Scintillator Films Research Articles

Highly Efficient Flexible Antimony Halide Scintillator Films with In Situ Preparation for High‐Resolution X‐Ray Imaging

AbstractFlexible scintillators with high light yield, spatial resolution and low light scattering are ideal for X‐ray imaging application. However, conventional scintillators are always prepared by crystallization of functional layer, grinding and mixing with polymers, resulting in serious light scattering. Herein, an in situ fabrication strategy is proposed to prepare a low light scattering flexible scintillator film based on 0D antimony halide C38H36P2SbCl5 (MTP2SbCl5). The prepared scintillator film exhibits bright yellow emission with an outstanding photoluminescence quantum yield (PLQY) of 99.69%, and it demonstrates linear responsiveness to X‐ray dose, achieving an impressive light yield of 39800 photons MeV−1 and a low detection limitation of 78.4 nGyair s−1. The scintillator film possesses strong radiation hardness and stability. In addition, low light scattering greatly inhibits optical crosstalk during X‐ray detection, effectively improving the spatial resolution of MTP2SbCl5 film from 4.5 to 10.2 lp mm−1. On account of the simple preparation method and high performance, this work provides guidance for the preparation of high‐efficiency, large‐area, low‐scattering and high‐resolution flexible scintillator in the future.

Tailoring efficient manganese bromide-based scintillator films with ethyl acetate assistance

Metal halide scintillators serve as a compelling substitute for traditional scintillators in X-ray detection and imaging due to their low-temperature fabrication process, high light yield and mechanical flexibility. Nevertheless, the spatial resolution and photoluminescence quantum yield (PLQY) of these films are hindered by the agglomeration and uneven distribution of metal halides crystal particles during the fabrication process. We introduce a modified fabrication approach for metal halide scintillator films involving an additional step of ethyl acetate (EA) treatment, resulting in the preparation of a smooth EA-treated (Ph4P)2MnBr4/Polydimethylsiloxane film. The carbonyl groups within EA interact with elements of the (Ph4P)2MnBr4 microcrystals powder, ensuring uniform dispersion and preventing agglomeration. The EA-treated composite film demonstrates a remarkable PLQY of approximately 95% and an impressive spatial resolution of 14 lp/mm, with enhanced stability under harsh environments. These characteristics ensure its suitability as a high-performance X-ray imaging scintillator.&#xD.

Reversible Interconversion between Ag2 and Ag6 Clusters and Their Responsive Optical Properties.

The exploration of structural interconversion in clusters triggered by external stimuli has attracted significant interest due to its potential to elucidate structure-property relationships of metal clusters. In this study, two types of silver clusters, Ag2 and Ag6, are synthesized. Interestingly, the clusters exhibit reversible transformations in response to changes in the solvent conditions. The structures and optical properties of these clusters are thoroughly characterized using techniques such as mass spectrometry, single-crystal X-ray diffraction, photoluminescence, and radioluminescence spectroscopy. While both Ag2 and Ag6 display excellent photoluminescence properties, Ag2 demonstrates superior performance in X-ray radioluminescence compared to Ag6. Flexible scintillator films fabricated from Ag2 clusters exhibit outstanding X-ray imaging capabilities, achieving a spatial resolution of 15.0 lp/mm and an impressive detection limit for an X-ray dose of 0.58 μGy s-1. This detection limit is nearly 10 times lower than the typical dose rate used in X-ray diagnostics (5.5 μGy s-1). This work introduces a novel approach for designing thiol-free silver clusters capable of solvent-dependent reversible interconversion, offering new insights into the development of silver clusters for advanced X-ray imaging applications.

3D printed microcrystalline CsI:Tl composite scintillating thin films for X-ray imaging

The utilization of additive manufacturing techniques, especially Digital Light Printing (DLP), in fabricating CsI:Tl scintillator films demonstrates considerable potential for streamlining the production of scintillators tailored for X-ray imaging applications. This research focuses on the fabrication of CsI:Tl-based composite plastic scintillator thin films. In this study, circular films measuring 1-inch in diameter and 0.1 mm & 0.2 mm in thickness are being produced and tested for gamma photon counts under alpha and gamma radiation. To establish the stopping power range of the films, a Monte Carlo based GEANT4 simulation has been carried out. Additionally, investigations into their suitability for X-ray imaging applications are being conducted, revealing the spatial resolution of the films (0.2 and 0.1 mm) between 100 and 130 μm and 1.26 lp/mm with a contrast range of 4.0–12.3 %. The observed decrease in spatial resolution and contrast for the 0.2 mm thick film is attributed to the thickness increase exacerbating the scattering phenomenon while simultaneously enhancing the X-ray stopping power. This highlights the significance of inherent trade-off between maximizing spatial resolution and compromising light yield of 0.1 mm films compared to the 0.2 mm thick film. By utilizing 3D printing, this approach offers a cost-effective and time-efficient method for producing thin-film scintillators with enhanced flexibility and customization options compared to conventional methods.

In Situ Growth of Lead‐Free Double Perovskite Micron Sheets in Polymethyl Methacrylate for X‐Ray Imaging

AbstractPb‐free double‐perovskite (DP) scintillators are highly promising candidates for X‐ray imaging because of their superior optoelectronic properties, low toxicity, and high stability. However, practical applications require Pb‐free DP crystals to be ground and mixed with polymers to produce scintillator films. Grinding can compromise film uniformity and optical properties, thereby affecting imaging resolution. In this study, an in situ fabrication strategy is proposed to facilitate the crystalline growth of Pb‐free Cs2AgInxBi1‐xCl6 micron sheets in polymethyl methacrylate in a single step. By adjusting the In3+/Bi3+ ratio, Cs2AgIn0.9Bi0.1Cl6/PMMA composite films (CFs) with excellent scintillation properties are obtained, including a light yield of up to 32000 photons per MeV and an X‐ray detection limit of 87 nGyairs−1. This strategy also enabled the production of large Cs2AgIn0.9Bi0.1Cl6/PMMA CFs, which demonstrated favorable flexibility and stability, fabricating products with advanced eligibility for commercial applications. The CFs exhibited outstanding performances in X‐ray imaging, producing high‐resolution structures and providing a new avenue for the development of Pb‐free DP materials in fields such as medical imaging and safety detection.

Thermal stability and flexible X-Ray scintillation screen through in-situ assembling Cs3Cu2Cl5 nanocrystals in polymer matrix

Copper-based halides have emerged as promising scintillator materials for X-ray imaging, attributed to their favorable photophysical characteristics, such as negligible self-absorption, high light output, and fast decay. Within this category of materials, Cs3Cu2Cl5 composite polymer scintillator films stand out, delivering excellent performance as flexible X-ray detector screens. However, severe scattering and light degradation induced by the inevitable agglomeration during recombination restricted the application in high-resolution and flexible X-ray imaging. In this study, a Cs3Cu2Cl5@PMMA film prepared by in-situ growth strategy is successfully developed, which represents uniform area, adjustable flexibility and excellent scintillation performance. The prepared large-area film exhibits green emission at 527 nm, with a high light yield, low detection limit and excellent spatial resolution. Meanwhile, the Cs3Cu2Cl5@PMMA film exhibits a remarkable degree of flexibility, enabling imaging applications on non-planar surfaces. Furthermore, it also demonstrates excellent resistance to high temperature environment, maintaining its high-quality imaging performance at 403 K.

One-Dimensional Copper-Doped Rb2AgI3 with Efficient Sky-Blue Emission as a High-Performance X-ray Scintillator.

Scintillators have garnered heightened attention for their diverse applications in medical imaging and security inspection. Nonetheless, commercial scintillators encounter challenges with costly rare-earth metals and toxic elements like thallium (Tl), driving the need for sustainable, cost-effective, and eco-friendly alternatives to meet contemporary X-ray detection demands. This study focuses on exploring the potential of Cu+-doped Rb2AgI3 as an effective metal halide (MH) scintillator. One-dimensional (1D) Rb2AgI3 and Cu+-doped Rb2AgI3 single crystals (SCs) were synthesized by using the conventional temperature-lowering crystallization method. When excited by UV light, Cu+-doped SCs emitted a broad sky-blue light at 490 nm with a high photoluminescence (PL) quantum yield (PLQY) of 76.48%. Remarkably, under X-ray excitation, these Cu+-doped SCs demonstrated an outstanding light yield of 36,293 photons MeV-1, a relatively low detection threshold of 1.022 μGyair s-1, and a rapid scintillation decay time of 465 ns. The prepared translucent scintillation film has good uniformity and flexibility, with a high spatial resolution of 10.2 lp mm-1. These results position Cu+-doped Rb2AgI3 as a leading candidate among promising X-ray scintillators, offering superior scintillation light yield, excellent stability, and nontoxicity.

Luminescence Improvement of Hybrid Zinc‐Based Halides via Sb3+‐Doping for Flexible X‐Ray Imaging

AbstractRecently, zinc‐based metal halides have attracted numerous attention due to their excellent stability, low toxicity, and wide bandgaps. However, [ZnX4]2− tetrahedra in zinc‐based halides are found to be non‐optically active, which leads to poor photoluminescence quantum yields (PLQYs). Herein, Sb3+ ions are doped into hybrid zinc‐based halides of (C8H26N4)ZnCl6 single crystals (SCs) via an evaporative crystallization method. Compared with undoped (C8H26N4)ZnCl6 SCs with weak blue emission, Sb3+‐doped (C8H26N4)ZnCl6 SCs exhibit a strong broadband emission centered at 694 nm with a high PLQY of 67%, which is confirmed to be derived from self‐trapped excitons (STEs) of Sb3+ luminescent centers. Subsequently, Sb3+‐doped (C8H26N4)ZnCl6 is employed in flexible scintillation films, which demonstrates remarkable X‐ray imaging of complex objects with a spatial resolution of 3.6 lp mm−1 and a detection limit of 123.8 µGyair s−1, proving its promising potential in flexible X‐ray imaging applications.

Enhancing X‐Ray Excited Persistent Luminescence in Lanthanide‐Doped Fluoride Nanoparticles via a Versatile Acid Pickling Strategy

AbstractX‐ray excited persistent luminescence (XEPL) of lanthanide‐doped fluoride nanoparticles (NPs) holds promise for applications in back‐ground free bio‐medicine and flexible 3D imaging. However, it remains a daunting challenge to develop a universal and convenient route to greatly improve the XEPL performance of most fluoride nanosystems. Herein, for the first time, a versatile acid pickling strategy is proposed to greatly enhance the XEPL intensity of lanthanide‐doped fluoride NPs with different chemical compositions and activator types. Especially, after treatment with diluted HCl, the XEPL intensity of the NaYF4: Tb NPs with a mean particle size of ≈ 7 nm is enhanced ≈17.4 times. Mechanistic studies indicate the trap density in the NPs upon X‐ray irradiation is greatly enhanced after HCl treatment, contributing to the enhanced XEPL intensity. By integrating the HCl‐treated NPs into a scintillation film, the X‐ray image resolution is significantly increased from 6.3 to 11 lp mm−1, and the quality of delayed X‐ray images improved, particularly at low‐dose irradiation rates. These findings are expected to advance the development of high‐performance X‐ray‐activated persistent fluoride NPs and their applications for low‐dose high‐resolution X‐ray imaging.

Optimized Gd2O2S:Pr Scintillation Films for X-ray Flat Panel Imaging: Balancing Enhanced Efficiency with Flexibility

Optimized Gd₂O₂S:Pr Scintillation Films for X-ray Flat Panel Imaging: Balancing Enhanced Efficiency with Flexibility

Ultrastable and flexible glass−ceramic scintillation films with reduced light scattering for efficient X−ray 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 nGyair 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 μGyair 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.

High-Resolution X-ray Image from Copper-Based Perovskite Hybrid Polymer.

Cs3Cu2I5 nanocrystals (NCs) are considered to be promising materials due to their high photoluminescence efficiency, lack of lead toxicity, and X-ray responsiveness. However, during the crystallization process, NCs are prone to agglomeration and exhibit uneven size distribution, resulting in several light scattering that severely affect their imaging resolution. Herein, we successfully developed a high-resolution scintillator film by growing copper-based perovskite NCs within a hybrid polymer matrix. By leveraging the ingenious integration of polyvinylidene fluoride (PVDF) and polymethyl methacrylate (PMMA), the size and distribution uniformity of Cs3Cu2I5 NCs can be effectively controlled. Consequently, a high spatial resolution of 14.3 lp mm-1 and a low detection limit of 105 nGy s-1 are achieved, and the scintillator film has excellent flexibility and stability. These results highlight the promising application of Cs3Cu2I5 scintillator films in low-cost, flexible, and high-performance medical imaging.

Development of a Method to Measure Trace Levels of Uranium and Thorium in Scintillation Films

Abstract We have established a method to measure picograms-per-gram (pg g−1) levels of 238U and 232Th in scintillation films by combining the dry ashing method and inductively coupled plasma mass spectrometry. Trace amounts of 238U and 232Th were measured in up to 2 g of scintillation film with almost 100% collection efficiency. This paper details the experimental procedure, including the pretreatment of the samples and labware, detection limit of the method, collection efficiencies of 238U and 232Th, and measurement of 238U and 232Th in a polyethylene naphthalate film. This method is also applicable to 238U and 232Th measurements in other low-background organic materials for rare-event search experiments.

In-situ growth of Cs5Cu3Cl6I2 nanocrystals within AAO arrays for X-ray imaging

Lead-free halide perovskites have shown promising application for indirect X-ray detection as fascinating scintillator. The fabrication of pixelated scintillator films leveraging directional confinement allows high-resolution imaging, yet process complexity and the potential crystal structure damage pose challenges that compromises the corresponding scintillator performance. In this work, a facile in-situ strategy for growing scintillation perovskite of Cs5Cu3Cl6I2 within anodic aluminum oxide (AAO) membrane is developed as scintillator Cs5Cu3Cl6I2@AAO film. The as-fabricated pixelated scintillator array with an enhanced light directional confinement for high-resolution X-ray imaging is demonstrated. The corresponding film achieves a spatial resolution of approximately 20 lp mm−1 and a detection limit of 0.152 Gy·s−1. Moreover, the Cs5Cu3Cl6I2@AAO film performs excellent stability under long-term X-ray irradiation, making it a reliable option for cost-effective pixelated indirect X-ray imaging.

Flexible Wood‐Based X‐Ray Scintillator Film Using Lead‐Free Cs3Cu2I5 Perovskite Nanoparticles

The prevalent use of unsustainable polymers in current X‐ray scintillators poses a significant environmental concern. The advancement of biodegradable X‐ray scintillators holds promise in mitigating escalating environmental issues tied to electronic or medical waste and carbon footprints. Herein, a biodegradable and flexible X‐ray scintillation film is presented employing lead‐free 0D Cs3Cu2I5 perovskite nanoparticles integrated into densified‐delignified wood (Cs3Cu2I5@D‐Wood). The Cs3Cu2I5@D‐Wood film demonstrates precise and detailed X‐ray imaging capabilities, achieving a high spatial resolution of 10 line pairs per millimeter (lp·mm−1). To minimize the environmental impact associated with disposal, metal and halide ions (e.g., Cs+, Cu+, I−) from Cs3Cu2I5@D‐Wood can be easily retrieved by a simple solvent extraction process. The approach showcases the potential of biodegradable wood‐based X‐ray scintillation screens as alternatives to conventional, plastic‐based screens. This offers a significant contribution to environmental sustainability by reducing electronic or medical waste.

Event-based x-ray imager with ghosting-free scintillator film

Dynamic x-ray imagers have undergone extensive study due to their wide-ranging applications. However, as frame rates and resolutions increase, the accompanying growth in data volume imposes constraints on system capabilities, including data transmission, temporal bandwidth, processing capability, and power consumption. Herein we present a demonstration of an event-based x-ray imager that integrates Cs5Cu3Cl6I2 scintillator film, free from ghosting, with an event-based vision sensor. Each pixel operates autonomously, producing a signal only upon detecting a change in contrast intensity. The Cs5Cu3Cl6I2 scintillator film exhibits minimal ghosting artifacts (0.1%), which is a significant improvement compared to a conventional CsI:Tl scintillator (4.1%). The assembled imaging system finds practical applications in radiography and edge sharpening, achieving an impressive data compression ratio of 23.7%. Remarkably, this ratio is equivalent to the performance of intricate and energy-intensive software-based computing processes.

Growth of ultimate high-density scintillating films for high-resolution X-ray imaging at synchrotrons

Scintillators are X-ray to visible light converters applied in X-ray imaging detectors used at synchrotrons. Drastically improved performances of the 4th generation synchrotron sources enable us to perform X-ray imaging experiments at higher energies. For high spatial resolution X-ray imaging (micrometer to submicrometer), thin scintillating films are required. Consequently, especially for high X-ray energies (30keV to 100keV), the detection efficiency is limited due to the low X-ray absorption efficiency of the thin films. We have used Liquid Phase Epitaxy (LPE) to grow thin films of one of the ultimate high-density materials, Lu2Hf2O7:Eu3+, which demonstrate scintillating properties and thus combine high spatial resolution and maximized absorption efficiency. X-ray imaging experiments demonstrate that the Modulation Transfer Function (MTF) reaches 10% at 900 lp/mm, and radiographs visually confirm the promising imaging properties. We present structural, luminescent, and scintillation characterization of Lu2Hf2O7:Eu thin films grown on ZrO2:Y substrates, showing that the films crystallize in the disordered fluorite structure and the europium ions incorporate into the structure and enhance the luminescence intensity. This contribution is a first step toward developing promising ultra-dense, hafnate-based scintillating screens for high spatial resolution X-ray imaging.

Efficient Near‐Infrared Emitting Halide Scintillators with Mitigating External Light Crosstalk for Portable X‐Ray Imaging

AbstractPortable X‐ray imaging technology plays a crucial role in enabling prompt diagnosis and treatment outdoors. Nevertheless, the persistent challenge of external optical signal crosstalk poses a significant bottleneck to its advancement. Herein, a solution utilizing near‐infrared (NIR) light to effectively mitigate optical crosstalk is proposed, thereby demonstrating the feasibility of portable X‐ray imaging even under ambient light. A series of rare earth ions doped Cs2AgxNa1‐xInyBi1‐yCl6 halide scintillators is reported, which possess bright broadband visible and NIR emissions. Taking Cs2Ag0.6Na0.4In0.95Bi0.05Cl6: 5%Tm as an example, it shows decent thermal quenching resistance, high PLQY up to 76.3%, and compelling light yield up to 33500 photons MeV−1. The highly efficient NIR emission is attributed to the energy transfer from the optimized host to lanthanide ions. A flexible scintillation film is prepared by mixing poly(dimethyl‐siloxane) with Cs2Ag0.6Na0.4In0.95Bi0.05Cl6: 5%Tm powder, realizing a low X‐ray detection limit of 55.2 nGyair/s and a high spatial resolution of 11.2 lp mm−1. Due to the efficient NIR emission, the scintillation film enables clear X‐ray imaging under bright LED illumination with the simple addition of filters, avoiding the necessity of a complex imaging apparatus. This work sheds light on NIR emissive scintillator for rapid outdoor response and portable X‐ray imaging.

Colloidal Synthesis of Hollow Double Perovskite Nanocrystals and Their Applications in X-ray Imaging.

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.

Preparing the In-doped lead-free Cs3Cu2I5 perovskite scintillator by a co-firing technique for its application in high-resolution X-ray imaging

The perovskite scintillators have been extensively studied recently for their merits of tunable emission spectra and simple preparation processes. However, the practical applications of perovskite scintillator-based X-ray image sensor are still impeded by inadequate radioluminescence, poor environmental stability, and low imaging resolution. Herein, we demonstrate a scalable co-firing method to fabricate high-quality lead-free Cs3Cu2I5 perovskite scintillator and an Indium (In)-doping strategy is introduced to enhance its radioluminescence performance at the same time. The In-doped Cs3Cu2I5 obtains a high PLQY of 77.9% and a relative light output of 53372 ph/MeV, which are 0.34 and 1.08 times higher than those of the undoped counterpart, respectively. The X-ray detection limit of the In:Cs3Cu2I5 can reach 150.55 nGyair/s, 36.53 times lower than the requirement for X-ray medical diagnosis. The synthesized scintillator also shows superior stability under continuous high dose X-ray irradiation of 6800 μGyair/s for 120 minutes, maintaining 95% of its initial radioluminescence intensity. Furthermore, a large-area (300 cm2) flexible perovskite scintillator film is prepared, which owns a much competitive resolution of 10 lp/mm and less distortion in X-ray imaging. This work provides a practical path for the wide application of perovskite scintillator in the field of X-ray detection and imaging in near future.