEDOT) as a metal‐replacement top anode for inverted solar cells is reported. Devices with both i) standard bulk heterojunction blends of poly(3‐hexylthiophene) (P3HT) donor and 1‐(3‐methoxycarbonyl)‐propyl‐1‐phenyl‐(6,6)C60 (PCBM) soluble fullerene acceptor and ii) hybrid inorganic/organic TiO2/P3HT acceptor/donor active layers are studied. Stamp transfer printing methods are used to deposit both the VPP‐PEDOT top anode and a work function enhancing PEDOT:polystyrenesulphonate (PEDOT:PSS) interlayer. The metal‐free devices perform comparably to conventional devices with an evaporated metal top anode, yielding power conversion efficiencies of 3% for bulk heterojunction blend and 0.6% for organic/inorganic hybrid structures. These encouraging results suggest that stamp transfer printed VPP‐PEDOT provides a useful addition to the electrode materials tool‐box available for low temperature and non‐vacuum solar cell fabrication.

We report herein the fabrication of hybrid conjugated polymer/ZnO photovoltaic devices using ZnO nanorod structures prepared by electrodeposition and study the effect of introducing a second metal oxide overlayer using a TiCl 4 post-treatment. We use transient absorption spectroscopy, scanning electron microscopy, and photovoltaic device measurements to study the microstructure and charge generation properties of the hybrid films and the performance of the resulting devices. We show how the ZnO nanostructure can be controlled via the nanorod growth conditions and demonstrate that photovoltaic device performance can be optimized by controlling the nanostructure in this way. Moreover, we show that a large increase in photocurrent generation can be achieved by coating the ZnO surface with a thin layer of titanium oxide by treating the ZnO nanostructure with a TiCl 4 solution.SECTION Electron Transport, Optical and Electronic Devices, Hard Matter P hotovoltaic devices based on molecular and nanostructured semiconductors are an alternative to conventional inorganic solar cells. The materials used in these types of devices present several advantages, such as easy processing, mechanical flexibility, and the potential low cost of large-area fabrication. They also offer potential applications in other optoelectronic devices such as light-emitting diodes and sensors. [1][2][3] One of the more interesting advantages of hybrid solar cells based on conjugated polymers and metal oxides is the high electron mobility of the inorganic phase compared with that of available organic acceptor materials, particularly n-type polymers. An inorganic acceptor phase can be utilized to overcome the limited electron mobility in organic materials and so to help balance charge transport. 4,5 In addition, another important property of the inorganic materials is their higher physical and chemical stability relative to that of organic materials.It is well-known that the morphology and the nanostructure of the different phases that form the devices have an important influence on the final properties. 5-9 For example, in the case of the inorganic phase, there are many examples of different kinds of metal oxide nanostructures that have been successfully integrated in devices, for instance, nanoparticles, 10 nanorods, 9,11 nanotubes, 12 or mesoporous networks, 13 giving in many cases an improved photovoltaic effect relative to that of simple layered structures. 5,11 One of the most widely studied metal oxide semiconductors is zinc oxide, which is attractive for a variety of practical applications 14 due to its exceptional electrical, optical, and magnetic properties. 15 One important characteristic of ZnO is the huge family of structures that have been reported, such as nanowires, nanorods, tetrapods, and nanoribbons/belts among many others. 15 Moreover, there are several techniques that have been developed for the growth of ZnO nanostructures, including thermal evaporation, metal-organic vaporphase epitaxy (MOVPE), metal-organic chemical vapor depos...

We demonstrate electron transporting thin-film transistors based on TiO2 films deposited from solution by spray pyrolysis under ambient atmosphere. The field-effect electron mobility is found to depend strongly on the device architecture and the type of source and drain electrodes employed. For optimized transistors a maximum mobility value of 0.05 cm2/V s is obtained. Furthermore, the TiO2 transistors show air-stable operating characteristics with a shelf life time of several months. This is the only report on electron transporting transistors based on thin-films of TiO2 deposited by spray pyrolysis. Such devices could be used for the study of charge carrier transport in TiO2 and other related materials.

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