Vanderbilt researchers upgrade LCD

LCDs are set to get a facelift as scientists at Vanderbilt University discover a new class of liquid crystals claimed to have “unique properties”. The research team says the crystals, which boast an “unprecedented electric dipole”, have the power to improve the performance of digital displays. The achievement was published last month in the Journal of Materials Chemistry.

Professor of Chemistry, Piotr Kaszynski and graduate student, Bryan Ringstrand, claim the results, which represent five years of research, could transform any type for LCD; from digital watches to flat panel televisions.

“We have created liquid crystals with an unprecedented electric dipole, more than twice that of existing liquid crystals,” says Kaszynski.

Electric dipoles are created in molecules by the separation of positive and negative charges. The stronger the charges and the greater the distance between them, the larger the electric dipole they produce.

In liquid crystals, the electric dipole is associated with the threshold voltage: the minimum voltage at which the liquid crystal operates. Higher dipoles allow lower threshold voltages. In addition, the dipole is a key factor in how fast liquid crystals can switch between bright and dark states. At a given voltage, liquid crystals with higher dipoles switch faster than those with lower dipoles.

The research team says the new liquid crystals are set apart by their zwitterionic" structure. Zwitterions are chemical compounds that have a total net electrical charge of zero but contain positively and negatively charged groups. The newly developed liquid crystals contain a zwitterion made up of negatively charged inorganic portion and a positively charged organic portion.

Vanderbilt has applied for a patent on the new class of materials and claims that some of the companies that manufacture liquid crystals for commercial applications have expressed interest and are currently evaluating it.

However, Kaszynski warns that we’re not likely to see the technology in displays quite yet. “Our liquid crystals have basic properties that make them suitable for practical applications, but they must be tested for durability, lifetime and similar characteristics before they can be used in commercial products,” he says.

If it passes commercial testing, the new class of liquid crystals will be added to the complex molecular mixtures that are used in liquid crystal displays.

The research was funded by a grant from the National Science Foundation.