Emerging properties of non-crystalline phases of graphene and boron nitride based materials

We review recent developments on the synthesis and properties of two-dimensional materials which, although being mainly of an sp^(2) bonding character, exhibit highly disordered, non-uniform and structurally random morphologies. The emergence of such class of amorphous materials, including amorphous graphene and boron nitride, have shown superior properties compared to their crystalline counterparts when used as interfacial films. In this paper we discuss their structural,vibrational and electronic properties and present a perspective of their use for electronic applications.

Toward integrated detection and graphene-based removal of contaminants in a lab-on-a-chip platform

一个新奇、使小型化的 microfluidic 平台为 polybrominated diphenyl 醚(PBDE ) 的同时的察觉和移动被开发。站台由 polydimethylsiloxane (PDMS ) 组成为免疫反应步，有为察觉的一个综合打印屏幕的电极(SPCE ) 的一个 PDMS 薄片，和为物理吸附和 PBDE 残余的随后的移动的一个减少 PDMS 的 graphene 氧化物(rGO ) 薄片的 microfluidic 薄片。察觉基于在与用方形的波浪监视 o-aminophenol (o-AP ) 的酶的氧化跟随的山葵 peroxidase (HRP-PBDE ) 修改的 PBDE 和 PBDE 之间的竞争连接免疫分析的绑定阳极的脱衣 voltammetry (SW-ASV ) 。PBDE 与好敏感和类似于与商业比色的测试(0.018 ppb ) ，但是与使用更低的试剂卷和一减少的分析时间的优点获得了那的察觉的限制被检测。microfluidic 薄片的使用也与用打印屏幕的电极与基于批的大小获得的那些相比提供改进线性和更好的重制度。以便设计对象 PBDE 那样的有毒的混合物合适的一个察觉系统，减少的 graphene oxide-PDMS 合成被开发并且优化了获得增加的吸附(基于两个 hydrophobicity 并且 - 在 rGO 和 PBDE 分子之间叠) 与那些相比非修改的 PDMS。就我们的知识而言，这是火焰 retardants 的电气化学的察觉和在一个 biosensing 系统合成的 rGO-PDMS 的一个新奇应用程序的第一示范。这个系统能容易被使用用适当免疫分析检测任何 analyte，它在象海水那样的复杂矩阵支持操作。

Additive engineering for stable halide perovskite solar cells

Halide perovskite solar cells(PSCs)have already demonstrated power conversion efficiencies above 25%,which makes them one of the most attractive photovoltaic technologies.However,one of the main bottlenecks towards their commercialization is their long-term stability,which should exceed the 20-year mark.Additive engineering is an effective pathway for the enhancement of device lifetime.Additives applied as organic or inorganic compounds,improve crystal grain growth enhancing power conversion efficiency.The interaction of their functional groups with the halide perovskite(HP)absorber,as well as with the transport layers,results in defect passivation and ion immobilization improving device performance and stability.In this review,we briefly summarize the different types of additives recently applied in PSC to enhance not only efficiency but also long-term stability.We discuss the different mechanism behind additive engineering and the role of the functional groups of these additives for defect passivation.Special emphasis is given to their effect on the stability of PSCs under environmental conditions such as humidity,atmosphere,light irradiation(UV,visible)or heat,taking into account the recently reported ISOS protocols.We also discuss the relation between deep-defect passivation,non-radiative recombination and device efficiency,as well as the possible relation between shallow-defect passivation,ion immobilization and device operational stability.Finally,insights into the challenge and criteria for additive selection are provided for the further stability enhancement of PSCs.

Zn_(1+x)Sb二元体系的相形成和热电性能

在Zn−Sb二元相图固相线以下使Zn和Sb粉末反应并随炉冷却,合成一系列Zn_(1+x)Sb(x=0,0.05,0.1,0.15,0.25,0.3)材料,分析Zn–Sb相图中心区域的相形成和热电性能。在此过程中,非化学计量比的混合粉末结晶形成ZnSb和β-Zn_(4)Sb_(3)相的组合。然后,将材料研磨并热压成致密的ZnSb/β-Zn_(4)Sb_(3)复合材料。X射线衍射、高分辨率透射电镜和电子能量损失谱分析均未发现Sb、Zn元素或其他相。所有材料的热电性能都可以归结为ZnSb和β-Zn_(4)Sb_(3)相的热电行为的结合,并由每种材料中的主相所决定,Zn1.3Sb复合材料具有最好的热电性能。研究发现,Ge掺杂可大幅增加Zn1.3Sb的Seebeck系数且显著提高其功率因数,540 K时达1.51 mW·m−1·K−2。总之,Zn1.28Ge0.02Sb具有优异、稳定的ZT值,650 K时为1.17。

Local and correlated studies of humidity-mediated ferroelectric thin film surface charge dynamics

Electrochemical phenomena in ferroelectrics are of particular interest for catalysis and sensing applications,with recent studies highlighting the combined role of the ferroelectric polarisation,applied surface voltage and overall switching history.Here,we present a systematic Kelvin probe microscopy study of the effect of relative humidity and polarisation switching history on the surface charge dissipation in ferroelectric Pb(Zr_(0.2)Ti_(0.8))O_(3)thin films.We analyse the interaction of surface charges with ferroelectric domains through the framework of physically constrained unsupervised machine learning matrix factorisation,Dictionary Learning,and reveal a complex interplay of voltage-mediated physical processes underlying the observed signal decays.Additional insight into the observed behaviours is given by a Fitzhugh–Nagumo reaction–diffusion model,highlighting the lateral spread and charge passivation process contributors within the Dictionary Learning analysis.

Angular dependence of nanoparticle generation in the matrix assembly cluster source

The matrix assembly cluster source(MACS)represents a bridge between conventional instruments for cluster beam deposition(CBD)and thelevel of industrial production.The method is based on Ar^+ion sputtering of a pre-condensed Ar-M matrix(where M,is typically a metal such asAg).Each Ar^+ion produces a collision cascade and thus the formation of metal clusters is in the matrix,which are then sputtered out.Here wepresent an experimental and computational investigation of the cluster emission process,specifically its dependence on the Ar^+ion angle of in cidence and the cluster emission angle.We find the in cide nee angle strongly in flue nces the emerging cluster flux,which is assigned to thespatial location of the deposited primary ion energy relative to the cluster into the matrix.We also found an approximately constant anglebetween the incident ion beam and the peak in the emitted cluster distribution,with value between 99°and 109°.

Heterogeneous catalysts with programmable topologies generated by reticulation of organocatalysts into metal-organic frameworks:The case of squaramide

A well-established strategy to synthesize heterogeneous,metal-organic framework(MOF)catalysts that exhibit nanoconfinement effects,and specific pores with highly-localized catalytic sites,is to use organic linkers containing organocatalytic centers.Here,we report that by combining this linker approach with reticular chemistry,and exploiting three-dimensioanl(3D)MOF-structural data from the Cambridge Structural Database,we have designed four heterogeneous MOF-based catalysts for standard organic transformations.These programmable MOFs are isoreticular versions of pcu IRMOF-16,feu UiO-68 and pillared-pcu SNU-8X,the three most common topologies of MOFs built from the organic linker p.p'-terphenyldicarboxylic acid(tpdc).To synthesize the four squaramide-based MOFs,we designed and synthesized a linker,4,4’-((3,4-dioxocyclobut-1-ene-1,2-diyl)bis(azanedyil))dibenzoic acid(Sq_tpdc),which is identical in directionality and length to tpdc but which contains organocatalytic squaramide centers.Squaramides were chosen because their immobilization into a framework enhances its reactivity and stability while avoiding any self-quenching phenomena.Therefore,the four MOFs share the same organocatalytic squaramide moiety,but confine it within distinct pore environments.We then evaluated these MOFs as heterogeneous H-bonding catalysts in organic transformations:a Friedel-Crafts alkylation and an epoxide ring-opening.Some of them exhibited good performance in both reactions but all showed distinct catalytic profiles that reflect their structural differences.

Bioluminescent nanopaper for rapid screening of toxic substances

环境污染由于现代农业技术和工业进步正在威胁人的健康和生态系统。一个简单基于 nanopaper 的平台结合了光细菌 Aliivibrio fischeri (一。fischeri ) 当简历指示物这里被介绍，为沾染物毒性的快速、敏感的评估。当暴露了到有毒物时， A 的光抑制。装饰 fischeri 的 bioluminescent nanopaper (十亿) 能被确定并且分析了分类一种污染物质的毒性水平。十亿合成以形态学和功能被描绘。仅仅为实验室使用与常规仪器相比为细菌的增长，有低费用的十亿完成的高敏感和简化过程给 nanocellulose 的突出的 biocompatibility。到环境样品的十亿台设备的宽广适用性在刺的真实矩阵(湖和海水) 被学习，并且他们的潜力为直接并且在 situ，屏蔽的毒性被表明。十亿体系结构不仅在冻结并且再循环进程期间熬过而且维持它的函数，作为交付品赋予十亿个系统以竞争优势，为大规模生产的 ready-to-use 设备。新奇光使细菌不能调动的、基于 nanocelullose 的设备为危险混合物的毒性生物鉴定显示出突出的能力，带新可能性为便宜、有效在新窗户中的潜在的 contamination.Open

Tunable electrochemistry of gold-silver alloy nanoshells

The widespread and increasing interest in enhancing biosensing technologies by increasing their sensitivities and lowering their costs has led to the exploration and application of complex nanomaterials as signal transducers and enhancers.In this work,the electrochemical properties of monodispersed AuAg alloy nanoshells (NSs) with finely tunable morphology, composition,and size are studied to assess their potential as electroactive labels.The controlled corrosion of their silver content,caused by the oxidizing character of dissolved oxygen and chlorides of the electrolyte,allows the generation of a reproducible electrochemical signal that is easily measurable through voltammetric techniques.Remarkably,the underpotential deposition of dissolved Ag+ catalyzed on AuAg NS surfaces is observed and its dependence on the nanoparticle morphology, size,and elemental composition is studied,revealing a strong correlation between the relative amounts of the two metals.The highest catalytic activity is found at Au/Ag ratios higher than ≈ 10,showing how the synergy between both metals is necessary to trigger the enhancement of Ag+ reduction.The ability of AuAg NSs to generate an electrocatalytic current without the need for any strong acid makes them an extremely promising material for biosensing applications.

Milliwatt terahertz harmonic generation from topological insulator metamaterials

Achieving effcient,high-power harmonic generation in the terahertz spectral domain has technological applications,for example,in sixth generation(6G)communication networks.Massless Dirac fermions possess extremely large terahertz nonlinear susceptibilities and harmonic conversion effciencies.However,the observed maximum generated harmonic power is limited,because of saturation effects at increasing incident powers,as shown recently for graphene.Here,we demonstrate room-temperature terahertz harmonic generation in a Bi_(2)Se_(3) topological insulator and topological-insulator-grating metamaterial structures with surface-selective terahertz field enhancement.We obtain a third-harmonic power approaching the miliwatt range for an incident power of 75 mW-an improvement by two orders of magnitude compared to a benchmarked graphene sample.We establish a framework in which this exceptional performance is the result of thermodynamic harmonic generation by the massless topological surface states,benefiting from ultrafast dissipation of electronic heat via surface-bulk Coulomb interactions.These results are an important step towards on-chip terahertz(opto)electronic applications.

Large edge magnetism in oxidized few-layer black phosphorus nanomeshes

房间温度的形成和控制磁性的顺序在二维(2D ) 材料是为创新磁性底、基于 spintronic 的技术的来临的挑战性的探索。迄今为止，在 2D 材料的边磁力试验性地在终止的氢(H) 被观察了 graphene nanoribbons (GNR ) 和 graphene nanomeshes (GNM ) ，而是测量磁化仍然保持太小允许想象实际应用。此处，我们报导从氧(O) 获得的大房间温度边强磁性(FM ) 的试验性的证据终止了很少层黑人磷(P) nanomeshes (BPNM ) 的之字形毛孔边。磁化价值比那些为终止 H 的 GNM 报导的每统一区域是大 100 倍的 ~ ，当磁力为终止 H 的 BPNM 是不在的时。磁化大小和第一原则的模拟建议如此的一份磁性的订单的起源能源自与 O 原子在边 P 之间联合的铁磁性的纺纱，导致在边原子价乐队的强壮的旋转本地化，并且从完整的毛孔的一致氧化，在一个大区域和夹层上的边旋转相互作用。我们的调查结果为认识到高效率的 2D 铺平道路灵活磁性并且没有稀罕磁性的元素的使用的 spintronic 设备。

Graphene quantum dots: From efficient preparation to safe renal excretion

Carbon nanomaterials offer excellent prospects as therapeutic agents,and among them,graphene quantum dots(GQDs)have gained considerable interest thanks to their aqueous solubility and intrinsic fluorescence,which enable their possible use in theranostic approaches,if their biocompatibility and favorable pharmacokinetic are confirmed.We prepared ultra-small GQDs using an alternative,reproducible,top-down synthesis starting from graphene oxide with a nearly 100%conversion.The materials were tested to assess their safety,demonstrating good biocompatibility and ability in passing the ultrafiltration barrier using an in vitro model.This leads to renal excretion without affecting the kidneys.Moreover,we studied the GQDs in vivo biodistribution confirming their efficient renal clearance,and we demonstrated that the internalization mechanism into podocytes is caveolae-mediated.Therefore,considering the reported characteristics,it appears possible to vehiculate compounds to kidneys by means of GQDs,overcoming problems related to lysosomal degradation.

Waste Tire Rubber-based Refrigerants for Solid-state Cooling Devices

Management of discarded tires is a compelling environmental issue worldwide.Although there are several approaches developed to recycle waste tire rubbers,their application in solid-state cooling is still unexplored.Considering the high barocaloric potential verified for elastomers,the use of waste tire rubber(WTR)as a refrigerant in solid-state cooling devices is very promising.Herein,we investigated the barocaloric effects in WTR and polymer blends made of vulcanized natural rubber(VNR)and WTR,to evaluate its feasibility for solid-state cooling technologies.The adiabatic temperature changes and the isothermal entropy changes reach giant values,as well as the performance parameters,being comparable or even better than most barocaloric materials in literature.Moreover,pure WTR and WTR-based samples also present a faster thermal exchange than VNR,consisting of an additional advantage of using these discarded materials.Thus,the present findings evidence the encouraging perspectives of employing waste rubbers in solid-state cooling based on barocaloric effects,contributing to both the recycling of polymers and the sustainable energy technology field.

The elphbolt ab initio solver for the coupled electron-phonon Boltzmann transport equations

elphbolt is a modern Fortran (2018 standard) code for efficiently solving the coupled electron–phonon Boltzmann transport equations from first principles.Using results from density functional and density functional perturbation theory as inputs,it can calculate the effect of the non-equilibrium phonons on the electronic transport (phonon drag) and non-equilibrium electrons on the phononic transport (electron drag) in a fully self-consistent manner and obeying the constraints mandated by thermodynamics.It can calculate the lattice,charge,and thermoelectric transport coefficients for the temperature gradient and electric fields,and the effect of the mutual electron–phonon drag on these transport properties.The code fully exploits the symmetries of the crystal and the transport-active window to allow the sampling of extremely fine electron and phonon wave vector meshes required for accurately capturing the drag phenomena.The coarray feature of modern Fortran,which offers native and convenient support for parallelization,is utilized.The code is compact,readable,well-documented,and extensible by design.