A team of scientists, led by László Forró from the School of Basic Sciences at the Ecole Polytechnique Federale de Lausanne (EPFL) in Switzerland, has developed a new X-Ray Photodetector based on perovskites and graphene.

Using 3D aerosol jet-printing technology, the team designed a new technique for creating highly efficient x-ray photodetectors that can be easily added to standard microelectronic circuits, creating more powerful medical imaging devices that can deliver better scan qualities.

The new photodetectors use perovskites together with graphene, a 2D carbon allotrope with many advantageous properties. The team reports that the new x-ray photodetectors are versatile, easy to synthesize, and could potentially have applications in energy harvest and storage (solar cells), lighting (LED lamps), lasers, and in medical imaging.

Aerosol jet-printing is an emerging fabrication technology that allows controlled and precise deposition of materials at the micron-scale, allowing for the embedding of materials on almost any surface. It has been used to create electronic components - resistors, inductors, capacitors, sensors, antenna - by 3D printing them.

The researchers used the aerosol jet printing device at the Centre Suisse d'Electronique et Microtechnique (CSEM) in Neuchatel, Switzerland, 3D printing perovskite layers on graphene substrates. The concept behind this is that the perovskite will serve as the photon detector and the electron discharger as well, with the graphene substrate amplifying the generated electrical signal.

The researchers used methylammonium lead iodide (MAPBI3) as the perovskite of choice, which is known to have favorable optoelectronic properties, as well as being relatively low cost.



"This perovskite has heavy atoms, which provide a high scattering cross-section for photons, and makes this material a perfect candidate for X-ray detection," explains Endre Horváth, the chemist of the research team.

"By using photovoltaic perovskites with graphene, the response to X-rays has increased tremendously," Forró notes on the resulting material. He also explains that if these materials are used for X-ray images, the required dosage for generating an image would be down by "more than a thousand times," which further decreases the health risks of this procedure on humans.

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