Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 85: Poster: Tribology and Misc.

O 85.9: Poster

Mittwoch, 14. März 2018, 18:15–20:30, Poster A

Increase of Porosity and Pore Size of Electrodeposited ZnO Films for Using Metal Complexes as Redox Shuttles in Dye-Sensitized Solar Cells — •Thi Hai Quyen Nguyen, Raffael Ruess, and Derck Schlettwein — IAP, JLU Giessen, Germany

Electrodeposited ZnO is an attractive alternative for the commonly used TiO₂ in dye-sensitized solar cells (DSSCs). Pores in such ZnO are typically narrow, making it difficult to use metal complexes as redox shuttles which worked well in TiO₂-based DSSCs. The present work is dedicated to an optimization of the porosity and pore size of ZnO. Porous ZnO films were prepared by electrodeposition in the presence of different structure directing agents (SDA) such as Eosin Y. The influence of the deposition time and the SDA-concentration was analysed. Furthermore, the combination of Eosin Y with other SDA was investigated. The films were studied by SEM, XRD, confocal Laser microscopy and profilometry. The internal surface of the films was determined by gas sorption and by electrochemical impedance spectroscopy. Sample porosity was determined from the amount of Zn in the films allowing to estimate the average pore size in the films. A combination of Eosin Y with a substituted derivative as SDA led to porous ZnO films with high stability and larger pore size compared to films prepared with Eosin Y only. Porous ZnO films could be obtained at less negative deposition potentials allowing increased control of growth parameters. The success of the present work was proven by photovoltaic characterization of test cells based on these new films providing easier diffusion of the large complexes through the ZnO pore structure.