The Role of Rubrene Concentration on Dielectric Parameters of Nematic Liquid Crystal

Authors : Gülsüm KOCAKÜLAH

Pages : 193-199

Doi:10.17350/HJSE19030000307

View : 60 | Download : 45

Publication Date : 2023-09-30

Article Type : Research Paper

Abstract :In this study, the dielectric parameters of E7 coded nematic liquid crystal insert ignore into journalissuearticles values(NLC); composites containing the different amounts of rubrene fluorescent dye were investigated. E7, E7+0.5 wt.% Rubrene, and E7+1.0 wt.% Rubrene samples were prepared. Frequency dependent dielectric constants insert ignore into journalissuearticles values(ɛ′ and ɛ′′);, dielectric anisotropy insert ignore into journalissuearticles values(Δε′);, and ac conductivity insert ignore into journalissuearticles values(σac); graphs of rubrene doped E7 NLC composites were obtained by dielectric spectroscopy method and compared with pure E7 NLC. By using these graphs, relaxation frequency insert ignore into journalissuearticles values(fR);, relaxation time insert ignore into journalissuearticles values(τR);, dielectric strength insert ignore into journalissuearticles values(δɛ′);, and crossover frequency insert ignore into journalissuearticles values(fc); parameters of the E7 NLC and its rubrene doped composites were determined. An increase in fR from 3.045 MHz to 3.697 MHz for 0 V and from 627 kHz to 686 kHz for 40 V was observed with increasing rubrene concentration. On the other hand, a decrease in τR from 0.052 μs to 0.043 μs for 0 V and from 0.254 μs to 0.232 μs for 40 V was seen with increasing rubrene concentration. Furthermore, an increase in fc from 1.145 MHz to 1.298 MHz was obtained with increasing rubrene concentration. The results show that the dielectric parameters change with the concentration of rubrene and it is thought that this study will provide a basis for investigating the dielectric properties of rubrene doped NLC composites. Moreover, it is concluded that the produced composites are a suitable base material for electro-optical device applications such as smart displays, photonics and electrical circuit elements.
Keywords : Dielectric anisotropy, Nematic liquid crystal, Relaxation frequency, Relaxation time, Rubrene