Open AccessBlue Phosphorescence and Hyperluminescence Generated from Imidazo[4,5‐b]pyridin‐2‐ylidene‐Based Iridium(III) Phosphors
Author(s) -
Yang Xilin,
Zhou Xiuwen,
Zhang YeXin,
Li Deli,
Li Chensen,
You Caifa,
Chou TaiChe,
Su ShiJian,
Chou PiTai,
Chi Yun
Publication year - 2022
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.202201150
Subject(s) - iridium , phosphorescence , phosphor , chemistry , quantum efficiency , homoleptic , full width at half maximum , oled , trifluoromethyl , isomerization , photochemistry , photoluminescence , quantum yield , fluorescence , analytical chemistry (journal) , materials science , optoelectronics , metal , catalysis , organic chemistry , optics , physics , alkyl , layer (electronics)
Four isomeric, homoleptic iridium(III) metal complexes bearing 5‐(trifluoromethyl)imidazo[4,5‐b]pyridin‐2‐ylidene and 6‐(trifluoromethyl)imidazo[4,5‐b]pyridin‐2‐ylidene‐based cyclometalating chelates are successfully synthesized. The meridional isomers can be converted to facial isomers through acid induced isomerization. The m ‐isomers display a relatively broadened and red‐shifted emission, while f ‐isomers exhibit narrowed blue emission band, together with higher photoluminescent quantum yields and reduced radiative lifetime relative to the mer ‐counterparts. Maximum external quantum efficiencies of 13.5% and 22.8% are achieved for the electrophosphorescent devices based on f ‐tpb1 and m ‐tpb1 as dopant emitter together with CIE coordinates of (0.15, 0.23) and (0.22, 0.45), respectively. By using f‐ tpb1 as the sensitizing phosphor and t ‐DABNA as thermally activated delayed fluorescence (TADF) terminal emitter, hyperluminescent OLEDs are successfully fabricated, giving high efficiency of 29.6%, full width at half maximum (FWHM) of 30 nm, and CIE coordinates of (0.13, 0.11), confirming the efficient Förster resonance energy transfer (FRET) process.