Most X-ray detectors work in one of two energy levels: hard or soft. Hard X-rays are utilized to penetrate dense substances such as bone or rock, whereas soft X-rays are necessary for imaging living matter like tissue and cells safely. Typically, single-energy detection happens in the hard X-ray range of 10 to hundreds of kiloelectron volts (KeV). For detection in the soft window, energy levels below 1 KeV may be required. Occasionally, an X-ray detector must be capable of functioning across both energy levels. Consider the case of searching for tumors in breast tissue. Currently available multi-energy X-ray detectors, constructed from silicon and selenium, can function in both regions, but their energy sensitivity and spatial resolution are restricted. A promising alternative with greater effectiveness and versatility is now available in the form of metal halide perovskites.

The field of imaging applications could witness a significant advancement following the demonstration of a pathway to multi-energy X-ray detection with increased flexibility and sensitivity by researchers at Exciton Science (Melbourne, VIC, Australia). Developed by a team at Monash University (Melbourne, VIC, Australia), the technology is based on solution-processed, printable diodes made utilizing perovskite thin films, a component generally associated with next-generation solar energy devices.

Perovskite materials are known for their crystal structure and can regulate the intensity of X-ray beams passing through matter. They are also cost-effective to produce. When perovskite is incorporated into a diode device, the process of X-ray attenuation creates charges that can be collected to determine the energy and intensity of the X-ray. The latest research has shown that a perovskite-based multi-energy X-ray detector can operate across a wide range of energies, from 0.1 KeV to the 10s of KeV, surpassing the capabilities of traditional multi-energy X-ray detectors. This breakthrough technology has the potential to revolutionize the field of imaging applications.

Perovskite-based devices have previously been demonstrated to detect hard X-rays on a small scale, ranging from millimeters to centimeters. For the first time, researchers have successfully utilized perovskites for soft X-ray detection, with the potential for scaling up to large areas for commercial applications. Furthermore, since the perovskite detectors can be produced as a thin film, they can be integrated with flexible substrates, opening up possibilities for new device shapes and sizes.

“These perovskite-based detectors can provide rapid response times and offer high sensitivities to enable real-time detection and imaging for complex purposes, including disease diagnoses, detection of explosives and identifying food contamination,” said Dr. Babar Shabbir, a Senior Exciton Science Research Fellow and the study’s first author.

“This work showcases that there's a natural extension of perovskites into printed X-ray detectors,” added Professor Jacek Jasieniak of Monash University, an Exciton Science Chief Investigator and the study’s senior author. “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.” 

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