Antisolvent-Assisted Synthesis of Bismuth Halide Perovskite Polycrystal Alloys for Sensitive X-ray Detection

Abstract

Perovskite X-ray detectors are promising in medical diagnosis and industrial inspection because of their high sensitivity and low limit of detection (LoD). Lead-free MA3Bi2I9 perovskite derivatives show good stability, environmental friendliness, and excellent electronic properties for sensitive X-ray detection. Here, we report the fabrication of MA3Bi2I9 X-ray detectors by a facile, high-throughput, and low-cost antisolvent-assisted synthesis (ASAS) method with a high product yield >90%. Electronic characteristics of MA3Bi2I9 were modulated by Cs alloying, leading to a high resistivity (1011 Ω cm) and a low dark carrier concentration (107 cm–3). As a result, (MA0.7Cs0.3)3Bi2I9-alloyed X-ray detectors show an LoD of 12.8 nGyair s–1 and a sensitivity of 130 μC Gyair –1 cm–2, outperforming that of a commercialized amorphous selenium (a-Se) detector. This study develops high-performance lead-free X-ray detectors with a robust, low-cost, and scalable fabrication process, which will pave the way for adopting polycrystalline MA3Bi2I9 in X-ray detectors.

Sensitive and Stable Ruddlesden–Popper Perovskite X-ray Detectors via Defect Passivation

“…The ABN device achieved an X-ray sensitivity of approximately 8000 μC Gy air –1 cm –2 , which is higher than the sensitivity of around 5400 μC Gy air –1 cm –2 for the pristine device and 2 orders of magnitude higher than the sensitivity of approximately 20 μC Gy air –1 cm –2 for a-Se X-ray detectors . It has been reported that sensitivity may decrease as the dose rate increases due to increased recombination rates with higher charge carriers induced by high X-ray dose rates . However, for BA 2 MA 9 Pb 10 I 31 RP perovskites, the sensitivity remains almost constant under various X-ray dose rates, which can be attributed to efficient charge collection features resulting from the high μτ product.…”

“…35 It has been reported that sensitivity may decrease as the dose rate increases due to increased recombination rates with higher charge carriers induced by high X-ray dose rates. 36 However, for BA 2 MA 9 Pb 10 I 31 RP perovskites, the sensitivity remains almost constant under various X-ray dose rates, which can be attributed to efficient charge collection features resulting from the high μτ product.…”

Halide perovskites for sensitive, stable and scalable X-ray detection and imaging

“…To simplify the process, the crystal powder was prepared by a low cost antisolvent-assisted synthesis (ASAS) method, in which the precursor solution was dropped into the antisolvent, and a red precipitate was obtained. 79 The powder was obtained by washing the red precipitate with chlorobenzene twice and drying in a vacuum oven at 50 °C for 4 h. The Cs alloying resulted in large resistivity and low carrier concentration, which led to an ultralow dark current, making it suitable for detecting radiation at ultralow dose rates. Other Bi-based wafers have also been reported.…”

Low-Dose and Stable X-ray Detection Enabled by Ferroelectric Perovskite Oxides

“…Though high bias voltages can provide a large driving force to ensure a sufficient separation of EHPs, large dark current is introduced as well, which is an unpleasant source of noise. , Noise is a random component added to the image signal, existing as white dots appearing randomly in the image. It reduces the signal-to-noise ratio (SNR) and contrast resolution of the image and degrades useful diagnostic information in the image. − Therefore, it is crucial to achieve sufficient charge collection without sharply increasing the dark current for high-quality low-dose X-ray imaging.…”