Multiphase Transition toward Colorless Bismuth-Germanate Scintillating Glass and Fiber for Radiation Detection

Enhanced Photoluminescence Quantum Yield of Metal Halide Perovskite Microcrystals for Multiple Optoelectronic Applications

Recently, metal 1halide perovskites have shown compelling optoelectronic properties for both light-emitting devices and scintillation of ionizing radiation. However, conventional lead-based metal halide perovskites are still suffering from poor material stability and relatively low X-ray light yield. This work reports cadmium-based all-inorganic metal halides and systematically investigates the influence of the metal ion incorporation on the optoelectronic properties. This work introduces the bi-metal ion incorporation strategy and successfully enhances the photoluminescence quantum yield (98.9%), improves thermal stability, and extends the photoluminescence spectra, which show great potential for white light emission. In addition, the photoluminescent decay is also modulated with single metal ion incorporation, the charge carrier lifetime is successfully reduced to less than 1 µs, and the high luminescent efficiency and X-ray light yield (41 000 photons MeV-1 ) are maintained. Then, these fast scintillators are demonstrated for high-speed light communication and sensitive X-ray detection and imaging.

Bismuth Vacancy-Induced Enhancement of Luminescence Intensity and Irradiation Resistance for Bi4Ge3O12

Bi₄Ge₃O₁₂ (BGO) is a traditional scintillator, widely used in high-energy physics and nuclear medicine. However, it not only suffers from low scintillation intensity but also tends to be damaged by high-energy rays. Herein, we prepare pure-phase BGO materials enriched with Bi vacancies by rationally reduced Bi content, showing significantly enhanced luminescence intensity and irradiation resistance ability. The optimized Bi_3.6Ge₃O₁₂ shows 178% of luminescence intensity compared to BGO. After 50 h of ultraviolet irradiation, Bi_3.6Ge₃O₁₂ possesses ∼80% of original luminescence intensity, much superior to the 60% for BGO. The existence of the Bi vacancy is identified by advanced experimental and theoretical studies. The mechanism studies show the Bi vacancies could cause the symmetry destruction of the local field around the Bi³⁺ ion. It enhances scintillation luminescence by increasing the probability of radiative transition while resisting nonradiative relaxation caused by irradiation damage. This study initiates vacancy-induced performance enhancement for inorganic scintillators.

Recent Advances in Optical Fiber Enabled Radiation Sensors

Optical fibers are being widely utilized as radiation sensors and dosimeters. Benefiting from the rapidly growing optical fiber manufacturing and material engineering, advanced optical fibers have evolved significantly by using functional structures and materials, promoting their detection accuracy and usage scenarios as radiation sensors. This paper summarizes the current development of optical fiber-based radiation sensors. The sensing principles of both extrinsic and intrinsic optical fiber radiation sensors, including radiation-induced attenuation (RIA), radiation-induced luminescence (RIL), and fiber grating wavelength shifting (RI-GWS), were analyzed. The relevant advanced fiber materials and structures, including silica glass, doped silica glasses, polymers, fluorescent and scintillator materials, were also categorized and summarized based on their characteristics. The fabrication methods of intrinsic all-fiber radiation sensors were introduced, as well. Moreover, the applicable scenarios from medical dosimetry to industrial environmental monitoring were discussed. In the end, both challenges and perspectives of fiber-based radiation sensors and fiber-shaped radiation dosimeters were presented.

Flexible Scintillation Silica Fiber with Engineered Nanocrystals for Remote Real-Time X-ray Detection

Scintillation fibers based on rare-earth ion-doped crystal materials have attracted significant attention for applications in a wide range of areas from security to healthcare. However, the scintillation performance of crystal fibers is severely limited owing to the complex preparation process. Here, we report a modified preparation process of the transparent Ce/Tb co-doped yttrium pyrosilicate (YPS) nanocrystal silica fiber for the first time, which was fabricated by the CO₂ laser-heated method assisted with optimal thermal annealing. An YPS nanocrystal phase with an average size of approximately 38 nm is obtained by controlling the diffusion concentration of SiO₂ in the fiber core region. Both Ce³⁺ and Tb³⁺ ions were successfully embedded into YPS nanocrystals, which enhanced the energy transfer with an efficiency of 59.87% between the dopants as well as brighter green light emission. Furthermore, the X-ray-excited remote radioluminescence response of the obtained YPS nanocrystal fiber with a length of 20 m was approximately 1 order of magnitude larger than that of the precursor fiber, while the dose rate response exhibited excellent linearity. It is believed that the novel transparent YPS nanocrystal-doped silica optical fibers, combined with their excellent fluorescent properties, could be promising candidates for scintillators, fiber lasers, and phosphors.

Improving the luminescence property of the novel yellow-emitting phosphor SrLa2Sc2O7:Bi3+ with charge compensators (Li+, Na+, K+) and its application in NUV-based white LEDs

In this work, a novel yellow-emitting phosphor SrLa2Sc2O7:Bi3+ was synthesized by high temperature solid-state method, ranging from 400 nm to 800 nm under near-ultraviolet (NUV) excitation and the full width at half maximum (FWHM) of up to 180 nm.

Structured Scintillators for Efficient Radiation Detection

Scintillators, which can convert high-energy ionizing radiation into visible light, have been serving as the core component in radiation detectors for more than a century of history. To address the increasing application demands along with the concern on nuclear security, various strategies have been proposed to develop a next-generation scintillator with a high performance in past decades, among which the novel approach via structure control has received great interest recently due to its high feasibility and efficiency. Herein, the concept of "structure engineering" is proposed for the exploration of this type of scintillators. Via internal or external structure design with size ranging from micro size to macro size, this promising strategy cannot only improve scintillator performance, typically radiation stopping power and light yield, but also extend its functionality for specific applications such as radiation imaging and therapy, opening up a new range of material candidates. The research and development of various types of structured scintillators are reviewed. The current state-of-the-art progresses on structure design, fabrication techniques, and the corresponding applications are discussed. Furthermore, an outlook focusing on the current challenges and future development is proposed.