Hydrogenated antimonene as quantum spin Hall insulator:A first-principles study

Using first-principles calculations based on density functional theory(DFT), the structural and electronic properties of hydrogenated antimonene have been systematically investigated. Phonon dispersion and molecular dynamics(MD)simulation reveal that fully hydrogenated(FH) antimonene has high dynamic stability and could be synthesized. A newσ-type Dirac cone related to Sb-px,y orbitals is found in FH antimonene, which is robust to tensile strain. Noticeably, the spin orbital coupling(SOC) opens a quantum spin Hall(QSH) gap of 425 meV at the Dirac cone, sufficiently large for practical applications at room temperature. Semi-hydrogenated antimonene is a non-magnetic metal. Our results show that FH antimonene may have great potential applications in next generation high-performance devices.

Tunable electronic structures of germanane/antimonene van der Waals heterostructures using an external electric field and normal strain

oscale devices.In the present work,we investigate the electronic structures of germanane/antimonene vdW heterostructure in response to normal strain and an external electric field by using the first-principles calculations based on density functional theory(DFT).The results demonstrate that the germanane/antimonene vdW heterostructure behaves as a metal in a[1,,0.6]V/A range,while it is a direct semiconductor in a[0.5,0.2]V/A range,and it is an indirect semiconduc-tor in a[0.3,1.0]V/A range.Interestingly,the band alignment of germanane/antimonene vdW heterostructure appears astype-II feature both in a[0.5,0.1]range and in a[0.3,1]V/A range,while it shows the type-I character at 0.2 V/A.In ad-dition,we find that the germanane/antimonene vdW heterostructure is an indirect semiconductor both in an in-plane biaxial strain range of[[5%,,3%]and in an in-plane biaxial strain range of[3%,5%],while it exhibits a direct semiconductor character in an in-plane biaxial strain range of[2%,2%].Furthermore,the band alignment of the germanane/antimonene vdW heterostructure changes from type-II to type-I at an in-plane biaxial strain of 3%.The adjustable electronic structure of this germanane/antimonene vdW heterostructure will pave the way for developing the nanoscale devices.

Tailoring electronic properties of two-dimensional antimonene with isoelectronic counterparts

Using ab initio density functional theory calculations, we explore the three most stable structural phases, namely, α,β, and cubic(c) phases, of two-dimensional(2D) antimonene, as well as its isoelectronic counterparts SnTe and InI. We find that the band gap increases monotonically from Sb to SnTe to InI along with an increase in ionicity, independent of the structural phases. The band gaps of this material family cover the entire visible-light energy spectrum, ranging from 0.26 eV to 3.37 eV, rendering them promising candidates for optoelectronic applications. Meanwhile, band-edge positions of these materials are explored and all three types of band alignments can be achieved through properly combining antimonene with its isoelectronic counterparts to form heterostructures. The richness in electronic properties for this isoelectronic material family sheds light on possibilities to tailor the fundamental band gap of antimonene via lateral alloying or forming vertical heterostructures.

Magnetic proximity effect induced spin splitting in two-dimensional antimonene/Fe_(3)GeTe_(2) van der Waals heterostructures

Recently, two-dimensional van der Waals(vd W) magnetic heterostructures have attracted intensive attention since they can show remarkable properties due to the magnetic proximity effect. In this work, the spin-polarized electronic structures of antimonene/Fe_(3)GeTe_(2)vdW heterostructures were investigated through the first-principles calculations. Owing to the magnetic proximity effect, the spin splitting appears at the conduction-band minimum(CBM) and the valence-band maximum(VBM) of the antimonene. A low-energy effective Hamiltonian was proposed to depict the spin splitting. It was found that the spin splitting can be modulated by means of applying an external electric field, changing interlayer distance or changing stacking configuration. The spin splitting energy at the CBM monotonously increases as the external electric field changes from-5 V/nm to 5 V/nm, while the spin splitting energy at the VBM almost remains the same. Meanwhile,as the interlayer distance increases, the spin splitting energies at the CBM and VBM both decrease. The different stacking configurations can also induce different spin splitting energies at the CBM and VBM. Our work demonstrates that the spin splitting of antimonene in this heterostructure is not singly dependent on the nearest Sb–Fe distance, which indicates that magnetic proximity effect in heterostructures may be modulated by multiple factors, such as hybridization of electronic states and the local electronic environment. The results enrich the fundamental understanding of the magnetic proximity effect in two-dimensional vdW heterostructures.

Graphitic carbon nitride/antimonene van der Waals heterostructure with enhanced photocatalytic CO_(2) reduction activity

Photocatalytic reduction of CO_(2) into valuable fuels is one of the potential strategies to solve the carbon cycle and energy crisis.Graphitic carbon nitride(g-C_(3)N_(4)),as a typical two-dimensional(2D)semiconductor with a bandgap of∼2.7 eV,has attracted wide attention in photocatalytic CO_(2) reduction.However,the performance of g-C_(3)N_(4) is greatly limited by the rapid recombination of photogenerated charge carriers and weak CO_(2) activation capacity.Construction of van der Waals heterostructure with the maximum interface contact area can improve the transfer/seperation efficiency of interface charge carriers.Ultrathin metal antimony(Sb)nanosheet(antimonene)with high carrier mobility and 2D layered structure,is a good candidate material to construct 2D/2D Sb/g-C_(3)N_(4) van der Waals heterostructure.In this work,the density functional theory(DFT)calculations indicated that antimonene has higher carrier mobility than g-C_(3)N_(4) nanosheets.Obvious charge transfer and in-plane structure distortion will occur at the interface of Sb/g-C_(3)N_(4),which endow stronger CO_(2) activation ability on di-coordinated N active site.The ultrathin g-C_(3)N_(4) and antimonene nanosheets were prepared by ultrasonic exfoliation method,and Sb/g-C_(3)N_(4) van der Waals heterostructures were constructed by self-assembly process.The photoluminescence(PL)and time-resolved photoluminescence(TRPL)indicated that the Sb/g-C_(3)N_(4) van der Waals heterostructures have a better photogenerated charge separation efficiency than pure g-C_(3)N_(4) nanosheets.In-situ FTIR spectroscopy demonstrated a stronger ability of CO_(2) activation to^ (∗)COOH on Sb/g-C_(3)N_(4) van der Waals heterostructure.As a result,the Sb/g-C_(3)N_(4) van der Waals heterostructures showed a higher CO yield with 2.03 umol g^(−1) h^(−1),which is 3.2 times that of pure g-C_(3)N_(4).This work provides a reference for activating CO_(2) and promoting CO_(2) reduction by van der Waals heterostructure.

A fast synthetic strategy for high-quality atomically thin antimonene with ultrahigh sonication power

Recent theoretical studies revealed that two-dimensional （2D） antimonene hasattractive characteristics, such as superior photothermal conductivity, absorptionover a wide range, high mobility, and good spintronic properties. Herein, we reporta reliable liquid phase exfoliation （LPE） route for the preparation of high-qualityhigh-stability atomically thin （AT） antimonene via high ultrasonic power. TheAT antimonene delivers a high specific capacity of up to 860 mA.h.g-1, with highrate capability and good cycling stability as an anode of a sodium ion battery（SIB）. The good conductivity and 2D structure endow AT antimonene with moreactive sites for sodium storage, a facilitated pathway for electron transfer andmass transport, and the capability to reduce the volume expansion during thedischarge-charge process.

2D antimonene-integrated composite nanomedicine for augmented low-temperature photonic tumor hyperthermia by reversing cell thermoresistance

The overexpression of heat shock proteins(HSPs)in tumor cells can activate inherent defense mechanisms during hyperthermia-based treatments,inducing thermoresistance and thus diminishing the treatment efficacy.Here,we report a distinct“non-inhibitor involvement”strategy to address this issue through engineering a calcium-based nanocatalyst(G/A@CaCO_(3)-PEG).The constructed nanocatalyst consists of calcium carbonate(CaCO_(3))-supported glucose oxidase(GOD)and 2D antimonene quantum dots(AQDs),with further surface modification by lipid bilayers and polyethylene glycol(PEG).The engineered G/A@CaCO_(3)-PEG nanocatalyst features prolonged blood circulation,which is stable at neutral pH but rapidly degrades under mildly acidic tumor microenvironment,resulting in rapid release of drug cargo in the tumor microenvironment.The integrated GOD effectively catalyzes the depletion of glucose for reducing the supplies of adenosine triphosphate(ATP)and subsequent down-regulation of HSP expression.This effect then augments the therapeutic efficacy of photothermal hyperthermia induced by 2D AQDs upon irradiation with near-infrared light as assisted by reversing the cancer cells’thermoresistance.Consequently,synergistic antineoplastic effects can be achieved via low-temperature photothermal therapy.Systematic in vitro and in vivo evaluations have demonstrated that G/A@CaCO_(3)-PEG nanocatalysts feature potent antitumor activity with a high tumor-inhibition rate(83.92%).This work thus paves an effective way for augmenting the hyperthermia-based tumor treatments via restriction of the ATP supply.

Recent progress in 2D group-V elemental monolayers:fabrications and properties

A large number of two-dimensional(2D)monoelemental materials with huge application potentials have been developed,since graphene was reported as a monoelemental material with unique properties.As cousins of graphene,2D group-V elemental monolayers have gained tremendous interest due to their electronic properties with significant fundamental bandgap.In this review,we extensively summarize the latest theoretical and experimental progress in group-V monoelemental materials,including the latest fabrication methods,the properties and potential applications of these 2D monoelementals.We also give a perspective of the challenges and opportunities of 2D monoelemental group-V monolayer materials and related functional nanodevices.

Single-atom catalysts with anionic metal centers: Promising electrocatalysts for the oxygen reduction reaction and beyond

Ongoing efforts to develop single-atom catalysts(SACs) for the oxygen reduction reaction(ORR) typically focus on SACs with cationic metal centers,while SACs with anionic metal centers(anionic SACs) have been generally neglected.However,anionic SACs may offer excellent active sites for ORR,since anionic metal centers could facilitate the activation of O_(2) by back donating electrons to the antibonding orbitals of O_(2).In this work,we propose a simple guideline for designing anionic SACs:the metal centers should have larger electronegativity than the surrounding atoms in the substrate on which the metal atoms are supported.By means of density functional theory(DFT) simulations,we identified 13 anionic metal centers(Co,Ni,Cu,Ru,Rh,Pd,Ag,Re,Os,Ir,Pt,Au,and Hg) dispersed on pristine or defective antimonene substrates as new anionic SACs,among which anionic Au and Co metal centers exhibit limiting potentials comparable to,or even better than,conventional Pt-based catalysts towards ORR.We also found that anionic Os and Re metal centers on the defective antimonene can electrochemically catalyze the nitrogen reduction reaction(NRR) with a limiting potential close to that of stepped Ru(0001).Overall,our work shows promise towards the rational design of anionic SACs and their utility for applications as electrocatalysts for ORR and other important electrochemical reactions.