High-performance light-emitting diodes based on carbene-metal-amides

Dawei Di, Alexander S. Romanov, Le Yang, Johannes M. Richter, Jasmine P. H. Rivett, Saul Jones, Tudor H. Thomas, Moijata Abdi Jalebi, Richard H. Friend, Mikko Linnolahti, Manfred Bochmann, Dan Credgington

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243 Citations (Scopus)
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Abstract

Organic LEDs promise highly efficient lighting and display technologies. We introduce a new class of linear donor-bridge-acceptor light-emitting molecules, which enable solution-processed LEDs with near-100% internal quantum efficiency at high brightness. Key to this performance is their rapid and efficient utilization of triplet states. Using time-resolved spectroscopy, we establish that luminescence via triplets occurs within 350 ns at ambient temperature, after reverse intersystem crossing to singlets. We find that molecular geometries exist at which the singlet-triplet energy gap (exchange energy) is close to zero, such that rapid interconversion is possible. Calculations indicate that exchange energy is tuned by relative rotation of donor and acceptor moieties about the bridge. Unlike other low exchange energy systems, substantial oscillator strength is sustained at the singlet-triplet degeneracy point.
Original languageEnglish
Pages (from-to)159-163
Number of pages5
JournalScience
Volume356
Issue number6334
Early online date30 Mar 2017
DOIs
Publication statusPublished - 14 Apr 2017

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