Photo-induced microstructured polymers for the optimisation and control of organic devices emission properties

Patterning and microstructuring of functional polymers is a key process in order to control the emission properties of polymer thin films towards the design and realisation of devices such as electroluminescent diodes (OLEDs) or organic lasers. We present an original method for the realisation of periodic structures in the visible wavelength region using laser controlled molecular motion. The optical pumping of an azo-dye aromatic polymer film was indeed shown to allow efficient mass-transport in conjunction with the interference pattern. We have implemented a compact organic laser using transversal one photon pumping of a sinusoidaly modulated surface of such periodically structured films upcovered with a luminescent dye. Efficient laser emission was observed over the whole emission spectrum of the luminescent dye following control of the surface relief grating periodicity. Patterning of gratings with periodicities going down to 200 nm has been recently achieved. Interestingly, surface relief gratings also appear to be a good way to optimise OLED emission properties.