Regensburg 2010 – scientific programme

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O: Fachverband Oberflächenphysik

O 86: Organic, electronics and photovoltaics

O 86.3: Talk

Friday, March 26, 2010, 11:45–12:00, H40

Analysis of systematic heat treatment of TiO2 nanocrystalline films for solid-state dye sensitized solar cells using photoelectron spectroscopy — •Xianjin Feng, René Hock, Eric Mankel, Thomas Mayer, and Wolfram Jaegermann — Institute of Materials Science, Darmstadt UniVersity of Technology, D-64287 Darmstadt, Germany

In this contribution we investigated the effect of heat treatment on the chemical and electronic structures of TiO2 nanocrystalline films for solid-state dye sensitized solar cells (SDSC). The samples were heated in air by an air-gun and a hot plate, respectively, within the temperature range of 300-600°C. The samples were chemically and electronically characterized using synchrotron-induced photoelectron spectroscopy (SXPS) and X-ray photoemission spectroscopy (XPS). The most prominent chemical variation after heating by air-gun was found in the SXPS the intensity increase of the Na2p core level and obvious changes both in the O2s core level and O2p valence band were also observed at 450°C. An increase in the Na1s core level was also observed in the XPS study. For the heat treatment using a hot plate, the intensity of the Na2p core level increased less strongly and no obvious change in the O2s core level and O2p valence band was observed even at 600°C. In both cases of heat treatment, the oxygen vacancies VO-related gap states around 1.3 eV and states just below the Fermi level were observed in the gap region and the intensity of the VO-related gap states decreased obviously after heating and almost vanished at high temperatures.