Chiral thermally activated delayed fluorescence materials for circularly polarized organic light-emitting diodes

Abstract

Chirality is an important natural characteristic of organic molecules, and chiral organic molecules have shown extensive application in areas such as pharmaceutical development and material science. Benefiting from the ability to achieve circularly polarized luminescence (CPL), chiral luminescent materials have shown potential applications in anti-glare display, optical communication and, 3D display, etc. Due to the ability to harvest both singlet and triplet excitons by a fast reverse intersystem crossing process without involving noble metals, chiral thermally activated delayed fluorescence (TADF) materials with point chirality, axial chirality, planar chirality and helical chirality are regarded as the state-of-the-art materials for circularly polarized organic light-emitting diodes (CP-OLEDs). In recent years, the chiral TADF materials and CP-OLEDs have rapidly developed, but unfortunately, the dissymmetry factors (g) are far from the requirement of practical applications. The ideal emitters and devices should have both high efficiency and a g factor, or at least a balance between these two elements. This review gives an overview of recent progress in chiral TADF materials, with a particular focus on the chiral skeleton, CPL property and device performance. Furthermore, the molecular design concept, device structure and methods to improve the g factors of chiral materials and CP-OLEDs are also discussed.