Thermally Activated Delayed Fluorescence Sensitization for Highly Efficient Blue Fluorescent Emitters

Hadi Abroshan, Yadong Zhang, Xiaoqing Zhang, Canek Fuentes-Hernandez, Stephen Barlow, Veaceslav Coropceanu, Seth R. Marder, Bernard Kippelen, Jean Luc Brédas

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

Hyperfluorescence is emerging as a powerful strategy to develop optoelectronic devices with high-color purity and enhanced stability. It requires appropriate integration of a sensitizer displaying efficient thermally activated delayed fluorescence (TADF) and an emitter displaying strong, narrow-band fluorescence. Here, through a joint computational and experimental approach, an unprecedented, end-to-end systems level description of the electronic and optical processes that take place in a hyperfluorescent emissive layer composed of a TADF sensitizer, 2,5-bis(2,6-di(9H-carbazol-9-yl)phenyl)-1,3,4-oxadiazole (4CzDPO), and a fluorescent emitter, 2,5,8,11-tetra-tert-butylperylene (TBPe) is provided. The photophysical properties measurement of the emissive layer is combined with the computational determination of the electronic properties, film morphology, and excitation transfer phenomena. The Förster resonance energy transfer rates from 4CzDPO to TBPe are on the order of 1011 s−1, considerably higher than the radiative and nonradiative recombination rates for 4CzDPO. These features ensure nearly complete energy transfer to TBPe, leading to a five-fold increase in the photoluminescence quantum yields in the 4CzDPO:TBPe system in comparison to neat films of 4CzDPO. This approach highlights the factors that can provide efficient energy transfer from TADF molecules to fluorescent emitters, suppress energy transfer among TADF molecules, and avoid the need for a host material within the emissive layer.

Original languageEnglish (US)
Article number2005898
JournalAdvanced Functional Materials
Volume30
Issue number52
DOIs
StatePublished - Dec 22 2020
Externally publishedYes

Keywords

  • TADF
  • energy transfer
  • fluorescence
  • hyperfluorescence
  • sensitizers

ASJC Scopus subject areas

  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics

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