Reconfigurable perovskite X-ray detector for intelligent imaging.

X-ray detection is widely used in various applications. However, to meet the demand for high image quality and high accuracy diagnosis, the raw data increases and imposes challenges for conventional X-ray detection hardware regarding data transmission and power consumption. To tackle these issues, we present a scheme of in-X-ray-detector computing based on CsPbBr3 single-crystal detector with convenient polarity reconfigurability, good linear dynamic range, and robust stability. The detector features a stable trap-free device structure and achieves a high linear dynamic range of 106 dB. As a result, the detector could achieve edge extraction imaging with a data compression ratio of ~50%, and could also be programmed and trained to perform pattern recognition tasks with a high accuracy of 100%. Our research shows that in-X-ray-detector computing can be used in flexible and complex scenarios, making it a promising platform for intelligent X-ray imaging.

Double Perovskite Single Crystals with High Laser Irradiation Stability for Solid-State Laser Lighting and Anti-counterfeiting.

Laser lighting devices, comprising an ultraviolet (UV) laser chip and a phosphor material, have emerged as a highly efficient approach for generating high-brightness light sources. However, the high power density of laser excitation may exacerbate thermal quenching in conventional polycrystalline or amorphous phosphors, leading to luminous saturation and the eventual failure of the device. Here, for the first time, we raise a single-crystal (SCs) material for laser lighting considering the absence of grain boundaries that scatter electrons and phonons, achieving high thermal conductivity (0.81 W m-1 K-1) and heat-resistance (575 °C). The SCs products exhibit a high photoluminescence quantum yield (89%) as well as excellent stability toward high-power lasers (>12.41 kW/cm2), superior to all previously reported amorphous or polycrystalline matrices. Finally, the laser lighting device was fabricated by assembling the SC with a UV laser chip (50 mW), and the device can maintain its performance even after continuous operation for 4 h. Double perovskite single crystals doped with Yb3+/Er3+ demonstrated multimodal luminescence with the irradiation of 355 and 980 nm lasers, respectively. This characteristic holds significant promise for applications in spectrally tunable laser lighting and multimodal anticounterfeiting.

Retinomorphic X-ray detection using perovskite with hydrion-conductive organic cations.

X-ray detection is crucial across various sectors, but traditional techniques face challenges such as inefficient data transmission, redundant sensing, high power consumption, and complexity. The innovative idea of a retinomorphic X-ray detector shows great potential. However, its implementation has been hindered by the absence of active layers capable of both detecting X-rays and serving as memory storage. In response to this critical gap, our study integrates hybrid perovskite with hydrion-conductive organic cations to develop a groundbreaking retinomorphic X-ray detector. This novel device stands at the nexus of technological innovation, utilizing X-ray detection, memory, and preprocessing capabilities within a single hardware platform. The core mechanism underlying this innovation lies in the transport of electrons and holes within the metal halide octahedral frameworks, enabling precise X-ray detection. Concurrently, the hydrion movement through organic cations endows the device with short-term resistive memory, facilitating rapid data processing and retrieval. Notably, our retinomorphic X-ray detector boasts an array of formidable features, including reconfigurable short-term memory, a linear response curve, and an extended retention time. In practical terms, this translates into the efficient capture of motion projections with minimal redundant data, achieving a compression ratio of 18.06% and an impressive recognition accuracy of up to 98.6%. In essence, our prototype represents a paradigm shift in X-ray detection technology. With its transformative capabilities, this retinomorphic hardware is poised to revolutionize the existing X-ray detection landscape.

Stereo-Hindrance Engineering of A Cation toward <110>-Oriented 2D Perovskite with Minimized Tilting and High-Performance X-Ray Detection.

2D <100>-oriented Dion-Jacobson or Ruddlesden-Popper perovskites are widely recognized as promising candidates for optoelectronic applications. However, the large interlayer spacing significantly hinders the carrier transport. <110>-oriented 2D perovskites naturally exhibit reduced interlayer spacings, but the tilting of metal halide octahedra is typically serious and leads to poor charge transport. Herein, a <110>-oriented 2D perovskite EPZPbBr4 (EPZ = 1-ethylpiperazine) with minimized tilting is designed through A-site stereo-hindrance engineering. The piperazine functional group enters the space enclosed by the three [PbBr6]4- octahedra, pushing Pb─Br─Pb closer to a straight line (maximum Pb─Br─Pb angle ≈180°), suppressing the tilting as well as electron-phonon coupling. Meanwhile, the ethyl group is located between layers and contributes an extremely reduced effective interlayer distance (2.22 Å), further facilitating the carrier transport. As a result, EPZPbBr4 simultaneously demonstrates high µτ product (1.8 × 10-3 cm2 V-1) and large resistivity (2.17 × 1010 Ω cm). The assembled X-ray detector achieves low dark current of 1.02 × 10-10 A cm-2 and high sensitivity of 1240 µC Gy-1 cm-2 under the same bias voltage. The realized specific detectivity (ratio of sensitivity to noise current density, 1.23 × 108 µC Gy-1 cm-1 A-1/2) is the highest among all reported perovskite X-ray detectors.

Template directed perovskite X-ray detectors towards low ionic migration and low interpixel cross talking.

The metal halide perovskites exhibit excellent performance as the direct X-ray detectors owing to their strong absorption capability, long carrier lifetime and diffusion length, radiation ruggedness, etc. For imaging applications, the ionic migration of perovskites and charge sharing effect between the adjacent pixels have a significantly negative impact on the spatial resolution. Herein, for the first time, the porous anodic aluminum oxides (AAO) have been used as a template to grow the CsPbBr2I thick film for the direct X-ray detection. Benefiting from the oxygen passivation effect, the activation energy for ionic migration has been observed to increase to 0.701 eV, whereas the dark current drift (1.01 × 10-5 nA cm-1s-1V-1) is one to two orders of magnitude lower than the other lead halide perovskite single crystals and films. Moreover, the AAO insulating wall effectively blocks the charge diffusion effect across a pixel pitch of 10 µm. Overall, the findings reported in this study open a new route for reducing the ionic migration and pixel crosstalk, thus, bringing the perovskite X-ray detectors close to the practical applications.