Effect of PEDOT:PSS on the performance of solution-processed blue phosphorescent organic light-emitting diodes with an exciplex host

Jaber Saghaei,Paul L Burn,Paul E Shaw,Almantas Pivrikas,Manikandan Koodalingam,Ian R Gentle

doi:10.1039/d1ma00729g

Abstract

The acidity of the PEDOT:PSS hole injection layer was found to effect the performance of efficient solution-processed organic light-emitting diodes incorporating a light-emitting layer composed of a blue phosphorescent dendrimer:exciplex host blend.

Highlights

While the creation of exciplex host blends for green and red guest emitters is relatively straightforward, it is more difficult to create donor–acceptor combinations that form suitable hosts for blue emissive materials,[14] and in particular, solutionprocessed blue phosphorescent emitters
Exciting the film at 270 nm excites both the phenylene] bis[diphenylphosphine oxide] (POPH) and TCTA and it can be seen in Fig. 2 that in addition to the exciplex and TCTA emission there was small component of the emission at 355 nm, which is consistent with POPH emission
We fabricated organic light-emitting diodes (OLEDs) with the structure ITO/PEDOT:PSS/ (1:1)TCTA:POPH:Ir(DTri)3/BP4mPy/LiF/Al [BP4mPy = 3,30,5,50tetra[(m-pyridyl)-phen-3-yl]biphenyl, LiF = lithium fluoride] with different wt% of Ir(DTri)[3] in the TCTA:POPH (1:1 molar ratio) host with the results shown in Fig. 4 and Table S2 (ESI†) summarising the key device performance parameters

Summary

Introduction

While the creation of exciplex host blends for green and red guest emitters is relatively straightforward, it is more difficult to create donor–acceptor combinations that form suitable hosts for blue emissive materials,[14] and in particular, solutionprocessed blue phosphorescent emitters. In the context of solution processed blue-phosphorescent emitters, there have been a number of reports of exciplex hosts composed of 4,40,400tris(carbazol-9-yl)triphenylamine (TCTA) (donor) (and derivatives) and phosphine oxide-based acceptors with bis[2-(4,6difluorophenyl)pyridinato-C2,N](picolinato)iridium (III) (FIrpic) as the emitter.[15,16,17,18,19] most reports describing solutionprocessed bulk exciplex hosts for blue emissive guests include the use of phosphine oxide derivatives as the acceptor in the. We report and discuss the photophysical, electronic and device properties of the blend emissive films and compare the device performance with films using FIrpic as the emissive material

Results and discussion

Conclusion

Conflicts of interest