Efficient organic light-emitting diodes fabricated on cellulose nanocrystal substrates

• Published in: Applied physics letters Vol. 105; no. 6
• Main Authors: Najafabadi, E., Zhou, Y. H., Knauer, K. A., Fuentes-Hernandez, C., Kippelen, B.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 11.08.2014
• Subjects: Applied physics; Biodegradability; Cellulose; Electroluminescence; Flat panel displays; Light emitting diodes; Lithium fluoride; Molybdenum oxides; Molybdenum trioxide; Nanocrystals; Organic light emitting diodes; Substrates
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4891046

Organic light-emitting diodes (OLEDs) fabricated on recyclable and biodegradable substrates are a step towards the realization of a sustainable OLED technology. We report on efficient OLEDs with an inverted top-emitting architecture on recyclable cellulose nanocrystal (CNC) substrates. The OLEDs have a bottom cathode of Al/LiF deposited on a 400 nm thick N,N′-Di-[(1-naphthyl)-N,N′-diphenyl]-(1,1′-biphenyl)-4,4′-diamine (α-NPD) layer and a top anode of Au/MoO3. They achieve a maximum luminance of 74 591 cd/m2 with a current efficacy of 53.7 cd/A at a luminance of 100 cd/m2 and 41.7 cd/A at 1000 cd/m2. It is shown that the α-NPD layer on the CNC substrate is necessary for achieving high performance OLEDs. The electroluminescent spectra of the OLEDs as a function of viewing angle are presented and show that the OLED spectra are subject to microcavity effects.