Thermally activated delayed fluorescence emitters showing wide-range near-infrared piezochromism and their use in deep-red OLEDs

Pagidi Sudhakar, Abhishek Kumar Gupta, David B. Cordes, Eli Zysman-Colman

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Organic small molecules exhibiting both thermally activated delayed fluorescence (TADF) and wide-ranging piezochromism (Δλ > 150 nm) in the near-infrared region have rarely been reported in the literature. We present three emitters MeTPA-BQ, tBuTPA-BQ and TPPA-BQ based on a hybrid acceptor, benzo[g]quinoxaline-5,10-dione, that emit via TADF, having photoluminescence quantum yields, ΦPL, of 39-42% at photoluminescence (PL) maxima, λPL, of 625-670 nm in 2 wt% doped films in 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP). Despite their similar chemical structures, the PL properties in the crystalline states of MeTPA-BQ (λem = 735 nm, ΦPL = 2%) and tBuTPA-BQ (λem = 657 nm, ΦPL = 11%) are significantly different. Further, compounds tBuTPA-BQ and TPPA-BQ showed a significant PL shift of ∼98 and ∼165 nm upon grinding of the crystalline samples, respectively. Deep-red organic light-emitting diodes with MeTPA-BQ and tBuTPA-BQ were also fabricated, which showed maximum external quantum efficiencies, EQEmax, of 10.1% (λEL = 650 nm) and 8.5% (λEL = 670 nm), respectively.

Original languageEnglish
Pages (from-to)545-554
Number of pages10
JournalChemical Science
Volume15
Issue number2
DOIs
StatePublished - 3 Jan 2024
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2024 The Royal Society of Chemistry.

Funding

This project is funded by European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska Curie grant agreements No. 891606 (TADFNIR). We thank the Engineering and Physical Sciences Research Council for funding. (EP/R035164/1).

FundersFunder number
Engineering and Physical Sciences Research CouncilEP/R035164/1
European Commission891606

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