Dresden 2011 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 18: Poster: Transport and Spectroscopy in Molecular Nanostructures (Intersectional Session with MO)

CPP 18.6: Poster

Tuesday, March 15, 2011, 18:00–20:00, P1

Investigation of Electron Transfer in the Dye/Semiconductor Interface of Dye-Sensitized Zinc Oxide Nanoparticles — •Kerstin Strauch^1,2,3, Christian Litwinski², Egmont Rohwer³, Heinrich Schwoerer³, Tebello Nyokong², and Derck Schlettwein¹ — ¹Institute of Applied Physics, Justus-Liebig-University Giessen, Germany. email:schlettwein@uni-giessen.de — ²Department of Chemistry, Rhodes University, Grahamstown, South Africa — ³Laser Research Insitute, Physics Department, University of Stellenbosch, South Africa

As an alternative to dye-sensitized solar cells based on TiO₂ nanoparticles, electrodeposited ZnO was proposed as a porous, crystalline semiconductor matrix. However, until now considerably lower power conversion efficiencies were reported. A decreased injection efficiency from the excited state of the dye to the conduction band of the semiconductor was discussed as possible reason for this lower efficiency. As a model system, ZnO nanoparticles were used in order to allow a detailed time-resolved spectroscopic investigation. Different dye molecules were investigated as sensitizers for these nanoparticles. Time-correlated single photon counting (TCSPC) was used to determine the fluorescence lifetime of the dissolved sensitizer compared to the molecule bound to ZnO. In order to characterize details of the sensitizer excited state bound to ZnO femtosecond- transient absorption spectroscopy (fs-TAS) experiments were done. Implications for the technical application of the different sensitizers on ZnO are discussed.