Npg Asia Materials最新文献

Lead-free Cs₃Bi₂I₉ single crystals have been demonstrated to be promising materials for direct X-ray detectors with remarkable performance. However, their application for 2D X-ray imaging is hindered by their time-consuming preparation and limited crystal size. In this paper, a thick Cs₃Bi₂I₉ perovskite film fabricated via facile spray coating at a low processing temperature, which increases the area of the photoactive film, reduces the processing time, decreases the energy budget and the production cost, and enhances the production yield due to high material utilization, has great potential for commercial applications. Careful control of the processing temperature and intervals during spray coating results in a dense and thick perovskite film with well-stacked perovskite domains. The compact perovskite film enhances the charge transport capability of the Cs₃Bi₂I₉ perovskite film and reduces the dark current density of the X-ray detector. The resultant X-ray detector, prepared through a two-step spray coating process, exhibited a sensitivity of 127.23 μC Gy_air⁻¹ cm⁻² and a detection limit of 7.4 μGy_air s⁻¹. In addition, the device delivers long-term stability with a consistent photoresponse when exposed to consecutive X-ray pulse irradiation.

Research on two-dimensional (2D) materials has made tremendous progress reflecting their unique properties and promising applications. In this perspective, we review the novel concept of “2.5-dimensional (2.5D) materials”, which represent new opportunities to extend the field of materials science beyond 2D materials. This concept consists of controlling van der Waals interactions and using interlayer nanospaces to synthesize new materials and explore their intriguing properties. It also includes combination with other dimensional materials, the fabrication of three-dimensional (3D) architectures of 2D materials, and practical applications in our 3D everyday life. We discuss recent research based on this concept and provide future perspectives.

Herein, we report on conductive ultrathin films (nanosheets) with the characteristics of stretchability and water vapor permeability for skin-conformable bioelectrodes. The films are fabricated by combining conductive fibrous networks of single-wall carbon nanotubes (SWCNTs) and poly(styrene-b-butadiene-b-styrene) (SBS) nanosheets (i.e., SWCNT-SBS nanosheets). An increase in the number of SWCNT coatings increases both the thicknesses and densities of the SWCNT bundles. The SBS nanosheets coated with three layers of SWCNTs (i.e., SWCNT 3rd-SBS nanosheets) show comparable sheet resistance to the SBS nanosheets coated with poly(3,4-ethylenedioxithiophene) doped with poly(4-styrenesulfonate acid) (PEDOT:PSS) containing 5 wt.% butylene glycol (i.e., PEDOT:PSS/BG5-SBS nanosheets). In addition, the SWCNT 3rd-SBS nanosheets exhibit significantly reduced elastic moduli and increased elongations at break compared to the PEDOT:PSS/BG5-SBS nanosheets. Furthermore, the calculated water vapor transmission ratio of the 210-nm-thick SBS nanosheets (268,172 g m⁻² (2 h)⁻¹) is greater than that of the filter paper (6345 g m⁻² (2 h)⁻¹). The SWCNT 3rd-SBS nanosheets attached to model skin show high tolerances to bending and artificial sweat at different pH values (i.e., the electrical resistance changes ~1.1 times). Finally, the SWCNT 3rd-SBS nanosheet is applied to detect the surface electromyogram from the forearm of a subject. This nanosheet displays a signal-to-noise ratio similar to that of the PEDOT:PSS/BG5-SBS nanosheet.

Drug-eluting stents are a commonly used treatment for coronary artery disease. However, the coatings used in drug-eluting stents have some limitations such as poor biocompatibility and drug loading capacity. In recent years, self-assembly methods have emerged as a promising alternative for stent coatings. Self-assembled coatings employ biomaterials and offer several advantages over traditional coatings, including thinner thickness, stronger binding capacity, and better biocompatibility. This review discusses the latest research on self-assembled biomaterial-based coatings for drug-eluting stents. We explore how layer-by-layer coatings and composite coating films have been utilized to load and release drugs with high drug loading capacity and biocompatibility, as well as how they promote endothelial adhesion and growth. Additionally, we examine how self-assembled coatings have been used to release active molecules for anti-coagulation and deliver gene therapy. Moreover, we discuss the potential of self-assembled coatings for future development, including intelligent targeted drug delivery, bionic stent coatings, and 3D printed stent coatings. These advancements have the potential to further improve the effectiveness of drug-eluting stents in treating coronary artery disease.

The intermediate-range order of covalently bonded glasses has been extensively studied in terms of their diffraction peaks observed at low scattering angles; these peaks are called the first sharp diffraction peaks (FSDPs). Although the atomic density fluctuations originating from the quasilattice planes are a critical scientific target, direct experimental observations of these fluctuations are still lacking. Here, we report the direct observation of the atomic density fluctuations in silica glass by energy-filtered angstrom-beam electron diffraction. The correspondence between the local electron diffraction patterns of FSDPs and the atomic configurations constructed based on the X-ray and neutron diffraction results revealed that the local atomic density fluctuations originated from the quasi-periodic alternating arrangements of the columnar chain-like atomic configurations and interstitial tubular voids, as in crystals. We also discovered longer-range fluctuations associated with the shoulder of the FSDP on the low-Q side. The hierarchical fluctuations inherent in materials could aid in the elucidation of their properties and performance.

All-inorganic lead halide perovskites (LHPs) and their use in optoelectronic devices have been widely explored because they are more thermally stable than their hybrid organic‒inorganic counterparts. However, the active perovskite phases of some inorganic LHPs are metastable at room temperature due to the critical structural tolerance factor. For example, black phase CsPbI₃ is easily transformed back to the nonperovskite yellow phase at ambient temperature. Much attention has been paid to improving the phase stabilities of inorganic LHPs, especially those with high solar cell efficiencies. Herein, we discussed the origin of phase stability for CsPbI₃ and the strategies used to stabilize the cubic (α) phase. We also assessed the CsPbI₃ black β/γ phases that are relatively stable at nearly room temperature. Furthermore, we determined the relationship between phase stabilization and defect passivation and reviewed the growing trend in solar cell efficiency based on black phase CsPbI₃. Finally, we provide perspectives for future research related to the quest for optimum device efficiency and green energy.

Mussel periostracum, a nonliving multifunctional gel that covers the rigid inorganic shells of mussels, provides protection against mechanical impacts, biofouling, and corrosion in harsh ocean environments. The inner part of the periostracum, which emerges from biological tissues, functions as a natural interface between tissue and inorganic materials. The periostracum shows significant potential for application in implantable devices that provide interfaces; however, this system remains unexplored. In this study, we revealed that the inner periostracum performs graded mechanical functions and efficiently dissipates energy to accommodate differences in stiffness and stress types on both sides. On the tissue end, the lightly pigmented periostracum exhibits extensibility and energy dissipation under repetitive tension. This process was facilitated by the slipping and reassembly of β-strands in the discovered major proteins, which we named periostracin proteins. On the shell end, the highly pigmented, mineralized, and porous segment of the periostracum provided stiffness and cushioned against compressive stresses exerted by the shell valves during closure. These findings offer a novel possibilities for the design of interfaces that bridge human tissue and devices.

Understanding the nucleation mechanism in glass is crucial for the development of new glass-ceramic materials. Herein, we report the structure of a commercially important glass-ceramic ZrO₂-doped lithium aluminosilicate system during its initial nucleation stage. We conducted an X-ray multiscale analysis, and this analysis was used to observe the structure from the atomic to the nanometer scale by using diffraction, small-angle scattering, absorption, and anomalous scattering techniques. The inherent phase separation between the Zr-rich and Zr-poor regions in the pristine glass was enhanced by thermal treatment without changing the spatial geometry at the nanoscale. Element-specific pair distribution function analysis using anomalous X-ray scattering data showed the formation of a liquid ZrO₂-like local structural motif and edge sharing between the ZrO_x polyhedra and (Si/Al)O₄ tetrahedra during the initial nucleation stage. Furthermore, the local structure of the Zr⁴⁺ ions resembled a cubic or tetragonal ZrO₂ crystalline phase and formed after 2 h of annealing the pristine glass. Therefore, the Zr-centric periodic structure formed in the early stage of nucleation was potentially the initial crystal nucleus for the Zr-doped lithium aluminosilicate glass-ceramic.

Patients suffering from osteoporotic fractures often require effective fixation and subsequent bone repair. However, the currently available materials are functionally limited and often fail to improve outcomes in this patient population. In this study, we developed orthopedic adhesives doped with romosozumab-loaded mesoporous bioactive glass nanoparticles to aid in osteoporotic fracture fixation and restore dysregulated bone homeostasis. These adhesives were designed to promote osteoblast formation while simultaneously inhibiting osteoclastic bone-resorbing activity, thus working synergistically to promote the healing of osteoporotic fractures. Orthopedic adhesives exhibit injectability, reversible adhesiveness, and malleability, enhancing their adaptability to complex clinical scenarios. Furthermore, the release of romosozumab from mesoporous bioactive glass nanoparticles accelerated osteogenesis and inhibited osteoclastogenesis, delaying the bone resorption process. This dual action contributes to the regulation of bone regeneration and remodeling. Notably, our orthopedic adhesive could restore the disrupted bone homeostasis associated with osteoporotic fractures.

Zinc-ion hybrid supercapacitors (ZHSCs) are attracting significant attention due to their high energies/power densities, safety, and low cost. In this review, recent advances in the development of ZHSCs are summarized. Particular emphasis is placed on state-of-the-art cathodes (including carbon, metal oxides, MXenes, and redox-active polymers), anodes (including Zn-based composites and Zn-free materials) and electrolytes for ZHSCs. Furthermore, the latest research on functional ZHSC devices with miniaturized ZHSCs, fiber-shaped ZHSCs, self-chargeable ZHSCs and self-healing devices is reported. Finally, further developments with ZHSCs are envisaged for future research in this thriving field.