by Brooks Hays
Shanghai (UPI) Oct 11, 2016
A team of researchers from China's Shanghai Jiao Tong University recently developed a new class of anti-reflective materials using nanostructures derived from titanium dioxide. The scientists cited cicada wings as their inspiration.
Cicada wings are marked by periodic conical structures, which researchers call "nano-nipples." Scientists were able to texture materials with tiny titanium dioxide structures that mimic the miniature dots. The added texture diminished the materials' reflectivity.
The tiny dots deflect light from a variety of angles into the space between each structure. The light becomes permanently trapped.
"The multiple reflective and scattering effects of the antireflective structures prevented the incident light from returning to the outside atmosphere," lead researcher Wang Zhang explained in a news release.
Researchers say the biomorphic titanium dioxide structures are relatively easy and cheap to produce.
"[They] show great potential for photovoltaic devices such as solar cells," Zhang added. "We expect our work to inspire and motivate engineers to develop antireflective surfaces with unique structures for various practical applications."
The nanostructures found on cicada wings have previously inspired novel antimicrobial materials.
The latest research was published in the journal Applied Physics Letters.
Study shows how hot molecules are cooled by liquid
Using laser pulses, scientists at the University of Bristol were able to image the ultra-fast movement of energy away from a hot molecule dropped into a vat of water.
"In our experiments, small dissolved molecules were given a very large amount of energy using a short burst of ultraviolet light," Andrew Orr-Ewing, a professor of chemistry at Bristol, said in a news release. "The energized molecules initially spin very fast and move with high speeds, but rapidly encounter molecules of the surrounding solvent."
The collisions between the cold and hot molecules are extremely fast, lasting less than a trillionth of a second -- too fast for most imaging technologies.
As the laser pulses revealed, the energy of the excited molecules dissipates as they continue to collide with their cooler neighbors. Researchers liken the process to a top spun across a table littered with obstacles.
"They ricochet off the solvent molecules and transfer energy in the process, so that they spin more and more slowly until they run out of excess energy," Orr-Ewing said.
Scientists detailed their investigation of the cooling process in the journal Nature Chemistry.
Space Technology News - Applications and Research
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