Ruizi Li

Organic scintillators that combine high triplet-exciton utilization with rapid radioluminescence are vital for achieving high-resolution dynamic X-ray imaging. Thermally activated delayed fluorescence (TADF) scintillators offer an attractive route to efficient triplet harvesting, yet conventional systems face an intrinsic trade-off between radioluminescence efficiency and decay lifetime. This limitation originates from inherently slow reverse intersystem crossing (RISC), which is difficult to accelerate because minimizing the singlet–triplet energy gap (ΔE_ST) often reduces spin–orbit coupling (SOC). Here, we present a molecular design strategy that overcomes this constraint by simultaneously reducing ΔE_ST and enhancing SOC through strengthened hybridization between charge-transfer (CT) and locally excited (LE) states, leading to a hybridized ³LE/³CT triplet manifold coupled to a predominantly ¹CT singlet state. Guided by this principle, we developed three TADF scintillators by pairing a 2-chloro-7-fluoroquinazoline acceptor with phenoselenazine, phenothiazine, or phenoxazine donors. These scintillators exhibit a high photoluminescence quantum yield of 96.3% and an accelerated RISC rate approaching 10⁷ s^–1. Impressively, under X-ray irradiation, they achieve a light yield of 26508 photons M eV^–1 and a fast radioluminescence lifetime of 3 μs, enabling both high-resolution static imaging and real-time dynamic radiography. This work provides a generalizable molecular design strategy for developing high-performance TADF scintillators for X-ray imaging.

Organic‐inorganic hybrid metal halides are promising X‑ray scintillators due to their tunable structures and strong X‑ray attenuation. However, inefficient energy transfer between organic ligands and metal halides severely limits exciton utilization, resulting in low brightness and poor imaging resolution. Herein, we present a design strategy that synergistically combines strong exciton confinement with hierarchical energy funneling in a Zn ²⁺ ‑doped hybrid material, producing the ultrabright scintillator (TPA) ₂ Mn _0.88 Zn _0.12 Br ₄ . This scintillator achieves a record relative light yield of 115,800 photons MeV ⁻¹ , surpassing its undoped counterpart by 103.9%, along with a near‑unity photoluminescence quantum yield of 99.5%, attributed to enhanced ligand‑to‑metal‑halide energy transfer and strongly confined excitons. When fabricated into a flexible scintillation film, it delivers an ultralow detection limit of 12.3 nGy _air s ⁻¹ , high spatial resolution of 23.3 lp mm ⁻¹ in static imaging, and a 3D dynamic imaging capability at 25 frames s ⁻¹ . It also shows remarkable scintillation stability under high−dose X−ray radiation (maintaining 96.4% intensity at 1.95 mGy _air s ⁻¹ for 3800 s) and during long‐term storage at 80 °C for 60 days. This work establishes a design paradigm that directly correlates radioluminescence kinetics with strong exciton confinement and hierarchical energy funneling, paving the way for next‐generation ultrabright scintillators.

Scintillators featuring bright and fast‐response properties are essential for high‐speed and dynamic X‐ray imaging. Nevertheless, simultaneously possessing high light yields and fast‐response remains a significant challenge for most scintillators. Herein, we propose a strategy to achieve the bright and fast‐response characteristics of scintillators by leveraging the combined effects of dielectric and molecular confinement in organic–inorganic hybrid scintillators (TPA) ₂ MnBr ₄ . Thereinto, large tetrapropylammonium cations (TPA ⁺ ) surround [MnBr ₄ ] ²⁻ units, forming a zero‐dimensional (0D) molecular confinement structure that promotes electron localization and achieves a notable light yield of 56800 photons MeV ⁻¹ . Meanwhile, the low dielectric constant of TPA ⁺ can enhance dielectric confinement of [MnBr ₄ ] ²⁻ units, mitigating exciton capture by deep defects. These synergistic effects in the scintillators lead to a large exciton binding energy of 1028.8 meV and an ultrafast response time of 500 fs. Notably, under the irradiation of X‐rays, (TPA) ₂ MnBr ₄ exhibits an extremely low detection limit of 18.7 nGy _air s ⁻¹ and an exceptional spatial resolution of 21.0 lp mm ⁻¹ . Given the bright and fast‐response features of scintillators, we demonstrate the potential applications in 3D dynamic and real‐time X‐ray imaging. These findings lay the groundwork for designing high‐performance scintillators and open avenues for innovative applications in high‐resolution and dynamic imaging.

Scintillators featuring bright and fast‐response properties are essential for high‐speed and dynamic X‐ray imaging. Nevertheless, simultaneously possessing high light yields and fast‐response remains a significant challenge for most scintillators. Herein, we propose a strategy to achieve the bright and fast‐response characteristics of scintillators by leveraging the combined effects of dielectric and molecular confinement in organic–inorganic hybrid scintillators (TPA) ₂ MnBr ₄ . Thereinto, large tetrapropylammonium cations (TPA ⁺ ) surround [MnBr ₄ ] ²⁻ units, forming a zero‐dimensional (0D) molecular confinement structure that promotes electron localization and achieves a notable light yield of 56800 photons MeV ⁻¹ . Meanwhile, the low dielectric constant of TPA ⁺ can enhance dielectric confinement of [MnBr ₄ ] ²⁻ units, mitigating exciton capture by deep defects. These synergistic effects in the scintillators lead to a large exciton binding energy of 1028.8 meV and an ultrafast response time of 500 fs. Notably, under the irradiation of X‐rays, (TPA) ₂ MnBr ₄ exhibits an extremely low detection limit of 18.7 nGy _air s ⁻¹ and an exceptional spatial resolution of 21.0 lp mm ⁻¹ . Given the bright and fast‐response features of scintillators, we demonstrate the potential applications in 3D dynamic and real‐time X‐ray imaging. These findings lay the groundwork for designing high‐performance scintillators and open avenues for innovative applications in high‐resolution and dynamic imaging.

The thickness of the scintillation films in indirect X−ray detectors can significantly influence their luminescence intensity. However, due to the scattering and attenuation of incoherent photons, thick scintillation films tend to reduce light yield. Herein, a highly transparent perovskite glass−ceramic scintillation film, in which the CsPbBr₃ nanocrystals are in-situ grown inside a transparent amorphous polymer structure, is designed to achieve ultrastable and efficient X-ray imaging. The crystal coordination−topology growth and in−situ film formation strategy is proposed to control the crystal growth and film thickness, which can prevent light scattering and non−uniform distribution of CsPbBr₃ nanocrystals while providing sufficient film thickness to absorb X−ray, thus enabling a high−quality glass−ceramic scintillator without agglomeration and Ostwald ripening. This glass−ceramic scintillation film with a thickness of 250 μm achieves a low detection limit of 326 nGy_air s⁻¹ and a high spatial resolution of 13.9 lp mm⁻¹. More importantly, it displays remarkable scintillation stability under X−ray irradiation (radiation intensity can still reach 95% at 278 μGy_air s⁻¹ for 3600 s), water soaking (150 days), and high−temperature storage (150 days at 60 °C). Hence, this work presents a approach to construct ultrastable and flexible scintillation films for X−ray imaging with reduced light scattering and improved resolution.

Copper halides, a new class of attractive and potential scintillators, have attracted tremendous attention in X‐ray imaging. However, the ambiguity surrounding their exciton properties and the unclear effect of crystal structure on their photophysical performance hinder an in‐depth understanding of their luminescence mechanism and their further application in the X‐ray imaging field. Herein, copper halide scintillators Cs₃Cu₂X₅ (X = I, Br, and Cl) with a 0D crystal structure is prepared, and their photophysical properties and luminescence mechanism are revealed using both theoretical calculation and experimental verification. The small exciton Bohr diameter together with the high exciton binding energy can cause Cs₃Cu₂X₅ to hold strongly confined excitons and lack quantum‐size effects. The 0D Cs₃Cu₂X₅ materials exhibit a structural framework with a soft crystal lattice and Frenkel excitons with strong confinement effects, further resulting in a luminescence mechanism with self‐trapped excitons. In particular, Cs₃Cu₂I₅ is demonstrated as an efficient scintillator with high radioluminescence efficiency and high spatial resolution of ≈106 µm in radiography, which is primarily attributed to strongly confined excitons to improve the radiative recombination probability of electron‐hole pairs. Overall, this work provides a pathway for developing 0D scintillators with strongly confined excitons to improve X‐ray imaging performance.

We compare the general Coherent Mode Decomposition (CMD) method implemented in SRW code and the method making use of Hermite-Gaussian functions implemented in SPECTRA code, both methods being applied to partially coherent Undulator Radiation (UR). The comparison is made in terms of modes required for the same accuracy of presentation of 4D cross spectral density and Wigner function of UR for the same electron beam and undulator systems (corresponding to modern high-brightness light sources – currently operating NSLS-II and the planned upgrade of SPring-8). We show that, even though the pre-defined orthogonal analytical functions are not the exact eigenmodes of the partially coherent UR, their use can be perfectly justified in many cases for the UR, especially when limited computational resources are available for performing the numerical decomposition. Before analyzing the CMD results, we also illustrate excellent agreement between UR characteristics computed with SPECTRA and with SRW. All the presented comparisons, and the agreements found, confirm the validity of methods used by the codes and accuracy of their results.

2D N-doped V₂O₃ (N-V₂O₃) is synthesized as an anode material for Li-ion batteries by a facile strategy. Benefiting from the 3D V–V tunnel structure, sufficient active sites and N modifications, N-V₂O₃ exhibits stable and ultrafast Li-ion storage.

The revolutionary and pioneering advancements of flexible electronics provide the boundless potential to become one of the leading trends in the exploitation of wearable devices and electronic skin. Working as substantial intermediates for the collection of external mechanical signals, flexible strain sensors that get intensive attention are regarded as indispensable components in flexible integrated electronic systems. Compared with conventional preparation methods including complicated lithography and transfer printing, 3D printing technology is utilized to manufacture various flexible strain sensors owing to the low processing cost, superior fabrication accuracy, and satisfactory production efficiency. Herein, up‐to‐date flexible strain sensors fabricated via 3D printing are highlighted, focusing on different printing methods based on photocuring and materials extrusion, including Digital Light Processing (DLP), fused deposition modeling (FDM), and direct ink writing (DIW). Sensing mechanisms of 3D printed strain sensors are also discussed. Furthermore, the existing bottlenecks and future prospects are provided for further progressing research.