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We report on the design and the optical properties of a spin-coated multilayer organic microcavity. Tri(stilbene)amine blended with polysulfone as the first layer and an oxadiazole derivative (BPBD) blended with polystyrene as the second layer are sandwiched between two planar mirrors. Enhancement of the luminescence and spectrally narrow emission are observed. By means of time resolved luminescence spectroscopy we show that the spontaneous emission rate is increased in the cavity.

The synthesis of triphenylamine-based oligo(arylenevinylene)s was accomplished by Pdcatalyzed one-pot coupling of styrenes and tris(4-bromophenylamine). These oligo(arylenevinylene)s are characterized by temperature-induced crystallization in bulk but are amorphous in guest-host systems with polysulfone from which high-quality films for optical applications were obtained. The photoluminescence spectra of the oligo(arylenevinylene)s differed significantly in different solvents as well as in different polymer hosts which is of interest for multicolored LEDs.

No abstract

Light‐emitting diodes that emit white light require active materials that are able to emit throughout the entire visible spectrum. A simple approach is reported here, based on hist‐guest systems in which the guest is a single chromophore and the host a polymer blend. It is demonstrated that the emission of the chromophore may depend strongly on the choice of the matrix polymer. The absorption, photoluminescence, and electroluminescence spectra of the chromophore PSA in matrices of polynorbornene, Durel (a polyarylate), polyvinylpyridine, and blends are presented.

Well defined oligo(ary1enevinylene)s were prepared by Pd-catalyzed coupling of dibromoarenes and styrenes. The mixing behavior of these oligo(ary1enevinylene)s with polymers is significantly influenced by the structure of the oligo(ary1enevinylene)s. Potential consequences for optical properties are discussed. Segmented polymers with arylenevinylene segments in the main chain are presented and discussed in detail. Light-emitting thermotropic polymers were obtained with modified distyrylbenzene segments in the main chain. These thermotropic light-emitting polymers show polarized photoluminescence on orientation on rubbed polyimide substrates. Light-emitting amorphous polymers with high fluorophore concentrations and high glass transition temperatures were obtained by polymers with arylenevinylene segments in the side chain.

Transient electroluminescence (EL) from organic bilayer light emitting diodes featuring an interfacial blockade for holes and electrons was studied. At the end of the driving voltage pulse an EL spike is observed whose magnitude exceeds the cw-EL intensity by up to two orders of magnitude. The effect is attributed to an increase of the recombination probability of minority carriers (electrons) with majority carriers upon switching off the external field.

The suitability fo columnar discotics for applications in light emitting diodes (LEDs) has been investigated following the demonstration of their unusually large charge carrier mobilities. Results of X‐ray diffraction, computer simulations, and electroluminescence measurements are presented and discussed for discotic systems such as that shown in the Figure. Their use in LEDs is expected to the advantageous. magnified image