Near-saturated red emitters: four-coordinate copper(i) halide complexes containing 8-(diphenylphosphino)quinoline and 1-(diphenylphosphino)naphthalene ligands

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 47; no. 28; pp. 9294 - 9302
• Main Authors: Liu, Li-Ping, Li, Qian, Xiang, Song-Po, Liu, Li, Zhong, Xin-Xin, Liang, Chen, Li, Guang Hua, Hayat, Tasawar, Alharbi, Njud S, Li, Fa-Bao, Zhu, Nian-Yong, Wong, Wai-Yeung, Qin, Hai-Mei, Wang, Lei
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 2018
• Subjects: Ambient temperature; Chemical synthesis; Coordination compounds; Copper; Emission analysis; Emission spectra; Emitters; Energy gap; Molecular chains; Naphthalene; Quinoline; Solid state
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c7dt04528j

Recently, highly emissive neutral copper halide complexes have received much attention. Here, a series of four-coordinate mononuclear Cu(i) halide complexes, [CuX(dpqu)(dpna)] (dpqu = 8-(diphenylphosphino)quinoline, dpna = 1-(diphenylphosphino)naphthalene, X = I (1), Br (2) and Cl (3)), were synthesized, and their molecular structures and photophysical properties were investigated. These complexes exhibit near-saturated red emission in the solid state at room temperature and have peak emission wavelengths at 669-691 nm with microsecond lifetimes (τ = 0.46-1.80 μs). Small S1-T1 energy gaps in the solid state indicate that the emission occurs from a thermally activated excited singlet state at ambient temperature. The emission of the complexes 1-3 mainly originates from MLCT transition. The solution-processed devices of complex 1 exhibit stable red emission with a CIE(x, y) of (0.62, 0.38) for a doped device and (0.63, 0.37) for a non-doped device.