Berlin 2012 – scientific programme

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DS: Fachverband Dünne Schichten

DS 22: Trends in atomic layer deposition I (Focused session – Organizer: Nielsch)

DS 22.2: Topical Talk

Wednesday, March 28, 2012, 15:30–16:00, H 0111

Energy conversion devices made using ALD — •Julien Bachmann — University of Hamburg, Hamburg, Germany

The interconversion of solar, electrical, and chemical forms of energy relies on the separation and recombination of charge carriers at interfaces. Because the transport of electrons, holes, and ions to and from the interface may be the factor limiting the overall device efficiency, nanostructuring often serves to increase the specific surface area of a device without elongating the diffusion distances excessively. The unique ability of atomic layer deposition to coat substrates of complex geometries --- highly porous ones in particular --- makes it particularly suited to the preparation of model systems in which to study the influence of geometric parameters on the efficiency of energy conversion devices.

We applied ALD to the creation of extremely thin antimony sulfide absorber layers in solar cells based on nanocrystalline titanium oxide. As a result, we were able to found an optimal thickness of the intrinsic absorber which maximizes the photovoltaic efficiency. In the area of electrolysis, we established the preparation of structured iron oxide surfaces the specific area of which is defined by cylindrical pores. The current density obtained for the oxidation of water at such electrodes depends on pore length and diameter linearly.