Inkjet printed polymer layer on flexible substrate for OLED applications

TitleInkjet printed polymer layer on flexible substrate for OLED applications
Publication TypeArticolo su Rivista peer-reviewed
Year of Publication2009
AuthorsVillani, Fulvia, Vacca P., Nenna G., Valentino O., Burrasca G., Fasolino T., Minarini Carla, and Della Sala Dario
JournalJournal of Physical Chemistry C
KeywordsDeposition methods, Electric properties, Electrical and optical properties, Electro-optical characteristics, Electroluminescence, Electroluminescent devices, Fabrication, Flexible substrate, Fluorenes, Helmet mounted displays, Hole-transporting layers, Hybrid structure, Ink-jet printing, Light emission, Light emitting diodes, Light transmission, Optical properties, Optoelectronic devices, Organic light emitting diodes (OLED), Organic light-emitting diode, Organic materials, Plastic coatings, Plastic films, Polymer films, Polymer layers, Polymer solutions, Polymers, Spin dynamics, Spin-coated films, Standard technology, Substrate surface, Substrates, Surface chemicals, Surface chemistry, surface tension, Surface treatment, Technological limit, Thermal evaporation, Thickness uniformity, Traditional techniques, Vacuum evaporation, Vacuum thermal evaporation

In optoelectronics, inkjet printing (IJP) technology is being developed as an alternative to the traditional techniques for organic materials deposition. In this work, we report the fabrication of organic light-emitting diodes (OLEDs) on the flexible substrate by studying the effect of a surface chemical treatment on the inkjet printed polymer film morphology. The employed piranha treatment increases the substrate surface energy and improves the wettability, thus inducing a decrease in the IJ printed drop thickness. The IJ printed polymer (poly(9, 9-dihexyl-9H-fluorene-2, 7-diyl)) is the hole-transporting layer (HTL) of a hybrid structure in which the other layers are deposited by vacuum thermal evaporation. Furthermore, in order to determine the effect of the IJ deposition method on the manufactured OLED performances, we compare them to those of Devices fabricated using standard technologies. With this aim, OLEDs with the same structure are fabricated by replacing the IJ printed polymer with a spin-coated film employing the same polymer solution. The electrical and optical properties of the electroluminescent Devices are investigated and discussed. Despite the lack of thickness uniformity in IJ printed film, which is an intrinsic, technological limit, OLEDs with IJ printed HTL show electro-optical characteristics that are similar to the ones of OLEDs with spin-coated HTL., © 2009 American Chemical Society.


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