Thermal Modulation of Nanomotor Movement

Motion control is essential for various applications of man‐made nanomachines. The ability to control and regulate the movement of catalytic nanowire motors is illustrated by applying short heat pulses that allow the motors to be accelerated or slowed down. The accelerated motion observed during the heat pulses is attributed primarily to the thermal activation of the redox reactions of the H₂O₂ fuel at the Pt and Au segments and to the decreased viscosity of the aqueous medium at elevated temperatures. The thermally modulated motion during repetitive temperature on/off cycles is highly reversible and fast, with speeds of 14 and 45 µm s^?1 at 25 and 65 °C, respectively. A wide range of speeds can be generated by tailoring the temperature to yield a linear speed–temperature dependence. Through the use of nickel‐containing nanomotors, the ability to combine the thermally regulated motion of catalytic nanomotors with magnetic guidance is also demonstrated. Such on‐demand control of the movement of nanowire motors holds great promise for complex operations of future manmade nanomachines and for creating more sophisticated nanomotors.     

Chemical Vapor Deposition Growth of High Crystallinity Sb2Se3 Nanowire with Strong Anisotropy for Near‐Infrared Photodetectors

Low‐dimensional semiconductors have attracted considerable attention due to their unique structures and remarkable properties, which makes them promising materials for a wide range of applications related to electronics and optoelectronics. Herein, the preparation of 1D Sb₂Se₃ nanowires (NWs) with high crystal quality via chemical vapor deposition growth is reported. The obtained Sb₂Se₃ NWs have triangular prism morphology with aspect ratio range from 2 to 200, and three primary lattice orientations can be achieved on the sixfold symmetry mica substrate. Angle‐resolved polarized Raman spectroscopy measurement reveals strong anisotropic properties of the Sb₂Se₃ NWs, which is also developed to identify its crystal orientation. Furthermore, photodetectors based on Sb₂Se₃ NW exhibit a wide spectral photoresponse range from visible to NIR (400–900 nm). Owing to the high crystallinity of Sb₂Se₃ NW, the photodetector acquires a photocurrent on/off ratio of about 405, a responsivity of 5100 mA W^?1, and fast rise and fall times of about 32 and 5 ms, respectively. Additionally, owing to the anisotropic structure of Sb₂Se₃ NW, the device exhibits polarization‐dependent photoresponse. The high crystallinity and superior anisotropy of Sb₂Se₃ NW, combined with controllable preparation endows it with great potential for constructing multifunctional optoelectronic devices.     

多元醇法制备和表征Sb2Se3纳米线

以自制的NaHSe乙醇溶液为硒源,在PEG-400无水体系中采用多元醇法,在180℃生长10h制备了直径100～200nm,长度可达十几微米的纳米线.产物通过XRD、TEM、HRTEM、FESEM、EDS和UV-Vis等手段进行了表征,并研究了不同多元醇对产物形貌的影响.研究表明,PEG-400作为结构导向剂在制备一维Sb₂Se₃纳米线中发挥着至关重要的作用,并且无水环境为纳米晶的生长提供了更加纯净的条件,有利于制备高质量的纳米晶.     

Sb2Se3管状化合物的制备和表征

用固相烧结法合成了管状Sb2Se3相变材料,并通过扫描电子显微镜（SEM）、X射线衍射仪（XRD）、透射电镜（TEM）、拉曼光谱仪（Raman）、热重分析（DSC）进行表征测试,结果表明成功制备出了正交晶系的Sb2Se3,计算所得晶格常数为a：11．6445A,b=11．792A,c=3．981A,;透射电镜结果说明Sb2Se3微米管晶体结构沿[001]方向择优生长;DSC测试Sb2Se3的熔点为624．5℃。同时本试验用固相烧结法制备了不同配比的Sb—Se材料,并用XRD和Raman表征测试了晶体结构.     

A Force to Be Reckoned With: A Review of Synthetic Microswimmers Powered by Ultrasound

Synthetic microswimmers are a class of artificial nano‐ or microscale particle capable of converting external energy into motion. They are similar to natural microswimmers such as bacteria in behavior and are, therefore, of great interest to the study of active matter. Additionally, microswimmers show promise in applications ranging from bioanalytics and environmental monitoring to particle separation and drug delivery. However, since their sizes are on the nano‐/microscale and their speeds are in the μm s^?1 range, they fall into a low Reynolds number regime where viscosity dominates. Therefore, new propulsion schemes are needed for these microswimmers to be able to efficiently move. Furthermore, many of the hotly pursued applications call for innovations in the next phase of development of biocompatible microswimmers. In this review, the latest developments of microswimmers powered by ultrasound are presented. Ultrasound, especially at MHz frequencies, does little harm to biological samples and provides an advantageous and well‐controlled means to efficiently power microswimmers. By critically reviewing the recent progress in this research field, an introduction of how ultrasound propels colloidal particles into autonomous motion is presented, as well as how this propulsion can be used to achieve preliminary but promising applications.     

新型Sb2S3-Sb2Se3与单晶二氧化钛纳米阵列复合结构在太阳能电池领域的应用

近年来,半导体量子点敏化太阳能电池作为新一代的太阳能电池,引起了广泛的关注．Sb2S2和Sb2Se3量子点由于具有出色的光吸收特性与带隙的可调控性,已成为敏化太阳能电池领域的重要组成部分．通过水热法,二氧化钛（TiO2）单晶纳米阵列被成功生长在FTO导电玻璃上．通过连续离子层吸附法（SILAR）,Sb2S3Sb2Se3复合纳米结构被生长在二氧化钛单晶纳米阵列的表面．利用x射线衍射（XRD）表征Sb2S3和Sb2Se3纳米晶体的晶相,利用扫描电子显微镜（SEM）表征其形貌,发现在这一复合结构中,二氧化钛单晶纳米阵列与Sb2S3结合之后所留下的空隙被Sb2Se3量子点填充,从而提高了结构表面积的利用率．随着连续离子层吸附法反应周期的增加,Sb2S3-Sb2Se3,与二氧化钛单晶纳米阵列共同形成复合结构的带隙发生了明显的红移,吸收边在可调控的情况下由1．7eV向红外波段发生了移动．这种纳米结构的比表面积大、工艺简单、结构致密、沉积速率快、可调控性强,对于今后敏化太阳能电池领域的应用有很大的启发作用．     

A Silicon Nanowire as a Spectrally Tunable Light‐Driven Nanomotor

Over the last decades, scientists have endeavored to develop nanoscopic machines and envisioned that these tiny machines could be exploited in biomedical applications and novel material fabrication. Here, a visible‐/near‐infrared light‐driven nanomotor based on a single silicon nanowire is reported. The silicon nanomotor harvests energy from light and propels itself by the self‐electrophoresis mechanism. Due to the high efficiency, the silicon nanowire can be readily driven by visible and near‐infrared illumination at ultralow light intensity (≈3 mW cm^?2). The experimental study and numerical simulation also show that the detailed structure around the concentrated reaction center determines the migration behavior of the nanomotor. Importantly, due to the optical resonance inside the silicon nanowire, the spectral response of the nanowire‐based nanomotor can be readily modulated by the nanowire's diameter. Compared to other methods, light controlling potentially offers more freedom and flexibility, as light can be modulated not only with its intensity and direction, but also with the frequency and polarities. This nanowire motor demonstrates a step forward to harness the advantages of light, which opens up new opportunities for the realization of many novel functions such as multiple channels communication to nanorobots and controllable self‐assembly.     

Highly Anisotropic Sb2Se3 Nanosheets: Gentle Exfoliation from the Bulk Precursors Possessing 1D Crystal Structure

2D materials, particularly those bearing in‐plane anisotropic optical and electrical properties such as black phosphorus and ReS₂, have spurred great research interest very recently as promising building blocks for future electronics. However, current progress is limited to layered compounds that feature atomic arrangement asymmetry within the covalently bonded planes. Herein, a series of highly anisotropic nanosheets (Sb₂Se₃, Sb₂S₃, Bi₂S₃, and Sb₂(S, Se)₃), which are composed of 1D covalently linked ribbons stacked together via van der Waals force, is introduced as a new member to the anisotropic 2D material family. These unique anisotropic nanosheets are successfully fabricated from their polymer‐like bulk counterparts through a gentle water freezing‐thawing approach. Angle‐resolved polarized Raman spectroscopy characterization confirms the strong in‐plane asymmetry of Sb₂Se₃ nanosheets, and photodetection study reveals their high responsivity and anisotropic in‐plane transport. This work can enlighten the synthesis and application of new anisotropic 2D nanosheets that can be potentially applied for future electronic and optoelectronic devices.     

SPS法制备Bi_2Te_3基热电合金的热电性能

用粉末冶金工艺结合SPS烧结制备了p型(Bi0.2Sb0.8)2Te3和n型Bi2(Te0.975Se0.025)3多晶半导体合金,研究烧结工艺对其热电性能的影响.结果表明,室温下,p型(Bi0.2Sb0.8)2Te3材料的热电优值Z为3.25×10<'-3K<'-1,n型Bi2(Te0.975Se0.025)3材料的热电优值Z为2.21×10<'-3K<'-1.     

超声场对中和法制备 Sb2O3的影响

对在超声场作用下采用氨水中和氯氧锑（Sb4O5Cl2）制备超细立方晶型Sb2O3的工艺过程和条件进行了研究．结果表明，在超声场作用下制得的Sb2O3为立方晶型，当超声功率为100W，超声时间30min，温度为20℃时，Sb2O3的平均粒径为0．777μm，其分散性较好．通过XRD、SEM和激光粒度仪等测试手段，探讨了超声功率、超声时间、氯氧锑与蒸馏水的调浆液固比和温度等条件对Sb2O3晶型和颗粒粒径的影响．     

Orientation Engineering in Low‐Dimensional Crystal‐Structural Materials via Seed Screening

The orientation of low‐dimensional crystal‐structural (LDCS) films significantly affects the performance of photoelectric devices, particularly in vertical conducting devices such as solar cells and light‐emitting diodes. According to film growth theory, the initial seeds determine the final orientation of the film. Ruled by the minimum energy principle, lying (chains or layers parallel to the substrate) seeds bonding with the substrate through van der Waals forces are easier to form than standing (chains or layers perpendicular to the substrate) seeds bonding with the substrate by a covalent bond. Utilizing high substrate temperature to re‐evaporate the lying seeds and preserve the standing seeds, the orientation of 1D crystal‐structural Sb₂Se₃ is successfully controlled. Guided by this seed screening model, highly [211]‐ and [221]‐oriented Sb₂Se₃ films on an inert TiO₂ substrate are obtained; consequently, a record efficiency of 7.62% in TiO₂/Sb₂Se₃ solar cells is achieved. This universal model of seed screening provides an effective method for orientation control of other LDCS films.     

Sb2O3@SiO2颗粒制备与热解及阻燃性能

以超声场醇盐水解法制备出微米级Sb2O3粒子,再通过溶胶-凝胶法获得复合阻燃剂Sb2O3@SiO2颗粒,并对该复合颗粒的结构与形貌进行表征。结果表明:制得的超微Sb2O3颗粒平均粒径为1.17μm,晶体类型为斜方晶型,颗粒的结晶度高、晶粒度大;同时较佳的硅包覆Sb2O3颗粒构建条件为:TEOS/Sb2O3摩尔比为3/3、温度为30℃、氨水浓度为0.75mol/L、十六烷基三甲基溴化铵(CTAB)/正硅酸四乙酯(TEOS)摩尔比为0.8,此时所得Sb2O3@SiO2为介孔结构,分散性及热稳定性优异。阻燃实验表明:复合颗粒在聚合物基体中分散均匀、结构稳定,复合阻燃效果中Sb2O3用量减少75%。     

气相传输法制备大尺寸单晶Bi2Se3纳米片、纳米带

低维Bi₂Se₃纳米材料是最新研究发现的一种新型三维拓扑绝缘体材料, 在微电子器件和传感器领域具有广阔的应用前景。本研究采用气相传输法在真空石英管中合成了大尺寸单晶Bi₂Se₃纳米片、纳米带。通过XRD、EDS、Raman、SEM等手段对Bi₂Se₃纳米片、纳米带的物相结构、组成、表面形貌等进行表征。测试结果表明: 气相传输法合成的单晶Bi₂Se₃纳米片、纳米带相纯度高, 结晶性能好, 均是{001}取向; Bi₂Se₃纳米片水平尺寸大, 约为15~180 μm; Bi₂Se₃纳米带长度达860 μm, 宽度约5 μm。根据不同温度下制备的Bi₂Se₃纳米片、纳米带SEM照片及其不同方向结合能的差异, 分析了其可能的生长机制: 在较高温度下沿<001>和方向生长速度快, 生成大尺寸单晶Bi₂Se₃纳米片; 在较低温度下, 沿方向生长速度快, 生成大尺寸单晶Bi₂Se₃纳米带。这些研究结果完善了大尺寸Bi₂Se₃纳米材料的制备工艺, 有望在微电子器件领域得到商业化应用。     

Epitaxial growth and thermal-conductivity limit of single-crystalline Bi2Se3/In2Se3 superlattices on mica

Nano Research - Thermal transport in superlattices is governed by various phonon-scattering processes. For extracting the phonon-scattering contribution of hetero-interfaces in chalcogenide...     

Simple synthesis of a porous Sb/Sb2O3 nanocomposite for a high-capacity anode material in Na-ion batteries

High-capacity anode materials are highly desirable for sodium ion batteries.Here,a porous Sb/Sb2O3 nanocomposite is successfully synthesized by the mild oxidization of Sb nanocrystals in air.In the composite,Sb contributes good conductivity and Sb2O3 improves cycling stability,particularly within the voltage window of 0.02-1.5 V.It remains at a reversible capacity of 540 mAh·g-1 after 180 cycles at 0.66 A·g-L Even at 10 A·g-1,the reversible capacity is still preserved at 412 mAh.g-1,equivalent to 71.6％ of that at 0.066 A.g-1.These results are much better than Sb nanocrystals with a similar size and structure.Expanding the voltage window to 0.02-2.5 V includes the conversion reaction between Sb2O3 and Sb into the discharge/charge profiles.This would induce a large volume change and high structure strain/stress,deteriorating the cycling stability.The identification of a proper voltage window for Sb/Sb2O3 paves the way for its development in sodium ion batteries.     

Striated 2D Lattice with Sub‐nm 1D Etch Channels by Controlled Thermally Induced Phase Transformations of PdSe2

2D crystals are typically uniform and periodic in‐plane with stacked sheet‐like structure in the out‐of‐plane direction. Breaking the in‐plane 2D symmetry by creating unique lattice structures offers anisotropic electronic and optical responses that have potential in nanoelectronics. However, creating nanoscale‐modulated anisotropic 2D lattices is challenging and is mostly done using top‐down lithographic methods with ≈10 nm resolution. A phase transformation mechanism for creating 2D striated lattice systems is revealed, where controlled thermal annealing induces Se loss in few‐layered PdSe₂ and leads to 1D sub‐nm etched channels in Pd₂Se₃ bilayers. These striated 2D crystals cannot be described by a typical unit cells of 1–2 Å for crystals, but rather long range nanoscale periodicity in each three directions. The 1D channels give rise to localized conduction states, which have no bulk layered counterpart or monolayer form. These results show how the known family of 2D crystals can be extended beyond those that exist as bulk layered van der Waals crystals by exploiting phase transformations by elemental depletion in binary systems.     

三价低熔点氧化物对TiO_2压敏电阻器性能的影响

研究了三价低熔点氧化物Ｓｂ２Ｏ３、Ｂ２Ｏ３等对ＴｉＯ２压敏电阻器性能的影响,采用扫描电镜、Ｃ－Ｖ分析、Ｉ－Ｖ测量和介电测量等实验手段,并结合理论分析了它们的作用机理。结果发现,适当掺入这类氧化物能促进晶体生长,还有助于形成ＴｉＯ２的粒界层,提高样品的非线性系数和稳定性,改善样品烧结性能     

Volatilization Kinetics of Sb2S3 in Steam Atmosphere

The volatilization kinetics of antimony trisulfide in steam atmosphere was studied with thermogravimetry at temperatures from 923 to 1123 K. A theoretical model was developed to calculate the overall rate constant and the mass transfer coefficient in gas phases. The experimental results show that the volatilization rate is enhanced with increasing temperature and steam flow rate. The volatilization rate is mainly controlled by the mass transport in gas phases. The apparent activation energy for the process is found to be 59.93 kJ/mol. It is demonstrated that Sb2S3 is dominantly oxidized into Sb2O3 and H2S by water vapor in the volatilization process. Some antimony metal is formed. The reaction mechanism is discussed in accordance with experimental data.     

Mn、Sb掺杂NBT—KBT—BT无铅压电陶瓷的研究

采用传统陶瓷制备工艺,利用XRD、SEM等测试分析方法,研究了MnCO3、Sb2O3掺杂对压电陶瓷晶体结构、表面形貌以及性能的影响。研究结果表明：所有组成均呈单一钙钛矿型固溶体特征,无其它晶相生成。掺杂陶瓷在1160℃左右烧结比较合适。MnCO3表现为典型的“受主”添加物特征。Sb2O3的掺杂对陶瓷性能的影响受多种因素共同作用,当Sb2O3的掺杂量为0.1％（质量分数）时,d33=148pC／N、tanδ=4.2％、εr=1516。MnCO3的掺杂可以促进晶粒生长,Sb2O3的掺杂使晶粒尺寸的均匀性降低。