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ACS Nano 2022 May 24. Epub 2022 May 24.

Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom.

Lead halide perovskites are leading candidates for photovoltaic and light-emitting devices, owing to their excellent and widely tunable optoelectronic properties. Nanostructure control has been central to their development, allowing for improvements in efficiency and stability, and changes in electronic dimensionality. Recently, formamidinium lead triiodide (FAPbI) has been shown to exhibit intrinsic quantum confinement effects in nominally bulk thin films, apparent through above-bandgap absorption peaks. Read More

ACS Nano 2022 May 24. Epub 2022 May 24.

Department of Chemistry, University of Marburg, Hans-Meerwein Strasse 4, 35032 Marburg, Germany.

Laser-based surface processing is an established way for the maskless generation of surface structures and functionalities on a large variety of materials. Laser-driven periodic surface texturing and structuring of thin films is reported for metallic-, semiconductive-, and polymeric films. Here, we introduce subwavelength surface patterning of metal-organic thin films of [MoS(SCNBu)], a MoS precursor. Read More

ACS Nano 2022 May 24. Epub 2022 May 24.

Department of Materials Science and Engineering, University of California, Berkeley, California 94720, United States.

Extensive prior work has shown that colloidal inorganic nanocrystals coated with organic ligand shells can behave as artificial atoms and, as such, form superlattices with different crystal structures and packing densities. Although ordered superlattices present a high degree of long-range positional order, the relative crystallographic orientation of the inorganic nanocrystals with respect to each other tends to be random. Recent works have shown that superlattices can achieve orientational alignment through combinations of nanocrystal faceting and ligand modification, as well as selective metal particle attachment to particular facets. Read More

ACS Nano 2022 May 23. Epub 2022 May 23.

ACS Nano 2022 May 23. Epub 2022 May 23.

Department of Physics, Sogang University, Seoul 04107, Korea.

ReS is a group-VII chalcogenide with a crystal structure that has inversion symmetry only. Due to the low symmetry, it has in-plane anisotropy, and the two vertical orientations are not equivalent. The in-plane anisotropy leads to optical birefringence that can be observed by using polarized optical microscopy. Read More

ACS Nano 2022 May 23. Epub 2022 May 23.

Department of Chemistry, Missouri University of Science and Technology, Rolla, Missouri 65409, United States.

Nanodiamonds are at the heart of a plethora of emerging applications in areas ranging from nanocomposites and tribology to nanomedicine and quantum sensing. The development of alternative synthesis methods, a better understanding, and the availability of ultrasmall nanodiamonds of less than 3 nm size with a precisely engineered composition, including the particle surface and atomic defects in the diamond crystal lattice, would mark a leap forward for many existing and future applications. Yet today, we are unable to accurately control nanodiamond composition at the atomic scale, nor can we reliably create and isolate particles in this size range. Read More

ACS Nano 2022 May 23. Epub 2022 May 23.

State Key Laboratory of Organic-Inorganic Composites, College of Materials Science and Engineering, Beijing University of Chemical Technology, 100029 Beijing, China.

Mechanical-electrical properties of macroscopic graphene films derived from graphene oxide (GO) sheets are substantially restricted by their surface wrinkles and structural misalignment. Herein, we propose a chemical-structure-engineering strategy to realize the spontaneously regular stacking of modified GO (GO-) with trace carboxyl. The highly aligned GO- film delivers a fracture strength and modulus of nearly 3- and 5-fold higher than a wrinkled film with conventional Hummer's method derived GO (GO-). Read More

ACS Nano 2022 May 23. Epub 2022 May 23.

Shenzhen Geim Graphene Center (SGC), Tsinghua-Berkeley Shenzhen Institute (TBSI), and Tsinghua Shenzhen International Graduate School (TSIGS), Tsinghua University, Shenzhen 51805, China.

Ball milling is a widely used method to produce graphene and other two-dimensional (2D) materials for both industry and research. Conventional ball milling generates strong impact forces, producing small and thick nanosheets that limit their applications. In this study, a viscous solvent-assisted planetary ball milling method has been developed to produce large thin 2D nanosheets. Read More

ACS Nano 2022 May 23. Epub 2022 May 23.

CAS Key Laboratory of Bio-inspired Materials and Interfacial Science, Technical Institute of Physics and Chemistry Chinese Academy of Sciences, Beijing 100190, China.

Biological ion pumps selectively transport target ions against the concentration gradient, a process that is crucial to maintaining the out-of-equilibrium states of cells. Building an ion pump with ion selectivity has been challenging. Here we show that a TiCT MXene film suspended in air with a trapezoidal shape spontaneously pumps K ions from the base end to the tip end and exhibits a K/Na selectivity of 4. Read More

ACS Nano 2022 May 23. Epub 2022 May 23.

Department of Electrical Communication Engineering, Indian Institute of Science, Bangalore 560012, India.

Strong Coulomb interactions in monolayer semiconductors allow them to host optically active large many-body states, such as the five-particle state, charged biexciton. Strong nonlinear light absorption by the charged biexciton under spectral resonance, coupled with its charged nature, makes it intriguing for nonlinear photodetection─an area that is hitherto unexplored. Using the high built-in vertical electric field in an asymmetrically designed few-layer graphene encapsulated 1L-WS heterostructure, here we report a large, highly nonlinear photocurrent arising from the strong absorption by two charged biexciton species under zero external bias (self-powered mode). Read More

ACS Nano 2022 May 23. Epub 2022 May 23.

Group of Biomimetic Smart Materials, CAS Key Laboratory of Bio-based materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences & Shandong Energy Institute, Songling Road 189, Qingdao 266101, P. R. China.

Efficient and nondestructive liquid exfoliation of MXene with large lateral size has drawn growing research interest due to its outstanding properties and diverse potential applications. The conventional sonication method, though enabling a high production yield of MXene nanosheets, broke them down into submicrometric sizes or even quantum dots, and thus sacrificed their size-dependent properties, chemical stability, and wide applications. Herein, rigid biological nanofibrils in combination of mild manual shake were found to be capable of peeling off MXene nanosheets by attaching on MXene surfaces and localizing the shear force. Read More

ACS Nano 2022 May 23. Epub 2022 May 23.

School of Optical and Electronic Information, Wuhan National Laboratory for Optoelectronics (WNLO), Optics Valley Laboratory, Huazhong University of Science and Technology, Wuhan 430074, China.

Li-S batteries have been regarded as one of the most promising alternatives of the next-generation Li batteries. However, the dissolution and shuttling of lithium polysulfides lead to low cycle stability and low Coulombic efficiency, which intensively hinder the practical application of Li-S batteries. Herein, we propose a strategy to simultaneously promote the redox kinetics and inhibit the shuttle of lithium polysulfides, through in situ synthesis of insoluble organopolysulfides by adding a special additive. Read More

ACS Nano 2022 May 22. Epub 2022 May 22.

Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80303-0596, United States.

Functionalization of nanoparticles with specific ligands is helpful to control specific diagnostic and therapeutic responses such as protein adsorption, cell targeting, and circulation. Precision delivery critically depends on a fundamental understanding of the interplay between surface chemistry, ligand dynamics, and interaction with the biochemical environment. Due to limited atomic-scale insights into the structure and dynamics of nanoparticle-bound ligands from experiments, relationships of grafting density and ligand chemistry to observable properties such as hydrophilicity and protein interactions remain largely unknown. Read More

ACS Nano 2022 May 20. Epub 2022 May 20.

Materials Science and Engineering Program and Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712, United States.

Motors that can convert different forms of energy into mechanical work are of profound importance to the development of human societies. The evolution of micromotors has stimulated many advances in drug delivery and microrobotics for futuristic applications in biomedical engineering and nanotechnology. However, further miniaturization of motors toward the nanoscale is still challenging because of the strong Brownian motion of nanomotors in liquid environments. Read More

ACS Nano 2022 May 20. Epub 2022 May 20.

State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Shaanxi Joint Laboratory of Graphene, Northwestern Polytechnical University, Xi'an 710072, P. R. China.

Featured with an exposed active facet, favorable ion diffusion pathway, and tailorable interfacial properties, low-dimensional structures are extensively explored as alternative electroactive materials with game-changing redox properties. Through a stepwise "proton exchange-insertion-exfoliation" procedure, in this article, we develop NaTiMoO (NTMO) nanosheets with weakened out-of-plane bonding and in-plane Mo doping of the tunnel structure. Real-time phase tracking of the laminated NTMO structures upon the lithiation/delithiation process suggests mitigated lattice variation; meanwhile, the kinetics simulation shows a mitigated Li-ion diffusion barrier along the [010] orientation. Read More

ACS Nano 2022 May 20. Epub 2022 May 20.

Department of Chemical Sciences and Bernal Institute, University of Limerick, V94T9PX Limerick, Ireland.

Direct colloidal synthesis of multinary metal chalcogenide nanocrystals typically develops dynamically from the binary metal chalcogenide nanocrystals with the subsequent incorporation of additional metal cations from solution during the growth process. Metal seeding of binary and multinary chalcogenides is also established, although the seed is solely a catalyst for nanocrystal nucleation and the metal from the seed has never been exploited as active alloying nuclei. Here we form colloidal Cu-Bi-Zn-S nanorods (NRs) from Bi-seeded CuS heterostructures. Read More

ACS Nano 2022 May 20. Epub 2022 May 20.

College of Materials Science and Engineering, Zhejiang University of Technology, Hangzhou 310014, China.

The lithium metal anode (LMA) is regarded as one of the most promising candidates for high-energy Li-ion batteries. However, the naturally formed solid electrolyte interface (SEI) is unsatisfied, which would cause continuous dendrite growth and thus prevent the practical application of the LMA. Herein, a stable electrolytic carbon-based hybrid (ECH) artificial SEI is constructed on the LMA via the in-situ electrodeposition of an electrolyte sovlent at ultrahigh voltage. Read More

ACS Nano 2022 May 19. Epub 2022 May 19.

Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States.

Organic crystals formed by small molecules can be highly functional but are often brittle or insoluble structures with limited possibilities for use or processing from a liquid phase. A possible solution is the nanoscale integration of polymers into organic crystals without sacrificing long-range order and therefore function. This enables the organic crystals to benefit from the advantageous mechanical and chemical properties of the polymeric component. Read More

ACS Nano 2022 May 19. Epub 2022 May 19.

School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, P.R. China.

The instability of Zn anode caused by severe dendrite growth and side reactions has restricted the practical applications of aqueous zinc-ion batteries (AZIBs). Herein, an enamel-like layer of nanohydroxyapatite (Ca(PO)(OH), nano-HAP) is constructed on Zn anode to enhance its stability. Benefiting from the ion exchange between Zn and Ca, the adsorption for Zn in enamel-like nano-HAP (E-nHAP) layer can effectively guide Zn deposition, ensuring homogeneous Zn flux and even nucleation sites to suppress Zn dendrites. Read More

ACS Nano 2022 May 19. Epub 2022 May 19.

Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371.

Magnetic van der Waals (vdW) materials possess versatile spin configurations stabilized in reduced dimensions. One magnetic order is the interlayer antiferromagnetism in A-type vdW antiferromagnet, which may be effectively modified by the magnetic field, stacking order, and thickness scaling. However, atomically revealing the interlayer spin orientation in the vdW antiferromagnet is highly challenging, because most of the material candidates exhibit an insulating ground state or instability in ambient conditions. Read More

ACS Nano 2022 May 19. Epub 2022 May 19.

Department of Materials Science and Engineering, Yonsei University, Yonsei-ro 50, Seodaemun-gu, Seoul 03722, Korea.

The development of electrodes with high conductivity, optical transparency, and reliable mechanical flexibility and stability is important for numerous solution-processed photoelectronic applications. Although transparent TiCT MXene electrodes with high conductivity are promising, their suitability for displays remains limited because of the high sheet resistance, which is caused by undesirable flake junctions and surface roughness. Herein, a flexible and transparent electrode has been fabricated that is suitable for a full-solution-processed quantum dot light-emitting diode (QLED). Read More

ACS Nano 2022 May 19. Epub 2022 May 19.

Innovative Centre for Flexible Devices (iFLEX), Max Planck-NTU Joint Lab for Artificial Senses, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.

Animals execute intelligent and efficient interactions with their surroundings through neural pathways, exhibiting learning, memory, and cognition. Artificial autonomous devices that generate self-optimizing feedback mimicking biological systems are essential in pursuing future intelligent robots. Here, we report an artificial neural pathway (ANP) based on a memristor synapse to emulate neuromorphic learning behaviors. Read More

ACS Nano 2022 May 19. Epub 2022 May 19.

Dipartimento di Ingegneria Industriale, Università di Roma Tor Vergata, Via del Politecnico 1, 00133, Rome, Italy.

Selectivity toward positive and negative ions in nanopores is often associated with electroosmotic flow, the control of which is pivotal in several micro-nanofluidic technologies. Selectivity is traditionally understood to be a consequence of surface charges that alter the ion distribution in the pore lumen. Here we present a purely geometrical mechanism to induce ionic selectivity and electroosmotic flow in uncharged nanopores, and we tested it molecular dynamics simulations. Read More

ACS Nano 2022 May 19. Epub 2022 May 19.

Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou 215123, P. R. China.

Aerogel films with a low density are ideal candidates to meet lightweight application and have already been used in a myriad of fields; however, their structural design for performance enhancement remains elusive. Herein, we put forward a laminated structural engineering strategy to prepare a free-standing carbon nanotube (CNT)-based aerogel film with a densified laminated porous structure. By directional densification and carbonization, the three-dimensional network of one-dimensional nanostructures in the aramid nanofiber/carbon nanotube (ANF/CNT) hybrid aerogel film can be reconstructed to a laminated porous structure with preferential orientation and consecutively conductive pathways, resulting in a large specific surface area (341. Read More

ACS Nano 2022 May 19. Epub 2022 May 19.

Department of Applied Physics, State Key Laboratory of Power Transmission Equipment and System Security and New Technology, Chongqing Key Laboratory of Soft Condensed Matter Physics and Smart Materials, Chongqing University, Chongqing 400044, China.

The state of neck motion reflects cervical health. To detect the motion state of the human neck is of important significance to healthcare intelligence. A practical neck motion detector should be wearable, flexible, power efficient, and low cost. Read More

ACS Nano 2022 May 19. Epub 2022 May 19.

Department of Biomedical Engineering, Tufts University, Medford, Massachusetts 02155, United States.

β-Sheet rich silk nanofiber hydrogels are suitable scaffolds in tissue regeneration and carriers for various drugs. However, unsatisfactory mechanical performance limits its applications. Here, insight into the silk nanofibers stimulates the remodeling of previous solvent systems to actively regulate the assembly of silk nanofibers. Read More

ACS Nano 2022 May 18. Epub 2022 May 18.

Department of Physics, National Taiwan University, Taipei 10617, Taiwan.

Resolving the momentum degree of freedom of photoexcited charge carriers and exploring the excited-state physics in the hexagonal Brillouin zone of atomically thin semiconductors have recently attracted great interest for optoelectronic technologies. We demonstrate a combination of light-modulated scanning tunneling microscopy and the quasiparticle interference (QPI) technique to offer a directly accessible approach to reveal and quantify the unexplored momentum-forbidden electronic quantum states in transition metal dichalcogenide (TMD) monolayers. Our QPI results affirm the large spin-splitting energy at the spin-valley-coupled Q valleys in the conduction band (CB) of a tungsten disulfide monolayer. Read More

ACS Nano 2022 May 18. Epub 2022 May 18.

Department of Physics and Astronomy and Photon Science Institute, The University of Manchester, Manchester M13 9PL, United Kingdom.

Optoelectronic micro- and nanostructures have a vast parameter space to explore for modification and optimization of their functional performance. This paper reports on a data-led approach using high-throughput single nanostructure spectroscopy to probe >8000 structures, allowing for holistic analysis of multiple material and optoelectronic parameters with statistical confidence. The methodology is applied to surface-guided CsPbBr nanowires, which have complex and interrelated geometric, structural, and electronic properties. Read More

ACS Nano 2022 May 18. Epub 2022 May 18.

State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, School of Materials Science and Engineering, South China University of Technology, Guangzhou, 510640, China.

Photodynamic therapy as an emerging phototheranostic approach holds great potential for antibacterial treatment, but is limited by compromised reactive oxygen species (ROS) generation in an aggregate and hypoxic microenvironment. Herein, we report a molecular cationization approach to boost the ROS, especially type I ROS generation of aggregation-induced emission (AIE) photosensitizers for photodynamic treatment of drug-resistant bacteria. Such cationization reinforces the electron-accepting ability of the cationic moiety, promotes intersystem crossing (ISC), and increases electron separation and transfer processes. Read More

ACS Nano 2022 May 18. Epub 2022 May 18.

School of Materials Science and Engineering, Sun Yat-sen University, Guangzhou 510275, P. R. China.

MXenes have shown great potential for supercapacitor electrodes due to their unique characteristics, but simultaneously achieving high capacitance, rate capability, and cyclic stability along with good mechanical flexibility is exceptionally challenging. Here, highly enhanced capacitance, rate capability, and cyclic stability, as well as good mechanical flexibility for TCT MXene-based supercapacitor electrodes are simultaneously obtained by engineering the electrode structure, modifying the surface chemistry, and optimizing the fabrication process an optimized integration approach. This approach combines and more importantly optimizes three methods that all require a calcination process: carbonizing grown polymer ("C") on the MXene, alkali treatment ("A"), and template sacrificing ("P"); and the optimized processes lead to more abundant active sites, faster ion accessibility, better chemical stability, and good mechanical flexibility. Read More