Efficient organic light-emitting diodes fabricated on cellulose nanocrystal substrates

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 (alpha-NPD) layer and a top anode of Au/MoO3. They achieve a maximum luminance of 74 591 cd/m(2) with a current efficacy of 53.7 cd/A at a luminance of 100 cd/m(2) and 41.7 cd/A at 1000 cd/m(2). It is shown that the alpha-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. (c) 2014 AIP Publishing LLC.