Solution-Processed Perovskite/Metal-Oxide Hybrid X-Ray Detector and Array with Decoupled Electronic and Ionic Transport Pathways

1D Pb halide perovskite-like materials for high performance X-ray detection

The strategy of bandgap regulation is important for X-ray detection, but has not been reported for 1D Pb halide perovskite materials. In this work, three such materials, 1, 2 and 3, with a tunable bandgap, were fabricated for application in X-ray detection. 3 shows high sensitivity, far superior to commercial X-ray detectors.

Solution-Processed Metal Oxide Thin-Film Transistor at Low Temperature via A Combination Strategy of H2 O2 -Inducement Technique and Infrared Irradiation Annealing

Solution processing has emerged as a promising technique for the fabrication of oxide thin-film transistors (TFTs), offering advantages such as low cost, high throughput, and exceptional compositional control. However, achieving reasonable electrical properties typically demands high annealing temperatures in the fabrication process. In addressing this challenge, a novel combination strategy is proposed that involves integrating the H2 O2 inducement technique with infrared (IR) irradiation annealing. The study investigates the effects of precursors and IR irradiation annealing temperatures on the electrical properties of In2 O3 TFTs. It is found that H2 O2 can help accelerate the decomposition of organic residues, while IR irradiation annealing could enhance the film densification. By employing the proposed strategy, metal oxide TFTs consisting of a Zr-Al-O dielectric fabricated at 230 °C and an In2 O3 channel layer fabricated at 185 °C demonstrated high performance with field-effect mobility = 31.7 cm2  V-1 ·s-1 , threshold voltage = 1.3 V, subthreshold swing = 0.13 V per decade, and on-to-off current ratio = 1.1 × 105 . This work demonstrates the proposed combinational strategy is a general method to fabricate not only metal oxide semiconductors but also dielectrics.

Enabling low-drift flexible perovskite photodetectors by electrical modulation for wearable health monitoring and weak light imaging

Metal halide perovskites are promising for next-generation flexible photodetectors owing to their low-temperature solution processability, mechanical flexibility, and excellent photoelectric properties. However, the defects and notorious ion migration in polycrystalline metal halide perovskites often lead to high and unstable dark current, thus deteriorating their detection limit and long-term operations. Here, we propose an electrical field modulation strategy to significantly reduce the dark current of metal halide perovskites-based flexible photodetector more than 1000 times (from ~5 nA to ~5 pA). Meanwhile, ion migration in metal halide perovskites is effectively suppressed, and the metal halide perovskites-based flexible photodetector shows a long-term continuous operational stability (~8000 s) with low signal drift (~4.2 × 10-4 pA per second) and ultralow dark current drift (~1.3 × 10-5 pA per second). Benefitting from the electrical modulation strategy, a high signal-to-noise ratio wearable photoplethysmography sensor and an active-matrix photodetector array for weak light imaging are successfully demonstrated. This work offers a universal strategy to improve the performance of metal halide perovskites for wearable flexible photodetector and image sensor applications.

Advances in the Application of Perovskite Materials

Nowadays, the soar of photovoltaic performance of perovskite solar cells has set off a fever in the study of metal halide perovskite materials. The excellent optoelectronic properties and defect tolerance feature allow metal halide perovskite to be employed in a wide variety of applications. This article provides a holistic review over the current progress and future prospects of metal halide perovskite materials in representative promising applications, including traditional optoelectronic devices (solar cells, light-emitting diodes, photodetectors, lasers), and cutting-edge technologies in terms of neuromorphic devices (artificial synapses and memristors) and pressure-induced emission. This review highlights the fundamentals, the current progress and the remaining challenges for each application, aiming to provide a comprehensive overview of the development status and a navigation of future research for metal halide perovskite materials and devices.

Realizing nearly-zero dark current and ultrahigh signal-to-noise ratio perovskite X-ray detector and image array by dark-current-shunting strategy

Although perovskite X-ray detectors have revealed promising properties, their dark currents are usually hundreds of times larger than the practical requirements. Here, we report a detector architecture with a unique shunting electrode working as a blanking unit to suppress dark current, and it theoretically can be reduced to zero. We experimentally fabricate the dark-current-shunting X-ray detector, which exhibits a record-low dark current of 51.1 fA at 5 V mm^-1, a detection limit of 7.84 nGy_air s^-1, and a sensitivity of 1.3 × 10⁴ μC Gy_air^-1 cm^-2. The signal-to-noise ratio of our polycrystalline perovskite-based detector is even outperforming many previously reported state-of-the-art single crystal-based X-ray detectors by serval orders of magnitude. Finally, the proof-of-concept X-ray imaging of a 64 × 64 pixels dark-current-shunting detector array is successfully demonstrated. This work provides a device strategy to fundamentally reduce dark current and enhance the signal-to-noise ratio of X-ray detectors and photodetectors in general.

Vertically Oriented Porous PET as Template to Integrated Metal Halide for High-Performance Large-Area and Ultra-Flexible X-Ray Detector

High-performance X-ray detectors have immense potential in medical and security inspections. However, the current X-ray detectors are limited in flexible, high-spatial-resolution large-scale detection, and integration for imaging. Here, nuclear track-etched porous polyethylene terephthalate (PET) is developed as the template for preparing uniform, large-area (≥10⁵ cm² ), and flexible metal halide (MH)-based X-ray detectors. Adjustable high-density vertically oriented porous PET with adjustable thickness can provide proper physical support for flexible thick absorption film, thus improving X-ray absorption ability with excellent bending stability. Moreover, vertical channels can block the ion migration, lateral charge diffusion, and water/oxygen attacks, increasing activation energy for ionic transport, charge collection rate of electrodes, and environmental stability. Hence, the related detectors eventually obtain large sensitivity (6722 µC Gy_air ^-1 cm^-2 ), low detection limit (1.87 nGy_air s^-1 ), and high spatial resolution (5.17 lp mm^-1 ) compared to the detectors without porous PET template. Meanwhile, the device shows no degradation after storage or working under various thermal attacks. MH-filled-PET is also monolithically integrated on the bottom circuit with different MHs and it is applied to single-pixel mode and fast linear-array imaging in a broad range of X-rays photon energy (20 to 160 keV).

Vapor-Deposited Amino Coupling of Hybrid Perovskite Single Crystals and Silicon Wafers toward Highly Efficient Multiwavelength Photodetection

The complementary integration of perovskite single crystals (PSCs) and silicon-based circuitry provides a feasible way to combine their superiority toward efficient multiwavelength photodetection and imaging readout; however, it suffers from distinct lattice mismatch as well as the ambiguous coupling interface effect. Herein, we develop a vacuum-assisted vapor deposition strategy to realize an ultrauniform aminosiloxane interface-modified silicon wafer, which enables the monolithic epitaxial growth of PSCs with the highest mechanical coupling strength up to 340,000 N m^-2 achieved so far. According to the molecular coupling engineering development with different aminosiloxanes, we achieve a highly efficient multiwavelength-responsive integrated photodetector, possessing specific photodetectivity values of 4.36 × 10¹² jones and 4.55 × 10¹¹ jones within the visible and NIR regions, respectively, as well as the lowest X-ray detection limit of 42.6 nGy_air s^-1. Moreover, a particularly wide -3dB cut-off frequency of 6350 Hz as well as a 120 dB linear dynamic range (LDR) also endows the integrated device with excellent dynamic photodetection capability. This work provides an efficacious approach in the integration technology for PSC-based optoelectronic applications.