Title
Thermally activated delayed fluorescence with 7% external quantum efficiency from a light-emitting electrochemical cell
Author
Petter Lundberg, Youichi Tsuchiya, E. Mattias Lindh, Shi Tang, Chihaya Adachi, Ludvig Edman
Year
2019
Journal
Nature Communications
Abstract
We report on light-emitting electrochemical cells, comprising a solution-processed single-layer active material and air-stabile electrodes, that exhibit efficient and bright thermally activated delayed fluorescence. Our optimized devices delivers a luminance of 120 cd m−2 at an external quantum efficiency of 7.0%. As such, it outperforms the combined luminance/efficiency state-of-the art for thermally activated delayed fluorescence light-emitting electrochemical cells by one order of magnitude. For this end, we employed a polymeric blend host for balanced electrochemical doping and electronic transport as well as uniform film formation, an optimized concentration (<1 mass%) of guest for complete host-to-guest energy transfer at minimized aggregation and efficient emission, and an appropriate concentration of an electrochemically stabile electrolyte for desired doping effects. The generic nature of our approach is manifested in the attainment of bright and efficient thermally activated delayed fluorescence emission from three different light-emitting electrochemical cells with invariant host:guest:electrolyte number ratio.
Full Article
Instrument
FP-8600
Keywords
Fluorescence, Photoluminescence, Phosphorescence, Solid state, Chemical stability, Materials