Dresden 2014 – scientific programme

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DS: Fachverband Dünne Schichten

DS 18: Organic Thin Films I

DS 18.7: Talk

Wednesday, April 2, 2014, 11:15–11:30, CHE 91

The phthalocyanine heterojunction MnPc/F₁₆CoPc- An initial representative of a fascinating incipient material class? — •Susi Lindner¹, Benjamin Mahns¹, Uwe Treske¹, Martin Knupfer¹, Rico Friedrich², Torsten Hahn², Jens Kortus², Francisc Haidu³, Michael Fronk³, and Dietrich R.T. Zahn³ — ¹IFW Dresden, P.O. Box 270116, 01171 Dresden, Germany — ²Institute of Theoretical Physics, TU Bergakademie Freiberg, Leipziger Str. 23, 09696 Freiberg, Germany — ³Physics Department/ Semiconductor Physics, Chemnitz University of Technology, Reichenhainer Str. 70, 09126 Chemnitz, Germany

Using x-ray photoelectron and x-ray absorbtion spectroscopy we demonstrate charge transfer at an interface between two transition metal phthalocyanines, MnPc and F₁₆CoPc, resulting in charged MnPc^δ+ and F₁₆CoPc^δ−, species. Density functional theory calculations reveal that a hybrid state is formed between the two types of phthalocyanines, which causes this charge transfer. For the hybrid state the Mn 3d_xz interacts with the Co 3d_z² orbital leading to a two-level system.

Moreover, we have prepared mixed films out of this pair, which were characterized also by means of electron energy-loss spectroscopy. Our data reveal the formation of MnPc/F₁₆CoPc charge transfer dimers in analogy to the heterojunction. The electronic excitation spectrum of these blends is characterized by a new low energy excitation at 0.6 eV.

This project is supported by the DFG (KN 393/14).