Berlin 2008 – scientific programme

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DS: Fachverband Dünne Schichten

DS 20: Organic Polymer-Metal Interfaces (SYSA 7)

DS 20.2: Talk

Wednesday, February 27, 2008, 18:15–18:30, H 2013

Photovoltaic effect in layer-by-layer self-assembled composite films of TiO₂ nanoparticles, polymers and quantum dots — •Rolf Kniprath¹, James T. McLeskey Jr.², Jürgen P. Rabe¹, and Stefan Kirstein¹ — ¹Humboldt University Berlin — ²Virginia Commonwealth University, Richmond

We report on the properties of thin film hybrid photovoltaic devices with sensitized nanoporous TiO₂ anodes and polymeric hole transport layers (HTL). The TiO₂ films were grown with a layer-by-layer self-assembly process that relies on electrostatic interaction between inorganic particles and charged polymers. This method provides a simple means to incorporate sensitizer materials such as semiconductor quantum dots or light absorbing polymers during the film growth.

We fabricated two types of devices. One employs a novel, water-soluble polythiophene derivative which acts both as a sensitizer and as a HTL, the other uses strongly light absorbing CdTe and CdSe quantum dots as sensitizers and a highly conductive transparent polymer as a HTL. Both types of devices were grown on glass substrates coated with bilayers of transparent fluorine-doped tin oxide (FTO) and compact TiO₂. Evaporated gold electrodes served as back contacts. Current-voltage-measurements under white light and in the dark showed a pronounced photovoltaic effect for both systems and yielded photovoltages of up to 0.80V for the polythiophene devices and 1.1 V for the quantum dot devices.