RESUMO
The synthesis, photophysical properties and application as emitters in solution-processed multi-layer organic light-emitting diodes (OLEDs) of a series of blue-green to red light-emitting phosphorescent platinum(II) complexes are reported. These complexes consist of phenylisoquinoline, substituted phenylpyridines or tetrahydroquinolines as C^N cyclometalating ligands and dipivaloylmethane as an ancillary ligand. Depending on both the structure of the C^N cyclometalating ligands and the dopant concentration in the matrix, these platinum(II) complexes exhibit different aggregation tendencies. This property affects the photoluminescence spectra of the investigated compounds and colour-stability of the fabricated OLEDs. Using the blue-green to yellow-green emitting complexes, the best results were obtained with the 2-(4-trifluoromethylphenyl)-5,6,7,8-tetrahydroquinoline based platinum(II) complex. A maximum luminous efficiency of 4.88 cd A(-1) and a power efficiency of 4.65 lm W(-1), respectively, were achieved. Employing the red emitting phenylisoquinoline based complex as an emitter, colour-stable and efficient (4.71 cd A(-1), 5.12 lm W(-1)) devices were obtained.
Assuntos
Luz , Compostos Orgânicos/química , Compostos Organoplatínicos/química , Estrutura Molecular , Compostos Organoplatínicos/síntese química , Processos FotoquímicosRESUMO
Two swivel cruciform oligothiophenes are investigated for the occurrence of oxidative ring closure reactions. Surprisingly, instead of intramolecular cyclizations, a regioselective side chain oxidation of two of the four alpha-methylene groups next to the terminal thiophene rings is detected for one of the oligomers. Such side chain oxidations may be one unintended degradation pathway in oligothiophene-based organic semiconductors used as the active layer of organic field effect transistors (OFETs), organic light emitting diodes (OLEDs), and organic solar cells (OSCs).
RESUMO
The bicyclic oxetanes and resulting from photocycloaddition of aromatic aldehydes to 2,3-dihydrofuran, were efficiently cleaved by means of electron-transfer reduction, photoinduced by the electronically excited reductants 1-methoxynaphthalene (MN) and 2,7-dimethoxynaphthalene (DMN) in acetonitrile. The fluorescence quenching rates of DMN/MN by and were determined by static methods, the triplet quenching rates were determined by means of laser flash photolysis (LFP). The product analysis established a "photo-photo metathesis" where both cycloaddition and cycloreversion processes are induced by photochemical processes.
Assuntos
Aldeídos/química , Alcenos/síntese química , Alcenos/efeitos da radiação , Éteres Cíclicos/síntese química , Éteres Cíclicos/efeitos da radiação , Furanos/química , Aldeídos/efeitos da radiação , Alcenos/química , Ciclização , Transporte de Elétrons/efeitos da radiação , Éteres Cíclicos/química , Furanos/efeitos da radiação , Estrutura Molecular , Oxirredução , Fotoquímica , Estereoisomerismo , Termodinâmica , Raios UltravioletaRESUMO
A pentathiophene-based swivel cruciform, which allows rotation between the cruciform arms, was synthesized. Homogeneous microcrystalline films were processed from solution, and field-effect transistors utilizing this dimer gave hole mobilities up to 0.012 cm2/V.s.