Regensburg 2010 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 48: [O] Organic Electronics and Photovoltaics III (Joint Session DS/CPP/HL/O)
DS 48.5: Vortrag
Freitag, 26. März 2010, 12:15–12:30, H40
Photoemission spectroscopy investigations of silicon organic dye interfaces for photovoltaic applications — •Andreas Decker1, Thomas Mayer1, Wolfram Jaegermann1, Sabin Suraru2, and Frank Würthner2 — 1Fachgebiet Oberflächenforschung, Fachbereich Materialwissenschaften, Technische Universität Darmstadt — 2Institut für Organische Chemie, Universität Würzburg
In a new solar cell concept, organic dyes (small molecules) are embedded in the hydrogenated microcrystalline i-layer of a silicon p-i-n structure to enhance the optical absorption. This approach aims at an increase in efficiency and a decreased silicon absorber layer thickness, thus potentially lowering deposition time and production cost.
The electrical lineup of the dye orbitals versus the silicon band edges plays a vital role for this sensitization process because a driving force is needed for the transfer of photogenerated electrons and holes from the dye molecules to the silicon matrix. For the two dyes Cl4MePTCDI and CuPc the electrical lineup on our model substrate, hydrogen terminated n-type Si(111), was investigated with photoemission interface experiments. Si(111):H was prepared from wafers with a native oxide by two-step wet-chemical etching in NH4F which leads to clean and flat terraces as shown in AFM measurements. By comparison of calculations with XPS measurements the Si(111):H surface was found to have flat bands, i. e. showing no Fermi level pinning due to dangling bonds or fresh adsorbates originating from the sample transport through air to the UHV system, thus being a suitable substrate for interface experiments.