Chiral Nematic Liquid Crystal Films for High-Performance Circularly Polarized Organic Light-Emitting Diodes

Circularly polarized organic light-emitting diodes (CP-OLEDs) have emerged as promising candidates for energy-efficient displays and eye-healthy lighting technologies. However, CP-OLEDs obtained from conventional chiral luminescent materials face critical limitations, including insufficient electroluminescence dissymmetry factors (g_EL), low external quantum efficiencies (EQEs), and broad emission bandwidths, which collectively impede their practical application. Herein, we proposed a strategy utilizing co-assembled chiral nematic liquid crystal (N*-LC) films as emitting layers (EMLs) to fabricate high-performance CP-OLEDs. Firstly, chiral inducers (P/M-THH) were incorporated into the N-LC (2PFP) host. Subsequent thermal annealing yielded intrinsically luminescent N*-LCs films exhibiting intense circularly polarized luminescence (CPL) with |g_lum| up to 1.33. Introducing the achiral energy acceptor BCz-BN at optimal concentrations enabled efficient Förster resonance energy transfer (FRET) (Φ_ET = 99%), producing ternary co-assembled N*-LCs films. These films retained the nematic order while inheriting the narrowband emission and high photoluminescence (PL) quantum yield of BCz-BN. This approach achieves unprecedented CP-OLED performance, delivering the highest reported combination of key metrics to date: a |g_EL| value of 0.61, a maximum EQE of 9.0%, and narrowband electroluminescence with a full width at half maximum (FWHM) of 32 nm. These findings establish a novel pathway for fabricating high-performance CP-OLEDs and open up a new avenue for exploring the chiral optoelectronic application.