Wicking-Driven Evaporation Self-Assembly of Carbon Nanotubes on Fabrics: Generating Controlled Orientational Structures.

Nanostructures with orientational order exhibit excellent electrical and optical properties; however, their construction on complex fabrics is challenging. Here, we demonstrate the potential of wicking-driven evaporation self-assembly in the oriented arrangement of carbon nanotubes (CNTs) on fabrics. The solution-evaporation self-assembly in combination with the fabric wicking effect leads to convective flows along the fibers, which makes it possible to prepare orientational nanostructures over large fabric surface areas. The orientation of CNTs is controlled by the fluid drag force from the convective flow during drying, thus the interaction between the CNT and the solution is crucial. We show that the nanostructures of CNTs on fibers depend, for example, on the evaporation temperature, component concentration, and solution pH. Weakening the viscous connection of the fluid with CNTs can lead to an interesting eddy nanostructure of CNTs. The electrical conductivity of the assembled fabrics increases strongly with the degree of orientation and the assembly cycles of CNTs. In this work, the large-scale orientational order of nanomaterial achieved by wicking-driven evaporation self-assembly offers a new strategy for constructing three-dimensional oriented conductive networks in electronic textiles.

Rapid Capillary-Assisted Solution Printing of Perovskite Nanowire Arrays Enables Scalable Production of Photodetectors.

Despite recent progress in producing perovskite nanowires (NWs) for optoelectronics, it remains challenging to solution-print an array of NWs with precisely controlled position and orientation. Herein, we report a robust capillary-assisted solution printing (CASP) strategy to rapidly access aligned and highly crystalline perovskite NW arrays. The key to the CASP approach lies in the integration of capillary-directed assembly through periodic nanochannels and solution printing through the programmably moving substrate to rapidly guide the deposition of perovskite NWs. The growth kinetics of perovskite NWs was closely examined by in situ optical microscopy. Intriguingly, the as-printed perovskite NWs array exhibit excellent optical and optoelectronic properties and can be conveniently implemented for the scalable fabrication of photodetectors.

Hierarchical porous dual-mode thermal management fabrics achieved by regulating solar and body radiations.

Personal thermal management (PTM) of fabrics is vital for human health; the ever-changing location of the human body poses a big challenge for fabrics to maintain a favorable metabolic temperature. Herein, a dual-mode thermal management fabric is designed to achieve both cooling and heating functions by regulating simultaneously solar and body radiations. The cooling or heating mode can be exchanged by flipping the fabric without an external energy supply. The passive cooling side consists of an electrospun polyacrylonitrile (PAN) fabric with a hierarchical porous structure, exhibiting high sunlight reflectance (91.42%) and an ∼14 °C temperature decrease under direct sunlight irradiation. The co-existence of nanoscale and microscale pores is proven to be essential for improved cooling performances. The other heating side, coated with an MXene layer, shows high photothermal conversion efficiency (37.5%) and outstanding heating capability outdoors. Furthermore, the contrary mid-infrared emissivity of the two sides (high emissivity of the cooling side while low emissivity of the heating side) leads to the dual-mode passive regulation of body thermal energy. Besides, this fabric demonstrates satisfactory wearability and excellent stability. Our work proposes an energy-saving and cost-effective approach for PTM fabrics potentially suitable for various scenarios (e.g., indoors/outdoors, summer/winter, low/high latitude areas).

Electric-magnetic dual-gradient structure design of thin MXene/Fe3O4 films for absorption-dominated electromagnetic interference shielding.

The challenge of achieving high-performance electromagnetic interference (EMI) shielding films, which focuses on electromagnetic waves absorption while maintaining thin thickness, is a crucial endeavor in contemporary electronic device advancement. In this study, we have successfully engineered hybrid films based on MXene nanosheets and Fe3O4 nanoparticles, featuring intricate electric-magnetic dual-gradient structures. Through the collaborative influence of a unique dual-gradient structure equipped with transition and reflection layers, these hybrid films demonstrate favorable impedance matching, abundant loss mechanisms (Ohmic loss, interfacial polarization and magnetic loss), and an "absorb-reflect-reabsorb" process to achieve absorption-dominated EMI shielding capability. Compared with the single conductive gradient structure, the dual-gradient structure effectively enhances the absorption intensity per unit thickness, and thus reduces the thickness of the film. The optimized film demonstrates a remarkable EMI shielding effectiveness (SE) of 49.98 dB alongside an enhanced absorption coefficient (A) of 0.51 with a thickness of only 180 µm. The thin films with a dual-gradient structure hold promise for crafting absorption-dominated electromagnetic shielding materials, highlighting the potential for advanced electromagnetic protection solutions.

Advanced Zinc Anode with Nitrogen-Doping Interface Induced by Plasma Surface Treatment.

Aqueous zinc-ion batteries (ZIBs) are one of the most ideal candidates for grid-scale energy storage applications due to their excellent price and safety advantages. However, formation of Zn dendrites and continuous side reactions during cycling result in serious instability problems for ZIBs. In this work, the authors develop a facile and versatile plasma-induced nitrogen-doped Zn (N-Zn) foil for dendrite-free Zn metal anode. Benefitting from the uniform nucleation sites and enhanced surface kinetics, the N-Zn anode exhibits exceptionally low overpotential (around 23 mV) at 1 mA cm-2 and can be cycled for over 3000 h under 1 mA cm-2 because of the enhanced interface behavior. The potential application of N-Zn anode is also confirmed by introducing a full Zn/MnO2 battery with outstanding capacity stability for 2000 cycles at 1 A g-1 . Overall, this work offers new fundamental insights into homogenizing Zn electrodeposition processes by pre-introduced active nucleation sites and provides a novel direction of interface design engineering for ultra-stable Zn metal anode.

Ultrathin MXene/Polymer Coatings with an Alternating Structure on Fabrics for Enhanced Electromagnetic Interference Shielding and Fire-Resistant Protective Performances.

Wearable electromagnetic interference (EMI) shielding fabrics are highly desirable with the rapid development of electronic devices and wireless communications where electromagnetic pollution is a great concern for human health and the reliability of precision equipment. The balance between EMI shielding efficiency (SE) and the flexibility of fabric is still challenging because of the generally opposite requirements for coating thickness. In this work, MXene/insulative polymer coating with an alternating structure is fabricated via a stepwise assembly technique to judiciously combine excellent shielding elements, a reasonable structure, and high nanofiller content together in the coating. Owing to this novel strategy, the coating with nanoscale thickness (∼500 nm) has realized the commercial requirement for EMI SE and well retained the flexibility and air permeability of the fabric. Compared with the corresponding pure MXene coating, such multilayered coating demonstrates 138.95% enhancement of EMI SE due to the improved dielectrical properties and intensive multiple reflections of electromagnetic waves. Additionally, this hybrid coating also acts as an excellent fire-resistant barrier for the inner flammable fabric to protect human beings and electronic devices in case of accidental fire. This work provides new insights into the rational design of shields with nanometer thickness to realize high EMI shielding performance and good fire resistance for new-generation portable and wearable EMI shielding products.

Multi-reflection-enhanced electromagnetic interference shielding performance of conductive nanocomposite coatings on fabrics.

With the rapid development of electronic communications, coated fabrics with EMI shielding capability have attracted increasing attention due to their broad applications in military, civilian, and commercial fields. The coating structure plays a vital role in EMI shielding performance and the fundamental understanding of how the coating structure affects the EMI shielding performance of the coated fabric is urgently needed. In this work, the coating structure has been systematically modulated to study its effects on the shielding performance of the corresponding coated fabric for the rational design of the high-performance EMI shielding materials. Owing to the multiple reflections of the electromagnetic waves triggered by the graphene oxide (GO)/ polypyrrole (PPy) interfaces, the shielding effectiveness (SE) of the coated fabric reaches 39.1 dB by increasing the amount of interface in the coating. Furthermore, more GO/PPy interfaces in the coating results in stronger EMI shielding enhancement once the conductive network is built. This work provides a guideline for the judicious design of shields to achieve excellent EMI shielding performances and offers opportunities for new-generation portable and wearable EMI shielding products.

Near-Instantaneously Self-Healing Coating toward Stable and Durable Electromagnetic Interference Shielding.

Durable electromagnetic interference (EMI) shielding is highly desired, as electromagnetic pollution is a great concern for electronics' stable performance and human health. Although a superhydrophobic surface can extend the service lifespan of EMI shielding materials, degradation of its protection capability and insufficient self-healing are troublesome issues due to unavoidable physical/chemical damages under long-term application conditions. Here, we report, for the first time, an instantaneously self-healing approach via microwave heating to achieve durable shielding performance. First, a hydrophobic 1H,1H,2H,2H-perfluorooctyltriethoxysilane (POTS) layer was coated on a polypyrrole (PPy)-modified fabric (PPy@POTS), enabling protection against the invasion of water, salt solution, and corrosive acidic and basic solutions. Moreover, after being damaged, the POTS layer can, for the first time, be instantaneously self-healed via microwave heating for a very short time, i.e., 4 s, benefiting from the intense thermal energy generated by PPy under electromagnetic wave radiation. This self-healing ability is also repeatable even after intentionally severe plasma etching, which highlights the great potential to achieve robust and durable EMI shielding applications. Significantly, this approach can be extended to other EMI shielding materials where heat is a triggering stimulus for healing thin protection layers. We envision that this work could provide insights into fabricating EMI shielding materials with durable performance for portable and wearable devices, as well as for human health care.

Axial Alignment of Carbon Nanotubes on Fibers To Enable Highly Conductive Fabrics for Electromagnetic Interference Shielding.

Conductive coatings show great promise for next-generation electromagnetic interference (EMI) shielding challenges on textile; however, their stringent requirements for electrical conductivity are difficult to meet by conventional approaches of increasing the loading and homogeneity of conductive nanofillers. Here, the axial alignment of carbon nanotubes (CNTs) on fibers that were obtained by spontaneous capillary-driven self-assembly is shown on commercial cotton fabrics, and its great potential for EMI shielding is demonstrated. The aligned CNTs structurally optimize the conductive network on fabrics and yield an 81-fold increase in electrical conductivity per unit of CNT, compared with the disordered CNT microstructure. The high-efficiency electrical conductivity allows a several-micron-thick coating on insulating fabrics to endow an EMI shielding effectiveness of 21.5 dB in the X band and 20.8 dB in the Ku band, which meets the standard shielding requirement in commercial applications. It is among the minimum reported thicknesses for conductive nanocomposite coatings to date. Moreover, the coated fabrics with aligned CNTs possess a desirable stability upon bending, scratching, stripping, and even washing, which is attributed to the dense CNT packing in the aligned microarchitecture. This work presents the anisotropic structure on large areas by self-assembly, offering new opportunities for next-generation portable and wearable electronic devices.

Revealing Electrical-Poling-Induced Polarization Potential in Hybrid Perovskite Photodetectors.

Despite recent rapid advances in metal halide perovskites for use in optoelectronics, the fundamental understanding of the electrical-poling-induced ion migration, accounting for many unusual attributes and thus performance in perovskite-based devices, remain comparatively elusive. Herein, the electrical-poling-promoted polarization potential is reported for rendering hybrid organic-inorganic perovskite photodetectors with high photocurrent and fast response time, displaying a tenfold enhancement in the photocurrent and a twofold decrease in the response time after an external electric field poling. First, a robust meniscus-assisted solution-printing strategy is employed to facilitate the oriented perovskite crystals over a large area. Subsequently, the electrical poling invokes the ion migration within perovskite crystals, thus inducing a polarization potential, as substantiated by the surface potential change assessed by Kelvin probe force microscopy. Such electrical-poling-induced polarization potential is responsible for the markedly enhanced photocurrent and largely shortened response time. This work presents new insights into the electrical-poling-triggered ion migration and, in turn, polarization potential as well as into the implication of the latter for optoelectronic devices with greater performance. As such, the utilization of ion-migration-produced polarization potential may represent an important endeavor toward a wide range of high-performance perovskite-based photodetectors, solar cells, transistors, scintillators, etc.

[Effect of phosphor on accumulation and chemical forms of cadmium, and physiological characterization in different varieties of Capsicum annuum L].

Pot experiments were carried out to investigate the influence of different Phosphor (P) levels (0, 0.3% and 0.5%) on the plant growth, activities of antioxidant enzymes, accumulation and chemical forms of cadmium (Cd) in Capsicum annuum L. when exposed to Cd (10 mg x kg(-1)). The results showed that dry weights of leaf, fruit, roots and total dry weights of plant, and concentration and accumulation of Cd significantly differed between two varieties of Capsicum annuum L. Dry weights of fruit and total plant of Chaotianjiao increased by P (0.3% and 0.5%), while that of Yanjiao425 was inhibited. Activities of catalase (CAT) were increased at first, and then reduced in the presence of P; Activities of superoxide dismutase (SOD) and peroxidase (POD) of Chaotianjiao increased with increasing levels of P, but activities of SOD and POD of Yanjiao425 decreased with increasing levels of P. Chemical forms of Cd in fruit of Capsicum annuum L. were in order of F(NaCl) > F(HAC) > F(E) > Fr > F(HC) > F(W). The total extractable Cd, ethanol-extractable Cd, hydrochloric acid-extractable Cd and residual Cd in fruit of Ynajiao425 obviously decreased in the presence of P compared to the control, while the total extractable Cd, water-extractable Cd, acetic acid-extractable Cd and residual Cd in fruit of Chaotianjiao increased. Cadmium accumulations of Capsicum annuum L. were in order of roots > stew > leaf > fruit. Cadmium accumulations in fruit and plant of Yanjiao425 were decreased by 47.7% and 58.5% , 5.5% and 13. 1% in the presence of 0.3% and 0.5% P when exposed to Cd, and Cd accumulations in fruit and plant of Chaotianjiao were decreased by 23.6% in the presence of 0.3% P.

[Effect of different zinc levels on accumulation and chemical forms of cadmium, and physiological characterization in Capsicum annuum L].

Pot experiments were carried out to investigate the influence of different zinc (Zn) levels (0, 100, 200, 400 and 600 micromol x L(-1)) on the plant growth,activities of antioxidant enzymes, contents of chlorophyll a and b, accumulation and chemical forms of cadmium (Cd) in Capsicum annuum L. when exposed to Cd (20 mg x kg(-1)). The results showed that dry weights of leaf, stem, fruit and root, and contents of chlorophyll a and b in Capsicum annuum L. were increased by Zn ( < or = 400 micromol x L(-1)), while inhibited by high Zn (600 micromol x L(-1)). Activities of superoxide dismutase (SOD) and catalase (CAT) were reduced by Zn ( < or =400 micromol x L(-1)), the lowest activities of SOD and CAT were recorded in 400 micromol x L(-1) Zn, but activities of SOD and CAT were increased when Zn >400 micromol x L(-1). Cadmium concentrations in stem, fruit and root of Capsicum annuum L. were decreased by 2.7%-5.4%, 7.5%-28.1% and 7.6%-21.8% in the presence of Zn when exposed to Cd. The total extractable Cd, NaCl- extractable Cd, water-extractable Cd and ethanol-extractable Cd in fruit were reduced by 7.7%-21.8%, 4.11%-23.6%, 54.5%-66.8% and 4.8%-86.7% in the presence of Zn,while acetic acid- extractable Cd and residual Cd were increased by 28.0%-68.0% and 12.6%-25.0%.