Switching of Vertical Alignment Liquid Crystal Cell Doped with Carbon Nanotubes

Abstract

This paper reports the fabrication and evaluation of light-emitting diodes using polyfluorene derivatives as emitter, which cover the entire visible spectral range. Depending on the composition of the copolymers, red (emission peak at 656 nm), green (488 nm) and blue (428 nm) emission was obtained without any excimer formation. The optimization of the device performances has been realized using a multilayered configuration which involves a spin-coated poly(ethylenedioxythiophene) doped with poly(styrene sulfonic acid) (PEDT-PSS) thin film on the ITO anode and an ultrathin lithium fluoride layer next to the Al cathode. These two layers improve the efficiency of the charge injection. Combining this device configuration with some additional charge-transporting molecules, luminances in the range of 50-300 cd m −2 have been obtained.

Liquid crystallinity of carbon nanotubes

“…Secondly, the response time will be improved for reasons as follows: the suppression of the eld screening effect, the increase in the dielectric anisotropy, the increase of the elastic constant as well as the decrease in the viscosity. 35,45,[97][98][99][100][101] For example, a faster response time can be achieved in a patterned vertical aligned (PVA) LC cell due to the increased bend elastic constant, 35 and in an in-plane switching LC cell, a faster response time can also be achieved due to the increased twist elastic constant. 45 Thirdly, the insertion of CNTs into LCs may also enhance or maintain the transparency of LC cells that is a useful indicator for display quality.…”

Scientific duo of carbon nanotubes and nematic liquid crystals

“…This outcome is assigned to the possible decline in rotational viscosity of the nematic host due to the addition of CNTs [13,64,66]. Moreover, under the CNT doping condition and the step-voltage driving scheme, the response time of a vertical alignment (VA) LC cell has been reported to reduce to 50% of that of the pristine cell under the conventional driving scheme [67].…”

Nanocomposites of a nematic liquid crystal doped with magic-sized CdSe quantum dots

“…1 K 11 ¼ (V th /p) 2 3 0 |D3|, (1) where 3 0 is the permittivity of free space. Doping LCs with colloidal particles such as aerosols, 2-5 or more recently with nanoscale materials such as carbon nanotubes [6][7][8][9][10][11] or quasi-spherical nanoparticles (NPs) is an active interdisciplinary research topic attracting interest from both academia and industry since such suspensions exhibit striking properties not observed for pure LCs or LC mixtures. For example, changing the optical behaviour by imposing discrete alignment modes different from the corresponding non-doped LC, generating rheological changes due to topological defects, improving response times, and lowering of V th values have all been reported for N-LCs doped with metal-based, ferroelectric, dielectric or semiconductor NPs, among others.…”