Improving the Blue Color Purity of Tetradentate Pt(II) Complexes with the Assistance of F···H Interaction towards High‐Performance Blue Phosphorescent OLEDs with EQE over 33%

Among the various challenges in the field of organic light‐emitting diodes (OLEDs), simultaneously achieving high efficiency, a long lifespan, and a narrow full‐width at half maximum (FWHM) in blue OLEDs remains a significant hurdle. Herein, we demonstrate a strategy to improve the color purity of tetradentate Pt(II) complexes with the assistance of F···H interaction by incorporating trifluoromethyl (‐CF3) groups into the well‐known blue tetradentate Pt(II) phosphorescent complex. The results show that the different substitution positions of ‐CF3 have significantly varying effects on the FWHM values of the complexes; specifically, introducing ‐CF3 on the benzene ring of carbazole effectively reduces the FWHM, while introducing it on the benzene ring linked to the carbene unit has a minimal impact. When utilized in a mixed host system of SiCzCz/SiTrzCz2, the OLEDs with these new complexes as emitters demonstrated maximum external quantum efficiencies (EQEs) of 27.1%, 33.8%, and 27.6% for PtON‐CF3‐1, PtON‐CF3‐2, and PtON‐2CF3, respectively, with excellent color purity (CIEy ≈ 0.14 for the PtON‐CF3‐2 based device). Notably, the device based on PtON‐CF3‐2 matched the stability of the benchmark PtON‐TBBI complex.This work offers an important guideline for the design of high efficient Pt(II) phosphorescent complexes with good blue color purity.