Red–green–blue–yellow (RGBY) magnetic circularly polarized electroluminescence from iridium(III)-magnetic circularly polarized organic light-emitting diodes

Abstract

In this study, optically inactive racemic phosphorescent iridium(III) luminophores were embedded into the luminescent active layer of each device, and red–green–blue–yellow (RGBY)-full-color external magnetic field-driven circularly polarized electroluminescence (CPEL) was generated from organic light-emitting diodes (OLEDs). The optically inactive organic iridium(III) luminophores selected for this study were IrIII(piq)3 and IrIII(ppy)3, composed of achiral organic ligands with homoleptic tris-cyclometalated structures, and IrIII(F2-ppy)2(pic) and IrIII(BT)2(acac), with heteroleptic bis-cyclometalated structures, where piq, ppy, F2-ppy, pic, BT, and acac refer to 1-phenylisoquinolinate, 2-phenylpyridinate, 2-(4′, 6′-difluorophenyl)pyridinate, picolinate, 2-phenylbenzo[d]thiazolate, and acetylacetonate, respectively. As a result, full-color magnetic CPELs (MCPELs) were successfully generated from each magnetic circularly polarized OLED (MCP-OLED) with high efficiency, despite the use of chirality-free organic iridium(III) luminophores. In this MCP-OLED system, the direction of rotation of the MCPEL can be controlled by the ligand environment of the IrIII luminophore (homoleptic or heteroleptic structure) and the direction of the applied magnetic field (Faraday geometry).