A new photon source for ultraviolet photoelectron spectroscopy of organic and other damage-prone materials

Alex M. Boehm, Jochen Wieser, Kamal Butrouna, Kenneth R. Graham

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Accurate measurements of the valence electronic structures of organic semiconductors are important for the development and understanding of organic electronic devices, materials, and interfaces. Ultraviolet photoelectron spectroscopy (UPS) is a well-established technique for probing valence electronic structures; however, many organic semiconductors undergo rapid sample degradation upon exposure to traditional laboratory-based vacuum ultraviolet (VUV) photon sources. Here, we report on a novel VUV photon source for UPS measurements that utilizes H Lyman-α emission with a narrow linewidth and a widely tunable intensity, and apply it to a number of organic materials of interest to show its ability to overcome this hurdle of sample degradation. Furthermore, the H Lyman-α source displays no measureable higher energy emission lines, which significantly reduces the background over typical He I discharge sources and allows for the onset of the density of states to be clearly observed over several orders of magnitude.

Original languageEnglish
Pages (from-to)9-16
Number of pages8
JournalOrganic Electronics
StatePublished - Feb 1 2017

Bibliographical note

Funding Information:
We greatly acknowledge Prof. Aram Amassian at KAUST for permitting use of data (NPD He I UPS data) taken during K.R.G.'s time as a post-doctoral researcher in the Amassian group. We also acknowledge Xikang Zhao and Prof. Jianguo Mei of the Department of Chemistry at Purdue University for providing DPP containing polymers. A.M.B., K.B., and K.R.G acknowledge the University of Kentucky for start-up funding.

Publisher Copyright:
© 2016 Elsevier B.V.


  • Electronic structure
  • NPD
  • Organic semiconductor
  • P3HT
  • Ultraviolet photoelectron spectroscopy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Chemistry (all)
  • Condensed Matter Physics
  • Materials Chemistry
  • Electrical and Electronic Engineering


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