Spectral and orientational properties of new group of naphthalene derivatives of bicarboxylic acid in liquid crystal 7CB

Abstract

The spectral and orientational properties of some dichroic fluorescent dyes (naphthalene derivatives of bicarboxylic acid) in some isotropic solvents and in an anisotropic matrix have been studied. The order parameter of the dyes in the nematogenic liquid crystal 7CB has been determined from measurements of polarized electronic absorption and fluorescence. The influence of the dye addition on the nematic-isotropic phase transition temperature of 7CB has been investigated. It was found that some of the dyes studied could be successfully utilized in guest-host liquid crystal display devices.

Characterization of Pure and Mixed Langmuir and Langmuir-Blodgett Films of Some Fluorescent Naphthalimide Dyes

“…Because the molar extinction coefficient of 1 -6 is quite large over 10,000 [22,23], in the LB films one can expect the dipole-dipole interaction leading to the exciton coupling. On the basis of the molecular exciton model [30,31], it is known that the interaction between transition dipoles results in the splitting of the energy level of the excited state into two levels with higher and lower energy relative to the undisturbed excited state (Davydov splitting).…”

“…First of all these compounds were prepared for colouration of polyester fabrics [22]. In our recent paper [23] we found, however, that derivatives of 4-aminonaphthalimide orient well in a liquid crystal matrix and do not destabilize the mesophase region of the liquid crystalline host. Therefore, they are very attractive for an application in passive and active guest/host liquid crystal displays [24].…”

Spectral properties of naphthalimide dyes mixed with 4-heptyl-4′-cyanobiphenyl (7CB) in Langmuir-Blodgett films

“…The derivatives of 4−aminonaphthalimide are known as organic dyes with very high quantum fluorescence yield and good orientation in 7CB [8]. The aim of our study was to determine spectral properties of the dyes and the intermolecular interactions in ultrathin ordered films deposited on the solid substrate.…”