2016-09-14

HKBU and French scholars jointly publish research on energy conversion in "Nature Communications"
A
team of Chemistry scholars from HKBU and their research collaborators
in France jointly announced the outcome of their research project
entitled “Room temperature molecular up conversion in solution”. The
paper which demonstrates that the photon up conversion process in energy
transfer can be achieved through a molecular level at room temperature
was published in leading scientific journal Nature Communications (http://www.nature.com/ncomms/2016/160615/ncomms11978/full/ncomms11978.html).
The HKBU team comprises Associate Professor Dr Gary Wong; Vice President
(Research and Development) and Chair Professor of Chemistry Professor
Rick Wong; and PhD alumnus Dr Chan Chi-fai. Meanwhile, the French
research team is led by Professor Loic J Charbonniere of L’Université de
Strasbourg, France.
This study reveals that fluoride anions added to a D2O solution of a macrocyclic erbium complex (ErL) leads to the formation of a supramolecular [(ErL)2F]+
assembly which is able to convert low energy photons to high energy
photons through a process known as “up conversion”. The structure has
the fluoride anions sandwiched between two complexes and held by
different chemical bonds.
Dr Gary Wong said, “Conventionally, luminescence processes often result
in the emission of photons at a lower energy level than that of the
incident beam, but up conversion process is far less common.”
Professor Rick Wong said, “This breakthrough revealed that there is a
way to excite our supramolecule with a near-infrared light source and
that it gives off green emission at a molecular level.” Near-infrared
light is considered less phototoxic to the human skin and produces green
emission that can be easily detected using microscopes in laboratories.
In the past few decades, the up conversion process has attracted great
scholarly interest. However, it can only be observed at low temperatures
or high complex concentration or by high power excitation. The erbium
complex dimer in the study revealed that the short metal-to-metal
distance is a crucial parameter for the up conversion process to occur
without harsh experimental conditions mentioned above. However, such a
short distance is attributed to various chemical bonds like
erbium-to-fluoride bond, hydrogen bonds and aromatic interaction.
Dr Wong added that future developments on the structure and compositions
of such complexes could lead to similar observations in non-deuterated
water, hence marking the beginning of luminescence tagging in numerous
bio-analytical applications.
from HKBU eNews
https://bunews.hkbu.edu.hk/news/knowledge/hkbu-and-french-scholars-jointly-publish-research-on-energy-conversion-in-nature-communications