Dielectric and Performance Analysis of CdTe Quantum Dots Doped Nematic Liquid Crystal
Abstract
In this work, cadmium telluride core type quantum dots (CdTe QDs) were dispersed in 4-pentyl-4′-cyanobiphenyl (5CB) nematic liquid crystal (LC) with a concentration of 0.05 % wt/wt; and their electrical and dielectric properties were investigated by using admittance measurements in the frequency range of 100 Hz - 10 MHz. In order to determine the effects of CdTe QDs in 5CB nematic LC, dielectric anisotropy (∆ε), crossover frequency (fcrossover), critical frequency (fcritical), real and imaginary parts of permittivity (ε' and ε") of neat LC and CdTe QDs dispersed LC composites were obtained using the experimental data. Moreover, threshold voltage (Vth), splay elastic constant (K11) were also calculated. It was found that Vth and K11 of QDs dispersed LC are significantly decreased due to the existence of CdTe QDs.
Keywords
Nematic liquid crystal, quantum dot, electrical and dielectric properties
References
- [1] U. B. Singh, R. Dhar, A. S. Pandey, S. Kumar, R. Dabrowski, and M. B. Pandey, “Electro-optical and dielectric properties of CdSe quantum dots and 6CHBT liquid crystals composites, ” AIP Advances, vol. 4, no. 11, pp. 117112-1 - 117112-9, 2014.
- [2] P. Malik, A. Chaudhary, R. Mehra, and K. K. Raina, “Electrooptic and dielectric studies in cadmium sulphide nanorods/ferroelectric liquid crystal mixtures,” Advances in Condensed Matter Physics, vol. 2012, pp. 1-8, 2012.
- [3] E. A. Konshina, E. O. Gavrish, A. O. Orlova, and M. V. Artem’ev, “Effect of dispersed CdSe/ZnS quantum dots on optical and electrical characteristics of nematic liquid crystal cells,” Tecnical Physics Letters, vol. 37, no. 11, pp. 1011-1014, 2011.
- [4] M. Yıldırım, A. Allı, G. Önsal, N. Gök, and O. Köysal, “Synthesis & chemical and dielectric characterization of poly (linoleic acid)-g-poly (dimethylaminoethyl methacrylate): A novel high-κ graft copolymer,” Composites: Part B, vol. 117, pp. 43-48, 2017
- [5] M. Gökçen and O. Köysal, “Effect of frequency on dielectric properties of liquid crystal doped with side-chain liquid crystalline polymer,” Materials Chemistry and Physics, vol. 129, pp. 1142-1145, 2011.
- [6] M. Yıldırım, O. Köysal, G. Önsal, and E. Gümüş,“Effect of iron phthalocyanine (FePc) concentration on electrical and dielectric properties of the nematic liquid crystal composites,” Journal of Molecular Liquids, vol. 223, pp. 868-872, 2016.
- [7] R. Basu and G. S. Iannacchione, “Evidence for directed self-assembly of quantum dots in a nematic liquid crystal,” Physical Review E, vol. 80, pp. 010701(R)-1 – 010701(R)-4, 2009.
- [8] O. Köysal, “Conductivity and dielectric properties of cholesteric liquid crystal doped with single wall carbon nanotube,” Synthetic Metals, vol. 160, 1097-1100, 2010.
- [9] J. Mirzaei, M. Reznikov, and T. Hegmann, “Quantum dots as liquid crystal dopants,” Journal of Materials Chemistry, vol. 22, pp. 22350-22365, 2012.
- [10] R. K. Shukla, Y. G. Galyametdinov, R. R. Shamilov, and W. Haase, “Effect of CdSe quantum dots doping on the switching time, localised electric field and dielectric parameters of ferroelectric liquid crystal,” Liquid Crystals, vol. 41, no. 12, pp. 1889-1896, 2014.