Multi-Mode Optical Chirality Extremizations on Incident Momentum Sphere

We study the momentum-space evolutions for chiral optical responses of multi-mode resonators scattering plane waves of varying incident directions. It was revealed, in our previous study [Phys. Rev. Lett. $\mathbf{126}$, 253901 (2021)], that for single-mode resonators the scattering optical chiralities characterized by circular dichroism ($\mathbf{CD}$) are solely decided by the third Stokes parameter distributions of the quasi-normal mode (QNM) radiations: $\mathbf{CD}=\mathbf{S}_3$. Here we extend the investigations to multi-mode resonators, and explore numerically the dependence of optical chiralities on incident directions from the perspectives of QNM radiations and their circular polarization singularities. In contrast to the single-mode regime, for multi-mode resonators it is discovered that $\mathbf{CD}$s defined in terms of extinction, scattering and absorption generally are different and cannot reach the ideal values of $\pm 1$ throughout the momentum sphere. Though the exact correspondence between $\mathbf{CD}$ and $\mathbf{S}_3$ does not hold anymore in the multi-mode regime, we demonstrate that the positions of the polarization singularities still serve as an efficient guide for identifying those incident directions where the optical chiralities can be extremized

Geometric Phase-Driven Scattering Evolutions

Conventional approaches for scattering manipulations rely on the technique of field expansions into spherical harmonics (electromagnetic multipoles), which nevertheless is non-generic (expansion coefficients depend on the position of the coordinate system's origin) and more descriptive than predictive. Here we explore this classical topic from a different perspective of controlled excitations and interferences of quasi-normal modes (QNMs) supported by the scattering system. Scattered waves are expanded into not spherical harmonics but radiations of QNMs, among which the relative amplitudes and phases are crucial factors to architect for scattering manipulations. Relying on the electromagnetic reciprocity, we provide full geometric representations based on the Poincar\'e sphere for those factors, and identify the hidden underlying geometric phases of QNMs that drive the scattering evolutions. Further synchronous exploitations of the incident polarization-dependent geometric phases and excitation amplitudes enable efficient manipulations of both scattering intensities and polarizations. Continuous geometric phase spanning $2\pi$ is directly manifest through scattering variations, even in the rather elementary configuration of an individual particle scattering waves of varying polarizations. We have essentially established a profoundly all-encompassing framework for the calculations of geometric phase in scattering systems, which will greatly broaden horizons of many disciplines not only in photonics but also in general wave physics where geometric phase is generic and ubiquitous

Evaluating the Role of Functional Groups in the Selective Capture of Ag(I) onto UiO-66-Type Metal–Organic Frameworks

UiO-66-type metal–organic frameworks have been considered as promising adsorbents for capturing Ag­(I) from wastewater. However, uncertainties persist regarding the specific absorptivity of individual functional groups to the UiO-66 framework structure. In this study, UiO-66-type metal–organic frameworks (UiO-66-X), featuring diverse functional groups (X = −(OH)2, −(COOH)2, −NO2, −NH2, −SO3H, −(SH)2), were synthesized in situ for Ag­(I) capture. The findings revealed that functionalization significantly enhanced the adsorption capacity of Ag­(I). Notably, quantitative analysis showed that 1 mol of −SH functional group onto the UiO-66 framework structure can adsorb 0.73 mol of Ag­(I) ions, surpassing those of −COOH, −OH, −NH2, −SO3H, and −NO2 by 2.4-, 3.5-, 3.8-, 9.1-, and 24.3-fold, respectively. This represents the first assessment of the adsorption capacity of functionalized UiO-66 for Ag­(I) based on each effective functional group, addressing limitations in traditional unit mass calculations. Further, the adsorption mechanism of UiO-66-X for selectively capturing Ag­(I) was elucidated through experimental and theoretical analyses. Additionally, selectivity and practical applications confirm that UiO-66-(SH)2 exhibits strong anti-interference ability, whether in natural water bodies with complex compositions or in industrial wastewater under harsh conditions. We anticipate that this study will enhance our understanding of structure–performance dependencies of multivariate MOFs for designing novel adsorbents for Ag­(I) capture

Patterning Vertically Oriented Graphene Sheets for Nanodevice Applications

Graphene has attracted growing interest in the past few years. Growing vertically oriented graphene sheets with a designed pattern is practically attractive for device applications based on graphene. Here we report a patterned synthesis of vertical graphene nanosheets using plasma-enhanced chemical vapor deposition. Both experimental and modeling results suggest that the electric field distribution above the substrate material plays a key role in the graphene coverage. Vertical graphene patterns can thus be designed through artificially designing the surface electric field distribution. A field-effect transistor (FET) sensor device has been demonstrated for detection of low-concentration gases using vertically patterned graphene sheets bridging a metal electrode gap

In Situ Synthesis of CuCo₂S₄@N/S-Doped Graphene Composites with Pseudocapacitive Properties for High-Performance Lithium-Ion Batteries

To satisfy the demand of high power application, lithium-ion batteries (LIBs) with high power density have gained extensive research effort. The pseudocapacitive storage of LIBs is considered to offer high power density through fast faradic surface redox reactions rather than the slow diffusion-controlled intercalation process. In this work, CuCo₂S₄ anchored on N/S-doped graphene is in situ synthesized and a typical pseudocapacitive storage behavior is demonstrated when applied in the LIB anode. The pseudocapacitive storage and N/S-doped graphene enable the composite to display a capacity of 453 mA h g^–1 after 500 cycles at 2 A g^–1 and a ultrahigh rate capability of 328 mA h g^–1 at 20 A g^–1. We believe that this work could further promote the research on pseudocapacitive storage in transition-metal sulfides for LIBs

High-Performance and Stable Perovskite X‑ray Detection and Imaging Based on a Ti Cathode

High-energy radiation detectors with a good imaging resolution, fast response, and high sensitivity are desired to operate at a high electric field. However, strong ion migration triggered by electrochemical reactions at the interface between a high-potential electrode and an organic–inorganic hybrid perovskite limits the stability of radiation detectors under a high electric field. Herein, we demonstrate that such ion migration could be effectively suppressed in devices with a Ti cathode, even at a high electric field of 50 V mm–1, through time-of-flight secondary-ion mass spectrometry. X-ray photoelectron spectroscopy illustrates that Ti–N bonds formed at the interface of MAPbBr3 perovskite single crystals/Ti electrode effectively inhibit the electrochemical reaction in organic–inorganic hybrid perovskite devices and ultimately improve the operating stability under a high electric field. The device with a Ti electrode reaches a high sensitivity of 96 ± 1 mC Gyair–1 cm–2 and a low detection limit of 2.8 ± 0.3 nGy s–1 under hard X-ray energy

Low-Temperature Cross-Linkable Hole Transport Material Based on Carbazole Derivatives Design and Applications in Solution-Processed OLEDs

Cross-linking is demonstrated to be an effective strategy to resolve the interface erosion problem facing solution process technique for large area commercial applications of organic electronics. However, most of the reported cross-linkable materials require a high temperature of over 150 °C, which is detrimental to device performance. In this study, an in situ cross-linking protocol is proposed based on a triphenylamine/carbazole core linked with a hexyl chain and styryl moiety, and a low cross-linking temperature down to 120 °C is achieved for the first time. The resultant thermally cross-linkable hole transportation molecules of TPA-VBCz and HTPA-VBCz possess high triplet energy levels of around 3.0 eV and high decomposition temperatures over 410 °C. The solution-processed hole transportation layer (HTL) is cured at 120 °C in 30 min to finish the cross-linking net structure. Applications of this HTL in solution-processed multilayer thermally delayed fluorescent green OLEDs are explored with significantly improved current efficiency up to 78.3 cd A–1 and external quantum efficiency of 24.6%

Ultrathin, Wrinkled, Vertically Aligned Co(OH)₂ Nanosheets/Ag Nanowires Hybrid Network for Flexible Transparent Supercapacitor with High Performance

Developing high-performance, flexible, transparent supercapacitors for wearable electronics represents an important challenge, as it requires active materials to be sufficiently transparent without compromising energy storage. Here, we manipulate the morphology of the active materials and the junctions on the current collector to achieve optimum electronic/ionic transport kinetics. Two-dimensional Co­(OH)2 nanosheets with single or two layers were vertically aligned onto a modified Ag nanowires (AgNWs) network using an electrochemical deposition–UV irradiation approach. The metallic AgNWs network endows high transparency while minimizing the contact resistance with the pseudocapacitive Co­(OH)2 nanosheets. The Co­(OH)2 nanosheets self-assembled into a three-dimensional array, which is beneficial for the fast ion movements. The rational materials design greatly boosts the electrochemical performance of the hybrid network, including an ultrahigh areal capacitance up to 3108 μC cm–2 (5180 μF cm–2) coupled with long cycle life (20 000 cycles). As a prototype device, the symmetric supercapacitor well combines high energy/power density and excellent mechanical flexibility and long-term performance, suggesting a promising application for the next-generation wearable electronics

Aging CsPbBr₃ Nanocrystal Wafer for Ultralow Ionic Migration and Environmental Stability for Direct X‑ray Detection

The outstanding photoelectric properties of perovskites demonstrate extreme promise for application in X-ray detection. However, the soft lattice of the perovskite results in severe ionic migration for three-dimensional materials, limiting the operation stability of perovskite X-ray detectors. Although ligand-decorated nanocrystals (NCs) exhibit significantly higher stability than three-dimensional perovskites, defects remaining on the interface of NCs could still trigger halide migration under a high bias due to the incomplete ligand decoration. Furthermore, it is still challenging to realize sufficient thickness of absorption layers based on NCs for X-ray detectors through traditional methods. Herein, we develop a centimeter-size and millimeter-thick wafer based on CsPbBr3 NCs through isostatic pressing for X-ray detectors, in which the interfacial defects of NCs are remedied by CsPb2Br5 during aging of wafer in ambient humidity. The wafer shows outstanding sensitivity (200 μC Gyair–1 cm–2) and ultralow dark current drift (1.78 × 10–8 nA cm–1 s–1 V–1 @ 400 V cm–1). Moreover, it shows storage stability with negligible performance degradation for 60 days in ambient humidity. Thus, aging perovskite NC wafers for X-ray detection holds huge potential for next-generation X-ray imaging plates

Production Characteristics of Volatiles from Anthracite Cracking via Microwave-Induced Discharge

The ignition of anthracite with arc plasma has not been applied due to its low chemical effect and volatile content in anthracite. The nonequilibrium plasma generated by a microwave-induced discharge has the ability to break branch chains and aromatic ring structures by kinetic effects, which has the potential for anthracite cracking and ignition. This work investigated anthracite cracking by microwave-induced discharges under an Ar/N2 atmosphere. Results showed that the maximum levels of CO production, total gas production, and total gas generation rate occur in 20% argon content due to an increase in the number of electrons and a decrease in the total electronic states excitation rate constant with an increase in the argon content. The total gas production in plasma cracking is larger than that by pyrolysis, indicating the crack of polycyclic aromatic hydrocarbon by plasma. In addition, we attempted anthracite combustion under an 80% N2 and 20% O2 atmosphere