Efficient Chiral Ultraviolet and Deep‐Blue Materials for High‐Performance Circularly Polarized OLEDs
Letian Xu, Yan Li, Hao Liu, Nuoling Qiu, Hui Chen, Yinhao Luo, Heping Shi, Ben Zhong Tang, Zujin Zhao
Abstract
ABSTRACT High‐performance circularly polarized organic light‐emitting diodes (CP‐OLEDs) with ultraviolet and deep‐blue circularly polarized electroluminescence (CP‐EL) are important for 3D displays, but designing short‐wavelength circularly polarized luminescence (CPL) materials remains a significant challenge. Herein, a series of ultraviolet and deep‐blue CPL materials was developed, successfully integrating high photoluminescence quantum yields with efficient high‐level reverse intersystem crossing (hRISC) properties. Efficient ultraviolet and deep‐blue CP‐OLEDs are created by utilizing these chiral materials as emitters, providing maximum external quantum efficiencies ( η ext,max s) of 6.7% at 398 nm (full‐width at half‐maximum [FWHM] = 44 nm) and 10.8% at 454 nm (FWHM = 68 nm) with obvious CP‐EL. Furthermore, by adopting these chiral materials as sensitizers or functional layers, well‐developed achiral multi‐resonance thermally activated delayed fluorescence green and yellow emitters are enabled to generate obvious CP‐EL with large dissymmetry factors and excellent EL performance ( η ext s = 34.5% and 35.3%, FWHM = 42 and 40 nm). These results demonstrate that the developed new ultraviolet and deep‐blue chiral materials can be used not only as emitters for ultraviolet and deep‐blue CP‐OLEDs, but also as sensitizers and functional layers to furnish a simple and universal way of achieving efficient narrow‐spectrum CP‐OLEDs with achiral emitters.