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ConspectusX-ray luminescence is an optical phenomenon in which chemical compounds known as scintillators can emit short-wavelength light upon the excitation of X-ray photons. Since X-rays exhibit well-recognized advantages of deep penetration toward tissues and a minimal autofluorescence background in biological samples, X-ray luminescence has been increasingly becoming a promising optical tool for tackling the challenges in the fields of imaging, biosensing, and theragnostics. In recent years, the emergence of nanocrystal scintillators have further expanded the application scenarios of X-ray luminescence, such as high-resolution X-ray imaging, autofluorescence-free detection of biomarkers, and noninvasive phototherapy in deep tissues. Meanwhile, X-ray luminescence holds great promise in breaking the depth dependency of deep-seated lesion treatment and achieving synergistic radiotherapy with phototherapy.In this Account, we provide an overview of recent advances in developing advanced X-ray luminescence for applications in imaging, biosensing, theragnostics, and optogenetics neuromodulation. We first introduce solution-processed lead halide all-inorganic perovskite nanocrystal scintillators that are able to convert X-ray photons to multicolor X-ray luminescence. We have developed a perovskite nanoscintillator-based X-ray detector for high-resolution X-ray imaging of the internal structure of electronic circuits and biological samples. We further advanced the development of flexible X-ray luminescence imaging using solution-processable lanthanide-doped nanoscintillators featuring long-lived X-ray luminescence to image three-dimensional irregularly shaped objects. We also outline the general principles of high-contrast

There are few reports about purely organic phosphorescence scintillators, and the relationship between molecular structures and radioluminescence in organic scintillators is still unclear. Here, we presented isomerism strategy to study the effect of molecular structures on radioluminescence. The isomers can achieve phosphorescence efficiency of up to 22.8 % by ultraviolet irradiation. Under X-ray irradiation, both m-BA and p-BA show excellent radioluminescence, while o-BA has almost no radioluminescence. Through experimental and theoretical investigation, we found that radioluminescence was not only affected by non-radiation in emissive process, but also highly depended on the material conductivity caused by the different molecular packing. This study not only allows us to clearly understand the relationship between the molecular structures and radioluminescence, but also provides a guidance to rationally design new organic scintillators.

Cell temperature monitoring is of great importance to uncover temperature-dependent intracellular events and regulate cellular functions. However, it remains a great challenge to precisely probe the localized temperature status in living cells. Herein, we report a strategy for in situ temperature mapping on an immune cell membrane for the first time, which was achieved by using the lanthanide-doped upconversion nanoparticles. The nanothermometer was designed to label the cell membrane by combining metabolic labeling and click chemistry and can leverage ratiometric upconversion luminescence signals to in situ sensitively monitor temperature variation (1.4% K

Non-invasive phototherapy has been emerging as an ambitious tactic for suppression of amyloid-β (Aβ) self-assembly against Alzheimer's disease (AD). However, it remains a daunting challenge to develop efficient photosensitizers for Aβ oxygenation that are activatable in a deep brain tissue through the scalp and skull, while reducing side effects on normal tissues. Here, we report an Aβ targeted, low-dose X-ray-excitable long-afterglow scintillator (ScNPs@RB/Ab) for efficient deep-brain phototherapy. We demonstrate that the as-synthesized ScNPs@RB/Ab is capable of converting X-rays into visible light to activate the photosensitizers of rose bengal (RB) for Aβ oxygenation through the scalp and skull. We show that the ScNPs@RB/Ab persistently emitting visible luminescence can substantially minimize the risk of excessive X-ray exposure dosage. Importantly, peptide KLVFFAED-functionalized ScNPs@RB/Ab shows a blood-brain barrier permeability. In vivo experimental results validated that ScNPs@RB/Ab alleviated Aβ burden and slowed cognitive decline in triple-transgenic AD model mice at extremely low X-ray doses without side effects. Our study paves a new pathway to develop high-efficiency transcranial AD phototherapy. STATEMENT OF SIGNIFICANCE: Non-invasive phototherapy has been emerging as an ambitious tactic for suppression of amyloid-β (Aβ) self-assembly against Alzheimer's disease (AD). However, it remains a daunting challenge to develop efficient photosensitizers for Aβ oxygenation that are activatable in a deep brain tissue through the scalp and skull, while reducing side effects on normal tissues. Herein, we report an Aβ targeted, low-dose X-ray-excitable long-afterglow scintillators (ScNPs@RB/Ab) for efficient deep-brain phototherapy. In vivo experimental results validated that ScNPs@RB/Ab alleviated Aβ burden and slowed cognitive decline in triple-transgenic AD model mice at extremely low X-ray doses without side effects.

Current X-ray imaging technologies involving flat-panel detectors have difficulty in imaging three-dimensional objects because fabrication of large-area, flexible, silicon-based photodetectors on highly curved surfaces remains a challenge1–3. Here we demonstrate ultralong-lived X-ray trapping for flat-panel-free, high-resolution, three-dimensional imaging using a series of solution-processable, lanthanide-doped nanoscintillators. Corroborated by quantum mechanical simulations of defect formation and electronic structures, our experimental characterizations reveal that slow hopping of trapped electrons due to radiation-triggered anionic migration in host lattices can induce more than 30 days of persistent radioluminescence. We further demonstrate X-ray luminescence extension imaging with resolution greater than 20 line pairs per millimetre and optical memory longer than 15 days. These findings provide insight into mechanisms underlying X-ray energy conversion through enduring electron trapping and offer a paradigm to motivate future research in wearable X-ray detectors for patient-centred radiography and mammography, imaging-guided therapeutics, high-energy physics and deep learning in radiology. Using lanthanide-doped nanomaterials and flexible substrates, an approach that enables flat-panel-free, high-resolution, three-dimensional imaging is demonstrated and termed X-ray luminescence extension imaging.

Materials that exhibit X-ray-excited luminescence have great potential in radiation detection, security inspection, biomedical applications and X-ray astronomy1–5. However, high-performance materials are almost exclusively limited to ceramic scintillators, which are typically prepared under high temperatures6. Herein we report metal-free organic phosphors based on a molecular design that supports efficient triplet exciton harvesting to enhance radioluminescence. These organic scintillators exhibit a detection limit of 33 nGy s–1, which is 167 times lower than the standard dosage for X-ray medical examination and we demonstrate their potential application in X-ray radiography. These findings provide a fundamental design principle and new route for the creation of promising alternatives to incumbent inorganic scintillators. Furthermore, they offer new opportunities for development of flexible, stretchable X-ray detectors and imagers for non-destructive radiography testing and medical imaging. Organic, metal-free materials that act as efficient X-ray scintillators could bring new opportunities for X-ray imaging.

ConspectusOwing to their unique features, the past decade has witnessed rapid developments of lanthanide-activated nanoparticles for biological applications. These include highly tunable upconverting and downshifting photoluminescence when illuminated in deep tissue, excellent photostability against blinking and bleaching effects, biocompatibility through versatile surface modification, and ease of achieving multifunctionality, as well as satisfactory signal output. These attributes make lanthanide-doped nanoparticles an ideal toolbox for advanced bioimaging and next-generation therapeutics.The interest in lanthanide-doped nanoparticles for biomedical research arises from their unique optical properties in response to deep-tissue-penetrable light sources. Upon near-infrared irradiation, these nanoparticles with properly doped emitters display photon upconversion with large anti-Stokes shifts and broad-spectrum tunability from the ultraviolet to the visible. It is also possible to achieve orthogonal photoluminescence with variations in wavelength and lifetime. Coupled with surface ligands, dyes, biomolecules, or other types of functional nanomaterials, lanthanide-doped nanoparticles offer new opportunities for applications in bioimaging, advanced oncotherapy, and neuromodulation. Given the possibility of locating downshifting luminescence at "biological transmission windows", exquisite design of lanthanide-doped nanoparticles also enables deep-tissue imaging with high spatial resolution. In addition, these nanoparticles can respond to high-energy photons, such as X-rays, to trigger nonradioactive and radiative pathways, making it possible to develop high-sensitivity X-ray detectors. Precise control of paramagnetic lanthanide ions in nanocrystal lattices also provides advanced materials for high-performance magnetic resonance imaging in medical diagnostics and biomedical research. Full consideration of fundamental attributes of lanthanide-doped nanoparticles will facilitate the design of multifunctional and sensitive probes and improve diagnostic and therapeutic outcomes.In this Account, we categorize various lanthanide-activation strategies into three modes: near-infrared excitation, X-ray irradiation, and magnetic field stimulation. We introduce energy manipulations in upconverting, downshifting, and persistence luminescence in spectral and time domains and discuss how they can be applied in biological practices. We assess general design principles for lanthanide-activated nanosystems with multiple modalities of bioimaging, oncotherapy, and neuromodulation. We also review the current state-of-the-art in the field of lanthanide-based theranostic nanoplatforms, with particular emphasis on energy conversion and nano-/biointerfacing as well as emerging bioapplications. In this context, we also highlight recent advances in controlling optical properties of nanoplatforms for single- or multimodal bioimaging, stimulus-responsive phototherapy, and optogenetics. Finally, we discuss future opportunities and challenges of this exciting research field.

Three-dimensional (3D) tumor spheroids offer unprecedented capability for drug screening because of their unique features such as spatial 3D structure, relevant physiological responses, more complex intercellular network, and stroma-cancer cell interactions. Microfluidic technology provides a facile strategy to make uniform tumor spheroids with potential of high-throughput production. In this article, we develop a microfluidic approach to produce core-shell alginate particles, which allows the separate confinement of different cells in the core and shell structure. To reconstitute the complex tumor structure, we encapsulated tumor cells in the core and stromal fibroblast cells in the shell. These coculture tumor spheroids were applied for drug evaluation showing similar drug resistance as those prepared using conventional methods in well plates. These results demonstrated that our microfluidic approach are facile and versatile for making various tumor spheroids with uniform size but different components to better mimic tumor microenvironment. Moreover, the production rate of around 200 spheroids/min indicates the great potential of this approach for high-throughput drug screening.

We present X-ray-excitable organic ultralong room temperature phosphorescence (X-OURTP) for afterglow scintillators through implanting lone-pair electron involved n–π* transitions and efficient charge transfer characters into H-aggregations of organic crystals. The thus designed X-OURTP molecule exhibits ultralong lifetimes up to 790 ms, high phosphorescence quantum yields of ∼8%, and excellent scintillation stability. These findings will pave the way to the design of organic afterglow scintillators, simulating extensive investigations on the extraordinary X-OURTP.

Materials that exhibit X-ray excited luminescence have great potential in radiation detection, security inspection, biomedical applications, and X-ray astronomy1-4. However, such materials are almost exclusively limited to inorganic crystals, which are typically prepared under high temperatures5. Herein, we report a design principle of purely organic phosphors to boost X-ray excited luminescence with sufficient utilization of triplet excitons. Our experimental data reveal that proportion of emission from bright triplet excitons is significantly improved upon X-ray irradiation, compared with UV excitation. These organic phosphors have a detection limit of 33 nGy/s, which is 167 times lower than the standard dosage for X-ray medical examinations. We further demonstrated their potential application in X-ray radiography, which can be conveniently recorded using a digital camera. These findings illustrate a fundamental principle to design efficient X-ray excited purely organic phosphors, propelling the development of radioluminescence related applications.

Current X-ray imaging technologies involving flat-panel detectors have difficulty in imaging three-dimensional objects because fabrication of large-area, flexible, silicon-based photodetectors on highly curved surfaces remains a challenge

Achieving efficient photon upconversion under low irradiance is not only a fundamental challenge but also central to numerous advanced applications spanning from photovoltaics to biophotonics. However, to date, almost all approaches for upconversion luminescence intensification require stringent controls over numerous factors such as composition and size of nanophosphors. Here, we report the utilization of dielectric microbeads to significantly enhance the photon upconversion processes in lanthanide-doped nanocrystals. By modulating the wavefront of both excitation and emission fields through dielectric superlensing effects, luminescence amplification up to 5 orders of magnitude can be achieved. This design delineates a general strategy to converge a low-power incident light beam into a photonic hotspot of high field intensity, while simultaneously enabling collimation of highly divergent emission for far-field accumulation. The dielectric superlensing-mediated strategy may provide a major step forward in facilitating photon upconversion processes toward practical applications in the fields of photobiology, energy conversion, and optogenetics., Emission levels useful for applications from upconversion nanoparticles require high laser irradiance. Here, Liang et al. exploit the superlensing effect from dielectric microbeads to enhance the luminescence efficiency of upconversion nanoparticles and show its application for optogenetics.

： Colloidal nanocrystal scintillators hold great potential in fabricating large-area, flexible X-ray detectors for high-resolution X-ray imaging of highly curved, irregularly shaped objects. The synthesis of high-efficiency, high-stability nanoscintillators is of great importance for the development of X-ray imaging detectors. In this study, we develop a class of cerium (Ce3+)-sensitized core-shell nanoscintillators that are suitable for achieving flexible X-ray luminescence imaging. We demonstrate that an epitaxial growth of NaGdF4:Ce(60%) on the surface of NaGdF4:Eu(15%) nanoscintillators as a sensitization layer allows for enhancing X-ray-induced radioluminescence. We reveal that the enhancement of X-ray luminescence in nanoscintillators could be attributed to the synergistic effect of high-Z composition-induced X-ray absorption, Ce3+ sensitization, and surface passivation to relieve energy quenching. By incorporating the nanoscintillators into a flexible elastomer of polydimethylsiloxane (PDMS), we demonstrate its utility in high-resolution flexible X-ray luminescence imaging.

Natural colorants, which impart a vivid color to food and add additional health benefits, are favored over synthetic colorants; however, their applications are limited by their low solubility in water and low stability. Here, we develop a versatile microfluidic strategy to incorporate natural colorants in shellac nanoparticles with controlled physicochemical properties. The rapid mixing in the microfluidic channels ensures that the mixing time is shorter than the aggregation time, thus providing control over the co-precipitation of the colorant and the polymer. By introducing molecular interactions, colorant nanoaggregates are efficiently embedded in the polymer matrix, forming hierarchical colorant-loaded nanoparticles. The colorant-loaded nanoparticles dispersed in water are transparent and stable over a wide pH range and their polymer matrix also provides a favorable microenvironment that greatly improves the shelf life of the colorants. The improved solubility, stability and bioavailability of the natural colorants suggest that shellac nanoparticles are ideal carriers and the stable, transparent dispersions of biocompatible colorant-loaded nanoparticles in water are well-suited for the development of functional foods, such as natural color drinks.

Solution-processed metal-halide perovskites hold great promise in developing next-generation low-cost, high-performance photodetectors. However, the weak absorption of perovskites beyond the near-infrared spectral region posts a stringent limitation on their use for broadband photodetectors. Here, the rational design and synthesis of an upconversion nanoparticles (UCNPs)-perovskite nanotransducer are presented, namely UCNPs@mSiO2 @MAPbX3 (X = Cl, Br, or I), for broadband photon detection spanning from X-rays, UV, to NIR. It is demonstrated that, by in situ crystallization and deliberately tuning the material composition in the lanthanide core and perovskites, the nanotransducers allow for a high stability and show a wide linear response to X-rays of various dose rates, as well as UV/NIR photons of various power densities. The findings provide an opportunity to explore the next-generation broadband photodetectors in the field of high-quality imaging and optoelectronic devices.

Microfluidic technologies enable temporal and spatial control of cellular microenvironments by mimicking the complex biological functions of normal cellular interactions, thus opening new opportunities for cell-based drug screening. Microfluidic devices with large-scale integration, automatic operation, and micro-sized scale offer many unique benefits including high throughputs, low cost, and high efficiency in drug development. Here, we review the recent fundamental development of microfluidic three-dimensional (3D) cellular scaffolds and highlight the perspective of drug assay applications in relation to drug screening and nanodrug cytotoxicity analysis. In particular, we discuss the advances in diverse biomimetic strategies including microfabricated 3D cell culture systems, droplet-based 3D hydrogel scaffolds for cell encapsulation, and organs- and tissues-on-chips. A brief summary is also presented along with a perspective of this field in the future.

Efficient platforms for cell isolation and analysis play an important role in applied and fundamental biomedical studies. As cells commonly have a size of around 10 microns, conventional handling approaches at a large scale are still challenged in precise control and efficient recognition of cells for further performance of isolation and analysis. Microfluidic technologies have become more prominent in highly efficient cell isolation for circulating tumor cells (CTCs) detection, single-cell analysis and stem cell separation, since microfabricated devices allow for the spatial and temporal control of complex biochemistries and geometries by matching cell morphology and hydrodynamic traps in a fluidic network, as well as enabling specific recognition with functional biomolecules in the microchannels. In addition, the fabrication of nano-interfaces in the microchannels has been increasingly emerging as a very powerful strategy for enhancing the capability of cell capture by improving cell-interface interactions. In this review, we focus on highlighting recent advances in microfluidic technologies for cell isolation and analysis. We also describe the general biomedical applications of microfluidic cell isolation and analysis, and finally make a prospective for future studies.

Biochemical analysis is crucial in understanding mechanism of life activities and giving biological insights into life process. With inherent merits in flexible design, microscale of operation, good incorporation with other techniques for manipulation and detection, microfluidic chip has introduced new paradigms in biochemical analysis field. Considering the explosive development of microfluidics over the past decades, in this review, we summarized recent advances in biochemical analysis on microfluidic platforms. Highlight was put on the integrated technologies such as optical, electrical, acoustic and magnetic techniques. Focus also was given on relative applications in biomimetics, drug screening, biomolecular detection, single cell and stem cell analysis.

Scintillators, which are capable of converting ionizing radiation into visible photons, are an integral part of medical, security, and commercial diagnostic technologies such as X-ray imaging, nuclear cameras, and computed tomography. Conventional scintillator fabrication typically involves high-temperature sintering, generating agglomerated powders or large bulk crystals, which pose major challenges for device integration and processability. On the other hand, colloidal quantum dot scintillators cannot be cast into compact solid films with the necessary thickness required for most X-ray applications. Here, we report the room-temperature synthesis of a colloidal scintillator comprising CsPbBr3 nanosheets of large concentration (up to 150 mg/mL). The CsPbBr3 colloid exhibits a light yield (∼21000 photons/MeV) higher than that of the commercially available Ce:LuAG single-crystal scintillator (∼18000 photons/MeV). Scintillators based on these nanosheets display both strong radioluminescence (RL) and long-term stability under X-ray illumination. Importantly, the colloidal scintillator can be readily cast into a uniform crack-free large-area film (8.5 × 8.5 cm2 in area) with the requisite thickness for high-resolution X-ray imaging applications. We showcase prototype applications of these high-quality scintillating films as X-ray imaging screens for a cellphone panel and a standard central processing unit chip. Our radiography prototype combines large-area processability with high resolution and a strong penetration ability to sheath materials, such as resin and silicon. We reveal an energy transfer process inside those stacked nanosheet solids that is responsible for their superb scintillation performance. Our findings demonstrate a large-area solution-processed scintillator of stable and efficient RL as a promising approach for low-cost radiography and X-ray imaging applications.

Lanthanide-doped upconversion nanoparticles capable of converting incident near-infrared (NIR) photons into visible emission have been widely used in light-mediated theranostics due to their advantages of deep-tissue penetration, nonblinking luminescence, high photostability, and excellent biocompatibility. These unique features make them attractive in biosensing, optical imaging, and noninvasive therapy for biomedical applications. In this chapter, we present an overview of recent developments of upconversion nanomaterials for NIR light-mediated theranostics. We give a brief introduction to lanthanide-doped upconversion nanoparticles and discuss their utility as nanoprobes in biological detection, in vivo optical imaging, and biomedical therapy. At the end of the chapter we give a summary on the development and perspectives in this field.

Droplet microfluidic techniques have been rapidly developed as a powerful tool to perform high-throughput and low-cost analysis of single cells. Microscale droplets can be easily produced by a microfluidic manipulation to encapsulate and manipulate single cells for precise analysis. This offers a new approach to measure genetic and functional heterogeneity of cell division, growth, metabolism, and apoptosis. Functional characteristics of cellular molecules, such as DNA, RNA, and proteins, can be realized at a single-cell level. In this chapter, we will present a general introduction to single-cell analysis involving droplet-based microfluidic techniques. We will highlight the current state of droplet-based microfluidic single-cell analysis for deep insights understanding the biological process at the single-cell level.

The rate-determining process for electrochemical energy storage is largely determined by ion transport occurring in the electrode materials. Apart from decreasing the distance of ion diffusion, the enhancement of ionic mobility is crucial for ion transport. Here, a localized electron enhanced ion transport mechanism to promote ion mobility for ultrafast energy storage is proposed. Theoretical calculations and analysis reveal that highly localized electrons can be induced by intrinsic defects, and the migration barrier of ions can be obviously reduced. Consistently, experiment results reveal that this mechanism leads to an enhancement of Li/Na ion diffusivity by two orders of magnitude. At high mass loading of 10 mg cm-2 and high rate of 10C, a reversible energy storage capacity up to 190 mAh g-1 is achieved, which is ten times greater than achievable by commercial crystals with comparable dimensions.

Glycans are crucial for many key biological processes and their alterations are often a hallmark of disease. Thus, multiplexed and sensitive analysis of glycans is of intense interest. Here we report a novel approach using DNA-mediated cell surface engineering for glycan profiling by MALDI-TOF mass spectrometry (MS). Following lectin binding, DNA amplification and hybridization, glycans on the cell surface are specifically labeled by short DNA probes, which can be facilely released, ionized and detected in MALDI-TOF MS. This strategy converts the analysis of glycans to the detection of DNA probes, overcoming the complicated composition and low ionization efficiency of glycans, enabling in situ detection and facilitating multiplex analysis. The amplification procedure also improves the sensitivity. This approach has been applied to evaluate glycomic alterations in cancer cells and provided the intrinsic distribution of glycans in tissues using MALDI imaging mass spectrometry.

Paper-supported cell culture is an unprecedented development for advanced bioassays. This study reports a strategy for in vitro engineering of cell-compatible paper chips that allow for adherent cell culture, quantitative assessment of drug efficiency, and label-free sensing of intracellular molecules via paper spray mass spectrometry. The polycarbonate paper is employed as an excellent alternative bioscaffold for cell distribution, adhesion, and growth, as well as allowing for fluorescence imaging without light scattering. The cell-cultured paper chips are thus amenable to fabricate 3D tissue construction and cocultures by flexible deformation, stacks and assembly by layers of cells. As a result, the successful development of cell-compatible paper chips subsequently offers a uniquely flexible approach for in situ sensing of live cell components by paper spray mass spectrometry, allowing profiling the cellular lipids and quantitative measurement of drug metabolism with minimum sample pretreatment. Consequently, the developed paper chips for adherent cell culture are inexpensive for one-time use, compatible with high throughputs, and amenable to label-free and rapid analysis.

In this work, the establishment of a glass spray mass spectrometry (GS-MS) platform for direct cell-based drug assay was described. Cell co-culture, drug-induced cell apoptosis, proliferation analysis and intracellular drug absorption measurement were performed simultaneously on this specifically designed platform. Two groups of co-cultured cells (NIH-3T3/HepG2 and HepG2/MCF-7) were cultivated and they showed high viability within 3 days. The biocompatibility of the platform facilitated the subsequent bioassays, in which, cyclophosphamide (CPA) and genistein were used as the model drugs. The distinctions of cell apoptosis and proliferation between the mono-cultured and co-cultured cells were clearly observed and well explained by in situ GS-MS measurements. A satisfactory linearity of the calibration curve between the relative MS intensity and CPA concentrations was obtained using stable isotope labeling method (y = 0.16545 + 0.0985x, R(2) = 0.9937). The variations in the quantity of absorbed drug were detected and the results were consistent with the concentration-dependence of cell apoptosis. All the results demonstrated that direct cell-based drug assay could be performed on the stable isotope labeling assisted GS-MS platform in a facile and quantitative manner.

The rising demand for radiation detection materials in many applications has led to extensive research on scintillators1–3. The ability of a scintillator to absorb high-energy (kiloelectronvolt-scale) X-ray photons and convert the absorbed energy into low-energy visible photons is critical for applications in radiation exposure monitoring, security inspection, X-ray astronomy and medical radiography4,5. However, conventional scintillators are generally synthesized by crystallization at a high temperature and their radioluminescence is difficult to tune across the visible spectrum. Here we describe experimental investigations of a series of all-inorganic perovskite nanocrystals comprising caesium and lead atoms and their response to X-ray irradiation. These nanocrystal scintillators exhibit strong X-ray absorption and intense radioluminescence at visible wavelengths. Unlike bulk inorganic scintillators, these perovskite nanomaterials are solution-processable at a relatively low temperature and can generate X-ray-induced emissions that are easily tunable across the visible spectrum by tailoring the anionic component of colloidal precursors during their synthesis. These features allow the fabrication of flexible and highly sensitive X-ray detectors with a detection limit of 13 nanograys per second, which is about 400 times lower than typical medical imaging doses. We show that these colour-tunable perovskite nanocrystal scintillators can provide a convenient visualization tool for X-ray radiography, as the associated image can be directly recorded by standard digital cameras. We also demonstrate their direct integration with commercial flat-panel imagers and their utility in examining electronic circuit boards under low-dose X-ray illumination. All-inorganic perovskite nanocrystals containing caesium and lead provide low-cost, flexible and solution-processable scintillators that are highly sensitive to X-ray irradiation and emit radioluminescence that is colour-tunable across the visible spectrum.

Important findings from a systematic investigation on Electro-Elasto-Optical characterization for PMN-PT based ferroelectric crystals. The new E-O material is biaxial EEO crystal with Ng=2.564, Nm=2.558, Np=2.545, 2V=109o and effective EO-coefficient γ c over 300∼600pm/V and Vπ less than 100 V.