Bulky iridium NHC complexes for bright, efficient deep-blue OLEDs
Date
18/01/2023Author
Grant ID
EP/P010482/1
EP/M02105X/1
EP/K503940/1
SRF\R1\201089
Metadata
Show full item recordAbstract
Four new deep-blue-emitting iridium(III) NHC complexes containing sterically demanding ligands are synthesized. The four complexes show bright, deep-blue emission, with emission maxima between 420 and 427 nm in both acetonitrile solution and 30 wt% doped films in TSPO1; the two meridional isomers showing photoluminescence quantum yields, ΦPL, in doped films of 80% and 89%. The two meridional isomers are used to assess the impact of emitters containing bulky, sterically demanding ligands on the performance of organic light-emitting diodes (OLEDs). OLEDs employing a stepped doping profile with mer-Ir(tfpi_tmBn)3 as the emitter produce the highest performing devices in this study, with these devices exhibiting deep-blue [λEL = 429 nm, CIE = (0.16, 0.08)] emission and a maximum external quantum efficiency (EQEmax) of 14.9%, which decreases to 11.7% at 100 cd m−2. The performance of the OLEDs shows very good efficiencies and moderate efficiency roll-offs in comparison to reported phosphorescent deep-blue OLEDs with CIEy ≤ 0.08, as required for commercial displays. The promising results suggest that the design strategy of adding steric bulk to blue emitting iridium complexes containing NHC ligands is a useful strategy for reducing intermolecular interactions between emitters in OLEDs.
Citation
Mackenzie , C F R , Zhang , L , Cordes , D B , Slawin , A M Z , Samuel , I D W & Zysman-Colman , E 2023 , ' Bulky iridium NHC complexes for bright, efficient deep-blue OLEDs ' , Advanced Optical Materials , vol. 11 , no. 2 , 2201495 . https://doi.org/10.1002/adom.202201495
Publication
Advanced Optical Materials
Status
Peer reviewed
ISSN
2195-1071Type
Journal article
Description
Funding: C.F.R.M. and L.Z. contributed equally to this work. The authors thank the University of St Andrews and EPSRC for financial support (grants EP/P010482/1 and EP/M02105X/1, EP/K503940/1). The authors thank Umicore AG for the gift of materials. E.Z.-C. was a Royal Society Leverhulme Trust Senior Research fellow (SRF\R1\201089).Collections
Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.