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Organic Photonics and Photovoltaics

Editor-in-Chief: Facchetti, Antonio

Ed. by Ponomarenko, Sergei

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Low-energy electron transmission for the analysis of the interface barrier formation and the density of the unoccupied electronic states in the ultra-thin layers of fluorinated copper-phthalocyanine

A. S. Komolov / E. F. Lazneva / S. N. Akhremtchik / N. B. Gerasimova / S. A. Pshenichnyuk
Published Online: 2015-01-29 | DOI: https://doi.org/10.1515/oph-2015-0002


The interfacial structure made from the thermally deposited 5 – 7 nm thick layers of hexadecafluoro copper phthalocyanine (F16-CuPc) and of the unsubstituted copper phthalocyanine (CuPc) was subjected to the studies. The surface work function and the density of the unoccupied electron states (DOUS) located 5- 20 eV above the Fermi level (EF) were investigated during the CuPc/F16-CuPc interface formation using the very low energy electron diffraction (VLEED) method and the total current spectroscopy (TCS) measurement scheme. The DOUS peak structure of the organic films studied obtained from the TCS results showed a good correspondence to the main π* and σ* DOUS bands obtained from the density functional theory (DFT) calculations. The interfacial barrier was characterized by the negative charge transfer from the CuPc overlayer to the F16-CuPc underlayer occurred within the 5 nm thick interfacial region in the CuPc overlayer which was accompanied by the decrease of the surface work function from 4.9±0.1 eV to 4.3±0.1 eV. The stabilization of the π* DOUS bands, as well as restructuring of the low lying σ* bands was observed in the in the case of the fluorinated film (F16- CuPc) compared to the case of the unsubstituted CuPc film.

Keywords: Organic semiconducting films; Surface electronic phenomena (work function, surface potential, surface states, etc.); interface charge transfer; DFT calculations; Density of states


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About the article

Received: 2014-09-01

Accepted: 2014-12-19

Published Online: 2015-01-29

Citation Information: Organic Photonics and Photovoltaics, Volume 3, Issue 1, ISSN (Online) 2299-3177, DOI: https://doi.org/10.1515/oph-2015-0002.

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©2015 A. S. Komolov et al.. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License. BY-NC-ND 3.0

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