CHUNG-CHIH WU2021-09-022021-09-02202119448244https://www.scopus.com/inward/record.uri?eid=2-s2.0-85103476691&doi=10.1021%2facsami.0c22109&partnerID=40&md5=5123891f611aa155448e7f4d5eb2f03dhttps://scholars.lib.ntu.edu.tw/handle/123456789/580758How to develop efficient red-emitting organometallics of earth-abundant copper(I) is a formidable challenge in the field of organic light-emitting diodes (OLEDs) because Cu(I) complexes have weak spin-orbit coupling and a serious excited-state reorganization effect. Here, a red Cu(I) complex, MAC*-Cu-DPAC, was developed using a rigid 9,9-diphenyl-9,10-dihydroacridine donor ligand in a carbene-metal-amide motif. The Cu(I) complex achieved satisfactory red emission, a high photoluminescence quantum yield of up to 70%, and a sub-microsecond lifetime. Thanks to a linear geometry and the acceptor and donor ligands in a coplanar conformation, the complex exhibited a high horizontal dipole ratio of 77% in the host matrix, first demonstrated for coinage metal(I) complexes. The resulting OLEDs delivered high external quantum efficiencies of 21.1% at a maximum and 20.1% at 1000 nits, together with a red emission peak at ?630 nm. These values represent the state-of-the-art performance for red-emitting OLEDs based on coinage metal complexes. ? 2021 American Chemical Society.Amides; Coinage; Efficiency; Excited states; Ligands; Metal complexes; Mints; Orbits; Organic light emitting diodes (OLED); Organometallics; Quantum efficiency; Spin orbit coupling; External quantum efficiency; Horizontal dipoles; Linear geometry; Organic light emitting diodes(OLEDs); Photoluminescence quantum yields; Red electroluminescence; State-of-the-art performance; Sub-microsecond; Copper compounds[SDGs]SDG7journal article10.1021/acsami.0c22109336892792-s2.0-85103476691