Analyzing Light-Induced Motion in Crystals
Panče Naumov and his team of researchers at NYU Abu Dhabi discover the "photosalient effect" where certain materials, when excited by strong continuous-wave ultraviolet light, travel 100-100,000 times their own length.

Analyzing Light-Induced Motion in Crystals

Several years ago, Panče Naumov and a team of researchers observed a startling effect: certain microscopic crystals, when heated, leapt distances of up to a meter — the microscopic equivalent of a human jumping nearly two kilometers.

Termed the "thermosalient effect" by the researchers, the phenomenon occurs as a crystal's structure is rearranged under moderately high heat. The accompanying mechanical effect — the hop — was unusual for such materials.

Last year at NYU Abu Dhabi, Naumov's team discovered that certain materials, when excited by strong continuous-wave ultraviolet light, traveled 100-100,000 times their own length. The effect was analogous to the heat-induced thermosalient effect, so the researchers called it the "photosalient effect".

Photoactuated motion, which is induced by application of light to physical object, tends to be less efficient than biomechanical motion, like that of plant and animal tissues. But crystals that undergo the photosalient effect may be able to mimic the motility of biological systems and provide a new means of transforming energy into motion. "The importance of the discovery of the thermosalient and photosalient effects extends beyond the mere fascination with the crystals moving or popping. It represents a new platform for a very fundamental process: the conversion of heat or light into mechanical work," said Naumov, who is associate professor of chemistry at NYUAD.

"This property provides extremely rapid energy transport which could be utilized … for efficient harvesting of solar or thermal energy, for design of artificial muscles in robotics, in medicine, in the printing industry, in microfluidics for diagnostic purposes, and in other applications which require controlled motion of dynamic technical elements," Naumov explained.

News of the photosalient effect, first published in the journal Angewandte Chemie, garnered widespread attention among solid-state chemists. The discovery received coverage in other scholarly journals, as well as in popular publications, such as New Scientist.

Naumov's work on the photosalient effect has also led to him being awarded the 2013 Asian and Oceanian Photochemistry Association (APA) Prize for Young Scientist, which honors chemists under 40 years of age who have made original and impactful contributions to photochemistry, which is the study of reactions initiated by the absorption of light.

"As a very prestigious award in the photochemistry field, the APA Prize for Young Scientist 2013 is not only an important achievement for our group at NYUAD, but it is also an acknowledgment of the efforts of the local government to foster the academic research and to internationalize the research community in the UAE and in the Middle East," Naumov said.