ABSTRACT
Beamline BL08U1A is a soft X-ray spectromicroscopy beamline at Shanghai Synchrotron Radiation Facility (SSRF) that exhibits the capabilities of high spatial resolution (30â nm) and high energy resolving power (over 104). As a first-generation beamline of SSRF, owing to its continuous operation over the last ten years, an urgent upgrade of the equipment including the monochromator was deemed necessary. The upgrade work included the overall construction of the monochromator and replacement of the mirrors upstream and downstream of the monochromator. Based on its original skeleton, two elliptically cylinder mirrors were designed to focus the beam horizontally, which can increase the flux density by about three times on the exit slits. Meanwhile, the application of variable-line-space gratings in the monochromator demonstrates the dual functions of dispersing and focusing on the exit slits which can decrease abberations dramatically. After the upgrade of the main components of the beamline, the energy range is 180-2000â eV, the energy resolving power reaches 16333 @ 244â eV and 12730 @ 401â eV, and the photon flux measured in the experimental station is over 2.45 × 109â photonsâ s-1 (E/ΔE = 6440 @ 244â eV).
ABSTRACT
Solution-processable perovskite-based devices are potentially very interesting because of their relatively cheap fabrication cost but outstanding optoelectronic performance. However, the solution spin-coating process involves complicated processes, including perovskite solution droplets, nucleation of perovskite, and formation of intermediate perovskite films, resulting in complicated crystallization pathways for perovskite films under annealing. Understanding and therefore controlling the fabrication process of perovskites is difficult. Recently, synchrotron radiation-based in situ grazing-incidence wide-angle X-ray scattering (GIWAXS) techniques, which possess the advantages of high collimation, high resolution, and high brightness, have enabled to bridge complicated perovskite structure information with device performance by revealing the real-time crystallization pathways of perovskites during the spin-coating process. Herein, the developments of synchrotron radiation-based in situ GIWAXS are discussed in the study of the crystallization process of perovskites, especially revealing the important crystallization mechanisms of state-of-the-art perovskite optoelectronic devices with high performance. At the end, several potential applications and challenges associated with in situ GIWAXS techniques for perovskite-based devices are highlighted.
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The limited pattern area of periodic nanostructures limits the development of practical devices. This study introduces an X-ray interference lithography (XIL) stitching technique to fabricate a large-area (1.5â cm × 1.5â cm) two-dimensional photonic crystal (PhC) on the YAG: Ce scintillator, which functions as an encoder in a high numerical aperture optical encoding imaging system to effectively capture high-frequency information. An X-ray imaging experiment revealed a substantial 7.64â dB improvement in the signal-to-noise ratio (SNR) across a large field of view (2.6â mm × 2.6 mm) and achieved comparable or superior image quality with half the exposure dose. These findings have significant implications for advancing practical applications of X-ray imaging.
ABSTRACT
Gas nanobubbles used for water treatment and recovery give rise to great concern for their unique advantages of less byproducts, higher efficiency, and environmental friendliness. Nanoscale zerovalent iron (nZVI), which has also been widely explored in the field of environmental remediation, can generate gas hydrogen by direct reaction with water. Whether nanoscale hydrogen bubbles can be produced to enhance the pollution removal of the nZVI system is one significant concern involved. Herein, we report direct observations of in situ generation of hydrogen nanobubbles (HNBs) from nZVI in water. More importantly, the formed HNBs can enhance indeed the reduction of Se(IV) beyond the chemical reduction ascribed to Fe(0), especially in the anaerobic environment. The possible mechanism is that HNBs enhance the reducibility of the system and promote electron transport in the solution. This study demonstrates a unique function of HNBs combined with nZVI for the pollutant removal and a new approach for in situ HNB generation for potential applications in the fields of in situ remediation agriculture, biotechnology, medical treatment, health, etc.
Subject(s)
Environmental Pollutants , Environmental Restoration and Remediation , Water Pollutants, Chemical , Water Purification , IronABSTRACT
The Shanghai Soft X-ray Free-Electron Laser (SXFEL) is the first X-ray free-electron laser facility in China. The SASE beamline, which consists of a pink-beam branch and a mono-beam branch, is one of the two beamlines in the Phase-I construction. The pink-beam branch opened for users in 2023 after successful first-round beamline commissioning. In this paper, the design of the beamline is presented and the performance of the pink-beam branch is reported. The measured energy-resolving power of the online spectrometer is over 6000 @ 400â eV. The focusing spot size of the pink beam is less than 3â µm in both the horizontal and vertical at the endstation.
ABSTRACT
X-ray ptychography is a popular variant of coherent diffraction imaging that offers ultrahigh resolution for extended samples. In x-ray ptychography instruments, the Fresnel zone-plate (FZP) is the most commonly used optical probe system for both soft x-ray and hard x-ray. In FZP-based ptychography with a highly curved defocus probe wavefront, the reconstructed image quality can be significantly impacted by the initial probe function form, necessitating the construction of a suitable initial probe for successful reconstruction. To investigate the effects of initial probe forms on FZP-based ptychography reconstruction, we constructed four single-mode initial probe models (IPMs) and three multi-mode IPMs in this study, and systematically compared their corresponding simulated and experimental reconstructions. The results show that the Fresnel IPM, spherical IPM, and Fresnel-based multi-mode IPMs can result in successful reconstructions for both near-focus and defocus cases, while random IPMs and constant IPMs work only for near-focus cases. Consequently, for FZP-based ptychography, the elaborately constructed IPMs that closely resemble real probes in wavefront phase form are more advantageous than natural IPMs such as the random or constant model. Furthermore, these IPMs with high phase similarity to the high-curvature large-sized probe adopted in experiments can help greatly improve ptychography experiment efficiency and decrease radiation damage to samples.
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Titanium selenide (TiSe2 ), a model transition metal chalcogenide material, typically relies on topotactic ion intercalation/deintercalation to achieve stable ion storage with minimal disruption of the transport pathways but has restricted capacity (<130 mAh g-1 ). Developing novel energy storage mechanisms beyond conventional intercalation to break capacity limits in TiSe2 cathodes is essential yet challenging. Herein, the ion storage properties of TiSe2 are revisited and an unusual thermodynamically stable twin topotactic/nontopotactic Cu2+ accommodation mechanism for aqueous batteries is unraveled. In situ synchrotron X-ray diffraction and ex situ microscopy jointly demonstrated that topotactic intercalation sustained the ion transport framework, nontopotactic conversion involved localized multielectron reactions, and these two parallel reactions are miraculously intertwined in nanoscale space. Comprehensive experimental and theoretical results suggested that the twin-reaction mechanism significantly improved the electron transfer ability, and the reserved intercalated TiSe2 structure anchored the reduced titanium monomers with high affinity and promoted efficient charge transfer to synergistically enhance the capacity and reversibility. Consequently, TiSe2 nanoflake cathodes delivered a never-before-achieved capacity of 275.9 mAh g-1 at 0.1 A g-1 , 93.5% capacity retention over 1000 cycles, and endow hybrid batteries (TiSe2 -Cu||Zn) with a stable energy supply of 181.34 Wh kg-1 at 2339.81 W kg-1 , offering a promising model for aqueous ion storage.
ABSTRACT
The mutual optical intensity (MOI) model is a partially coherent radiation propagation tool that can sequentially simulate beamline optics and provide beam intensity, local degree of coherence and phase distribution at any location along a beamline. This paper extends the MOI model to non-ideal two-dimensional (2D) optical systems, such as ellipsoidal and toroidal mirrors with 2D figure errors. Simulation results show that one can tune the trade-off between calculation efficiency and accuracy by varying the number of wavefront elements. The focal spot size of an ellipsoidal mirror calculated with 100â ×â 100 elements gives less than 0.4% deviation from that with 250â ×â 250 elements, and the computation speed is nearly two orders of magnitude faster. Effects of figure errors on 2D focusing are also demonstrated for a non-ideal ellipsoidal mirror and by comparing the toroidal and ellipsoidal mirrors. Finally, the MOI model is benchmarked against the multi-electron Synchrotron Radiation Workshop (SRW) code showing the model's high accuracy.
ABSTRACT
High-energy metal anodes for large-scale reversible batteries with inexpensive and nonflammable aqueous electrolytes promise the capability of supporting higher current density, satisfactory lifetime, nontoxicity, and low-cost commercial manufacturing, yet remain out of reach due to the lack of reliable electrode-electrolyte interphase engineering. Herein, in situ formed robust interphase on copper metal electrodes (CMEs) induced by a trace amount of potassium dihydrogen phosphate (0.05 m in 1 m CuSO4 -H2 O electrolyte) to fulfill all aforementioned requirements is demonstrated. Impressively, an unprecedented ultrahigh-speed copper plating/stripping capability is achieved at 100 mA cm-2 for over 12 000 cycles, corresponding to an accumulative areal capacity up to tens of times higher than previously reported CMEs. The use of solid-electrolyte interface-protection strategy brings at least an order of magnitude improvement in cycling stability for symmetric cells (Cu||Cu, 2800 h) and full batteries with CMEs using either sulfur cathodes (S||Cu, 1000 cycles without capacity decay) or zinc anodes (Cu||Zn with all-metal electrodes, discharge voltage ≈1.02 V). The comprehensive analysis reveals that the hydrophilic phosphate-rich interphase nanostructures homogenize copper-ion deposition and suppress nucleation overpotential, enabling dendrite-free CMEs with sustainability and ability to tolerate unusual-high power densities. The findings represent an elegant forerunner toward the promising goal of metal electrode applications.
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With fast advances in enhancing the focusing/imaging resolution of Fresnel zone plate lenses toward sub-10â nm, low diffraction efficiency in connection with their rectangular zone shape still remains a big issue in both soft and hard X-ray microscopy. In hard X-ray optics, encouraging progress has recently been reported in our earlier attempts of high focusing efficiency by 3D kinoform shaped metallic zone plates, formed by greyscale electron beam lithography. This paper addresses our efforts towards high focusing/imaging efficiency by developing a novel dielectric kinoform zone plate lens for soft X-rays. The effects of the zone materials and zone shapes on the focusing/imaging quality were first theoretically investigated by a modified thin-grating-approximation method, revealing superior efficiencies of dielectric kinoform zone plates over rectangular ones in metals. Optical characterizations of replicated dielectric kinoform zone plates by greyscale electron beam lithography demonstrate a focusing efficiency of 15.5% with a resolution of 110â nm in the water window of X-rays. Apart from high efficiency, the novel kinoform zone plate lenses developed in this work exhibit significant advantages over conventional zone plates, i.e. simplified process, low cost and no need for a beamstop.
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Combining wave optics propagation and geometric ray tracing, the mutual optical intensity (MOI) model is extended to quantitatively simulate the propagation of partially coherent light through a kinoform lens at high speed. The MOI model can provide both a high accuracy and a high efficiency simulation. The intensity and coherence degree distributions at the focal plane are calculated using the MOI model. It is beneficial to improve the focusing capability of the kinoform lens by reducing the coherence or increasing the number of lens steps. In addition, increasing the number of steps is also beneficial to increase the photon flux and reduce the depth of focus.
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Metal/nitrogen-doped carbons (M-N-C) are promising candidates as oxygen electrocatalysts due to their low cost, tunable catalytic activity and selectivity, and well-dispersed morphologies. To improve the electrocatalytic performance of such systems, it is critical to gain a detailed understanding of their structure and properties through advanced characterization. In situ X-ray absorption spectroscopy (XAS) serves as a powerful tool to probe both the active sites and structural evolution of catalytic materials under reaction conditions. In this review, we firstly provide an overview of the fundamental concepts of XAS and then comprehensively review the setup and application of in situ XAS, introducing electrochemical XAS cells, experimental methods, as well as primary functions on catalytic applications. The active sites and the structural evolution of M-N-C catalysts caused by the interplay with electric fields, electrolytes and reactants/intermediates during the oxygen evolution reaction and the oxygen reduction reaction are subsequently discussed in detail. Finally, major challenges and future opportunities in this exciting field are highlighted.
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X-ray microscope as an important nanoprobing tool plays a prevailing role in nano-inspections of materials. Despite the fast advances of high resolution focusing/imaging reported, the efficiency of existing high-resolution zone plates is mostly around 5% in soft x-ray and rapidly goes down to 1%-2% when the resolution approaches 10 nm. It is well known that the rectangular zone shape, beamstop, limited height/width ratios, material absorption of light and structural defects are likely responsible for the limited efficiency. Although zone plates with Kinoform profile are supposed to be efficient, progress for achieving both high resolution (<30 nm) and high efficiency (>5%) have hardly been addressed in soft x-ray. In this work, we propose a compound Kinoform/Fresnel zone plate (CKZP) by combing a dielectric Kinoform zone plate with a 15 nm resolution zone plate. Greyscale electron beam lithography was applied to form the 3D Kinoform zone plate and atomic layer deposition was carried out to form the binary zone plate. Optical characterizations demonstrated 15 nm resolution focusing/imaging with over 7.8% efficiency in soft x-ray. The origin of the efficiency improvement behind the proposed compound lens is theoretically analyzed and discussed.
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Pursuing conversion-type cathodes with high volumetric capacity that can be used in aqueous environments remains rewarding and challenging. Tellurium (Te) is a promising alternative electrode due to its intrinsic attractive electronic conductivity and high theoretical volumetric capacity yet still to be explored. Herein, the kinetically/thermodynamically co-dominat copper-tellurium (Cu-Te) alloying phase-conversion process and corresponding oxidation failure mechanism of tellurium are investigated using in situ synchrotron X-ray diffraction and comprehensive ex situ characterization techniques. By virtue of the fundamental insights into the tellurium electrode, facile and precise electrolyte engineering (solvated structure modulation or reductive antioxidant addition) is implemented to essentially tackle the dramatic capacity loss in tellurium, affording reversible aqueous Cu-Te conversion reaction with an unprecedented ultrahigh volumetric capacity of up to 3927 mAh cm-3 , a flat long discharge plateau (capacity proportion of ≈81%), and an extraordinary level of capacity retention of 80.4% over 2000 cycles at 20 A g-1 of which lifespan thousand-fold longer than Cu-Te conversion using CuSO4 -H2 O electrolyte. This work paves a significant avenue for expanding high-performance conversion-type cathodes toward energetic aqueous multivalent-ion batteries.
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Combining geometric ray tracing and wave optics propagation, a new simulation model named LWF is established to calculate the full coherent X-ray propagation through a kinoform lens. The LWF model is used to analyze the X-ray propagation through long and short kinoform lenses and calculate the intensity distribution at the focal plane. When the aperture is large, the focal spot for the long kinoform lens is smaller than that for the short kinoform lens. Due to the use of the geometric ray-tracing method to calculate the beam propagation inside the kinoform lens, the LWF model takes a low number of transversal wavefront segments, i.e. a short time, to achieve high accuracy. The simulation times for the one-dimensional and two-dimensional LWF models are 0.025â s and 5.3â s, respectively, with a calculation error of less than 0.5%. The high efficiency and high accuracy make the LWF model a strong tool in designing kinoform lenses.
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Characterizing relationships between Zn2+, insulin, and insulin vesicles is of vital importance to the study of pancreatic beta cells. However, the precise content of Zn2+ and the specific location of insulin inside insulin vesicles are not clear, which hinders a thorough understanding of the insulin secretion process and diseases caused by blood sugar dysregulation. Here, we demonstrated the colocalization of Zn2+ and insulin in both single extracellular insulin vesicles and pancreatic beta cells by using an X-ray scanning coherent diffraction imaging (ptychography) technique. We also analyzed the elemental Zn2+ and Ca2+ contents of insulin vesicles using electron microscopy and energy dispersive spectroscopy (EDS) mapping. We found that the presence of Zn2+ is an important characteristic that can be used to distinguish insulin vesicles from other types of vesicles in pancreatic beta cells and that the content of Zn2+ is proportional to the size of insulin vesicles. By using dual-energy contrast X-ray microscopy and scanning transmission X-ray microscopy (STXM) image stacks, we observed that insulin accumulates in the off-center position of extracellular insulin vesicles. Furthermore, the spatial distribution of insulin vesicles and their colocalization with other organelles inside pancreatic beta cells were demonstrated using three-dimensional (3D) imaging by combining X-ray ptychography and an equally sloped tomography (EST) algorithm. This study describes a powerful method to univocally describe the location and quantitative analysis of intracellular insulin, which will be of great significance to the study of diabetes and other blood sugar diseases.
Subject(s)
Insulin-Secreting Cells , Insulin , Secretory Vesicles , Zinc , Animals , Blood Glucose , Cell Line , Insulin/analysis , Insulin/metabolism , Insulin-Secreting Cells/metabolism , Insulin-Secreting Cells/ultrastructure , Rats , Secretory Vesicles/chemistry , Secretory Vesicles/metabolism , Spectrometry, X-Ray Emission , X-Ray Diffraction , Zinc/analysisABSTRACT
Engineering multifunctional superstructure cathodes to conquer the critical issue of sluggish kinetics and large volume changes associated with divalent Zn-ion intercalation reactions is highly desirable for boosting practical Zn-ion battery applications. Herein, it is demonstrated that a MoS2/C19H42N+ (CTAB) superstructure can be rationally designed as a stable and high-rate cathode. Incorporation of soft organic CTAB into a rigid MoS2 host forming the superlattice structure not only effectively initiates and smooths Zn2+ transport paths by significantly expanding the MoS2 interlayer spacing (1.0 nm) but also endows structural stability to accommodate Zn2+ storage with expansion along the MoS2 in-plane, while synchronous shrinkage along the superlattice interlayer achieves volume self-regulation of the whole cathode, as evidenced by in situ synchrotron X-ray diffraction and substantial ex situ characterizations. Consequently, the optimized superlattice cathode delivers high-rate performance, long-term cycling stability (â¼92.8% capacity retention at 10 A g-1 after 2100 cycles), and favorable flexibility in a pouch cell. Moreover, a decent areal capacity (0.87 mAh cm-2) is achieved even after a 10-fold increase of loading mass (â¼11.5 mg cm-2), which is of great significance for practical applications. This work highlights the design of multifunctional superlattice electrodes for high-performance aqueous batteries.
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X-ray microscopes are powerful tools in the nano-inspection of materials owing to their ultra-high resolution at the molecular level. However, the focusing efficiency of binary zone plate lenses as key components in such probes is merely 5% in practice, hindering their application in advanced scientific research. Although kinoform zone plate lenses are in principle supposed to possess high efficiency beyond binary ones, little progress has been reported so far due to the shortage of both a theoretical calculation approach and greyscale lithography for generating fine three-dimensional (3D) kinoform zones of the lenses. This paper reports our theoretical work for a modified beam propagation method to compute the focusing performance and state-of-the-art 3D greyscale electron beam lithography for kinoform zone plate lenses. Three different zone shapes - binary, kinoform and top-flat kinoform (nicknamed the trapezoid-kinoform) - were compared both theoretically and experimentally. Theoretical calculations suggest, for the first time, that the trapezoid-kinoform zone plate gives rise to the highest focusing efficiency among the three lenses, which was proved by optical characterization of the fabricated lens with hard X-rays. As high as 40% of the focusing efficiency by Au trapezoid-kinoform lenses with resolution of 250â nm at 8â keV has been achieved, which is two times higher than that of binary zone plate lenses. The origin of the enhanced efficiency in the trapezoid-kinoform zone plate lens was explained by the joint contributions from both the refraction through the kinoform slope and the diffraction through the top flat part of the trapezoid-kinoform zone plate. Such a breakthrough in focusing efficiency sheds light on the further development of X-ray lenses with both high resolution and high efficiency.
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Surfaces with nanostructure patterning are broadly encountered in nature, and they play a significant role in regulating various phenomena such as phase transition at the liquid/solid interface. Here, we designed two kinds of template substrates with periodic nanostructure patterns [i.e., nanotrench (NT) and nanopore (NP)]. Surface nanodroplets produced on these nanostructure surfaces were characterized to acquire their morphology and wetting properties. We show that nanostructure patterning could effectively regulate the shape, contact radius, and nucleate site of nanodroplets. While nanodroplets on the NT structure are constrained in one dimension, nanodroplets on the NP structure have enhanced the wetting property with constraints from two dimensions. Further numerical analysis indicates that the morphology and contact angles of nanodroplets on the NT structure depend on the substrate wettability and the droplet volume. These observations demonstrate how physical geometry and chemical heterogeneity of a substrate surface affect the growth and spreading of surface nanodroplets, which deepens our understanding on nanoscale phase separation.
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Aqueous zinc batteries (AZBs) are considered promising candidates for large-scale energy storage systems because of their low cost and high safety. However, currently developed AZB cathodes always suffer from the intense charge repulsion of multivalent-ion and complex multiphase electrochemistry, resulting in an insufficient cycling life and impracticable high-sloping discharge profile. Herein, we found that the synthesized ultrathin Bi2O2Se nanosheets can effectively activate stable protons storage in AZBs rather than large zinc ions. This proton-dominated cathode provides an ultraflat discharge plateau (72% capacity proportion) and exhibits long-term cyclability as 90.64% capacity retention after 2300 cycles at 1 A g-1. Further in situ synchrotron X-ray diffraction, ex situ X-ray photoelectronic spectroscopy, and density functional theory confirm the energy storage mechanism regarding the highly reversible proton insertion/extraction process. Benefiting from the proton-dominated fast dynamics, reliable energy supply (>81.5% discharge plateau capacity proportion) is demonstrated at a high rate of up to 10 A g-1 and in the frozen electrolyte below -15 °C. This work provides a potential design of high-performance electrode materials for AZBs.