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Showing papers on "Fabrication published in 2022"


Journal ArticleDOI
TL;DR: In this article , the edge of a graphene layer was used as the gate electrode for side-wall molybdenum disulfide (MoS2) transistors with an atomically thin channel and a physical gate length of sub-1 nm.
Abstract: Ultra-scaled transistors are of interest in the development of next-generation electronic devices1-3. Although atomically thin molybdenum disulfide (MoS2) transistors have been reported4, the fabrication of devices with gate lengths below 1 nm has been challenging5. Here we demonstrate side-wall MoS2 transistors with an atomically thin channel and a physical gate length of sub-1 nm using the edge of a graphene layer as the gate electrode. The approach uses large-area graphene and MoS2 films grown by chemical vapour deposition for the fabrication of side-wall transistors on a 2-inch wafer. These devices have On/Off ratios up to 1.02 × 105 and subthreshold swing values down to 117 mV dec-1. Simulation results indicate that the MoS2 side-wall effective channel length approaches 0.34 nm in the On state and 4.54 nm in the Off state. This work can promote Moore's law of the scaling down of transistors for next-generation electronics.

132 citations


Journal ArticleDOI
21 Jan 2022-Science
TL;DR: Three-dimensional (3D) direct lithography of PNCs with tunable composition and bandgap in glass was reported, and encapsulated P NCs exhibited long-term stability after prolonged heating or organic solvent and ultraviolet light exposure.
Abstract: Material composition engineering and device fabrication of perovskite nanocrystals (PNCs) in solution can introduce organic contamination and entail several synthetic, processing, and stabilization steps. We report three-dimensional (3D) direct lithography of PNCs with tunable composition and bandgap in glass. The halide ion distribution was controlled at the nanoscale with ultrafast laser–induced liquid nanophase separation. The PNCs exhibit notable stability against ultraviolet irradiation, organic solution, and high temperatures (up to 250°C). Printed 3D structures in glass were used for optical storage, micro–light emitting diodes, and holographic displays. The proposed mechanisms of both PNC formation and composition tunability were verified. Description Perovskite nanocrystals under glass Perovskite nanocrystals (PNCs) such as cesium lead triiodide (CsPbI3) can display bright photoemission with narrow linewidths for display applications, but their long-term stability requires passivation and encapsulation steps after synthesis in solution. Sun et al. created three-dimensional arrays of PNCs in doped metal oxide glasses using ultrafast laser pulses that caused local melting and subsequent crystallization. They tuned the bandgap of PNCs and their photoluminescence between 480- and 700-nanometer wavelengths by transforming the composition from CsPb(Cl1-xBrx)3 to CsPbI3. These encapsulated PNCs exhibited long-term stability after prolonged heating or organic solvent and ultraviolet light exposure. —PDS Melting of a doped metal oxide glass with ultrafast laser pulses created perovskite nanocrystal arrays for optoelectronics.

117 citations


Journal ArticleDOI
TL;DR: A comprehensive review about the most recent progress in the synthesis and applications of graphene-based composites is provided in this paper , where the difficulties and challenges in the current development of graphene are summarized and indicated.
Abstract: In the new era of modern flexible and bendable technology, graphene-based materials have attracted great attention. The excellent electrical, mechanical, and optical properties of graphene as well as the ease of functionalization of its derivates have enabled graphene to become an attractive candidate for the construction of flexible devices. This paper provides a comprehensive review about the most recent progress in the synthesis and applications of graphene-based composites. Composite materials based on graphene, graphene oxide (GO), and reduced graphene oxide (rGO), as well as conducting polymers, metal matrices, carbon–carbon matrices, and natural fibers have potential application in energy-harvesting systems, clean-energy storage devices, and wearable and portable electronics owing to their superior mechanical strength, conductivity, and extraordinary thermal stability. Additionally, the difficulties and challenges in the current development of graphene are summarized and indicated. This review provides a comprehensive and useful database for further innovation of graphene-based composite materials.

116 citations


Journal ArticleDOI
TL;DR: In this paper , the authors used the dry etching process of tantalum (Ta) film to obtain transmon qubits with the best lifetime (T1) for multi-qubit fabrication.
Abstract: By using the dry etching process of tantalum (Ta) film, we had obtained transmon qubit with the best lifetime (T1) 503 us, suggesting that the dry etching process can be adopted in the following multi-qubit fabrication with Ta film. We also compared the relaxation and coherence times of transmons made with different materials (Ta, Nb and Al) with the same design and fabrication processes of Josephson junction, we found that samples prepared with Ta film had the best performance, followed by those with Al film and Nb film. We inferred that the reason for this difference was due to the different loss of oxide materials located at the metal-air interface.

116 citations


Journal ArticleDOI
TL;DR: In this paper , the main preparation methods of cellulose nanopaper including filtration method and casting method as well as the newly developed technology are systematically elaborated and compared, and the prospects and ongoing challenges of cellulosophane nanopaper are summarized.
Abstract: Cellulose nanopaper has shown great potential in diverse fields including optoelectronic devices, food packaging, biomedical application, and so forth, owing to their various advantages such as good flexibility, tunable light transmittance, high thermal stability, low thermal expansion coefficient, and superior mechanical properties. Herein, recent progress on the fabrication and applications of cellulose nanopaper is summarized and discussed based on the analyses of the latest studies. We begin with a brief introduction of the three types of nanocellulose: cellulose nanocrystals, cellulose nanofibrils and bacterial cellulose, recapitulating their differences in preparation and properties. Then, the main preparation methods of cellulose nanopaper including filtration method and casting method as well as the newly developed technology are systematically elaborated and compared. Furthermore, the advanced applications of cellulose nanopaper including energy storage, electronic devices, water treatment, and high-performance packaging materials were highlighted. Finally, the prospects and ongoing challenges of cellulose nanopaper were summarized.

99 citations


Journal ArticleDOI
TL;DR: In this paper , the authors summarize the progress made in controllable design of NF membrane properties in recent years from the perspective of optimizing interfacial polymerization techniques and adopting new manufacturing processes and materials.
Abstract: Tailored design of high-performance nanofiltration (NF) membranes is desirable because the requirements for membrane performance, particularly ion/salt rejection and selectivity, differ among the various applications of NF technology ranging from drinking water production to resource mining. However, this customization greatly relies on a comprehensive understanding of the influence of membrane fabrication methods and conditions on membrane properties and the relationships between the membrane structural and physicochemical properties and membrane performance. Since the inception of NF, much progress has been made in forming the foundation of tailored design of NF membranes and the underlying governing principles. This progress includes theories regarding NF mass transfer and solute rejection, further exploitation of the classical interfacial polymerization technique, and development of novel materials and membrane fabrication methods. In this critical review, we first summarize the progress made in controllable design of NF membrane properties in recent years from the perspective of optimizing interfacial polymerization techniques and adopting new manufacturing processes and materials. We then discuss the property-performance relationships based on solvent/solute mass transfer theories and mathematical models, and draw conclusions on membrane structural and physicochemical parameter regulation by modifying the fabrication process to improve membrane separation performance. Next, existing and potential applications of these NF membranes in water treatment processes are systematically discussed according to the different separation requirements. Finally, we point out the prospects and challenges of tailored design of NF membranes for water treatment applications. This review bridges the long-existing gaps between the pressing demand for suitable NF membranes from the industrial community and the surge of publications by the scientific community in recent years.

98 citations



Journal ArticleDOI
TL;DR: Li et al. as discussed by the authors proposed a reduced graphene oxide (rGO) decorated silver nanowire (Ag NW) film, which realizes a seamless integration of optical transparency, highly efficient EMI shielding, reliable durability and stability.
Abstract: Silver nanowire (Ag NW) has been considered as the promising building block for the fabrication of transparent electromagnetic interference (EMI) shielding films. However, the practical application of Ag NW-based EMI shielding films has been restricted due to the unsatisfactory stability of Ag NW. Herein, we proposed a reduced graphene oxide (rGO) decorated Ag NW film, which realizes a seamless integration of optical transparency, highly efficient EMI shielding, reliable durability and stability. The Ag NW constructs a highly transparent and conductive network, and the rGO provides additional conductive path, showing a superior EMI shielding effectiveness (SE) of 33.62 dB at transmittance of 81.9%. In addition, the top rGO layer enables the hybrid film with reliable durability and chemical stability, which can maintain 96% and 90% EMI SE after 1000 times bending cycles at radius of 2 mm and exposure in air for 80 days. Furthermore, the rGO/Ag NW films also possess fast thermal response and heating stability, making them highly applicable in wearable devices. The synergy of Ag NW and rGO grants the hybrid EMI shielding film multiple desired functions and meanwhile overcomes the shortcomings of Ag NW. This work provides a reference for preparing multifunctional integrated transparent EMI shielding film.

93 citations


Journal ArticleDOI
TL;DR: In this article , the main preparation methods of cellulose nanopaper including filtration method and casting method as well as the newly developed technology are systematically elaborated and compared, and the prospects and ongoing challenges of cellulosophane nanopaper are summarized.
Abstract: Cellulose nanopaper has shown great potential in diverse fields including optoelectronic devices, food packaging, biomedical application, and so forth, owing to their various advantages such as good flexibility, tunable light transmittance, high thermal stability, low thermal expansion coefficient, and superior mechanical properties. Herein, recent progress on the fabrication and applications of cellulose nanopaper is summarized and discussed based on the analyses of the latest studies. We begin with a brief introduction of the three types of nanocellulose: cellulose nanocrystals, cellulose nanofibrils and bacterial cellulose, recapitulating their differences in preparation and properties. Then, the main preparation methods of cellulose nanopaper including filtration method and casting method as well as the newly developed technology are systematically elaborated and compared. Furthermore, the advanced applications of cellulose nanopaper including energy storage, electronic devices, water treatment, and high-performance packaging materials were highlighted. Finally, the prospects and ongoing challenges of cellulose nanopaper were summarized.

92 citations


Journal ArticleDOI
TL;DR: In this paper , the influence of polymer film thickness on the dielectric properties, film quality issues in thinner polymer films with different filler contents, and major processing methods in decreasing polymeric film thickness are discussed.

91 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of polymer film thickness on the dielectric properties, film quality issues in thinner polymer films with different filler contents, and major processing methods in decreasing polymeric film thickness are discussed.

Journal ArticleDOI
TL;DR: Li et al. as mentioned in this paper proposed a reduced graphene oxide (rGO) decorated silver nanowire (Ag NW) film, which realizes a seamless integration of optical transparency, highly efficient EMI shielding, reliable durability and stability.
Abstract: Silver nanowire (Ag NW) has been considered as the promising building block for the fabrication of transparent electromagnetic interference (EMI) shielding films. However, the practical application of Ag NW-based EMI shielding films has been restricted due to the unsatisfactory stability of Ag NW. Herein, we proposed a reduced graphene oxide (rGO) decorated Ag NW film, which realizes a seamless integration of optical transparency, highly efficient EMI shielding, reliable durability and stability. The Ag NW constructs a highly transparent and conductive network, and the rGO provides additional conductive path, showing a superior EMI shielding effectiveness (SE) of 33.62 dB at transmittance of 81.9%. In addition, the top rGO layer enables the hybrid film with reliable durability and chemical stability, which can maintain 96% and 90% EMI SE after 1000 times bending cycles at radius of 2 mm and exposure in air for 80 days. Furthermore, the rGO/Ag NW films also possess fast thermal response and heating stability, making them highly applicable in wearable devices. The synergy of Ag NW and rGO grants the hybrid EMI shielding film multiple desired functions and meanwhile overcomes the shortcomings of Ag NW. This work provides a reference for preparing multifunctional integrated transparent EMI shielding film.

Journal ArticleDOI
TL;DR: In this article , the Ni-based powder catalysts for urea-assisted hydrogen generation via water splitting were reviewed and the main fabrication approaches were summarized and discussed, and the problems and challenges were also concluded for the Nibased powder catalyst fabrication, the performance evaluation, and their application.
Abstract: Water splitting has been regarded as a sustainable and environmentally-friendly technique to realize green hydrogen generation, while more energy is consumed due to the high overpotentials required for the anode oxygen evolution reaction. Urea electrooxidation, an ideal substitute, is thus received increasing attention in assisting water-splitting reactions. Note that highly efficient catalysts are still required to drive urea oxidation, and the facile generation of high valence state species is significant in the reaction based on the electrochemical-chemical mechanisms. The high cost and rareness make the noble metal catalysts impossible for further consideration in large-scale application. Ni-based catalysts are very promising due to their cheap price, facile structure tuning, good compatibility, and easy active phase formation. In the light of the significant advances made recently, herein, we reviewed the recent advances of Ni-based powder catalysts for urea oxidation in assisting water-splitting reaction. The fundamental of urea oxidation is firstly presented to clarify the mechanism of urea-assisted water splitting, and then the prevailing evaluation indicators are briefly expressed based on the electrochemical measurements. The catalyst design principle including synergistic effect, electronic effect, defect construction and surface reconstruction as well as the main fabrication approaches are presented and the advances of various Ni-based powder catalysts for urea assisted water splitting are summarized and discussed. The problems and challenges are also concluded for the Ni-based powder catalysts fabrication, the performance evaluation, and their application. Considering the key influencing factors for catalytic process and their application, attention should be given to structure−property relationship deciphering, novel Ni-based powder catalysts development and their construction in the real device; specifically, the effort should be directed to the Ni-based powder catalyst with multi-functions to simultaneously promote the fundamental steps and high anti-corrosion ability by revealing the local structure reconstruction as well as the integration in the practical application. We believe the current summarization will be instructive and helpful for the Ni-based powder catalysts development and understanding their catalytic action for urea-assisted hydrogen generation via water splitting technique. Advances and challenges of Ni based powder catalyst were reviewed for urea oxidation in assisting water-splitting reaction.

Journal ArticleDOI
TL;DR: In this paper , the authors present recent advances in the fabrication of metal oxide-, 2D nanomaterials-, as well as 2D material/metal oxide composite-based gas sensors with highly sensitive and selective functions.
Abstract: Metal oxide nanoparticles have been widely utilized for the fabrication of functional gas sensors to determine various flammable, explosive, toxic, and harmful gases due to their advantages of low cost, fast response, and high sensitivity. However, metal oxide-based gas sensors reveal the shortcomings of high operating temperature, high power requirement, and low selectivity, which limited their rapid development in the fabrication of high-performance gas sensors. The combination of metal oxides with two-dimensional (2D) nanomaterials to construct a heterostructure can hybridize the advantages of each other and overcome their respective shortcomings, thereby improving the sensing performance of the fabricated gas sensors. In this review, we present recent advances in the fabrication of metal oxide-, 2D nanomaterials-, as well as 2D material/metal oxide composite-based gas sensors with highly sensitive and selective functions. To achieve this aim, we firstly introduce the working principles of various gas sensors, and then discuss the factors that could affect the sensitivity of gas sensors. After that, a lot of cases on the fabrication of gas sensors by using metal oxides, 2D materials, and 2D material/metal oxide composites are demonstrated. Finally, we summarize the current development and discuss potential research directions in this promising topic. We believe in this work is helpful for the readers in multidiscipline research fields like materials science, nanotechnology, chemical engineering, environmental science, and other related aspects.

Journal ArticleDOI
TL;DR: In this article , the authors used the dry etching process of tantalum (Ta) film to obtain transmon qubits with the best lifetime (T1) for multi-qubit fabrication.
Abstract: By using the dry etching process of tantalum (Ta) film, we had obtained transmon qubit with the best lifetime (T1) 503 us, suggesting that the dry etching process can be adopted in the following multi-qubit fabrication with Ta film. We also compared the relaxation and coherence times of transmons made with different materials (Ta, Nb and Al) with the same design and fabrication processes of Josephson junction, we found that samples prepared with Ta film had the best performance, followed by those with Al film and Nb film. We inferred that the reason for this difference was due to the different loss of oxide materials located at the metal-air interface.

Journal ArticleDOI
TL;DR: In this paper , the preparation methods of MXenes focusing on the recent investigations on their thermal structure-stability relationships in inert, oxidizing, and aqueous environments are systematically introduced.
Abstract: As an emerging star of 2D nanomaterials, 2D transition metal carbides and nitrides, named MXenes, present a large potential in various research areas owing to their intrinsic multilayer structure and intriguing physico-chemical properties. However, the fabrication and application of functional MXene-based devices still remain challenging as they are prone to oxidative degradation under ambient environment. Within this review, the preparation methods of MXenes focusing on the recent investigations on their thermal structure-stability relationships in inert, oxidizing, and aqueous environments are systematically introduced. Moreover, the key factors that affect the oxidation of MXenes, such as, atmosphere, temperature, composition, microstructure, and aqueous environment, are reviewed. Based on different scenarios, strategies for avoiding or delaying the oxidation of MXenes are proposed to encourage the utilization of MXenes in complicated environments, especially at high temperature. Furthermore, the chemistry of MXene-derived oxides is analyzed, which can offer perspectives on the further design and fabrication of novel 2D composites with the unique structures of MXenes being preserved.

Journal ArticleDOI
13 May 2022-Science
TL;DR: In this article , an electrically conductive conformal "diffusion barrier" is introduced between interconnecting subcells to improve the power conversion efficiency (PCE) and stability of all-perovskite tandem solar modules.
Abstract: Challenges in fabricating all-perovskite tandem solar cells as modules rather than as single-junction configurations include growing high-quality wide-bandgap perovskites and mitigating irreversible degradation caused by halide and metal interdiffusion at the interconnecting contacts. We demonstrate efficient all-perovskite tandem solar modules using scalable fabrication techniques. By systematically tuning the cesium ratio of a methylammonium-free 1.8–electron volt mixed-halide perovskite, we improve the homogeneity of crystallization for blade-coated films over large areas. An electrically conductive conformal “diffusion barrier” is introduced between interconnecting subcells to improve the power conversion efficiency (PCE) and stability of all-perovskite tandem solar modules. Our tandem modules achieve a certified PCE of 21.7% with an aperture area of 20 square centimeters and retain 75% of their initial efficiency after 500 hours of continuous operation under simulated 1-sun illumination. Description Large-area tandem perovskite solar cells Tandem solar cells allow more of the solar spectrum to be used. For all-perovskite implementations with large illumination areas, different bad-gap compositions must be grown with fully scalable methods. Xiao et al. blade coated high-quality, wide-bandgap perovskite layers by tuning the cesium concentration in a mixed solvent system. They avoided diffusion between the perovskite layers with a tin oxide layer grown by atomic layer deposition that also served as an electron extractor. Small-area cells (1 square centimeter) have a power conversion efficiency (PCE) of about 25%, and a 20-square-centimeter module had a certified PCE of 21.7%. The encapsulated tandem module maintained more than 75% of its initial PCE after maximum power point operation for over 500 hours in ambient air. —PDS Improved crystallization enables all-perovskite, large-area tandem solar module fabrication with fully scalable processing.

Journal ArticleDOI
23 Sep 2022-Science
TL;DR: In this paper , the solvent dielectric constant and Gutmann donor number were used to grow phase-pure 2D halide perovskite stacks of the desired composition, thickness, and bandgap without dissolving the underlying substrate, which achieved a photovoltaic efficiency of 24.5% with less than 1% degradation under continuous light at 55°C and 65% relative humidity.
Abstract: Realizing solution-processed heterostructures is a long-enduring challenge in halide perovskites because of solvent incompatibilities that disrupt the underlying layer. By leveraging the solvent dielectric constant and Gutmann donor number, we could grow phase-pure two-dimensional (2D) halide perovskite stacks of the desired composition, thickness, and bandgap onto 3D perovskites without dissolving the underlying substrate. Characterization reveals a 3D–2D transition region of 20 nanometers mainly determined by the roughness of the bottom 3D layer. Thickness dependence of the 2D perovskite layer reveals the anticipated trends for n-i-p and p-i-n architectures, which is consistent with band alignment and carrier transport limits for 2D perovskites. We measured a photovoltaic efficiency of 24.5%, with exceptional stability of T99 (time required to preserve 99% of initial photovoltaic efficiency) of >2000 hours, implying that the 3D/2D bilayer inherits the intrinsic durability of 2D perovskite without compromising efficiency. Description Pure perovskite topcoats Two-dimensional (2D) halide perovskite passivation layers grown on three-dimensional (3D) perovskite can boost the power conversion efficiency (PCE) of solar cells, but spin-coating of these layers usually forms heterogeneous 2D phases or only ultrathin layers. Sidhik et al. found that solvents with the appropriate dielectric constant and donor strength could grow phase-pure 2D phases of controlled thickness and composition on 3D substrates without dissolving them. Solar cells maintained a peak PCE of 24.5% for 2000 hours with less than 1% degradation under continuous light at 55°C and 65% relative humidity. —PDS Solvents enable growth of phase-pure two-dimensional perovskites without dissolving three-dimensional perovskite substrates.



Journal ArticleDOI
TL;DR: In this paper, a magnetically responsive and flexible superhydrophobic photothermal film (PFe-PCS) consisting of polydimethylsiloxane (PDMS), iron powder (Fe), and candle soot (CS) was demonstrated.

Journal ArticleDOI
TL;DR: In this paper , a comprehensive review of the development of nanocellulose materials for sustainable energy storage, particularly on supercapacitors, is presented and summarized, followed by highlighting the use of natural nanocellulate for constructing composite electrode materials including two-dimensional film electrodes, and three-dimensional aerogel electrodes for supercapACitors.
Abstract: With the increasing demand for sustainable energy storage systems, the development of various advanced materials from a renewable source is imminent. Owing to the advantages of high specific surface area, unique nanostructure, modifiability, and excellent mechanical strength, nanocellulose integrated with other conductive materials, such as nanocarbons, conducting polymers, and metal oxides, has been emerged as promising candidate materials for green and renewable energy storage devices. Besides, nanocellulose-derived carbon materials with good electrical conductivity and tunable microstructures can be fabricated via simple carbonization, which has been widely used as supercapacitor electrode materials. Herein, we present a comprehensive review that focuses on the development of nanocellulose materials for sustainable energy storage, particularly on supercapacitors. The fabrication strategies of nanocellulose-derived hybrid materials are first presented and summarized, followed by highlighting the use of natural nanocellulose for constructing composite electrode materials including two-dimension film electrodes, and three-dimension aerogel electrodes for supercapacitors. In addition, the possible limitations and potentials of nanocellulose in supercapacitors are outlooked.

Journal ArticleDOI
TL;DR: In this paper , photovoltaics (PV) is now an established technology and the most promising method for harvesting energy from the sun, which is attracting increasing attention as the traditional fossil-based energy sources are being depleted.
Abstract: Harnessing energy from the sun is attracting increasing attention as the traditional fossil-based energy sources are being depleted. Photovoltaics (PV) is now an established technology and the most promising method...

Journal ArticleDOI
TL;DR: In this paper , a review of metal-organic frameworks (MOFs)-based flexible solid-state supercapacitors (FSSCs) is presented, and a summary of the overall electrochemical performances and current development of the reported MOFs-based material assembled devices are presented gradually to predict the future tendency toward the actualization of an ultimate performance MOFsbased FSSC.

Journal ArticleDOI
TL;DR: In this article, a review of metal-organic frameworks (MOFs)-based flexible solid-state supercapacitors (FSSCs) is presented to predict the future tendency toward the actualization of an ultimate performance MOFs-based FSSC.

Journal ArticleDOI
TL;DR: In this article , the evaluation methods and influence factors of low-reflectivity green EMI shielding materials are introduced, and the recently reported fabrication approaches as well as the corresponding EMI shielding performance and mechanism in regards to the lowreflectivity Green EMI shields are summarized and the ways for dynamic performance regulation of recently reported EMI shield materials are concluded.
Abstract: Electromagnetic interference (EMI) shielding materials have been employed to diminish environmental electromagnetic radiations by reflecting and absorbing transmitted EM wave. However, most of the researchers focus on improving the electrical conductivity of the materials, which is conducive to improving EMI shielding performance, but it will also increase the EM reflection, leading to the inevitable secondary EM pollution. Therefore, it is momentous to develop novel green EMI shielding materials with low reflectivity for environmentally friendly applications. In this review, we introduce the evaluation methods and influence factors of low-reflectivity green EMI shielding materials. Subsequently, the recently reported fabrication approaches as well as the corresponding EMI shielding performance and mechanism in regards to the low-reflectivity green EMI shields are summarized, and the ways for dynamic performance regulation of recently reported EMI shielding materials are concluded as well. Finally, the extant challenges of design and fabrication for low-reflectivity EMI shielding materials needed to be concerned are proposed, and the research tendency of low-reflectivity EMI shielding materials are prospected.

Journal ArticleDOI
TL;DR: In this article , a femtosecond laser direct processing was used to construct micron-level grooves and protrusions on substrates to form a protective layer and then the substrates covered by polytetrafluoroethylene (PTFE) were scanned to make the surfaces of the substrate surfaces superhydrophobic.
Abstract: On account of their wide range of applications in self-cleaning, anti-icing, frost suppression, etc., superhydrophobic surfaces have attracted considerate attention. However, most of the superhydrophobic surfaces can only be prepared on the surfaces of specific materials and are easily damaged in the case of friction. In this work, we propose a facile method to achieve superhydrophobicity on various substrate surfaces. By femtosecond laser direct processing, micron-level grooves and protrusions are constructed on substrates to form a protective layer. Then, the substrates covered by polytetrafluoroethylene (PTFE) were scanned to make the surfaces of the substrates superhydrophobic. Since the PTFE micro-nano-particles are evenly distributed on the grooves and protrusions, the surfaces exhibit robust superhydrophobicity with excellent anti-friction performance that is independent of the substrate properties. This work provides an efficient and environmentally friendly path for achieving robust superhydrophobic surfaces on various substrates.

Journal ArticleDOI
24 Jan 2022-Polymers
TL;DR: In this paper , a review of green materials for fused filament fabrication can be found, referring to all kinds of possible industrial applications, and in particular to the field of Cultural Heritage.
Abstract: Recently, Fused Filament Fabrication (FFF), one of the most encouraging additive manufacturing (AM) techniques, has fascinated great attention. Although FFF is growing into a manufacturing device with considerable technological and material innovations, there still is a challenge to convert FFF-printed prototypes into functional objects for industrial applications. Polymer components manufactured by FFF process possess, in fact, low and anisotropic mechanical properties, compared to the same parts, obtained by using traditional building methods. The poor mechanical properties of the FFF-printed objects could be attributed to the weak interlayer bond interface that develops during the layer deposition process and to the commercial thermoplastic materials used. In order to increase the final properties of the 3D printed models, several polymer-based composites and nanocomposites have been proposed for FFF process. However, even if the mechanical properties greatly increase, these materials are not all biodegradable. Consequently, their waste disposal represents an important issue that needs an urgent solution. Several scientific researchers have therefore moved towards the development of natural or recyclable materials for FFF techniques. This review details current progress on innovative green materials for FFF, referring to all kinds of possible industrial applications, and in particular to the field of Cultural Heritage.

Journal ArticleDOI
TL;DR: In this article , the authors report the fabrication and measurement of high-bandgap tandem thermophotovoltaics (TPV) cells with efficiencies of more than 40% and experimentally demonstrate the efficiency of high bandgap tandem TPV cells.
Abstract: Thermophotovoltaics (TPVs) convert predominantly infrared wavelength light to electricity via the photovoltaic effect, and can enable approaches to energy storage1,2 and conversion3-9 that use higher temperature heat sources than the turbines that are ubiquitous in electricity production today. Since the first demonstration of 29% efficient TPVs (Fig. 1a) using an integrated back surface reflector and a tungsten emitter at 2,000 °C (ref. 10), TPV fabrication and performance have improved11,12. However, despite predictions that TPV efficiencies can exceed 50% (refs. 11,13,14), the demonstrated efficiencies are still only as high as 32%, albeit at much lower temperatures below 1,300 °C (refs. 13-15). Here we report the fabrication and measurement of TPV cells with efficiencies of more than 40% and experimentally demonstrate the efficiency of high-bandgap tandem TPV cells. The TPV cells are two-junction devices comprising III-V materials with bandgaps between 1.0 and 1.4 eV that are optimized for emitter temperatures of 1,900-2,400 °C. The cells exploit the concept of band-edge spectral filtering to obtain high efficiency, using highly reflective back surface reflectors to reject unusable sub-bandgap radiation back to the emitter. A 1.4/1.2 eV device reached a maximum efficiency of (41.1 ± 1)% operating at a power density of 2.39 W cm-2 and an emitter temperature of 2,400 °C. A 1.2/1.0 eV device reached a maximum efficiency of (39.3 ± 1)% operating at a power density of 1.8 W cm-2 and an emitter temperature of 2,127 °C. These cells can be integrated into a TPV system for thermal energy grid storage to enable dispatchable renewable energy. This creates a pathway for thermal energy grid storage to reach sufficiently high efficiency and sufficiently low cost to enable decarbonization of the electricity grid.

Journal ArticleDOI
01 Jan 2022-Matter
TL;DR: Additive manufacturing (AM) has enabled the customized fabrication of objects with complex geometries and functionalities in mechanical and electrical properties as mentioned in this paper , but many challenges, such as the suboptimal quality of manufactured products and limited material available for 3D printing, need to be addressed for the broad adoption of additively manufactured polymer composites.