Regensburg 2007 – scientific programme

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SYOE: Symposium Organic Thin Film Electronics: From Molecular Contacts to Devices

SYOE 8: Poster Session SYOE

SYOE 8.55: Poster

Tuesday, March 27, 2007, 18:00–20:00, Poster B

Electronic transport properties of self-assembled thin films of inorganic nanoparticles and polymers — •Rolf Kniprath and Stefan Kirstein — Institut für Physik, Humboldt Universität zu Berlin

We report on the electronic transport properties and the photovoltaic effect observed in composite thin films of nanoporous TiO₂ and hole-conducting polymers. These organic-inorganic heterojunction structures represent a hybrid of all-organic and inorganic dye-sensitized solar cell concepts. The nanoporous films of TiO₂ were grown on transparent conducting oxide substrates with a layer-by-layer self-assembly process using TiO₂ nanoparticles and served as electron conductors. By drop-casting polymer solutions on top we fabricated two types of heterojunction devices: For the first type, we applied a water-soluble thiophene polymer that acted as both a light absorber and a hole transport layer (HTL). For the second type we sensitized TiO₂ with strongly light absorbing CdTe nanoparticles and used the transparent polymer TFB as a HTL. I-V-measurements through Au back contacts under white light and in the dark yielded a diode characteristic with photovoltages of up to 0.8 V for both setups and photocurrent densities on the order of 1 µ A/cm².