Application of neutral d(10) coinage metal complexes with an anionic bidentate ligand in delayed fluorescence-type organic light-emitting diodes

作者：Osawa Masahisa^*; Kawata Isao; Ishii Ryuji; Igawa Satoshi; Hashimoto Masashi; Hoshino Mikio

来源：Journal of Materials Chemistry C, 2013, 1(28): 4375-4383.

DOI：10.1039/c3tc30524d

A series of heteroleptic coinage metal(I) complexes [Cu(PP)(PS)] 1, [Ag(PP)(PS)] 2, and [Au(PP)(PS)] 3 [PP = 1,2-bis(diphenylphosphino)benzene and PS = 2-diphenylphosphinobenzenethiolate] were synthesized. X-ray crystallography demonstrated that 1-3 possessed tetrahedral structures containing two types of bidentate ligands, PP and PS-. Photophysical studies and time-dependent density functional theory calculations indicated that the emission from 1-3 in the solid state at room temperature originated from thermally activated delayed fluorescence (TADF). The thiolate ligand with strong electron-donating character (PS-) reduced the contribution from metal orbitals to the highest occupied molecular orbitals of the complexes, decreasing the metal-to-ligand charge-transfer character of the excited states of 1-3. The origin of TADF in 1-3 was attributed to ligand-to-ligand charge-transfer on the basis of molecular orbital calculations. Au(I) complex 3 was unstable in solution because of a rapid ligand exchange reaction, and Ag(I) complex 2 showed limited solubility in organic solvents. Cu(I) complex 1, which exhibited efficient green TADF with a maximum emission wavelength of 521 nm and a quantum yield of 0.52 in the solid state, was used to fabricate TADF-type organic light-emitting diodes via a wet process.

• 出版日期2013