The structural characteristics of biological specimens, such as wet proteins and living cells, can be conveniently probed in their host aqueous media using soft X-rays. Conventional X-ray detectors in this area have low spatial resolution, limited sensitivity, and require complex fabrication procedures. Many of these limitations are overcome by introducing a direct soft X-ray detector based on nanosheets of tin monosulfide (SnS).
Tin monosulfide nanosheets possess high photon absorption coefficients, allowing them to be used in making ultrathin soft X-ray detectors with high sensitivity and a rapid response time. Image credit: Shabbir et al., doi: 10.1002/adfm.202105038.
“The SnS nanosheets respond very quickly, within milliseconds,” said co-lead author Professor Jacek Jasieniak, a researcher in the Department of Materials Science and Engineering and the ARC Centre of Excellence in Exciton Science at Monash University.
“You can scan something and get an image almost instantaneously. The sensing time dictates the time resolution.”
“In principle, given the high sensitivity and high time resolution, you could be able to see things in real time.”
“You might be able to use this to see cells as they interact,” he added.
“You’re not just producing a static image, you could see proteins and cells evolving and moving using X-rays.”
The soft X-ra detector created by Professor Jasieniak and colleagues is less than 10 nanometers thick.
Previously, the thinnest X-ray detectors created were between 20 and 50 nanometers.
“The sensitivity and efficiency of SnS nanosheets depends greatly on their thickness and lateral dimensions, which are not possible to control through traditional fabrication methods,” said co-lead author Dr. Nasir Mahmood, a researcher at RMIT University and Quaid-I-Azam University.
Using a liquid metal-based exfoliation method allowed the researchers to produce high quality, large area sheets with controlled thickness, which can efficiently detect soft X-ray photons in the water region.
Their sensitivity can be further enhanced by a process of stacking the ultrathin layers.
They represent major improvements in sensitivity and response time compared to existing direct soft X-ray detectors.
The authors hope their findings will open new avenues for the development of next-generation, highly sensitive X-ray detectors based on ultrathin materials.
“In the long run, to commercialise this, we need to test a many-pixel device,” said first author Dr. Babar Shabbir, a researcher in the Department of Materials Science and Engineering and the ARC Centre of Excellence in Exciton Science at Monash University.
“At this stage we don’t have the imaging system. But this provides us with a knowledge platform and a prototype.”
The team’s work was published in the journal Advanced Functional Materials.
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Babar Shabbir et al. Soft X-ray Detectors Based on SnS Nanosheets for the Water Window Region. Advanced Functional Materials, published online October 27, 2021; doi: 10.1002/adfm.202105038
Source link: https://www.sci.news/physics/worlds-thinnest-x-ray-detector-10250.html
