Qingsong Hu

Manganese-based hybrid metal halides are attractive for scintillator applications due to their high emission efficiency and good stability. However, most high-performance manganese scintillators rely on bulky and complex organic cations as A-site components, which reduce the lattice density and compromise X-ray absorption. To address this issue, we employed a small piperidinium cation (C₅H₁₂N⁺) to synthesize a zero-dimensional manganese halide, (C₅H₁₂N)₂MnBr₄, via solvent evaporation. This material shows green Mn²⁺ emission but suffers from concentration quenching, giving a low PLQY of 23.86%. Through Cd²⁺ alloying, the optimized (C₅H₁₂N)₂MnBr₄: 20%Cd achieves a markedly enhanced PLQY of 78.54%. As a scintillator, it exhibits excellent X-ray absorption─among the highest reported for hybrid manganese scintillators─and a high light yield of 21086 photons/MeV. This improvement results from the synergy between the small A-site cation (providing a compact lattice for strong absorption) and Cd²⁺ alloying (suppressing concentration quenching). A 10 × 10 cm flexible film fabricated by incorporating the alloyed powder into a TPU matrix shows outstanding radiation stability and a high X-ray imaging resolution of 14 lp mm^-1. The combination of strong X-ray absorption, enhanced luminescence, and solution processability opens new opportunities for low-cost, large-area, flexible X-ray detectors and imaging.

Developing high-performance dual imaging applications, such as fast neutron and X-ray applications, using a single material presents a very significant challenge across chemistry, material science, physics, and engineering. Integrating both imaging capabilities into a single material for specialized detection applications will simplify device design and significantly reduce overall detection costs. This work represents the first demonstration of a lead-free system designed for high-performance dual imaging applications. It features a multifunctional hybrid copper(I) iodide scintillator, in which hydrogen-rich and luminescent units are synergistically coupled at the molecular level, enabling the simultaneous imaging of fast neutrons and X-rays. The perfect synergy of exciton confinement and thermally activated delayed fluorescence (TADF) effects empowers this material with exceptional dual imaging capabilities. The confined structure formed by heavy-atom modules at the core imparts a high exciton binding energy, suppressing the nonradiative recombination of excitons. The TADF mechanism channels phonons generated by high-energy radiation into the radiative recombination process. Additionally, the lack of self-absorption guarantees efficient photon utilization. Leveraging these properties, the material achieves an impressive X-ray light yield of approximately 42,000 photons/MeV and an exceptional spatial resolution of 25.8 lp/mm for X-ray imaging, surpassing most commercial scintillators available in the X-ray market. Furthermore, the material demonstrates an outstanding spatial resolution of 1.47 lp/mm in fast neutron imaging, representing the best level reported to date for a Pb-free scintillator. This environmentally friendly and high-performance multifunctional scintillator significantly advances next-generation scintillation materials, presenting exciting opportunities for high-precision and dual imaging applications at a low cost.

All-inorganic perovskite CsPbBr3 single crystals have emerged as a transformative platform for room-temperature gamma-ray spectrometers, driving significant advancements from fundamental research to practical applications over the past decade. In this review, we systematically analyze their material advantages for radiation detection and summarize their recent advances in gamma-ray detection technology. Owing to the critical dependence of device performance on crystal quality, we critically evaluate material synthesis strategies, including solution-based methods (inverse temperature crystallization and antisolvent vapor crystallization) and melt-growth approaches (particularly the Bridgman method). Special emphasis is placed on breakthroughs in crystal quality and dimensional control achieved through additive engineering, precise thermal management, and advanced precursor purification. Regarding device architecture, we assess innovative designs such as Schottky junctions, quasihemispherical electrodes, pixelated arrays, and virtual Frisch grids, which have significantly enhanced energy resolution from basic photon counting to performance levels approaching the theoretical limit. We also address persistent challenges, including ion migration effects, manufacturing scalability, and long-term operational stability. We further outline strategic research directions encompassing advanced material engineering, device architectures, and standardization frameworks, providing valuable guidance for accelerating the industrialization of this technology.

Rare earth-based halide double perovskites are regarded as an emerging class of X-ray scintillation materials. However, the majority of related scintillator applications are still focused on single crystal and powder systems; the application of nanocrystal (NC) scintillators is rarely reported. Here, we present the synthesis of high-purity Cs₂NaTbCl₆ NCs by an improved hot-injection method. Interestingly, hollow Cs₂NaTbCl₆ NCs are observed, the monitoring of the growth process indicates that micrometer-sized NaCl is the initial product, and then the NaCl would convert into Cs₂NaTbCl₆ NCs through the diffusion of Cs⁺ and Tb³⁺ into NaCl lattice, and the faster outward diffusion of Na⁺ results in the formation of hollow NCs. The double perovskite NCs exhibit green light emission, and the photoluminescence intensity can be significantly enhanced through Ce³⁺ doping. In particular, the Cs₂NaTbCl₆:5%Ce³⁺ scintillator exhibits a linear response and a low detection limit of 79.09 nGy/s when exposed to X-rays. Furthermore, a flexible scintillator film for X-ray imaging is prepared by mixing NCs with polymer, showing a high spatial resolution imaging capability of 10 lp/mm. This work provides a new strategy for hollow perovskite NCs and may shed light on the synthesis of related hollow NCs and their applications in X-ray detection.

Intrinsic dual-emission (DE) of gold nanoclusters in the near-infrared (NIR) are fascinating for fundamental importance and practical applications, but their synthesis remains a formidable challenge and sophisticated excited-state processes make elucidating DE mechanisms much more arduous. Here, we report an all-alkynyl–protected gold nanocluster, Au20 , showing a prolate Au ₁₂ tri-octahedral kernel surrounded by two Au ₂ (CZ-PrA) ₃ dimers, four Au(CZ-PrA) ₂ monomers, and two CZ-PrA ⁻ bridges. Au20 exhibits distinguished photophysical properties including NIR DE at 820 and 940 nm, microsecond radiative relaxation, and 6.26% photoluminescent quantum yield at ambient environment in nondegassed solution. Combining systematic studies on steady/transient spectroscopy and theoretical calculation, we identified two triplet charge transfer (CT) states, ligand-to-kernel and kernel-based CT states as DE origins. Furthermore, this NIR DE exhibits highly independent and sensitive response to surrounding environments, which well coincide with its mechanism. This work not only provides a substantial structure model to understand a distinctive DE mechanism but also motivates the further development of NIR DE materials.

In recent years, lead-free metal halide luminescent materials have attracted extensive attention because of their excellent properties including but not limited to good environmental compatibility, ultrawide emission band, and high photoluminescence quantum yield. They are considered to have great application potential in the photoelectric field. We modified the previously reported synthesis and prepared pure phase Cs2SnCl6 : Bi3 + , Te4 + using simple solution method. Then the emitter was further coated with polysiloxane to form polysiloxane luminescent ceramic (PSOLC). The prepared PSOLCs have almost the same luminescence as the powders, and their color coordinates and color temperature can be tuned freely by adjusting the ratio of blue and yellow emission, which both encourage outdoor-lighting application. Additionally, they are demonstrated to support flexible luminescence and show highly improved machinability. To test their performance in practical application, we apply the PSOLCs to safety identification board and finally get a satisfactory result, directly indicating that the PSOLCs prepared from lead-free perovskite are quite suitable for flexible-lighting-related display applications.

The low efficiency triplet emission of hybrid copper(I) iodide clusters is a critical obstacle to their further practical optoelectronic application. Herein, we present an efficient hybrid copper(I) iodide cluster emitter (DBA)₄Cu₄I₄, where the cooperation of excited state structure reorganization and the metallophilicity interaction enables ultra‐bright triplet yellow‐orange emission with a photoluminescence quantum yield over 94.9 %, and the phonon‐assisted de‐trapping process of exciton induces the negative thermal quenching effect at 80–300 K. We also investigate the potential of this emitter for X‐ray imaging. The (DBA)₄Cu₄I₄ wafer demonstrates a light yield higher than 10⁴ photons MeV⁻¹ and a high spatial resolution of ≈5.0 lp mm⁻¹, showing great potential in practical X‐ray imaging applications. Our new copper(I) iodide cluster emitter can serve as a model for investigating the thermodynamic mechanism of photoluminescence in hybrid copper(I) halide phosphorescence materials.

The low efficiency triplet emission of hybrid copper(I) iodide clusters is a critical obstacle to their further practical optoelectronic application. Herein, we present an efficient hybrid copper(I) iodide cluster emitter (DBA)₄Cu₄I₄, where the cooperation of excited state structure reorganization and the metallophilicity interaction enables ultra‐bright triplet yellow‐orange emission with a photoluminescence quantum yield over 94.9 %, and the phonon‐assisted de‐trapping process of exciton induces the negative thermal quenching effect at 80–300 K. We also investigate the potential of this emitter for X‐ray imaging. The (DBA)₄Cu₄I₄ wafer demonstrates a light yield higher than 10⁴ photons MeV⁻¹ and a high spatial resolution of ≈5.0 lp mm⁻¹, showing great potential in practical X‐ray imaging applications. Our new copper(I) iodide cluster emitter can serve as a model for investigating the thermodynamic mechanism of photoluminescence in hybrid copper(I) halide phosphorescence materials.