Chiral luminescent compounds as a perspective for cholesteric liquid crystal lasers

• Published in: Optical materials Vol. 31; no. 11; pp. 1693 - 1696
• Main Authors: Petriashvili, Gia, Chilaya, Guram, Matranga, Mario Ariosto, Santo, Maria Penelope De, Cozza, Gaetano, Barberi, Riccardo, Barrio, Jesus del, Chinelatto, Luiz Silvino, Oriol, Luis, Piñol, Milagros
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 01.09.2009; Elsevier
• Subjects: Cholesteric liquid crystals; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Liquid crystals; Luminescent materials; Optical materials; Optics; Photonic band gap materials; Photonic bandgap materials; Physics; Cholesteric liquid crystals; 42.70.−a; Photonic band gap materials; Luminescent materials; 42.70.Df; 42.70.Qs; Fluorene; Photonic band gap; Photonic crystals; Luminescence; Photoluminescence; 42.70.-a; Chiral compound; Quantum yield; Liquid crystals; Oligomers; Cavity resonators; Cholesteric crystals; Mirrors
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2009.04.010

We present the synthesis and characterization of fluorene based materials for mirror less laser applications. Mirror less lasing is obtained from a cholesteric liquid crystals mixture, that acts as a resonator, doped with a photoluminescent dye, that acts as an active medium. We propose to use fluorene based compounds to combine two necessary properties to achieve laser emission: chirality and luminescence. Two different compounds, a trimer and an oligomer are synthesized. The trimer and the oligomer are both prepared with chiral moieties and, in addition, they are liquid crystalline compatible. More, oligofluorenes are good blue emitters and the emission quantum yield is around 0.8 in the violet–blue range. These fluorene based compounds are used in cholesteric liquid crystals mixtures as luminescent chiral dopants and a fine tuning of the laser emission is obtained. The dependence of lasing efficiency on concentration and the handedness of chiral luminescent dopants are investigated.