Organic light-emitting diodes (OLEDs) show promise for applications as high-quality self-emissive displays for portable devices such as cellular phones and personal organizers. Although monochrome operation is sufficient for some applications, the extension to multi-colour devices--such as RGB (red, green, blue) matrix displays--could greatly enhance their technological impact. Multi-colour OLEDs have been successfully fabricated by vacuum deposition of small electroluminescent molecules, but solution processing of larger molecules (electroluminescent polymers) would result in a cheaper and simpler manufacturing process. However, it has proved difficult to combine the solution processing approach with the high-resolution patterning techniques required to produce a pixelated display. Recent attempts have focused on the modification of standard printing techniques, such as screen printing and ink jetting, but those still have technical drawbacks. Here we report a class of electroluminescent polymers that can be patterned in a way similar to standard photoresist materials--soluble polymers with oxetane sidegroups that can be crosslinked photochemically to produce insoluble polymer networks in desired areas. The resolution of the process is sufficient to fabricate pixelated matrix displays. Consecutive deposition of polymers that are luminescent in each of the three RGB colours yielded a device with efficiencies comparable to state-of-the-art OLEDs and even slightly reduced onset voltages.

The synthesis and characterization of side-chain polymers functionalized with holetransporting units and photo-cross-linkable groups, which can be used for solution-based preparation of multilayer organic light-emitting devices (OLEDs), are discussed. The concept deals with triarylamine and oxetane-functionalized styrenes, which are copolymerized by radical polymerization. Four different types of hole-transporting monomers were combined with one cross-linkable monomer in two different ratios, yielding two groups of each four polymers (P1A...P4A and P1B...P4B). The polymers were investigated by NMR spectroscopy, molecular weights were determined by GPC with light scattering, and the thermal properties were measured with differential scanning calorimetry (DSC). Optical characterization by UV-vis and fluorescence spectroscopy was performed. Electrochemical and crosslinking characteristics of the copolymers were investigated to proove this strategy's potential in application for modern multilayer polymer OLEDs. Finally, hole-only devices were prepared for evaluation of the semiconductive performance of the materials.

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We demonstrate the synthesis and use of a new class of EL polymers, which can be applied similar to a standard photoresist. Soluble poly‐spiros with oxetane sidegroups were crosslinked photochemically to yield insoluble polymer networks in the desired areas with μm resolution. Consecutive deposition of the three colors yielded an RGB device with efficiencies and lifetimes comparable to state‐of‐the‐art EL polymers.