Helically Chiral Tetradentate Pt(II) Emitters via Efficient Diastereoselective Synthesis for High‐Performance Deep‐Blue CP‐PhOLEDs

ABSTRACT Highly efficient circularly polarized phosphorescent organic light‐emitting diodes (CP‐PhOLEDs) with narrowband deep‐blue emission remain a formidable challenge, owing to the difficult chiral HPLC resolution, poor stability, low color purity, and limited brightness of chiral phosphorescent emitters. Herein, we report a novel central chirality adaptively induced helical chirality (CAIH) strategy for the diastereoselective synthesis of helically chiral tetradentate Pt(II) emitters. By introducing inexpensive and optically pure R‐ / S‐ amino alcohol‐derived centrally chiral units into a rigid N ‐heterocyclic carbene (NHC)‐based ligand, and using a diisopropylphenyl group to suppress intermolecular interactions, two pairs of emitters ( M ‐/ P ‐PtCP1 and M ‐/ P ‐PtCP2) were obtained on a gram scale. These diastereomers exhibit excellent CP luminescence properties with dissymmetry factor (| g PL |= 10 −3 ), ultrapure deep‐blue emissions ( λ PL /FWHM ≈ 456/20 nm), photoluminescence quantum efficiency ( Φ PL ) values up to 99%, and high configurational stability. The M ‐/ P ‐PtCP1‐ and M ‐/ P ‐PtCP2‐based devices also display distinct mirror‐symmetric CPEL signals with | g EL | values of 10 −4 . Impressively, the P ‐PtCP1‐based device simultaneously achieves record‐high external quantum efficiency (EQE = 18.3% at 1000 cd m −2 ) and maximum brightness ( L max = 19933 cd m −2 ) values among reported CP‐OLEDs with CIE y < 0.12. This study provides valuable insight and new perspectives on the construction of stable helically chiral tetradentate Pt(II) emitters for high‐performance CP‐PhOLEDs.