Polycrystalline hybrid perovskite with enhanced ordered crystal domains for sensitive X-ray detection

Organic-inorganic halide perovskites, which integrate organic and inorganic elements, hold great potential for direct X-ray detection. Economical production methods, such as slurry blade coating, enable the manufacture of large-area X-ray detectors based on these materials. However, numerous pores and pinholes in the resulting polycrystalline thick films lead to detrimental effects like non-radiative recombination and ion migration, compromising detection performance. To overcome this challenge, we promote the growth of oriented crystal domains to assist in the fabrication of high-quality and thick perovskite X-ray photoconductor films. This approach leverages the synergistic effects of enhanced hydrogen bonding and A-site incorporation by carefully controlling the amount of guanidinium iodide. As a result, the film exhibits larger grains and fewer grain boundaries, leading to lower trap state densities and a higher carrier mobility-lifetime product. The resulting detector achieves a sensitivity of 7.6 × 104 μC Gyair−1 cm−2 and a limit of detection of 28 nGyair s−1. The devices also demonstrate improved stability by effectively eliminating ion migration pathways. This study proposes a methodological strategy for producing high-quality polycrystalline thick films, pivotal for advancing large-area flat-panel X-ray detection systems.