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Grazing-incidence X-ray diffraction
pattern from an amorphous film
(see article, Figure 1A)

Cornell chemist Héctor Abruña tells readers of the Journal of Materials Chemistry how advances in organic light emitting diodes (OLEDs) depend upon synchrotron radiation studies similar to this done at CHESS.  He starts his interview with:

“The performance of devices such as organic light emitting diodes (OLEDs) that depend on thin films are strongly correlated with the film's microstructure.  While single crystal films generally exhibit the highest transport rates and quantum efficiencies, there are no cost effective methods to deposit such films over large areas.  The use of polycrystalline films presents great challenges due to their high surface roughness and the fact that grain boundaries serve as efficient trapping and recombination sites resulting in dramatic degradation of performance.  The use of amorphous films is most attractive because of their ease of deposition and because their hopping mode of transport is often sufficient for OLEDs and photovoltaic devices.  Thus, an understanding of the local structure of nominally amorphous films could provide a great deal of insight as to how film morphology affects device performance.  Our results provide a first characterization of a nominally amorphous molecular semiconductor thin film, and indicate that ordering actually occurs on an intermediate range, with crystalline domains in the range of a few nanometers.  Such intermediate range order has been a hot topic in the community studying glassy materials in recent years.”

See Abruña's full comment archived pdf

And the actual paper: (archived pdf):