OLED thin film fabrication from poorly soluble terbium o-phenoxybenzoate through soluble mixed-ligand complexes

•Mixed-ligand complex Tb(pobz)3(monoglyme)(H2O)2 was used as precursor for thin films of Tb(pobz)3 with quantum yield of 96%.•Deposited thin films with roughness down to 2.3 nm and transparency up to 95% were successfully tested in OLED devices.•Mixed layer composition was thoroughly examined with an emphasis on luminescence and EXAFS spectroscopy.

Features and advantages of the approach of the luminescent thin film deposition of non-volatile and non-soluble lanthanide aromatic carboxylates were exemplified by thin film deposition of terbium o-phenoxybenzoate Tb(pobz)3(H2O)2 (I) with quantum yield measured to be 96%. This approach is based on the formation and decomposition of mixed-ligand complexes, and thus mixed-ligand complex Tb(pobz)3(MG)(H2O)2 (II) (MG – monoglyme) was synthesized, characterized and used as a precursor for I thin films. Electroluminescent (EL) properties of high quality thin films of I and those with suitable host material were studied in a series of OLED devices.

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