Relationship between structure and electroluminescence of oligo( p-phenylenevinylene)s

• Published in: Optical materials 1998, Vol.9 (1), p.77-81
• Main Authors: Stalmach, Ulf, Detert, Heiner, Meier, Herbert, Gebhardt, Volker, Haarer, Dietrich, Bacher, Andreas, Schmidt, Hans-Werner
• Format: Article
• Language: English
• Subjects: Application fields; Applied sciences; Electrical, magnetic and optical properties; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Optical materials; Optics; Organic polymers; Physicochemistry of polymers; Physics; Polymer industry, paints, wood; Polymers and organics; Properties and characterization; Technology of polymers
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/S0925-3467(97)00108-0

The preparation of LEDs with poly( p-phenylenevinylene) (PPV) as emitting material is well established. However, due to the presence of a distribution of conjugated chain lengths in the polymer, systematic investigations of the electroluminescence with polymeric materials are difficult, as far as the optical emission is concerned. We are studying the relationship between structural variation of substituted oligo( p-phenylenevinylene)s and their electroluminescent behaviour using a series of distyrylbenzenes with a variety of substituents in order to investigate their influence on the electroluminescence (EL). Furthermore, we synthesized a homologous series of monodisperse oligo(2,5-dipropoxy-1,4-phenylenevinylene)s with up to 11 repeating units. This series covers the spectrum from monomer to polymer. The influence on the EL can be investigated by preparing single layer LEDs using vapor deposition or spincoating of the oligomers in a polystyrene (PS) matrix. The comparison of photoluminescence (PL)- and EL-spectra shows that the photophysical properties of the oligomers are strongly altered by aggregation phenomena.