Packman, Lachlan, Philippa, Bronson, Pivrikas, Almantas, Burn, Paul L., and Gentle, Ian (2024) Reconstructing the 3D Coordinates of Guest:Host OLED Blends with Single Atom Resolution. Small Methods. 2301305. (In Press)

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Abstract

The performance of electronic and semiconductor devices is critically dependent on the distribution of guest molecules or atoms in a host matrix. One prominent example is that of organic light-emitting diode (OLED) displays containing phosphorescent emitters, now ubiquitous in handheld devices and high-end televisions. In such OLEDs the phosphorescent guest [normally an iridium(III)-based complex] is typically blended into a host matrix, and charge injection and transport, exciton formation and decay, and hence overall device performance are governed by the distribution of the emissive guest in the host. Here high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) is used with depth sectioning to reconstruct the 3D distribution of emissive iridium(III) complexes, fac-tris(2-phenylpyridine)iridium(III) [Ir(ppy)3], blended into the amorphous host material, tris(4-carbazoyl-9-ylphenyl)amine (TCTA), by resolving the position of each single iridium(III) ion. It is found that most Ir(ppy)3 complexes are clustered with at least one other, even at low concentrations, and that for films of 20 wt.% Ir(ppy)3 essentially all the complexes are interconnected. The results validate the morphology of blend films created using molecular dynamics simulations which mimic the evaporation film-forming process and are also consistent with the experimentally measured charge transport and photophysical properties.

Item ID:	82511
Item Type:	Article (Research - C1)
ISSN:	2366-9608
Copyright Information:	© 2024 The Authors. Small Methods published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Funders:	Australian Research Council (ARC)
Projects and Grants:	ARC DP210102192
Date Deposited:	04 Apr 2024 00:23
FoR Codes:	40 ENGINEERING > 4016 Materials engineering > 401608 Organic semiconductors @ 100%
SEO Codes:	28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280110 Expanding knowledge in engineering @ 100%
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