Judicious Heteroatom Doping Produces High-Performance Deep-Blue/Near-UV Multiresonant Thermally Activated Delayed Fluorescence OLEDs

Subeesh Madayanad Suresh; Le Zhang; Tomas Matulaitis; David Hall; Changfeng Si; Gaetano Ricci; Alexandra M Z Slawin; Stuart Warriner; David Beljonne; Yoann Olivier; Ifor D W Samuel; Eli Zysman-Colman

doi:10.1002/adma.202300997

Judicious Heteroatom Doping Produces High-Performance Deep-Blue/Near-UV Multiresonant Thermally Activated Delayed Fluorescence OLEDs

Adv Mater. 2023 Aug;35(33):e2300997. doi: 10.1002/adma.202300997. Epub 2023 Jul 6.

Authors

Subeesh Madayanad Suresh¹, Le Zhang^{1

2}, Tomas Matulaitis¹, David Hall^{1

3}, Changfeng Si¹, Gaetano Ricci⁴, Alexandra M Z Slawin¹, Stuart Warriner⁵, David Beljonne³, Yoann Olivier^{3

4}, Ifor D W Samuel², Eli Zysman-Colman¹

Affiliations

¹ Organic Semiconductor Centre, EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, UK.
² Organic Semiconductor Centre, SUPA School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS, UK.
³ Laboratory for Chemistry of Novel Materials, University of Mons, Mons, 7000, Belgium.
⁴ Laboratory for Computational Modeling of Functional Materials, Namur Institute of Structured Matter, Université de Namur, Rue de Bruxelles, 61, Namur, 5000, Belgium.
⁵ School of Chemistry, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.

PMID: 37140188
DOI: 10.1002/adma.202300997

Abstract

Two multiresonant thermally activated delayed fluorescence (MR-TADF) emitters are presented and it is shown how further borylation of a deep-blue MR-TADF emitter, DIDOBNA-N, both blueshifts and narrows the emission producing a new near-UV MR-TADF emitter, MesB-DIDOBNA-N, are shown. DIDOBNA-N emits bright blue light (Φ_PL = 444 nm, FWHM = 64 nm, Φ_PL = 81%, τ_d = 23 ms, 1.5 wt% in TSPO1). The deep-blue organic light-emitting diode (OLED) based on this twisted MR-TADF compound shows a very high maximum external quantum efficiency (EQE_max ) of 15.3% for a device with CIE_y of 0.073. The fused planar MR-TADF emitter, MesB-DIDOBNA-N shows efficient and narrowband near-UV emission (λ_PL = 402 nm, FWHM = 19 nm, Φ_PL = 74.7%, τ_d = 133 ms, 1.5 wt% in TSPO1). The best OLED with MesB-DIDOBNA-N, doped in a co-host, shows the highest efficiency reported for a near-UV OLED at 16.2%. With a CIE_y coordinate of 0.049, this device also shows the bluest EL reported for a MR-TADF OLED to date.

Keywords: boron; deep-blue emitters; multiresonant thermally activated delayed fluorescence (MR-TADF); near-UV emitters; organic light-emitting diodes (OLEDs).

Abstract

Grants and funding