Bulky‐Group‐Functionalized Bidentate Pt(II) Complexes With Aggregation‐Induced Emission for Blue Phosphorescent Organic Light‐Emitting Diodes

Abstract

Pt(II) metal complexes with aggregation‐induced emission (AIE) properties are creating new opportunities in the fields of optoelectronics and their applications. We synthesized a series of AIE‐active sky blue and bluish green Pt(II) complexes with varying structures, such as (Pt1–Pt4). Their photophysical, electrochemical, thermal, and electroluminescence properties were systematically investigated. The suppression of low‐energy excimer emission in (Pt1–Pt4) was confirmed by PL studies of neat films. This is due to the introduction of bulky trityl and diphenyl phosphine oxide Ph 2 (P═O) in the main ligand and di‐mesityl groups on the ancillary ligand. All the complexes exhibited better photoluminescence quantum yield (PLQYs) in the film state. Consequently, the phosphorescent organic light‐emitting (PHOLED) device with Pt2 as a dopant achieved a maximum current efficiency (CE) of 20 cd/A and a power efficiency (PE) of 14.4 lm/W at a 10 wt% doping ratio, outperforming Pt1 (CE:7.5 cd/A, PE:5.3 lm/W at 15 wt%). Notably, the vacuum deposition PHOLEDs demonstrated significantly superior performance compared to their solution‐processed counterparts. This work provides a foundation for future research into AIE/AIEE‐active emitters for advanced display applications.