Efficient production of ligand-free microscintillators at gram-scale for high-resolution X-ray luminescence imaging

The efficient production of high-quality scintillators with long radioluminescence afterglow is crucial for high-performance X-ray luminescence extension imaging.However,scaling-up the synthesis of ligand-free scintillators to fabricate large-area X-ray imaging screens for industrial applications remains a challenge.In this study,we report an efficient method to synthesize ligand-free,lanthanide-doped microscintillators by a one-pot reaction via the concentrated hydrothermal method.The as-synthesized microscintillators exhibit prolonged persistent radioluminescence for up to 30 days after X-ray exposure and remain high stability in air or water for more than 18 months without deterioration.Monte Carlo simulations indicate that the size effect is responsible for the excellent afterglow performance of the microscintillators.We employ these high-quality lanthanide-doped microscintillators to fabricate a large-area X-ray imaging detector using a blade-coating method,a spatial resolution of 24.9 lp/mm for X-ray imaging.Our study offers a solution for scaling-up the synthesis of low-cost microscintillators for practical applications.

Breaking the boundaries of biological penetration depth:X-ray luminescence in light theranostics

Advances in luminescence materials have markedly propelled research in light theranostics,spanning luminescence biosensing[1],in vivo optical imaging[2],photodynamic therapy[3],optogenetics[4],and related fields[5-7].Nevertheless,conventional light sources have limited penetration depths within deep tissues,and the current state of light theranostics in superficial tissues does not fulfill the requirements for deep tissue treatments in clinical applications.

Efficient and Fast X-Ray Luminescence in Organic Phosphors Through High-Level Triplet-Singlet Reverse Intersystem Crossing

Organic scintillators that efficiently generate bright triplet excitons are of critical importance for highperformance X-ray-excited luminescence in radiation detection.However,the nature of triplet-singlet spinforbidden transitions in these materials often result in long-lived phosphorescence,which is undesirable for ultrafast X-ray detection and imaging.Here we demonstrate that the effect of hybridized local and charge-transfer(HLCT)excited states enables organic scintillators to exhibit highly efficient and fast radioluminescence(RL)in response to X-ray irradiation.Our experimental and theoretical investigation shows that the oxidized 1,8-naphthalimide-phenothiazine dyad(OMNI-PTZ 2)with HLCT-excited states has an enhanced overlap integral of the highest occupied molecular orbital(HOMO)and lowest unoccupied molecular orbital(LUMO)on MNIπ-orbitals,and moderate donor–acceptor electron interactions.As a result,the RL of these crystals exhibits a 61-fold increase and its monoexponential decay lifetime is three orders of magnitude faster compared to its corresponding thermally activated delayed fluorescence(TADF)molecule MNI-PTZ 1.We further demonstrate the practical utility of the OMNI-PTZ 2(G)in high-performance X-ray detection and imaging,achieving an X-ray dose sensitivity of 97 nGy s−1 and an exceptional spatial resolution of 20 lp/mm.Our study provides a promising molecular design principle for utilizing triplet excitons to develop high-efficiency and fast X-ray scintillators for the development of next-generation flexible and stretchable X-ray imaging detectors.

Halogenated Thermally Activated Delayed Fluorescence Materials for Efficient Scintillation

Organic scintillators,materials with the ability to exhibit luminescence when exposed to X-rays,have aroused increasing interest in recent years.However,the enhancement of radioluminescence and improving X-ray absorption of organic scintillators lie in the inherent dilemma,due to the waste of triplet excitons and weak X-ray absorption during scintillation.Here,we employ halogenated thermally activated delayed fluorescence materials to improve the triplet exciton utilization and X-ray absorption simultaneously,generating efficient scintillation with a low detection limit,which is one order of magnitude lower than the dosage for X-ray medical diagnostics.Through experimental study and theoretical calculation,we reveal the positive role of X-ray absorption,quantum yields of prompt fluorescence,and intersystem crossing in promoting the radioluminescence intensity.This finding offers an opportunity to design diverse types of organic scintillators and expands the applications of thermally activated delayed fluorescence.

Recent Development in X-Ray Imaging Technology:Future and Challenges

X-ray imaging is a low-cost,powerful technology that has been extensively used in medical diagnosis and industrial nondestructive inspection.The ability of X-rays to penetrate through the body presents great advances for noninvasive imaging of its internal structure.In particular,the technological importance of X-ray imaging has led to the rapid development of highperformance X-ray detectors and the associated imaging applications.Here,we present an overview of the recent development of X-ray imaging-related technologies since the discovery of X-rays in the 1890s and discuss the fundamental mechanism of diverse X-ray imaging instruments,as well as their advantages and disadvantages on X-ray imaging performance.We also highlight various applications of advanced X-ray imaging in a diversity of fields.We further discuss future research directions and challenges in developing advanced next-generation materials that are crucial to the fabrication of flexible,low-dose,highresolution X-ray imaging detectors.

Recent advances in metal-organic frameworks for X-ray detection

Metal-organic frameworks(MOFs)are a class of fascinating supramolecular crystalline materials that have been widely developed for catalysis,gas storage,illumination,drug delivery/cytoprotection,and so on.Recently,MOFs have been found to have potential applications in X-ray detection due to their high sensitivity,fast response time,high absorption coefficient,and radiation stability.In this review,we present an overview on the fundamental mechanism of using MOFs for X-ray scintillation.We further discuss the recent developments in X-ray detection based on indirect X-ray scintillation and direct X-ray conversion.Finally,we provide a summary and a perspective on the future of this promising research field.

Recent Development in X-Ray Imaging Technology: Future and Challenges

X-ray imaging is a low-cost,powerful technology that has been extensively used in medical diagnosis and industrial nondestructive inspection.The ability of X-rays to penetrate through the body presents great advances for noninvasive imaging of its internal structure.In particular,the technological importance of X-ray imaging has led to the rapid development of highperformance X-ray detectors and the associated imaging applications.Here,we present an overview of the recent development of X-ray imaging-related technologies since the discovery of X-rays in the 1890s and discuss the fundamental mechanism of diverse X-ray imaging instruments,as well as their advantages and disadvantages on X-ray imaging performance.We also highlight various applications of advanced X-ray imaging in a diversity of fields.We further discuss future research directions and challenges in developing advanced next-generation materials that are crucial to the fabrication of flexible,low-dose,highresolution X-ray imaging detectors.