Operating organic light-emitting diodes imaged by super-resolution spectroscopy.

Citation data:

Nature communications, ISSN: 2041-1723, Vol: 7, Page: 11691

Publication Year:
2016
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Repository URL:
http://scholarworks.unist.ac.kr/handle/201301/20074
PMID:
27325212
DOI:
10.1038/ncomms11691
Author(s):
King, John T.; Granick, Steve
Publisher(s):
Springer Nature; NATURE PUBLISHING GROUP
Tags:
Chemistry; Biochemistry, Genetics and Molecular Biology; Physics and Astronomy; CONJUGATED POLYMERS; CHARGE-TRANSPORT; FLUORESCENCE MICROSCOPY; INTERCHAIN INTERACTIONS; STIMULATED-EMISSION; MORPHOLOGY; RESOLUTION; POLY(P-PHENYLENEVINYLENE); ELECTROLUMINESCENCE; CONFORMATION
article description
Super-resolution stimulated emission depletion (STED) microscopy is adapted here for materials characterization that would not otherwise be possible. With the example of organic light-emitting diodes (OLEDs), spectral imaging with pixel-by-pixel wavelength discrimination allows us to resolve local-chain environment encoded in the spectral response of the semiconducting polymer, and correlate chain packing with local electroluminescence by using externally applied current as the excitation source. We observe nanoscopic defects that would be unresolvable by traditional microscopy. They are revealed in electroluminescence maps in operating OLEDs with 50 nm spatial resolution. We find that brightest emission comes from regions with more densely packed chains. Conventional microscopy of an operating OLED would lack the resolution needed to discriminate these features, while traditional methods to resolve nanoscale features generally cannot be performed when the device is operating. This points the way towards real-time analysis of materials design principles in devices as they actually operate.