R. Dhar, S. Kumar, R. Dabrowski
University of Allahabad, IN
discotic-nano composties, electrical conductivity, display and photo-voltaic applications
Electrical parameters of the nano particle and carbon nano tube dispersed room temperature liquid crystalline materials 5CB and 6CHBT have been determined. Due to the dispersion, nematic to isotropic transition temperatures are highly affected. Threshold voltage required to switch molecules from planar orientation (bright state) to homeotropic (dark state) orientation is decreased. Dielectric parameters viz. longitudinal component of the dielectric permittivity and hence dielectric anisotropy are also affected in such a way that it improves display properties. Relaxation frequency corresponding to flip-flop motion of the molecules about their short axes is generally increased due to the presence of nano entities. Doping of functionalized nano particles have drastically enhanced conductivities through the columns of the discotic liquid crystals which are useful in several applications including one dimensional conductor. This includes application of discotic-nano composites in flexible photovoltaic areas as well. Our results shows appreciable enhancement in the efficiency due to the doping of the metallic and semi conducting nano-particles. We have also determined effect of nano-particles on the dielectric permittivity and loss along and normal to the columns in the frequency range of sub Hz to MHz. Detailed results will be discussed during the talk.