Nanocomposite provides picture-perfect X-ray capture
by Mohammed Arafat
Friday 17th of December 2021
To get clearer X-ray scans for medical imaging and security screening, international researchers recently introduced a new nanocomposite approach. The approach absorbs X-rays and then reproduces the captured energy capture as light with almost perfect efficiency.
A report by phys.org stated that the new method could contribute to the improvement of high-resolution for the said two purposes and could result in efficiency gains in devices that range from light-emitting diodes or LEDs, as well as X-ray imaging scintillators, all the way to solar cells.
Jian-Xin Wang, one of the researchers, said that high-Performance Scintillators comprise mainly of either ceramic that requires tough and costly preparation conditions or perovskite materials with poor light and air stability and high toxicity.
“Organic scintillator materials have a good processability and stability but low imaging resolution and detection sensitivity because of the low atomic weight. So, there is limited absorption of X-ray of their component atoms.” He added.
Omar Mohammed, another researcher, and his colleagues have improved the X-ray capture of scintillators at his lab. They did so by combining them with the so-called metal-organic framework (MOF), Zr-FCU-BADC-MOF, integrating high atomic weight zirconium within highly ordered structures.
When X-rays captured the MOF layer of the nanocomposite, the excited pairs of negatively charged electrons known as "excitons" and the positively charged holes were produced. These energy carriers transferred from the MOF to the organic TADF chromophore, supported by the extremely short distance between them, and the energy was produced as light.
"Our energy transfer strategy promotes organic X-ray imaging scintillators from an almost-dead research field into one of the most exciting applications for radiology and security screening. It also applies to other light-conversion applications including light-emitting diodes and solar cells." Mohammed said.
On the other hand, Wang emphasised that the direct harnessing of singlet and triplet excitons of the TADF chromophores contributed greatly to its remarkably enhanced radioluminescence intensity and X-ray sensitivity. Efficient energy transfer, which the ultrashort distance between layers, and the direct use of singlet and triplet excited states of the TADF chromophore were key. The material's detection limit was improved even more, reaching more than 140 times lower than a standard X-ray medical imaging dose. Mohammed’s team is planning to further improve the performance of their large-scale X-ray imaging scintillators before they take it to the market.