Purely organic electroluminescent material realizing 100% conversion from electricity to light
By H. Kaji, Hajime Suzuki, Tatsuya Fukushima, Katsuyuki Shizu, Katsuaki Suzuki, Shosei Kubo, T. Komino, Hajime Oiwa, Furitsu Suzuki, Atsushi Wakamiya and 2 more. Nature Communications, 2015
809 citations recorded by the source corpus.
Efficient organic light-emitting diodes have been developed using emitters containing rare metals, such as platinum and iridium complexes. However, there is an urgent need to develop emitters composed of more abundant materials. Here we show a thermally activated delayed fluorescence material for organic light-emitting diodes, which realizes both approximately 100% photoluminescence quantum yield and approximately 100% up-conversion of the triplet to singlet excited state. The material contains electron-donating diphenylaminocarbazole and electron-accepting triphenyltriazine moieties. The typical trade-off between effective emission and triplet-to-singlet up-conversion is overcome by fine-tuning the highest occupied molecular orbital and lowest unoccupied molecular orbital distributions. The nearly zero singlet–triplet energy gap, smaller than the thermal energy at room temperature, results in an organic light-emitting diode with external quantum efficiency of 29.6%. An external quantum efficiency of 41.5% is obtained when using an out-coupling sheet. The external quantum efficiency is 30.7% even at a high luminance of 3,000 cd m−2. Organic light-emitting diodes promise a more environment-friendly future for light sources, but many use rare metals. Here, the authors present an approach that achieves external quantum efficiency over 40% by realising 100% up-conversion from triplet to singlet excitons and thus 100% radiative emission.
Subfields: Electrical and Electronic Engineering, Materials Chemistry
View Paper: https://www.semanticscholar.org/paper/f5e18098750372135d8ceabbcbf4a6d2ad1f0a5e
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Citations in the corpus
- ChemTS: an efficient python library for de novo molecular generation (2017, background): “In modern society, a variety of organic molecules are used as important materials such as solar cells [1], organic light-emitting diodes [2], conductors [3], sensors [4] and ferroelectrics [5].”
- Recent advances in organic thermally activated delayed fluorescence materials. (2017, methodology): “A molecular design strategy to achieve a small DEST by utilizing meta-linking between the donor and acceptor has been presented by Kaji et al. (2015).76 It was found that in two isomers constructed with electron-donating carbazolyl groups substituted onto an electron-accepting triphenyltriazine…”