High concentration (5?wt?%) of nanosphere (NS) has been dispersed in the ferroelectric liquid crystal (FLC) to analyze the effect of high dopant concentration in the FLC matrix. The FLC molecules actively interact with the NS. The presence of NS enhances the photoluminescence of the pure FLC material due to the coupling of localized surface plasmon resonance from NS with FLC molecules. The high concentration of NS causes an aggregation in the FLC matrix and creates topological defects. The defects and aggregation cause the change in electro-optical and dielectric properties of the pure FLC material. The bigger size of NS as compared to the smectic layer separation causes the warping in the smectic layer. Semiconducting nature of NS also affects the conductivity of the pure FLC. 1. Introduction The scope of nanotechnology, in the present age, is not only limited within the field of material science but also extended to all the fields of research and application. The fields like electronics, condense matter, and medical sciences are benefited from the application point of view when used with nanoscience [1–3]. The use of nanoscience in fields of liquid crystal has created some interesting and useful properties [4]. Ferroelectric liquid crystals (FLCs) have salient features over the trivial liquid crystals (LCs) because of their tilted smectic phase and the chirality of the molecules [5]. They have proved their applicability of showing faster response time and the instruments based on less threshold voltage [6]. In addition to these properties, they have also shown their potential for the field effect transistors (FETs), spatial light modulators (SLMs), switchable devices, and nonvolatile memory effects [7, 8]. The prospective of tuning the properties of liquid crystals due to the addition of nanomaterial is currently a hot topic in liquid crystal research [9–11]. The composite system of the pure FLC and nanomaterial has already shown its utility in the FLC-based devices with greater efficiency [12]. In the present paper, we report a comprehensive study of the dielectric and electro-optical (E-O) properties of a ferroelectric liquid crystal highly doped with nanospheres (NS). The present work has a motive to analyze the effect of high concentration of the nanomaterial on the FLC matrix and also on the E-O and dielectric parameters. The NS were added in 5%?wt/wt concentration to the pure FLC 16/100. The results show that the doping of NS alters the physical properties of the pure FLC. The investigated results are discussed and explained on the basis of the
References
[1]
L. J. Yu and M. M. Labes, “Fluorescent liquid-crystal display utilizing an electric-field-induced cholesteric-nematic transition,” Applied Physics Letters, vol. 31, no. 11, pp. 719–720, 1977.
[2]
R. C. Y. King and F. Roussel, “Transparent carbon nanotube-based driving electrodes for liquid crystal dispersion display devices,” Applied Physics A, vol. 86, no. 2, pp. 159–163, 2007.
[3]
L. Calucci, G. Ciofani, D. de Marchi et al., “Boron nitride nanotubes as T2-weighted MRI contrast agents,” Journal of Physical Chemistry Letters, vol. 1, no. 17, pp. 2561–2565, 2010.
[4]
D. P. Singh, S. K. Gupta, A. Srivastava, and R. Manohar, “The phenomenon of induced photoluminescence in ferroelectric mesophase,” Journal of Luminescence, vol. 139, pp. 60–63, 2013.
[5]
R. B. Meyer, L. Liebert, L. Strzelecki, and P. Keller, “Ferroelectric liquid crystals,” Journal de Physique Lettres, vol. 36, no. 3, pp. 69–71, 1975.
[6]
T. Joshi, A. Kumar, J. Prakash, and A. M. Biradar, “Low power operation of ferroelectric liquid crystal system dispersed with zinc oxide nanoparticles,” Applied Physics Letters, vol. 96, no. 25, Article ID 253109, 3 pages, 2010.
[7]
R. Martel, V. Derycke, C. Lavoie et al., “Ambipolar electrical transport in semiconducting single-wall carbon nanotubes,” Physical Review Letters, vol. 87, no. 25, Article ID 256805, 4 pages, 2001.
[8]
J. Prakash, A. Choudhary, A. Kumar, D. S. Mehta, and A. M. Biradar, “Nonvolatile memory effect based on gold nanoparticles doped ferroelectric liquid crystal,” Applied Physics Letters, vol. 93, no. 11, Article ID 112904, 3 pages, 2008.
[9]
D. P. Singh, S. K. Gupta, K. K. Pandey, S. P. Yadav, M. C. Varia, and R. Manohar, “Ferroelectric liquid crystal matrix dispersed with Cu doped ZnO nanoparticles,” Journal of Non-Crystalline Solids, vol. 363, pp. 178–186, 2013.
[10]
V. N. Vijayakumar and M. L. N. M. Mohan, “Enhancement of the display parameters of 4′-pentyl-4-cyanobiphenyl due to the dispersion of functionalised gold nano particles,” Journal of Dispersion Science and Technology, vol. 33, no. 1, pp. 111–116, 2012.
[11]
A. Kumar, G. Singh, T. Joshi, G. K. Rao, A. K. Singh, and A. M. Biradar, “Tailoring of electro-optical properties of ferroelectric liquid crystals by doping Pd nanoparticles,” Applied Physics Letters, vol. 100, no. 5, Article ID 054102, 4 pages, 2012.
[12]
A. K. Srivastava, E. P. Pozhidaev, V. G. Chigrinov, and R. Manohar, “Single walled carbon nano-tube, ferroelectric liquid crystal composites: excellent diffractive tool,” Applied Physics Letters, vol. 99, no. 20, Article ID 201106, 3 pages, 2011.
[13]
D. P. Singh, S. P. Yadav, P. K. Tripathi et al., “Concentration dependent physical parameters of ferroelectric liquid crystal and ZnOS nano material composite system,” Soft Materials, vol. 11, no. 3, pp. 305–314, 2013.
[14]
R. Manohar, A. K. Srivastava, P. K. Tripathi, and D. P. Singh, “Dielectric and electro-optical study of ZnO nano rods doped ferroelectric liquid crystals,” Journal of Materials Science, vol. 46, no. 18, pp. 5969–5976, 2011.
[15]
K. Skarp and S. T. Lagerwall, “Rotational viscosities in ferroelectric smectic liquid crystals,” Ferroelectrics, vol. 84, no. 1, pp. 119–142, 1988.
[16]
K. S. Cole and R. H. Cole, “Dispersion and absorption in dielectrics I. Alternating current characteristics,” The Journal of Chemical Physics, vol. 9, no. 4, pp. 341–351, 1941.
[17]
A. Kumar, J. Prakash, D. S. Mehta, A. M. Biradar, and W. Haase, “Enhanced photoluminescence in gold nanoparticles doped ferroelectric liquid crystals,” Applied Physics Letters, vol. 95, no. 2, Article ID 023117, 3 pages, 2009.
[18]
A. Kumar, J. Prakash, A. D. Deshmukh, D. Haranath, P. Silotia, and A. M. Biradar, “Enhancing the photoluminescence of ferroelectric liquid crystal by doping with ZnS quantum dots,” Applied Physics Letters, vol. 100, no. 13, Article ID 134101, 4 pages, 2012.
[19]
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, Article ID 853160, 8 pages, 2012.
[20]
R. Pratibha, W. Park, and I. I. Smalyukh, “Colloidal gold nanosphere dispersions in smectic liquid crystals and thin nanoparticle-decorated smectic films,” Journal of Applied Physics, vol. 107, no. 6, Article ID 063511, 5 pages, 2010.
[21]
F. V. Podgornov, A. V. Ryzhkova, and W. Haase, “Influence of gold nanorods size on electro-optical and dielectric properties of ferroelectric liquid crystals,” Applied Physics Letters, vol. 97, no. 21, Article ID 212903, 3 pages, 2010.
[22]
X. Nie, R. Lu, H. Xianyu, T. X. Wu, and S. Wu, “Anchoring energy and cell gap effects on liquid crystal response time,” Journal of Applied Physics, vol. 101, no. 10, Article ID 103110, 5 pages, 2007.
[23]
S. K. Gupta, D. P. Singh, and R. Manohar, “SWCNT doped ferroelectric liquid crystal: the electro-optical properties with enhanced dipolar contribution,” Current Applied Physics, vol. 13, no. 4, pp. 684–687, 2013.
[24]
T. P. Majumder, M. Mitra, and S. K. Roy, “Dielectric relaxation and rotational viscosity of a ferroelectric liquid crystal mixture,” Physical Review E, vol. 50, no. 6, pp. 4796–4800, 1994.
[25]
H. S. Kitzerow and C. Bahr, Chirality in Liquid Crystals, Springer, Berlin, Germany, 2001.
[26]
Y. P. Panarin, Y. P. Kalmykov, S. T. M. Lughadha, H. Xu, and J. K. Vij, “Dielectric response of surface stabilized ferroelectric liquid crystal cells,” Physical Review E, vol. 50, no. 6, pp. 4763–4772, 1994.
[27]
F. Kremer and A. Schonhals, Broadband Dielectric Spectroscopy, Springer, Berlin, Germany, 2003.