Oligofluorene blue emitters for cholesteric liquid crystal lasers

We present the synthesis and characterization of an oligofluorene series whose chemical structure has been tuned to have amorphous nature, compatibility with liquid crystalline matrices and intrinsic chirality. Oligofluorenes are good blue emitters and the emission quantum yield is around 0.8 in the violet-blue range. The prepared materials are suitable for mirror-less laser applications based on a dye-doped liquid crystal resonator. We propose to use fluorene-based compounds to combine two necessary properties to achieve laser emission from cholesteric liquid crystal mixtures: chirality and luminescence. A good intensity emission and a fine tuning of the laser emission are demonstrated.The UZ acknowledges financial support from MECFEDER Spanish projects under the project MAT2008-06522-C02-01 and HI2005-0258 (Spain-Italy cooperation program), from the Departamento de Ciencia, Tecnología y Universidad of the Government of Aragón and FEDER founding. J. del Barrio acknowledges his grant from Government of Aragón. This work was partially supported from the MIUR (Azioni Integrate Italia–Spagna, 2005) project: “Wide range tunable UV–vis cholesteric liquid crystal micro-laser”.Peer Reviewe