铱
材料科学
有机发光二极管
二极管
光电子学
配体(生物化学)
光化学
发光二极管
纳米技术
催化作用
有机化学
化学
生物化学
受体
图层(电子)
作者
Manikandan Koodalingam,Junhyuk Jang,Chandana Sampath Kumara Ranasinghe,Mile Gao,Paul L. Burn,Jos C. M. Kistemaker,Emma V. Puttock,Paul E. Shaw
标识
DOI:10.1002/adom.202400640
摘要
Abstract Tris‐bidentate iridium(III) complexes used in organic light‐emitting diodes (OLEDs) are typically homoleptic or heteroleptic with three or two identical emissive ligands, respectively. Herein red phosphorescence emitting dendrimers composed of first generation biphenyl dendrons, 2‐ethylhexyloxy surface groups and an iridium(III) complex core with three, two or one emissive [4‐phenyl]−2‐[thiophen‐2‐yl]quinoline ligands are reported. The dendrimers have similar photoluminescence quantum yields (PLQYs) in solution (84–88%), neat film (23–25%) and when blended with tris(4‐carbazoyl‐9‐ylphenyl)amine (72–73%), enabling the effect of the number of emissive ligands on OLED performance to be determined. The external quantum efficiency (EQE) of OLEDs composed of neat dendrimer films increased with decreasing number of emissive ligands, with the device composed of the dendrimer having a single emissive ligand having an EQE of 9.2%, which is almost double that expected from a bottom emitting device and a film PLQY of 25 ± 3.6%. The emission is Lambertian and the higher‐than‐expected EQE is ascribed to alignment of the single emissive ligand being optimal for light‐outcoupling. The EQE of OLEDs containing the blend film also increased with decreasing emissive number of ligands (maximum EQE = 15.4%).
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