Constructing Highly Efficient Circularly Polarized Multiple Resonance Thermally Activated Delayed Fluorescence Materials with Intrinsically Helical Chirality.

Abstract

Advanced circularly polarized multiple resonance thermally activated delayed fluorescence (CP-MR-TADF) materials synergize the advantages of circularly polarized luminescence (CPL), narrowband emission and TADF characteristic, which can be fabricated into highly efficient circularly polarized organic light-emitting diodes (CP-OLEDs) with high color purity, directly facing the urgent market strategic demand of ultra-high-definition and 3D displays. In this contribution, based on edge topology molecular engineering (ETME) strategy, a pair of high-performance CP-MR-TADF enantiomers, (P and M)-BN-Py, has been developed, which merges the intrinsically helical chirality into MR framework. The optimized CP-OLEDs with emitters (P and M)-BN-Py and the newly developed ambipolar transport host PhCbBCz exhibit pure green emission with sharp peaks of 532nm, full-width at half-maximums (FWHMs) of 37nm, and Commission Internationale de L'Eclairage (CIE) coordinates of (0.29, 0.68). Importantly, they achieve remarkable maximum external quantum efficiencies (EQEs) of 30.6% and 29.2%, and clear circularly polarized electroluminescence (CPEL) signals with electroluminescence dissymmetry factors (gEL s) of -4.37 × 10-4 and +4.35 × 10-4 for (P)-BN-Py and (M)-BN-Py, respectively. This article is protected by copyright. All rights reserved.