Printable multi

How perovskite thin films enhance X-Ray detector sensitivity

Current X-Ray detectors operate at either hard or soft energy levels. Hard X-Rays penetrate dense materials like bone or rock, while soft X-Rays are used for safely imaging living matter such as tissue and cells. However, existing multi-energy X-Ray detectors made from silicon and selenium are limited in their energy sensitivity and spatial resolution.

The researchers have discovered that metal halide perovskites, which are inexpensive to produce and highly effective in managing X-Ray beam intensity, offer a more versatile alternative. When perovskite is fabricated within a diode device, the X-Ray attenuation process creates charges that can be collected to provide a signature of the X-Ray energy and its intensity.

The new perovskite-based multi-energy X-Ray detectors can operate in a broad energy range from 0.1 KeV into the 10s of KeV, significantly wider than existing conventional detectors. Additionally, the new detectors are suitable for large-scale commercial use and can be combined with flexible substrates to create a variety of device shapes and sizes.

Professor Jacek Jasieniak of Monash University, an Exciton Science Chief Investigator and the senior author on the paper, said: "This work showcases that there's a natural extension of perovskites into printed X-Ray detectors. They should be cheaper to make and could also involve modified film form factors, where you need inherent flexibility. It opens up the field to a whole new set of questions about how to use these types of devices."

The research was conducted in collaboration with Australia's national science agency CSIRO, the University of Illinois, the University of Cambridge, and Nanyang Technological University in Singapore. This breakthrough in perovskite-based X-Ray detectors holds significant promise for a wide range of imaging applications, enabling new possibilities in disease diagnosis, security, and food safety.

Study Abstract:

Multi energy X-ray detection is critical to effectively differentiate materials in a variety of diagnostic radiology and nondestructive testing applications. Silicon and selenium X-ray detectors are the most common for multi energy detection; however, these present poor energy discrimination across the broad X-ray spectrum and exhibit limited spatial resolution due to the high thicknesses required for radiation attenuation. Here, an X-ray detector based on solution-processed thin-film metal halide perovskite that overcomes these challenges is introduced. By harnessing an optimized n-i-p diode configuration, operation is achieved across a broad range of soft and hard X-ray energies stemming from 0.1 to 10's of keV. Through detailed experimental and simulation work, it is shown that optimized Cs0.1FA0.9PbI3 perovskites effectively attenuate soft and hard X-rays, while also possessing excellent electrical properties to result in X-ray detectors with high sensitivity factors that exceed 5 × 103 µ◂...▸ and 6 × 104 µC Gy−1 cm−2 within soft and hard X-ray regimes, respectively. Harnessing the solution-processable nature of the perovskites, roll-to-roll printable X-ray detectors on flexible substrates are also demonstrated.