15 October 2024

Professor Feng Gao has been granted SEK 31 million from the Knut and Alice Wallenberg Foundation over five years to develop a new type of X-ray technology that can be used in medicine and security. The goal is a flexible material that can improve X-ray detector image quality.

Portrait Feng Gao.
Feng Gao, professor at the Department of Physics, Chemistry and Biology at Linköping University, has been granted SEK 31 million from the Knut and Alice Wallenberg Foundation. Photographer: Thor Balkhed

The physicist Wilhelm Röntgen was awarded the first Nobel Prize in Physics in 1901 for his discovery of X-rays. Since then, the technology has developed and contributed to both medical and technical breakthroughs.

Today, X-ray technology is used, for instance, to make medical diagnoses, check the contents of bags at airports and inspect cracks in buildings.

How this technology works is that short-wave x-rays can pass through some materials but not others, for example through muscles but not bones. When a broken body part is to be examined, it is irradiated and the rays passing through the body are captured by an X-ray detector.

X-ray image of hand.
One of the first X-ray images taken.Photographer: Wilhelm Röntgen/Public domain
This means that the X-ray image shows the “shadow” of the body parts that the rays did not pass through.

Better diagnostics

During the almost 130-year history of this technology, the material in the X-ray detector has evolved but always been rigid. This is something LiU researcher Feng Gao will now try to change by developing a flexible material for the detector.

“This will be a huge advantage if, for example, you have broken your elbow. In this case it’s difficult to get a clear picture with today's X-ray technology, and high radiation doses are required. But if you could create an X-ray detector that can be “worn” by the patient, this would require much less X-ray radiation. and the diagnostics would improve,” says Feng Gao, professor at the Department of Physics, Chemistry and Biology at Linköping University.

To succeed, he plans to use electrically conductive plastic, so-called organic semiconductors. The problem is that organic semiconductors are largely composed of carbon and hydrogen atoms and have poor X-ray absorption.

“The idea is to create a type of hybrid material. So we use the conductive plastic as a host material and integrate heavy metals into it. But it’s not easy to do this in a way that provides uniformity across the entire detector,” says Feng Gao.

Strong team

In addition to the ability to absorb X-rays, the new material will also convert the X-rays into electrical charges and then effectively direct the charges to electrodes, which in turn send signals to the detector system monitor.

Researcher in the labb.
Even if is a difficult task, Feng Gao thinks the strong team will get it done.Photographer: Anna Nilsen
Although the project is very challenging the team has the ambition to develop a working prototype within five years. Apart from Feng Gao, the project includes Professor Mats Fahlman at the Department of Science and Technology at LiU, Professor Eva Olsson at Chalmers University of Technology and Professor Sascha Ott at Uppsala University

“We have a strong team with complementary skills and access to the best infrastructure to take on the challenge,” says Feng Gao.

Previously, he has primarily explored perovskites and organic semiconductors for the manufacture of, among other things, cheap solar cells and LEDs, and is one of the world’s most cited researchers in this field. Feng Gao is now adding a new research direction.

“This is a new direction for my research group. But the fundamental working mechanisms have a lot in common. Whether it’s solar cells, LEDs, lasers or X-ray detectors, it involves either converting light into electricity or converting electricity into light.”

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