title: Electron transporting organic materials with an exceptional large scale homeotropic molecular orientation.
abstract: An electron transporting anthraquinone derivative demonstrated a stable large-scale homeotropic alignment on an open substrate surface, which substantially improved its charge carrier mobility. The electron mobility (μ(E)) increased by two orders of magnitude from 3.2 × 10(-4) cm(2) V(-1) s(-1) for the film without alignment to 1.2 × 10(-2) cm(2) V(-1) s(-1) for the homeotropically aligned film. A distinct enhancement in the UV absorption spectra of the films around the short wavelength range was observed to be associated with the molecular alignments. These alignments are less sensitive to the substrate under test. The anchoring force of the columnar stacks appears to be related to the nature of the material associated with the strong interaction between the molecules and substrate interface.
authors.affiliation: Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, P. R. China. zhqhe@bjtu.edu.cn.
authors.forename: Huan
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, P. R. China. zhqhe@bjtu.edu.cn.
authors.forename: Zhiqun
authors.initials: Z
authors.lastname: He
authors.affiliation: Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, P. R. China. zhqhe@bjtu.edu.cn.
authors.forename: Min
authors.initials: M
authors.lastname: Xu
authors.affiliation: Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, P. R. China. zhqhe@bjtu.edu.cn.
authors.forename: Chunjun
authors.initials: C
authors.lastname: Liang
authors.affiliation: Raman Research Institute, C.V. Raman Avenue, Bangalore 560 080, India.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Kumar