Spin-polarized white organic light-emitting diodes based on chirality-induced spin selectivity effect

Abstract

Chirality-induced spin selectivity (CISS) effect refers to charge carriers become spin-polarized when traversing through chiral materials, but this unique phenomenon has never been reported for organic light-emitting diodes (OLEDs). Herein, robust chiral near-ultraviolet and deep-blue materials with wide energy gaps are explored and demonstrated to possess CISS effect. By aligning a chiral deep-blue layer next to an achiral green layer in OLEDs, spin-polarized charge carriers are generated from the chiral layer and get recombined to form spin-polarized excitons in the adjacent achiral green layer, furnishing green circularly polarized electroluminescence (CP-EL). Furthermore, by incorporating multiple achiral sky-blue, green and red layers with chiral near-ultraviolet or deep-blue layers, complex three-emitting-layer or four-emitting-layer spin-polarized white OLEDs are realized, providing distinct CP-EL signals from different achiral emitting layers simultaneously and outstanding EL performance with excellent external quantum efficiencies reaching 26.6% and high color rendering indexes of 94, much superior to the performances of the reported white OLEDs with circularly polarized light so far. This work introduces CISS effect into OLEDs for achieving CP-EL for the first time, and virtually presents a novel and feasible approach towards high-performance circularly polarized white OLEDs with a single organic chiral layer.