Molecular alignment effects on spectroscopic properties 2,1,3-benzothiadiazole guested in liquid–crystalline compounds

• Published in: Chemical physics letters 2010-03, Vol.487 (4), p.263-267
• Main Authors: Alliprandini-Filho, P., Borges, G.F., Calixto, W.B., Bechtold, I.H., Vieira, A.A., Cristiano, R., Gallardo, H., Silva, R.A., Neto, N.M. Barbosa, Marletta, Alexandre
• Format: Article
• Language: English
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2010.01.031

This work concerns about the polarized emission by a new compound based on 2,1,3-benzothiadiazole guested in liquid crystals structures. Besides, we show that the ellipsometry technique is a useful tool to investigate phase transitions in fluorescent systems. This Letter reports about the molecular alignment effects on absorbance and emission properties of a new compound based on 2,1,3-benzothiadiazole guested in liquid crystals. The molecular ordering is available for different chromophore concentrations. Despite of the increasing in molecular disorder above the concentration of 0.20%, samples always present a high degree of linear polarization in fluorescence. A considerable amount of polarized emission is observed during the isotropic phase ( T > 58 °C), which is attributed to emission of light by aligned molecules before loosing the coherence among them. Finally, we demonstrate the feasibility of ellipsometry technique to investigate phase transitions in fluorescent systems.