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Title: Method for measurement of the density of thin films of small organic molecules

Journal Article · · Review of Scientific Instruments
DOI:https://doi.org/10.1063/1.2712932· OSTI ID:20953395
; ; ; ;  [1]
  1. Department of Electrical and Electronic Engineering, Department of Chemistry and HKU-CAS Joint Laboratory on New Materials, University of Hong Kong, Pokfulam Road, Hong Kong (China)

An accurate and sensitive method is reported to measure the thin-film density of vacuum-deposited, small-molecular organic semiconductor materials. A spectrophotometer and surface profiler had been used to determine the mass and thickness of organic thin film, respectively. The calculated density of tris-(8-hydroxyquinolato) aluminum (Alq{sub 3}) thin film was 1.31{+-}0.01 g/cm{sup 3}. Vacuum pressures and thin-film growth rates are found to have less impact on the thin-film density of organic material. However, the thin-film density of organic material strongly depends on its chemical structure and molecular weight. Specifically, the chemical structure determines the density of organic material that affects the molecular volume and intermolecular stacking.

OSTI ID:
20953395
Journal Information:
Review of Scientific Instruments, Vol. 78, Issue 3; Other Information: DOI: 10.1063/1.2712932; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
Country of Publication:
United States
Language:
English