Organic light-emitting diodes have been recently focused for flexible display and solid-state lighting applications and so much effort has been devoted to achieve highly efficient organic light-emitting diodes. Here, we improve the efficiency of inverted polymer light-emitting diodes by introducing a spontaneously formed ripple-shaped nanostructure of ZnO and applying an amine-based polar solvent treatment to the nanostructure of ZnO. The nanostructure of the ZnO layer improves the extraction of the waveguide modes inside the device structure, and a 2-ME+EA interlayer enhances the electron injection and hole blocking in addition to reducing exciton quenching between the polar-solvent-treated ZnO and the emissive layer. Therefore, our optimized inverted polymer light-emitting diodes have a luminous efficiency of 61.6cd A-1 and an external quantum efficiency of 17.8%, which are the highest efficiency values among polymer-based fluorescent light-emitting diodes that contain a single emissive layer.
Bibliographical noteFunding Information:
We thank Cambridge Display Technology (CDT), Ltd., for supplying F8BT. This study was supported by the Mid-Career Researcher Program (2012R1A2A2A06046931, 2013R1A2A2A01067144). This study was also financially supported by the KIST-UNIST partnership program (2.130400.01). S.O.K. was financially supported by Institute for Basic Science (IBS) [CA1301]. S.H.M. was supported by BK21 plus (10Z20130011057) funded by the Ministry of Education of Korea.
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All Science Journal Classification (ASJC) codes
- Biochemistry, Genetics and Molecular Biology(all)
- Physics and Astronomy(all)