Self-Powered X-ray Detection and Imaging using Cs₂AgBiCl₆ Lead-Free Double Perovskite Single Crystal

Abstract

Despite the high performance of lead-halide perovskite-based X-ray detectors, the toxicity and instability of lead require the development of lead-free perovskites for X-ray detection applications. Here, we demonstrate lead-free and environmentally friendly, all-inorganic millimeter-sized Cs2AgBiCl6 double perovskite single crystal (SC) for X-ray detection and imaging. The high dark resistivity (3.1 × 1010 Ω cm), high carrier mobility-lifetime product (5.36 × 10–4 cm2 V–1), and lower trap density (1.18 × 109 cm–3) in these double perovskite SCs render them a potential material for X-ray detection. The fabricated vertical structured X-ray detector exhibits a sensitivity of 325.78 μC Gy air–1 cm–2 and a limit of detection of 241 nGy s–1. Additionally, the Cs2AgBiCl6 SCs exhibit self-powered X-ray detection at zero bias with a sensitivity of 7 μC Gy air–1 cm–2. Moreover, the fabricated perovskite X-ray detector exhibits a stable and robust performance under continuous X-ray irradiation and long-term ambient storage. Further, we demonstrated the imaging capability of the Cs2AgBiCl6 X-ray detector using a metal test object and obtained a distortion-free image. Our findings demonstrate that the Cs2AgBiCl6 single crystal-based X-ray detectors have great potential as practical X-ray detectors and imaging for medical radiography.

Negative Photoconductivity: Bizarre Physics in Semiconductors

“…Metal halide perovskites are widely explored in photodetection applications. ,− The charge carrier generation under illumination leads to positive photoconductivity in these materials. A lot of reports demonstrate the PPC in perovskite materials. − Recently, the NPC was reported in halide perovskites under certain conditions. − In this line, Yuan et al presented the NPC under illumination in Cs 4 PbBr 6 perovskite single crystals . A significant amount of reduction was observed in the current under illumination than in the dark current.…”

Anisotropy in Perovskite Single Crystals: From Fundamentals to Applications

“…However, the toxicity of lead and poor environmental stability of these lead halide PSCs hinder their applications in commercialization. As an alternative to lead, lead-free PSCs are emerging now in optoelectronics applications. − Therefore, the study of anisotropic responses in lead-free PSCs should be promoted largely as they are rising potential materials in the field of detection. In this article, we have focused our discussion on the structural, optical, and electrical anisotropy of PSCs. Besides, PSCs should exhibit anisotropy in their mechanical, thermal, and magnetic properties. − Magneto-optical experiments will be useful to probe the anisotropic electron–hole interactions and reveal the magnetic properties along different facets.…”

“…However, the toxicity of lead and poor environmental stability of these lead halide PSCs hinder their applications in commercialization. As an alternative to lead, lead-free PSCs are emerging now in optoelectronics applications. − Therefore, the study of anisotropic responses in lead-free PSCs should be promoted largely as they are rising potential materials in the field of detection.…”

Lead-free all-inorganic halide double perovskite materials for optoelectronic applications: progress, performance and design

“…79 Wang et al synthesized Cs 4 CuSb 2 Cl 12 NCs through top-down ultrasonic stripping technology, 126 where the interlayer van der Waals force and in-plane chemical bond play key roles. 126 LFAIHDP single crystals can be prepared through hydrothermal synthesis, 129 cooling HX-based precursor solution method, 130 controlled cooling crystallization method, 131,132 and high-temperature molten salt method. 133 The temperature, compound concentration, oxygen, and humidity conditions should be carefully controlled during the synthesis of LFAIHDP single crystals.…”

“…3, scheme 2), 129 Chang et al successfully avoided the formation of Ag vacancies and the subsequent formation of secondary phase Cs 3 Bi 2 Br 9 . Likewise, Cs 2 AgBiBr 6 131 and Cs 2 Ag-BiCl 6 132 single crystals were prepared by adopting the cooling crystallization method. The cooling HX-based precursor solution method and high-temperature molten salt method have been successfully applied for the synthesis of Cs 2 Ag-FeCl 6 130 and Cs 2 NaVCl 6 133 single crystals, respectively.…”