Smarter liquid-crystal display
doi:10.1038/nindia.2011.123 Published online 23 August 2011
Researchers have used alumina nanoparticles to trap ionic impurities in ferroelectric liquid crystal (FLC)-based displays, which may help improve display resolutions.
FLCs have good optical contrast, low turn-on voltage, memory effect and fast response. Nanomaterials such as carbon nanotubes, zinc oxide nanoparticles and gold nanoparticles have been used to improve the optical properties of FLCs. However, there is no technique to remove ionic impurities, which degrade the quality of FLC-based display devices.
To suppress the effects of ionic impurities, the researchers mixed varying concentrations of alumina nanoparticles (AL-NPs) with FLCs and studied their efficacy to adsorb impure ions. They found that AL-NPs with diameters in the range of 20–30 nm were suitable for effectively suppressing the ionic impurities of the FLC material.
To confirm the role of nanoparticles in the suppression of ionic impurities, the researchers studied the electrical resistance of both pure and AL-NP-doped FLC material. AL-NP-doped FLC material exhibited higher resistivity than the undoped material, which implies the presence of AL-NPs reduced the number of ionic impurities.
Repeated experiments showed no increase in the number of ionic impurities present, thus proving that impure ions can be efficiently trapped by AL-NPs for long durations.
"FLC materials free from ionic impurities have higher resolution and better contrast," says lead researcher A. M. Biradar.
The authors of this work are from: National Physical Laboratory, Council of Scientific and Industrial Research, New Delhi, and Department of Physics, Banaras Hindu University, Varanasi, India.
- Joshi, T. et al. Alumina nanoparticles find an application to reduce the ionic effects of ferroelectric liquid crystal. J. Phys. Appl. Phys. 44, 315404 (2011)