The rapid evolution of portable and wearable electronic devices has fueled the development of smart functional textiles that are able to conduct electricity,sense body movements,or store energy.One main challenge inhi...The rapid evolution of portable and wearable electronic devices has fueled the development of smart functional textiles that are able to conduct electricity,sense body movements,or store energy.One main challenge inhibiting the further development of functional textile-based electronics is the lack of robust functional fibers with suitable electrical,electrochemical and sensing functionalities.MXenes,an emerging family of two-dimensional(2D)materials,have shown to be promising candidates for producing functional fibers due to their exceptional electrical and electrochemical properties combined with solution processability.The unique ability of MXenes to readily form liquid crystal phases in various solvents has allowed them to generate additive-free fibers using a wet spinning process.In this work,we review the recent exciting developments in the fabrication of neat MXenes fibers and present a critical evaluation of practical challenges in MXenes processing that influence the macroscale material properties and the performance of the subsequent devices.We also provide our assessment for the future opportunities and challenges in producing MXene fibers to help pave the way for their widespread use in advanced wearable applications.展开更多
Activated carbons (ACs) were prepared from a lignocellulosic-based waste material by a chemical impregnation method using KOH, NaOH or CaCl2 as the activating agent. These ACs were characterized by different technique...Activated carbons (ACs) were prepared from a lignocellulosic-based waste material by a chemical impregnation method using KOH, NaOH or CaCl2 as the activating agent. These ACs were characterized by different techniques such as N2 adsorption, FTIR, XRD and SEM. Electrostatic properties viz. pH and pHpzc of AC suspensions in aqueous media were measured. The concentration of surface oxygenated functional groups of the ACs was estimated following the Boehm titration method. Cyclic voltammetry was conducted in H2SO4 after fabricating two-electrode capacitor cells of the ACs. The correlation of AC surface chemistry and morphology with electrochemical performance (capacitance) of powdered electrodes is analyzed and discussed.展开更多
Our goal is to develop a facile process to create patterns of inorganic oxides and metals on a substrate that can act as hard masks. These materials should have high etch contrast （compared to silicon） and so allow ...Our goal is to develop a facile process to create patterns of inorganic oxides and metals on a substrate that can act as hard masks. These materials should have high etch contrast （compared to silicon） and so allow high-aspect-ratio, high- fidelity pattern transfer whilst being readily integrable in modem semiconductor fabrication （FAB friendly）. Here, we show that ultra-small-dimension hard masks can be used to develop large areas of densely packed vertically and horizontally orientated Si nanowire arrays. The inorganic and metal hard masks （Ni, NiO, and ZnO） of different morphologies and dimensions were formed using microphase- separated polystyrene-b-poly（ethylene oxide） （PS-b-PEO） block copolymer （BCP） thin films by varying the BCP molecular weight, annealing temperature, and annealing solvent（s）. The self-assembled polymer patterns were solvent-processed, and metal ions were included into chosen domains via a selective inclusion method. Inorganic oxide nanopatterns were subsequently developed using standard techniques. High-resolution transmission electron microscopy studies show that high-aspect-ratio pattern transfer could be affected by standard plasma etch techniques. The masking ability of the different materials was compared in order to create the highest quality uniform and smooth sidewall profiles of the Si nanowire arrays. Notably good performance of the metal mask was seen, and this could impact the use of these materials at small dimensions where conventional methods are severely limited.展开更多
Tungsten ditelluride(WTe_(2))is a layered transition metal dichalcogenide(TMD)that has attracted increasing research inter-est in recent years.WTe_(2) has demonstrated large non-saturating magnetoresistance,potential ...Tungsten ditelluride(WTe_(2))is a layered transition metal dichalcogenide(TMD)that has attracted increasing research inter-est in recent years.WTe_(2) has demonstrated large non-saturating magnetoresistance,potential for spintronic applications and promise as a type-II Weyl semimetal.The majority of works on WTe_(2) have relied on mechanically exfoliated flakes from chemical vapour transport(CVT)-grown crystals for their investigations.While producing high-quality samples,this method is hindered by several disadvantages including long synthesis time,high-temperature annealing and an inherent lack of scalability.In this work,a synthesis method is demonstrated that allows the production of large-area polycrystalline films of WTe_(2).This is achieved by the reaction of pre-deposited films of W and Te at a relatively low temperature of 550℃.Sputter X-ray photoelectron spectroscopy reveals the rapid but self-limiting nature of the oxidation of these WTe_(2) films in ambient conditions.The WTe_(2) films are composed of areas of micrometre-sized nanobelts that can be isolated and offer potential as an alternative to CVT-grown samples.These nanobelts are highly crystalline with low defect densities indicated by transmission electron microscopy and show promising initial electrical results.展开更多
Atomic force microscopy(AFM)and scanning probe lithography can be used for the mechanical treatment of various surfaces,including polymers,metals,and semiconductors.The technique of nanoshaving,in which materials are ...Atomic force microscopy(AFM)and scanning probe lithography can be used for the mechanical treatment of various surfaces,including polymers,metals,and semiconductors.The technique of nanoshaving,in which materials are removed using the AFM tip,is employed in this work to produce nanopatterns of self-assembled monolayers(SAMs)on two-dimensional(2D)materials.The materials used are monolayers of transition metal dichalcogenides(TMDs),namely,MoS_(2)and WS_(2),which are noncovalently functionalized with perylene diimide(PDI),a perylene derivative.The approach involves rastering an AFM probe across the surface at a controlled increased load in ambient conditions.As a result of the strong bond between PDI SAM and TMD,loads in excess of 1|1N are required to pattern the monolayer.Various predefined patterns,including a grating pattern with feature sizes below 250 nm,are demonstrated.Results indicate the high precision of nanoshaving as an accurate and nondestructive lithographic technique for 2D materials.The work functions of shaved heterostructures are also examined using Kelvin probe force microscopy.展开更多
基金The authors acknowledge financial support from the National Natural Science Foundation of China(No.22105106)the Natural Science Foundation of Jiangsu Province of China(No.BK20210603)+1 种基金Nanjing Science and Technology Innovation Project for overseas Students,Start-up Funding from NUPTSF(No.NY221003)Research Grant from the Royal Society,UK(No.RGS\R1\221044).
文摘The rapid evolution of portable and wearable electronic devices has fueled the development of smart functional textiles that are able to conduct electricity,sense body movements,or store energy.One main challenge inhibiting the further development of functional textile-based electronics is the lack of robust functional fibers with suitable electrical,electrochemical and sensing functionalities.MXenes,an emerging family of two-dimensional(2D)materials,have shown to be promising candidates for producing functional fibers due to their exceptional electrical and electrochemical properties combined with solution processability.The unique ability of MXenes to readily form liquid crystal phases in various solvents has allowed them to generate additive-free fibers using a wet spinning process.In this work,we review the recent exciting developments in the fabrication of neat MXenes fibers and present a critical evaluation of practical challenges in MXenes processing that influence the macroscale material properties and the performance of the subsequent devices.We also provide our assessment for the future opportunities and challenges in producing MXene fibers to help pave the way for their widespread use in advanced wearable applications.
文摘Activated carbons (ACs) were prepared from a lignocellulosic-based waste material by a chemical impregnation method using KOH, NaOH or CaCl2 as the activating agent. These ACs were characterized by different techniques such as N2 adsorption, FTIR, XRD and SEM. Electrostatic properties viz. pH and pHpzc of AC suspensions in aqueous media were measured. The concentration of surface oxygenated functional groups of the ACs was estimated following the Boehm titration method. Cyclic voltammetry was conducted in H2SO4 after fabricating two-electrode capacitor cells of the ACs. The correlation of AC surface chemistry and morphology with electrochemical performance (capacitance) of powdered electrodes is analyzed and discussed.
基金We acknowledge financial support from the Science Foundation Ireland AMBER grant 12/RC/2278 and Semiconductor Research Corporation （SRC） grant 2013-OJ-2444. The contribution of the Foundation＇s Principal Investigator support is also acknowledged. We would also like to thank Dr. Clive Downing for the TEM assistance.
文摘Our goal is to develop a facile process to create patterns of inorganic oxides and metals on a substrate that can act as hard masks. These materials should have high etch contrast （compared to silicon） and so allow high-aspect-ratio, high- fidelity pattern transfer whilst being readily integrable in modem semiconductor fabrication （FAB friendly）. Here, we show that ultra-small-dimension hard masks can be used to develop large areas of densely packed vertically and horizontally orientated Si nanowire arrays. The inorganic and metal hard masks （Ni, NiO, and ZnO） of different morphologies and dimensions were formed using microphase- separated polystyrene-b-poly（ethylene oxide） （PS-b-PEO） block copolymer （BCP） thin films by varying the BCP molecular weight, annealing temperature, and annealing solvent（s）. The self-assembled polymer patterns were solvent-processed, and metal ions were included into chosen domains via a selective inclusion method. Inorganic oxide nanopatterns were subsequently developed using standard techniques. High-resolution transmission electron microscopy studies show that high-aspect-ratio pattern transfer could be affected by standard plasma etch techniques. The masking ability of the different materials was compared in order to create the highest quality uniform and smooth sidewall profiles of the Si nanowire arrays. Notably good performance of the metal mask was seen, and this could impact the use of these materials at small dimensions where conventional methods are severely limited.
基金This work was financially supported by Science Foundation Ireland(SFI,grant numbers:15/SIRG/3329,12/RC/2278_P2,PI_15/IA/3131)the Irish Research Council(Project 204486,Award 13653)+2 种基金Science Foundation Ireland and the Royal Society Fellowship(URF/RI/191637)The SEM and(S)TEM imaging for this project was carried out at the Advanced Microscopy Laboratory(AML),Trinity College Dublin,Ireland.The AML is an SFI supported imaging and analysis centre,part of the CRANN Institute and affiliated to the AMBER centre.G.S.D and T S-L acknowledge the European Commission under the project Graphene Flagship(Grant No.881603)the German Ministry of Education and Research(BMBF)under ACDC(Grant No.13N15100).
文摘Tungsten ditelluride(WTe_(2))is a layered transition metal dichalcogenide(TMD)that has attracted increasing research inter-est in recent years.WTe_(2) has demonstrated large non-saturating magnetoresistance,potential for spintronic applications and promise as a type-II Weyl semimetal.The majority of works on WTe_(2) have relied on mechanically exfoliated flakes from chemical vapour transport(CVT)-grown crystals for their investigations.While producing high-quality samples,this method is hindered by several disadvantages including long synthesis time,high-temperature annealing and an inherent lack of scalability.In this work,a synthesis method is demonstrated that allows the production of large-area polycrystalline films of WTe_(2).This is achieved by the reaction of pre-deposited films of W and Te at a relatively low temperature of 550℃.Sputter X-ray photoelectron spectroscopy reveals the rapid but self-limiting nature of the oxidation of these WTe_(2) films in ambient conditions.The WTe_(2) films are composed of areas of micrometre-sized nanobelts that can be isolated and offer potential as an alternative to CVT-grown samples.These nanobelts are highly crystalline with low defect densities indicated by transmission electron microscopy and show promising initial electrical results.
基金Science Foundation Ireland,PI_15/IA/3131,Georg Stefan Duesberg。
文摘Atomic force microscopy(AFM)and scanning probe lithography can be used for the mechanical treatment of various surfaces,including polymers,metals,and semiconductors.The technique of nanoshaving,in which materials are removed using the AFM tip,is employed in this work to produce nanopatterns of self-assembled monolayers(SAMs)on two-dimensional(2D)materials.The materials used are monolayers of transition metal dichalcogenides(TMDs),namely,MoS_(2)and WS_(2),which are noncovalently functionalized with perylene diimide(PDI),a perylene derivative.The approach involves rastering an AFM probe across the surface at a controlled increased load in ambient conditions.As a result of the strong bond between PDI SAM and TMD,loads in excess of 1|1N are required to pattern the monolayer.Various predefined patterns,including a grating pattern with feature sizes below 250 nm,are demonstrated.Results indicate the high precision of nanoshaving as an accurate and nondestructive lithographic technique for 2D materials.The work functions of shaved heterostructures are also examined using Kelvin probe force microscopy.
