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Aromatic polyethers with oxadiazole units – synthesis and application in organic light emitting diodes
Author(s) -
Brütting Rita,
Pösch Peter,
Strohriegl Peter,
Buchwald Elke,
Brütting Wolfgang,
Schwoerer Markus
Publication year - 1997
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1997.021980907
Subject(s) - oxadiazole , glass transition , polymer chemistry , thermal stability , chemistry , bathochromic shift , solvent , nucleophilic aromatic substitution , oled , nucleophilic substitution , polymer , fluorescence , materials science , organic chemistry , layer (electronics) , physics , quantum mechanics
Detailed synthetic aspects of new aromatic polyethers containing oxadiazole units are described. They are obtained by the nucleophilic displacement reaction of 2,2‐bis(4‐hydroxyphenyl)hexafluoropropane with 2,5‐bis(4‐fluorophenyl)‐1,3,4‐oxadiazole and 2,5‐bis(4‐fluoronaphthyl)‐1,3,4‐oxadiazole. The purity of the polyethers strongly depends on the reaction solvent. Best results were achieved with Ph 2 SO 2 as compared to N ‐methyl‐2‐pyrrolidone (NMP) and 1,3‐dimethyltetrahydro‐2(1H)‐pyrimidinone (DMPU) in the temperature range from 190–200°C. All polyethers are fully soluble in common organic solvents and excellent films are obtained by spin‐coating. High molecular weight polyethers without oligomers were only achieved, when Ph 2 SO 2 was used as solvent. All polyethers are characterized by high thermal stability and high glass transition temperatures. The substitution of bisphenyloxadiazole by bisnaphthyloxadiazole units in the polyethers leads to a bathochromic shift of the absorption from 299 nm to 345 nm. Polyethers with bisnaphthyloxadiazole units show a blue fluorescence with a maximum at 427 nm. The application of these novel polyethers as efficient electron transport and injection layer in bilayer light emitting diodes based on poly(1,4‐phenylenevinylene) is shown. The best results were obtained with oxadiazole polyethers containing bisnaphthyloxadiazole units.