| AVS 65th International Symposium & Exhibition | |
| Surface Science Division | Thursday Sessions |
| Session SS+AS+BI+MI+NS-ThA |
| Session: | Organic/Inorganic Surfaces, Interfaces and Nanostructures |
| Presenter: | Sujitra Pookpanratana, National Institute of Standards and Technology (NIST) |
| Authors: | S. Pookpanratana, National Institute of Standards and Technology (NIST) E.G. Bittle, National Institute of Standards and Technology (NIST) C.A. Hacker, National Institute of Standards and Technology (NIST) S.W. Robey, National Institute of Standards and Technology (NIST) R. Ovsyannikov, Helmholtz-Zentrum Berlin, Germany E. Giangrisostomi, Helmholtz-Zentrum Berlin, Germany |
| Correspondent: | Click to Email |
Organic and molecular-based compounds have found commercial application in consumer-based electronics. Organic semiconductors can be integrated onto device structures in different physical forms such as single crystals, polycrystalline thin-films, or amorphous thin-films. The structural order of the molecular solid profoundly influences the electronic properties, that in turn controls important properties, such as the transport gap and binding energy of the highest occupied molecular orbital (HOMO) [1, 2], that govern how an electronic device operates. Photoemission can play a vital role in illuminating these important electronic properties. While there are numerous photoemission spectroscopic measurements of organic semiconductors in thin-film structures, far fewer attempts have been made to determine the “fundamental” electronic properties for pristine organic single crystals.
Here, we present results of photoemission measurements for single crystalline (SC) dinaphthothienothiophene (DNTT). DNTT is a small molecule-based thienoacene and has demonstrated carrier mobilities approaching 10 cm2/(V s) [3], is air-stable [4] and durable against accelerated temperatures and humidity conditions.[5] While there are many device studies that establish DNTT and other related thienoacenes for a variety of applications, detailed electronic and chemical structure studies are lacking. Electronic “band” structure measurements using a novel angle-resolved time-of-flight electron spectrometer is performed on SC-DNTT, and multiple highest occupied molecular orbitals are resolved of varying widths. Modest dispersion of the frontier HOMO is observed, and this result will be discussed in context of the charge carrier behavior of DNTT reported in the literature.
[1] J. Ivanco et al., Adv. Mater. 15, 1812 (2003)
[2] S. Krause et al., Org. Electron. 14, 584 (2013)
[3] W. Xie et al., Adv. Mater. 25, 3478 (2013)
[4] U. Zschieschang et al., Adv. Mater. 22, 982 (2010)
[5] N. K. Za’aba et al., Org. Electron. 45, 174 (2017)