Donor-modified tetradentate platinum(ii) complexes for red OLEDs

Abstract

Tailoring the ligand architecture in emissive complexes plays a critical role in modulating the luminescence characteristics of materials. In this work, a series of robust Pt(II) complexes featuring a rigid tetradentate N^C^C^N coordination framework were developed by systematically modifying the donor moiety from diphenylamine to dimethylacridine units. These complexes exhibit excellent thermal stability and efficient red photoluminescence characterized by high quantum yields and short excited-state lifetimes. The OLEDs doped with these complexes exhibited electroluminescence (EL) peaks at 648, 636, and 616 nm, with maximum external quantum efficiencies (EQE_max) of 19.5%, 20.1%, and 19.2%, respectively. All devices show minimal efficiency roll-off across a broad doping range (1–7 wt%), low turn-on voltages of 2.4 V, and excellent spectral stability under varying doping concentrations. This combination of remarkable spectral stability, high efficiency, and reduced aggregation-induced quenching provides a valuable reference for the practical application of OLED technology.