A unique characteristic of a crystal has been discovered by a group of
scientists from Osaka University in Japan. The solid organic substance
changes into a liquid when it is subjected to the soothing glow of
ultraviolet (UV) radiation.
Additionally, when this crystal melts, it experiences a fascinating series
of variations in its luminescence that indicate modifications to the
crystal's molecular structure.
It's not the first chemical to be found to go through the so-called
photo-induced crystal-to-liquid transition (PCLT), however it is rare. But
by utilizing light to examine the transition, researchers may be able to
better comprehend it, which might lead to a variety of possible applications
in photonics, electronics, and medicine administration.
According
to scientist Mao Komura, this is the first organic crystal that we are aware
of that displays a luminous evolution during crystal melting, demonstrating
variations in intensity and hue, from green to yellow.
The substance is a heteroaromatic diketone, a kind of organic chemical that
the scientists named "SO" because of the sulfur and oxygen found in its two
rings.
The SO crystal compound emits a weak green glow when first exposed to UV
light. But as the exposure goes on, it glows yellow and starts to dissolve.
It is obvious that heating isn't what caused the transition based on careful
observations of how sharp the border was between the two states.
The scientists discovered that diketone SO was actually changing from one
chemical shape (skew) to another (planar) using theoretical calculations, a
number of
study
approaches (including X-ray analysis and thermodynamic property analysis),
as well as data from prior studies.
Other comparable crystal compounds that either didn't melt or did melt but
didn't change color provided more information. That provides information to
the researchers on the chemical alterations that take place as these
crystals transform from solid to liquid.
Chemist Yosuke Tani from Osaka University explains, "We discovered that the
changes in luminescence arise from sequential processes of crystal loosening
and conformational changes prior to melting."
Working backwards, it demonstrates that these materials' unique molecular
configuration is what causes them to melt and change phases when exposed to
specific wavelengths of light.
And since it is non-invasive, ecologically safe, and very easy to
accomplish, being able to manipulate materials with light might be highly
valuable. A reversible adhesive that may be altered by exposure to light is
one such use that the researchers offer.
The manner the diketone SO altered color was crucial to the advancements
described in this work because it provided the researchers with crucial
information about what was happening at the tiniest scales inside the
crystal complex.
According to Tani, "These visual representations of the PCLT process steps
allowed us to advance the current understanding of crystal melting at the
molecular level."
The research has been published in
Chemical Science.
