Organic light-emitting diodes (OLEDs) could become the leading technology for fabrication of next generation displays and solid state lightening in the near future. To meet this goal, cheap and easy methods of OLEDs fabrication have to be developed. Modern OLEDs are generally prepared by multiple layer deposition. Vacuum deposition is the most common method of building such multilayer structure but it is costly and limited to vaporizable low molecular weight materials. By contrast, solution-processing technologies are much easier, less costly, and suitable for flexible display applications. A potential disadvantage of such techniques for fabricating multilayer devices is that preexisting layers could be partially dissolved by the solvent used in one of the following deposition steps. To overcome this problem, the cross-linking concept can be applied.
This thesis pursues investigation on diazirine-functionalized semiconductor materials, which can be transformed to insoluble layers by photo- or themo-cross-linking. In particular, it focuses on its synthesis, optical and electrochemical characterization, polymerization, and first application in an OLED device. α-NPD, a commonly used hole-transport material, triphenylamine, diphenyl ether, bromo- and iodo-benzene were functionalized with diazirine groups within this work. Diazirine compounds undergo decomposition reaction (irreversible nitrogen loss) upon UV irradiation or pyrolysis forming highly reactive carbenes, which display high propensity for intermolecular bond insertions to form a polymer. Since the cross-linking is induced by UV light, the organic films become, not only insoluble, but can simultaneously be patterned as a negative photoresist using standard photolithography techniques. Photo patterning capability of diazirine-functionalized compounds may be advantageous for future OLEDs applications.