Peripheral Cycloalkyl Functionalized Tetradentate Platinum(II) Phosphorescent Complex: Synthesis, Optical Tuning, and OLED Applications

A tetradentate Pt(II) complex with a 5/6/6 structural backbone, Pt(PhPiPy-O-PytmCz), was synthesized by incorporating two distinct cycloalkyl groups. These structural modifications significantly enhanced the photoluminescence quantum yield and effectively increased the distance between molecules, thereby mitigating undesirable intermolecular interactions and triplet-state quenching. This strategic molecular design resulted in an external quantum efficiency of 11.5% at a wavelength of 539 nm and significantly enhanced operational lifetimes in green phosphorescent organic light-emitting diodes (OLEDs). These findings are expected to inspire the development of new green luminescent materials and innovative strategies in OLED technology.