Developing highly sensitive X-ray detectors with high atomic-number elements is crucial for reducing dose rates in medical applications. An X-ray detector with high sensitivity can accurately and efficiently detect even small amounts of X-ray radiation and convert it into an electrical signal, effectively implying that smaller doses can be applied in X-ray instruments in the medical field. Traditional X-ray detector materials such as Si and CdTe suffer from disadvantages such as low-to-moderate atomic numbers, high thermal noise and crystal impurities, all negatively impacting the overall detector performance. Bismuth (Bi)-based materials offer significant advantages, including excellent stability and high atomic numbers, to name a few, making them highly interesting candidates for applications such as X-ray detection.¹ This study investigates fully inorganic compounds, such as Cs₂AgBiBr₆ and other fully inorganic materials, as well as hybrid organic-inorganic Bi-based materials.

Mechanosynthesis is showcased as an effective method for fabricating new materials with precise stoichiometries, with the possibility for swift upscaling.^2,3 We aim to explore mechanosynthesis for the targeted synthesis of Bi-based materials and then utilize these synthesized powders for different applications, such as X-ray detection. These materials were synthesized using, for instance, dry mechanochemical ball-milling under various reaction conditions. The study emphasizes the impact of different reaction conditions, material composition, additives, and post-treatment processes on the performance of the detectors.

X-ray diffraction (XRD) was utilized to analyze the structural properties and composition of the synthesized pellets. The performance of the detectors was evaluated by measuring their photocurrent response under X-ray illumination. Our results indicate that Bi-based materials significantly outperform conventional commercial X-ray detectors in terms of sensitivity and detection limit. Optimizing the mechanosynthesis reaction conditions and carefully selecting additives and post-treatments further enhances the properties and performance of the Bi-based detectors.

This research demonstrates that Bi-based perovskite-inspired materials, in both single-crystal and pellet forms, have significant potential as effective X-ray detectors. These findings pave the way for developing safer, more stable, and high-performance alternatives to current commercial X-ray detectors. Additionally, this work highlights mechanosynthesis as a swift and viable route for fabricating these materials, contributing to more environmentally friendly and commercially viable solutions, for instance, in photovoltaics, LEDs, and X-ray detection.