Ultralow Density Research Articles

One pot synthesis of hydrophobic nanochitin aerogel via tert-butyl alcohol/water binary solvents as antibacterial and renewable oil superabsorbent

In this study, hydrophobic nanochitin aerogels are synthesized via one-pot synthesis strategy and subsequent freeze-drying technique, employing nanochitin, hexanal and formaldehyde as primary components. The tert-butyl alcohol (TBA)/water binary solvents are found efficient for well mixing of hydrophilic nanochitin and hydrophobic hexanal, which is fundamental for fabricating hydrophobic aerogels with water contact angle as high as 105°. Schiff base reaction between amino groups in nanochitin and aldehyde groups in hexanal is believed to be the main reason for the successful hydrophobization of nanochitin aerogels. Additionally, formaldehyde is employed to enhance the mechanical properties of aerogels via ice templated crosslinking technique. Nanochitin aerogels prepared in this work possess surface area as high as 237 m2 g−1, which are believed benefiting from the TBA/water binary solvents with lower density, smaller ice crystal and convenience in freeze-drying. The ultralow density, ultrahigh porosity, and hydrophobicity nature also lead to the advanced oil adsorption (as high as 210 g g−1) of nanochitin aerogels. The simple preparation process, nature sustainability and excellent adsorption performance is believed rendering nanochitin aerogels as a viable alternative for the remediation of oil spills.

Lightweight and recyclable hybrid multifunctional foam based cellulose fibers with excellent flame retardant, thermal, and acoustic insulation property

The development of eco-friendly and good-performance foam materials is essential for the environment and energy saving. Conventional inorganic and organic foams suffer from brittleness and contamination problems. Here, we report a facile and scalable hybrid strategy to prepare shape-stable cellulose-based multifunctional foam via physical cross-linking of PVA and stabilization of HGMs. The prepared foam exhibits ultra-low density (27.0 mg/cm3), enhanced flame-retardant performance (the PHRR decreased from 161.8 to 89.1 kW/m2, LOI value up to 26.2%), low thermal conductivity (48.2 mW/mK), good acoustic insulation property (NRC of 0.41), and good mechanical properties (with specific compressive modulus of 15.3 MPa cm3/g). Moreover, the foam can be recycled under simplified procedures. Our approach provides a novel alternative to the manufacture of low-cost, eco-friendly, and scalable foam materials. This multifunctional lightweight material is highly sought after for modern engineering construction applications.

Flexible, Thermally Stable, and Ultralightweight Polyimide-CNT Aerogel Composite Films for Energy Storage Applications.

Polyimide (PI) aerogels are promising in various fields of application, ranging from thermal insulators to aerospace. However, they are typically in the form of a bulk monolith, which suffers from a lack of conformability and drapability. Moreover, their electrical conductivity is limited, and they mainly display an insulative behavior. These shortcomings can limit the applications of PI aerogels in energy storage systems, which require ultralightweight flexible conductive films, which at the same time offer high thermal stability, ultralow density, and high surface area. To overcome these obstacles, the present study reports the fabrication of PI-carbon nanotube (PI-CNT) aerogel composite films with varying CNT content prepared through a sol-gel preparation method, followed by a supercritical drying procedure. Compared to pristine PI aerogels, which displayed a large shrinkage and density of 18.3% and 0.12 g cm-3, respectively, the incorporation of only 5 wt % CNTs resulted in a significant reduction of both shrinkage and density to only 11.5% and 0.10 g cm-3, respectively. This suggests the importance of CNTs in improving the dimensional stability of aerogels and creating a robust network. Further characterizations showed that incorporation of 5 wt % CNTs also resulted in the highest pore volume (1.25 cm3 g-1), highest surface area (324 m2 g-1), highest real permittivity (80), highest electrical conductivity (3 × 10-1 S m-1), and ultrahigh service temperature (575 °C). It was also shown that the aerogel films can withstand a large degree of bending, can be twisted, and can be fully rolled with no obvious cracks propagated in the structure. The combined outstanding properties of the developed aerogel composite films make them promising potential candidates for supercapacitor electrodes. Therefore, the electrochemical performance of the devices based on aerogel electrodes was further studied. The device demonstrated a high energy density of 2.6 Wh kg-1 at a power density of 303.8 W kg-1. The total capacitance after 5000 cycles was 91.8% of the initial capacitance, which indicated excellent stability and durability of the device. Overall, this work provides a facile yet effective methodology for the development of high-performance aerogel materials for energy storage applications.

Synthesis of carbon aerogels with controlled morphology and pore structure to modulate their bulk density and thermal conductivity via a quick one-pot preparation strategy

How to improve the preparation efficiency and reduced production costs in synthesizing high-performance polymer-derived carbon aerogel materials with ultra-low density and excellent thermal protection properties is currently a crucial research topic that has been plaguing scientists for decades. In this study, we innovatively propose a “one-pot” preparation strategy to synthetize carbon aerogel, which can simplify the complex processes of conventional fabrication methods, greatly shorten the preparation time of phenolic resin-based organic aerogel, and obtain the corresponding carbon aerogels after carbonization. Here, a series of carbon aerogel samples are obtained by regulating the solvent species, and their physicochemical properties such as morphology, pore structure shrinkage, density, and thermal conductivity of these samples are discussed in detail. CA@isoamylol is screened out exhibiting the lowest bulk density (0.15 g/cm3) and thermal conductivity (0.0499 ± 0.0029 W/m·K at 25 °C and 0.1069 ± 0.0090 W/m·K at 1200 °C), which is comparable to the reported values of best-in-class carbon aerogel values, and much lower than the conventional carbon foams. The synthesized CA@isoamylol is promising as a condidate for thermal insulation material. It is expected that the “one-pot” method could alleviate the above-mentioned bottlenecks of the carbon aerogel discipline to produce high-performance carbon aerogel materials with a low-cost and efficient routes.

3D Electrospinning of Al2O3/ZrO2 fibrous aerogels for multipurpose thermal insulation

Ceramic aerogels are excellent ultralight-weight thermal insulators yet impractical due to their tendency towards structural degradation at elevated temperatures, under mechanical disturbances, or in humid environments. Here, we present flexible and durable alumina/zirconia fibrous aerogels (AZFA) fabricated using 3D sol–gel electrospinning — a technique enabling in situ formation of 3D fiber assemblies with significantly reduced time consumption and low processing cost compared to most existing methods. Our AZFAs exhibit ultralow density (> 3.4 mg cm−3), low thermal conductivity (> 21.6 mW m−1 K−1), excellent fire resistance, while remaining mechanically elastic and flexible at 1300 °C, and thermally stable at 1500 °C. We investigate the underlying structure-thermal conductivity relationships, demonstrating that the macroscopic fiber arrangement dictates the solid-phase thermal conduction, and the mesopores in the fiber effectively trap air thereby decreasing the gas conduction. We show experimentally and theoretically that directional heat transport, i.e., anisotropic thermal conductivity, can be achieved through compressing the fiber network. We further solve the moisture sensitivity problem of common fibrous aerogels through fluorination coating. The resulting material possesses excellent hydrophobicity and self-cleaning properties, which can provide reliable thermal insulation under various conditions, including but not limited to high-temperature conditions in vehicles and aircraft, humid conditions in buildings, and underwater environments for oil pipelines.Graphical

Room-temperature growth of perovskite single crystals via antisolvent-assisted confinement for high-performance electroluminescent devices

Organic-inorganic halide perovskite single crystals (OIHP-SCs) are promising light-emitting materials for bright electroluminescence (EL) devices due to their superior optoelectronic properties and excellent stability. However, the conventional high-temperature growth methods will inevitably disturb the ordered growth and introduce massive defects in OIHP-SCs, leading to the degradation of device performance. The preparation of thin OIHP-SCs with low trap-state densities for high-performance EL devices remains a formidable challenge. Here, we develop an efficient antisolvent-assisted confined growth (AACG) method for the room-temperature growth of formamidinium lead bromide (FAPbBr3) perovskite SCs. An antisolvent vapour environment is intentionally introduced in the spatially confined growth process to lower the free energy barrier for nucleation, enabling the growth of high-quality FAPbBr3 SCs at room temperature. Consequently, FAPbBr3 SCs with ultralow trap-state density of 2.15 × 109 cm−3 and amplified spontaneous emission (ASE) threshold of 7.1 µJ cm−2 could be achieved, representing the best results ever reported for FAPbBr3 SCs. By leveraging the high crystal quality of FAPbBr3 SCs, SC-based perovskite light-emitting diodes (PeLEDs) with a high luminance of over 26,000 cd m−2 and a peak current efficiency (CE) of 13.02 cd A−1 are demonstrated. Our work opens up new opportunities for the development of high-performance EL devices based on OIHP-SCs.

Flexible, high strength and low thermal conductivity of a novel high entropy oxide ceramic fiber membranes

Single-component oxide fibers encounter various issues, including grain transition growth and mechanical property degradation at high temperatures, which restrict their potential usage for high-temperature applications. The unique properties of high-entropy materials, including lattice distortion, sluggish diffusion, and cocktail effects, can effectively maintain small grains and excellent mechanical properties even in extreme conditions. Therefore, developing high-entropy oxide fibers provides a dependable solution to address the issues associated with single-component fibers. This paper successfully obtained the (Zr0.2Hf0.2Ti0.2Gd0.2Y0.2)O2-δ (ZHTGY) high-entropy oxide fibers by commencing from molecular design. Compared to other high entropy oxide materials, ZHTGY fibers exhibit a low crystallization temperature of 700 °C and exceptional high-temperature stability with no phase changes observed from RT to 1500 °C. In addition, the ZHTGY fiber membranes exhibit a density of merely 33 mg·cm−3, a tensile strength of 2.73 MPa@1000 °C, excellent flexibility, knot-free and fold-free properties, as well as the ability to bend freely even in environments with butane flame or liquid nitrogen. The ZHTGY fiber membranes have excellent thermal insulation properties due to their ultra-low density and high-temperature structural stability. With a thermal conductivity of only 25.7 mW·m−1K−1, an 8 mm thick sample laminated with these fiber membranes can reduce the temperature of a 1370 °C heat source to just 320 °C. The fiber membranes maintain good flexibility and strength even after heat treatment at 1200 °C for 50 h and 1400 °C for 180 s. This study provides a novel approach for preparing high-entropy oxidation fibers, thereby enabling the development of lightweight high-temperature thermal protection materials.

Formaldehyde oxidation boosts ultra-low cell voltage industrial current density water electrolysis for dual hydrogen production

The high cost is a major issue that has contributed to the slow industrialization of electrolytic water. To reduce the cell voltage to below 0.5 V, we constructed a hybrid electrolytic water system with coupled hydrogen evolution reaction (HER) and formaldehyde oxidation reaction (FOR). For FOR, the abundant Cu0 and Cu+ in nitrogen-doped Cu/Cu2+1O on Cu foam (N-Cu/Cu2+1O/CF) can effectively promote the adsorption and activation of H2O and HCHO molecules, and facilitate the cleavage of O-H and C-H, while nitrogen doping can promote the exposure of Cu active sites. For HER//FOR, a cell voltage of only 0.42 V is required to achieve 500 mA cm−2. The system can not only produce H2 routinely at the cathode through HER but also release H2 by HCHO oxidation. The construction of a dual hydrogen production system with industrial current density at ultra-low voltage provides a new idea to reduce the cost of hydrogen production.

Hybrid electrolyte engineering enables reversible Zn metal anodes at ultralow current densities

Parasitic reactions in aqueous Zn metal batteries tend to be intensified along with the decrease of current density, deteriorating the cycling stability of Zn anodes, which unfortunately have been overlooked in previous studies. Herein, an organic solvent N-Methylacetamide (NMA) is introduced into ZnSO4 electrolyte for improving the reversibility of Zn anodes. Combined with theoretical and experimental investigations, it is uncovered that NMA additives are capable of entering not only the pristine Zn2+ solvation structure ([Zn(H2O)x]2+) but also the electrical double layer structure, reducing active H2O molecule proportions and thus suppressing the corrosion reactions. Meanwhile, nucleation and growth processes are also constrained with NMA additive for its strong coordination with Zn2+, inducing dendrite-free Zn depositions. Consequently, an average Coulombic efficiency (CE) of 98.5% for 600 cycles in Zn|Cu half-cells with NMA/ZnSO4 electrolyte is obtained at an ultralow current density of 0.3 mA cm−2. Moreover, Zn|Zn symmetric cells utilizing 20 vol% NMA additive exhibit stable cycle lifespan of 1000 h. Benefitting from the enhanced reversibility of Zn anodes in NMA/ZnSO4 electrolytes, full-cells assembled with carbon cloth as cathodes deliver high performance of 5200 cycles at the current density of 64 mA g−1 with 10 μm thin Zn anodes, favoring the practical applications.

Phase Engineering of 2D Spinel-Type Manganese Oxides.

2D magnetic materials have been of interest due to their unique long-range magnetic ordering in the low-dimensional regime and potential applications in spintronics. Currently, most studies are focused on strippable van der Waals magnetic materials with layered structures, which typically suffer from a poor stability and scarce species. Spinel oxides have a good environmental stability and rich magnetic properties. However, the isotropic bonding and close-packed nonlayered crystal structure make their 2D growth challenging, let alone the phase engineering. Herein, a phase-controllable synthesis of 2D single-crystalline spinel-type oxides is reported. Using the van der Waals epitaxy strategy, the thicknesses of the obtained tetragonal and hexagonal manganese oxide (Mn3 O4 ) nanosheets can be tuned down to 7.1nm and one unit cell (0.7nm), respectively. The magnetic properties of these two phases are evaluated using vibrating-sample magnetometry and first-principle calculations. Both structures exhibit a Curie temperature of 48 K. Owing to its ultrathin geometry, the Mn3 O4 nanosheet exhibits a superior ultraviolet detection performance with an ultralow noise power density of 0.126 pA Hz-1/2 . This study broadens the range of 2D magnetic semiconductors and highlights their potential applications in future information devices.

Carbon dots enhanced ultra‐low‐density fluorescence proppants with both high‐compressive strength and anti‐deformation ability

AbstractThe polymer ultra‐low‐density proppants are critical to the development of slick‐water fracture technology, but which were prone to obvious deformation under high pressure in the fractures. To increase the stiffness of the styrene‐divinylbenzene copolymer (SDB) and obtain desired ultra‐low‐density (ULD) proppants, carbon dots (CDs) were introduced in‐situ considering their characteristics as the zero‐dimensional carbon nanomaterial. Taking the compressive strength and axial deflection, and so forth into consideration, the synthesis conditions of CDs modified SDB microspheres (CDs‐SDBs) were optimized. Taking the graphite modified SDBs (MG‐SDBs) as a reference, the density of CDs‐SDBs did keep almost constant at about 1.1800 ~ 1.1899 g·cm−3 with the increase of CDs amount. The CDs‐SDBs not only possess high‐peak pressure (41.5 N) but also minute axial deflection (0.090 mm). The advantages of CDs‐SDBs over MG‐SDBs become even more pronounced under higher pressure, which can withstand closure pressure of 80 MPa with a small crush ratio of 4.47%. CDs‐SDBs exhibit significant photoluminescence performances with maximum excitation and emission wavelengths of 634 nm and 554 nm.Highlights CDs‐SDBs as ULD proppants with high strength and anti‐deformation were developed. Advantages of CDs‐SDBs become more pronounced under high‐closure pressure. With increasing of CDs amount, apparent density of CDs‐SDBs keep almost constant. Axial deflection of CDs‐SDBs is only 0.09 mm under 41.5 N. The crush ratio is only 4.47% under 80 MPa closure pressure.

Liquid-Templating Aerogels.

Modern materials science has witnessed the era of advanced fabrication methods to engineer functionality from the nano- to macroscales. Versatile fabrication and additive manufacturing methods are developed, but the ability to design a material for a given application is still limited. Here,a novel strategy that enables target-oriented manufacturing of ultra-lightweight aerogels with on-demand characteristics is introduced. The process relies on controllable liquid templating through interfacial complexation to generate tunable, stimuli-responsive 3D-structured (multiphase) filamentous liquid templates. The methodology involves nanoscale chemistry and microscale assembly of nanoparticles (NPs) at liquid-liquid interfaces to produce hierarchical macroscopic aerogels featuring multiscale porosity, ultralow density (3.05-3.41mg cm-3 ), and high compressibility (90%) combined with elastic resilience and instant shape recovery. The challenges are overcome facing ultra-lightweight aerogels, including poor mechanical integrity and the inability to form predefined 3D constructs with on-demand functionality, for a multitude of applications. The controllable nature of the coined methodology enables tunable electromagnetic interference shielding with high specific shielding effectiveness (39 893dB cm2 g-1 ), and one of the highest-ever reported oil-absorption capacities (487 times the initial weight of aerogel for chloroform), to be obtained. These properties originate from the engineerable nature of liquid templating, pushing the boundaries of lightweight materials to systematic function design and applications.

Ultralight, elastic, magnetic and superhydrophobic cellulose nanofibril based aerogel with layer-support structure designed for both excellent oil-water separation and efficient PM2.5 removal

It is unquestionably a great challenge to develop elastic cellulose nanofibril (CNF) based aerogels satisfying both excellent oil-water separation and efficient PM2.5 removal. In this work, the CNF based aerogel with a layer-support structure was design through CNF as the aerogel scaffold and compositing with bamboo activated charcoal (BAC) and Fe3O4 as the functional particles, followed by hydrophobic modification. The resultant aerogel displays ultra-low density (30.12 mg/cm3), good specific surface area (25.38 m2/g), magnetism (9.44 emu/g) and superhydrophobicity (water contact angle (WCA) of 153.8° and slide angle (SA) of 7°). Benefiting from high internal porosity of the layer-support structure, the system shows excellent absorption efficiency (16.79–51.93 g/g) for various oils and filtration efficiency (97.85 ± 1.2%) for PM2.5 with a low pressure drop (58 Pa). As well as it also shows outstanding mechanical properties and able to maintain a high recovery of 75.4% at 50% strain (corresponding 25.29 kPa) due to the flexibility of the “support” structure given by methyltrimethoxysilane (MTMS). Based on its simple preparation and excellent properties, the magnetic and superhydrophobic CNF/Fe3O4@BAC composite aerogel shows great potential in multifaceted separation technique and recycling of natural resources.

Self-cross-linking of metal-organic framework (MOF-801) in nanocellulose aerogel for efficient adsorption of Cr (VI) in water

Chromium (Cr) poses significant hazards to both human health and the natural environment. Therefore, in this study, metal-organic framework (MOF-801) was compounded with nanocellulose aerogel for the first time. And a nanocellulose/metal-organic framework composite aerogel was developed for efficient chromium ion adsorption. The resulting aerogel has an ultra-low density (0.017 g/cm3) and high porosity (98.87%). The removal efficiency of this aerogel for Cr (VI) (93.86%) was measured to be higher than that of cellulose nanofiber aerogel (TCNF: 50.08%) and MOF-801 powder (59.86%). It was also higher than the cellulose nanocellulose aerogel prepared without MOF-801 (TMPA: 70.58%). This is because MOF-801 cross-linked with nanocellulose increased its porosity and provided a large number of adsorption sites. The maximum adsorption of Cr (VI) by this aerogel was 350.64 mg/g (5.96 mg/cm3). The adsorption mechanism was investigated by adsorption isotherms, adsorption kinetics, XPS, and FT-IR analysis. The aerogel has good reusability, with no significant loss of adsorption performance over 6 cycles. It is worth mentioning that 0.69 g (V: 7.363 cm3) of aerogel could effectively remediate 3710 mL of chromium-containing wastewater in a fixed-bed column adsorption experiment. In addition, the aerogel can effectively remove many metal ions from wastewater. As a result, the aerogel made in this study has the ability to be an effective adsorbent for metal ion removal.

"Rigid-Flexible" Anisotropic Biomass-Derived Aerogels with Superior Mechanical Properties for Oil Recovery and Thermal Insulation.

Aerogels with low density, high mechanical strength, and excellent elasticity have a wide potential for applications in wastewater treatment, thermal management, and sensors. However, the fabrication of such aerogels from biomass materials required complex preparation processes. Herein, a sustainable and facile strategy was reported to construct lignin/cellulose aerogels (LCMA) with three-dimensional interconnected structures by introducing homologous lignin with a polyphenyl propane structure as a structural enhancer through a top-down directional freezing approach, prompting a 2036% enhancement in compressive modulus and an 8-12-fold increase in oil absorption capacity. In addition, the hydrophobic aerogels with superelasticity were achieved by combining the aligned polygon-like structure and flexible silane chains, which exhibited remarkable compressional fatigue resistance and superhydrophobicity (WCA = 168°). Attributed to its unique pore design and surface morphology control, the prepared aerogel exhibited excellent performance in immiscible oil-water separation and water-in-oil emulsion separation. Due to the ultra-low density (8.3 mg·cm-3) as well as high porosity (98.87%), the obtained aerogel showed a low thermal conductivity (0.02565 ± 0.0024 W·m-1·K-1), demonstrating a potential in insulation applications. The synthetic strategy and sustainability concept presented in this work could provide guidance for the preparation of advanced biomass-based aerogels with unique properties for a wide range of applications.

Dual bionics of structure and preparation: Gradient architectured carbon/ceramic composite as light as water but bearing ultra-high temperature max to 2500 °C

The ultra-lightweight and high-performance materials have always been in demand for modern technology, especially in the aerospace industry. A rational solution to learning from nature is constructing gradient architectures, which remains a great challenge. Inspired by the cellulose fibrous structure in trees for absorbing nutrition from the soil, a convenient strategy based on capillary adsorption is proposed to achieve autonomous and controllable transportation of ceramic inside carbon fabric. Using this method, we obtained gradient architectured carbon/ceramic composites with density at 1.0 and 1.4 g/cm3, which endured 2000 °C and 2500 °C over 300s respectively. The excellent thermal endurance with ultralow density realized great performance as thermal protection material. The ultralight carbon/ceramic composite offered competitive thermal insulation performance with a back temperature below 120 °C while enduring 1300∼1400 °C for 30 min on the front side. This dual bionics of structure and preparation provides flexible designing and constructing gradient architecture composites based on a fibrous framework.

A facile and clean strategy to manufacture functional polylactic acid bead foams

Expanded poly (lactic acid) (EPLA) is a promising bio-material with ultra-low density, thermal insulation, cushioning properties, as well as the ability to be fabricated products in complex shapes. However, the time consuming of inducing double melt peaks of PLA and the complex two-steps process of steam-sintering assisted supercritical CO2 foaming is inevitable since PLA belongs crystalline polymer. To develop a facile and simple method to produce EPLA foams with functions, we used the bulk polymerization of liquid reactants to form a sintering layer between PLA beads. Meanwhile, carbon nanotubes (CNT) were synchronously introduced and distributed in the sintering layer. And a unique EPLA foam with functional sintering layer was produced using supercritical CO2 foaming technology. The reported method could prepare EPLA foam with high expansion ratio of 8.5 times and high cell density of 8.25 × 108 cell/cm3. Compared with other methods, the novel EPLA foams exhibited excellent tensile strength and compressive strength, superior electrical conductivity of 0.12 S/m, electromagnetic shielding ability of 99% in the X-band at CNT content of 2.68 wt.%, as well as sensitive and accurate stress-sensing function. It facilitates the development of novel manufacturing technology and the expansion of applications fields of EPLA foam.

Preparation of aerogels from corn stalks and research on their properties and gelation behavior

Corn straw is a kind of agricultural biomass waste produced by the corn crop. It is a question of how to make effective use of this waste resource. Biomass aerogel is a good adsorbent which can be used to deal with water pollution. The direct use of non-component separated maize straw as the raw material in this paper can effectively reduce the experimental cost, simplify the experimental procedures and make efficient use of maize straw compared to traditional cellulosic raw materials. The inorganic salt lithium bromide (LiBr) solution was used as the solvent, and the environmentally friendly corn stover whole component aerogels (CA) with excellent performance were prepared by solvent replacement and freeze-drying. The optimum process for the preparation of aerogels was obtained using a single factor test method: 1:200, 150 ℃, 40 min, 70 wt% LiBr. The full-component aerogels from maize straw contained cellulose, hemicellulose and lignin, which indicated that the maize straw was effectively utilised. CA has a three-dimensional network pore structure, mainly composed of micropores and mesoporous pores. It has ultra-low density (9 mg/cm3) and excellent adsorption capacity for methylene blue and soybean oil (123.59 mg/g, 103.58 g/g). At the same time, the Rheolaser Master Microrheological (RMM) analyzer of French Formulaction Company was used to investigate the changes in solution gel process. The mean azimuth shift (MSD) curve of the sample was measured by optical microrheometer. The elastic factor (EI), macroscopic viscosity factor (MVI), solid-liquid equilibrium point (SLB), and photon free path (I*) values of the samples were calculated to explore the microstructure and rheological characteristics of the samples during the gel process. The gel behaviour and processes have been explored based on the analysis of these parameters. Potential applications of whole-component aerogels from corn stalks include building insulation, thermal insulation, light-blocking materials, and packaging materials.

A Universal Assembly Strategy of All‐Inorganic Non‐Layered Perovskite Single Crystals for High‐Responsivity Photodetectors

AbstractNon‐layered all‐inorganic perovskite single crystals (AIPSCs) have ultralow trap density and exceptional optoelectronic properties, which can be used for developing high‐performance perovskite optoelectronic devices with high efficiency and stability. However, there is a lack of comprehensive insight and universal principles to guide the preparation of high‐quality AIPSCs. Herein, a universal liquid–air interfacial assembly strategy is proposed for synthesizing non‐layered AIPSCs, in virtue of which a series of AIPSCs including whole structural dimensions from 0D to 3D are acquired. Specially, the CsPbI3 AIPSCs exhibit an ultrathin thickness of 40 nm, and the CsPbBr3 AIPSCs show ultra‐narrow PL FWHM of 11 nm. Photodetectors (PDs) based on CsPbBr3 show excellent performance with responsivity up to 120 A W−1 and detectivity exceeding 2 × 1013 Jones. Moreover, vertically integrated heterojunctions of mixed‐dimensions are fabricated, and the 2D/3D heterostructure PDs further display enhanced self‐powered characteristics. This work provides general synthetic guidance toward the synthesis of non‐layered AIPSCs and promotes their application in AIPSCs‐based optoelectronics.

Three-Dimensional-Printed Carbon Nanotube/Polylactic Acid Composite for Efficient Electromagnetic Interference Shielding.

High-performance electromagnetic interference (EMI) shielding materials with ultralow density and environment-friendly properties are greatly demanded to address electromagnetic radiation pollution. Herein, carbon nanotube/polylactic acid (CNT/PLA) materials with different CNT contents, which exhibit characteristics of light weight, environmental protection and good chemical stability, are fabricated using 3D printing technology, where CNTs are evenly distributed and bind well with PLA. The performances of 3D-printed CNT/PLA composites are improved compared to pure 3D-printed PLA composites, which include mechanical properties, conductive behaviors and electromagnetic interference (EMI) shielding. The EMI shielding effectiveness (SE) of CNT/PLA composites could be improved when the content of CNTs increase. When it reaches 15 wt%, the EMI SE of 3D-printed CNT/PLA composites could get up to 47.1 dB, which shields 99.998% of electromagnetic energy. Meanwhile, the EMI shielding mechanism of 3D-printed CNT/PLA composites is mainly of absorption loss, and it generally accounts for more than 80% of the total shielding loss. These excellent comprehensive performances endow a 3D-printed CNT/PLA composite with great potential for use in industrial and aerospace areas.