A poly(urethane)-encapsulated benzo[2,3-d:6,7-d']diimidazole organic down-converter for green hybrid LEDs

Alan A. Wiles, Jochen Bruckbauer, Nabeel Mohammed, Michele Cariello, Joseph Cameron, Neil J. Findlay, Elaine Taylor-Shaw, David J. Wallis, Robert W. Martin, Peter J. Skabara, Graeme Cooke

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8 Citations (Scopus)
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The development of organic down-converting materials continues to attract attention in hybrid LED technology by obviating the need for non-sustainable rare-earth elements. In this work, a benzodiimidazole-based system (TPA-BDI) has been employed as a down-converting layer in a hybrid organic-inorganic LED device. A commercially available poly(urethane)-based resin is used as the encapsulating material, providing a dilute layer of TPA-BDI that is deposited on top of the GaN-based LED. Crucially, the solution-state emissive performance is generally maintained when encapsulated at low concentrations within this resin. A maximum luminous efficacy of 87 lm W -1 was demonstrated using a 1.0 mg ml -1 concentration of TPA-BDI in the resin. The suitability of using organic down-converters to produce green light from hybrid devices was demonstrated by the excellent repeatability of the device characteristics across a series of encapsulated LEDs.

Original languageEnglish
Pages (from-to)1006-1012
Number of pages7
JournalMaterials Chemistry Frontiers
Issue number3
Early online date6 Feb 2020
Publication statusPublished - 1 Mar 2020


  • down-converter
  • LEDs
  • hybrid LED technology


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