Applied Science and Convergence Technology 2015; 24(5): 151-155
Published online September 30, 2015
Copyright © The Korean Vacuum Society.
Yunwoo Jung, Nalae Lee, Jonghoon Kim, Yeong Ji Im, and Sang Wan Cho*
Department of Physics, Yonsei University, Wonju 26493, Korea
Correspondence to:Sang Wan Cho
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
The interfacial electronic structure between zinc phthalocyanine (ZnPc) and aluminumdoped zinc oxide (AZO) substrates has been evaluated by ultraviolet photoemission spectroscopy and angle-dependent x-ray absorption spectroscopy to understanding the molecular orientation of a ZnPc layer on the performance of small molecule organic photovoltaics (OPVs). We find that the ZnPc tilt angle improves the π-π interaction on the AZO substrate, thus leading to an improved short-circuit current in OPVs based on phthalocyanine. Furthermore, the molecular orientation-dependent energy level alignment has been analyzed in detail using ultraviolet photoemission spectroscopy. We also obtained complete energy level diagrams of ZnPc/AZO and ZnPc/indium thin oxide.
Keywords: Organic semiconductors, Molecular orientation, ZnPc, AZO