25-27 November 2015
National Centre for Synchrotron Science
Australia/Melbourne timezone

Observation of crystalline orthogonal self-stratification in spin-coated conjugated polymer thin films with depth-sensitive X-ray scattering

26 Nov 2015, 15:05
Oliphant Auditorium ()

Oliphant Auditorium

Oral Advanced Materials Advanced Materials II


Dr Eliot Gann (Australian Synchrotron)


We report the observation of an orthogonally realigned crystalline surface layer in a spin-coated conjugated polymer film as used in organic field-effect transistors. The ability of Grazing Incidence Wide Angle X-ray Scattering to provide some surface sensitivity of scattering features within thin films is known, but until now an unambiguous orthogonal stratified crystalline microstructure in high performance polymeric materials has not been demonstrated. By comparing angle-resolved scattering intensity collected at the SAXS/WAXS beamline of the Australian Synchrotron to simulated X-ray electric field intensity within a 72 nm thin polymer film, we find the data is consistent with 9 nm of edge-on aligned crystallites on top of 63 nm of highly crystalline face-on crystallites. We propose that a balance of air-polymer, polymer-polymer, and substrate-polymer interactions encourage edge-on surface realignment and stratification. This type of surface reorganization and alignment will be increasingly important to measure and predict as further organic electronic devices are developed.
Keywords Scattering, Depth Sensitivity, GIWAXS, Crystalline Stratification

Primary author

Dr Eliot Gann (Australian Synchrotron)


Prof. Chris McNeill (Monash University)

Presentation Materials

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