Synthesis and Application of Highly Fluorinated Light-Emitting Polymers for Orthogonal Processing

초록

As with traditional displays, polymeric light-emitting devices (PLEDs) require patterning to tailor emitting polymers into small, multi-layered elements. Solutions of polymers can be dispensed onto the desired area by ink-jet printing, or cast to regions a sacrificial imaging material has defined. Although the latter lithographic methods possess better resolution and higher productivity, these have not been recognized as suitable for PLEDs. There has been concern that organic solvents in photoresist deposition and stripping steps harm the quality of emitting polymers. Recently, we have identified hydrofluoroethers (HFEs) as universal, non-damaging solvents for non-fluorinated polymers.1 By exploiting these solvents and a fluorinated photoresist, we were able to lithographically pattern functional materials down to 5 μm resolution.2 This success prompted us to consider the converse combination of materials, ‘highly fluorinated functional polymers and non-fluorinated conventional photoresists and solvents’. Films of highly fluorinated polymers are stable upon exposure to ordinary organic solvents.3 In this presentation, we report the synthesis and processing of semi-perfluoroalkyl polyfluorenes. Their optical and EL properties are discussed, which are distinctive from their non-fluorinated derivatives. This fluorinated polymer is then successfully patterned with a conventional photoresist and organic solvents.