Recent progress on fabrication, spectroscopy properties, and device applications in Sn-doped CdS micro-nano structures

One-dimensional semiconductor materials possess excellent photoelectric properties and potential for the construction of integrated nanodevices. Among them, Sn-doped CdS has different micro-nano structures, including nanoribbons,nanowires, comb-like structures, and superlattices, with rich optical microcavity modes, excellent optical properties, and a wide range of application fields. This article reviews the research progress of various micrometer structures of Sn-doped CdS, systematically elaborates the effects of different growth conditions on the preparation of Sn-doped CdS micro-nano structures, as well as the spectral characteristics of these structures and their potential applications in certain fields. With the continuous progress of nanotechnology, it is expected that Sn-doped CdS micro-nano structures will achieve more breakthroughs in the field of optoelectronics and form cross-integration with other fields, jointly promoting scientific, technological, and social development.

Superamphiphobic, light-trapping FeSe2 particles with a micro-nano hierarchical structure obtained by an improved solvothermal method

Wettability and the light-trapping effect of FeSe2 particles with a micro-nano hierarchical structure have been inves- tigated. Particles are synthesized by an improved solvothermal method, wherein hexadecyl trimetbyl ammonium bromide （CTAB） is employed as a surfactant. After modifying the particles with heptadecafluorodecyltrimethoxy-silane （HTMS）, we find that the water contact angle （WCA） of the FeSe2 particles increases by 6.1~ and the water sliding angle （WSA） decreases by 2.5~ respectively, and the diffuse reflectivity decreases 29.4% compared with similar FeSe2 particles synthe- sized by the conventional method. The growth process of the particles is analyzed and a growth scenario is given. Upon altering the PH values of the water, we observe that the superhydrophobic property is maintained quite consistently across a wide PH range of 1-14. Moreover, the modified particles were also found to be superoleophobic. To the best of our knowledge, there is no systematic research on the wettability of FeSe2 particles, so our research provides a reference for other researchers.

Investigation on Surface Plasmon Polaritons and Localized Surface Plasmon Production Mechanism in Micro-Nano Structures

The simulation mechanism of surface plasmon polaritons(SPPs)and localized surface plasmon(LSP)in different structures was studied,including the Au reflection grating(Au grating),Au substrate with dielectric ribbons grating(Au substrate grating),and pure electric conductor(PEC)substrate with Au ribbons grating(Au ribbons grating).And the characteristics of the Smith-Purcell radiation in these structures were presented.Simulation results show that SPPs are excited on the bottom surface of Au substrate grating grooves and LSP is stimulated on the upper surface both of Au ribbons grating grooves and Au grating grooves.Owing to the irreconcilable contradiction between optimizing the grating diffraction radiation efficiency and optimizing the SPPs excitation efficiency in the Au substrate grating,only 40-times enhancement of the radiation intensity was obtained by excited SPPs.However,the LSP enhanced structure overcomes the above problem and gains much better radiation enhancement ability,with about 200-times enhancement obtained in the Au ribbons grating and more than 500-times enhancement obtained in the Au grating.The results presented here provide a way of developing miniature,integratable,tunable,high-power-density radiation sources from visible light to ultraviolet rays at room temperature.

Potential application of functional micro-nano structures in petroleum

This paper takes micro-nano motors and metamaterials as examples to introduce the basic concept and development of functional micro nano structures, and analyzes the application potential of the micro-nano structure design and manufacturing technology in the petroleum industry. The functional micro-nano structure is the structure and device with special functions prepared to achieve a specific goal. New functional micro-nano structures are classified into mobile type(e.g. micro-nano motors) and fixed type(e.g. metamaterials), and 3 D printing technology is a developed method of manufacturing. Combining the demand for exploration and development in oil and gas fields and the research status of intelligent micro-nano structures, we believe that there are 3 potential application directions:(1) The intelligent micro-nano structures represented by metamaterials and smart coatings can be applied to the oil recovery engineering technology and equipment to improve the stability and reliability of petroleum equipment.(2) The smart micro-nano robots represented by micro-motors and smart microspheres can be applied to the development of new materials for enhanced oil recovery, effectively improving the development efficiency of heavy oil, shale oil and other resources.(3) The intelligent structure manufacturing technology represented by 3 D printing technology can be applied to the field of microfluidics in reservoir fluids to guide the selection of mine flooding agents and improve the efficiency of mining.

Synthesis and electrochemical performance of micro-nano structured Li Fe1-xMnxPO4/C(0≤x≤0.05)cathode for lithium-ion batteries

Micro-nano structured Li Fe（1-x）MnxPO4/C（0≤x≤0.05）cathodes were prepared by spray drying,followed by calcination at 700°C.The spherical Li Fe（1-x）MnxPO4/C（0≤x≤0.05）particles with the size of 0.5 to5.0μm are composed of lots of nanoparticles of 20 to 30 nm,and have the well-developed interconnected pore structure.In contrast,when Mn doping content is 3 mol%（x=0.03）,the Li Fe（0.97）Mn（0.03）PO4/C demonstrates maximum specific surface area of 31.30 m^2/g,more uniform pore size and relatively better electrochemical performance.The initial discharge capacities are 161.59,157.04 and 153.13 m Ah/g at a discharge rate of 0.2,0.5 and 1 C,respectively.Meanwhile,the discharge capacity retentions are～100%after 120 cycles.The improved electrochemical performance should be attributed to higher specific surface,smaller polarization voltage,and a high Li~＋diffusion rate due to the micro-nano porous structure and lattice expansion produced by Mn doping.

Generalized model for laser-induced surface structure in metallic glass

The details of the special three-dimensional micro-nano scale ripples with a period of hundreds of microns on the surfaces of a Zr-based and a La-based metallic glass irradiated separately by single laser pulse are investigated.We use the small-amplitude capillary wave theory to unveil the ripple formation mechanism through considering each of the molten metallic glasses as an incompressible viscous fluid.A generalized model is presented to describe the special morphology,which fits the experimental result well.It is also revealed that the viscosity brings about the biggest effect on the monotone decreasing nature of the amplitude and the wavelength of the surface ripples.The greater the viscosity is,the shorter the amplitude and the wavelength are.

Reservoir micro structure of Da'anzhai Member of Jurassic and its petroleum significance in Central Sichuan Basin, SW China

Based on the qualitative study of microscopic reservoir features using core analysis,cast and fluorescence thin sections inspection,scanning electron microscope(SEM)and field emission scanning electron microscope(FESEM)and quantitative examination of pore size and geometry using mercury injection,nano-CT and nitrogen adsorption,reservoir rock of Da’anzhai Member were divided into 9 types,while storage spaces were divided into 4 types and 14 sub-types.The study shows that sparry coquina is the most promising reservoir type.Pores that smaller than 1μm in diameter contribute 91.27%of storage space volume.Most of them exhibit slot-like geometry with good connectivity.By building up storage space models,it was revealed that micron scale storage spaces mainly composed of fractures and nanometer scale pores and fractures form multi-scale dual porosity system.Low resource abundance,small single well controlled reserve,and low production are related to the nano-scale pore space in Da’anzhai Memer,whereas the dual-porosity system composed of pores and fractures makes for long-term oil yield.Due to the existence of abundant slot-like pore space and fractures,economic tight oil production was achieved without stimulations.

Directionally tailoring micro-nano hierarchical tower structured Mn_(0.6)Ni_(1.4)Co_(2)O_(y) toward solar interfacial evaporation

Solar interfacial evaporation has been considered as a promising method to alleviate fresh water re-sources shortage.The shortage of freshwater resources requires advanced materials that can accelerate the evaporation of water by the sun.However,the simple structure of photothermal materials are vitally restricted by finite light absorption.Herein,this work presents a strategy for the synthesis of a spinel-type micro-nano hierarchical tower structure solar absorbent(Mn_(0.6)Ni_(1.4)Co_(2)O_(y))with the low forbidden band(=1.56 eV)and high absorption(97.88%).The products show great potential in solar-thermal energy conversion by creating a trapping effect.The prepared solar absorbent and epoxy resin are evenly mixed and then fully immersed in polyurethane(PU)sponge for water evaporation.The hydrophilic and porous Mn_(0.6)Ni_(1.4)Co_(2)O_(y)@PU sponge can quickly deliver water upwards,suppress the heat loss,and concentrate the absorbed heat on the evaporation of water.The products exhibited an excellent evaporation rate of 2.261 kg m^(-2) h^(-1) and an impressive evaporation efficiency of 156%under a single sun exposure.Besides,the samples also can maintain the stability and recycling performance for a long time.These findings show that Mn_(0.6)Ni_(1.4)Co_(2)O_(y) have great application prospects in the solar interfacial evaporation.

Surface Micro-Nano Structures on GaN Thin Films Induced by 355 nm Nanosecond Laser Irradiation

Gallium nitride(GaN)has widespread applications in the semiconductor industry because of its desirable optoelectronic properties.The fabrication of surface structures on GaN thin films can effectively modify their optical and electrical properties,providing additional degrees of freedom for controlling GaN-based devices.Compared with lithography-based techniques,laser processing is maskless and much more efficient.This paper shows how surface micronano structures can be produced on GaN thin films using 355 nm nanosecond laser irradiation.The effects of the laser pulse energy,number of pulses,and polarization direction were studied.It was found that distinct micro-nano structures were formed under different irradiation conditions,and their geometries and elemental compositions were analyzed.The results indicate that different types of surface micro-nano structures can be produced on GaN thin films in a controllable manner using 355 nm nanosecond laser irradiation.The results of our study provide valuable guidance for the surface modification of GaN-based optoelectronic devices.

ZnO micro-nano composite hydrophobic film prepared by the three-step method

The hydrophobicity of the lotus leaf is mainly due to its surface micro-nano composite structure. In order to mimic the lotus structure, ZnO micro-nano composite hydrophobic films were prepared via the three-step method. On thin buffer films of SiO2, which were first fabricated on glass substrates by the so,gel dip-coating method, a ZnO seed layer was deposited via RF magnetron sputtering. Then two different ZnO films, micro-nano and micro-only flowerlike structures, were grown by the hydrothermal method. The prepared films have different hydrophobic properties after surface modification. The structures of the obtained ZnO films were characterized using x-ray diffraction and field-emission scanning electron microscopy. A conclusion that a micro-nano composite structure is more beneficial to hydrophobicity than a micro-only structure was obtained through research into the effect of structure on hydrophobic properties.

Micro-nano structured functional coatings deposited by liquid plasma spraying

Inspired by the micro-nano structure on the surface of biological materials or living organisms,micro-nano structure has been widely investigated in the field of functional coatings.Due to its large specific surface area,porosity,and dual-scale structure,it has recently attracted special attention.The typical fabrication processes of micro-nano structured coatings include sol-gel,hydrothermal synthesis,chemical vapor deposition,etc.This paper presents the main features of a recent deposition and synthesis technique,liquid plasma spraying(LPS).LPS is an important technical improvement of atmospheric plasma spraying.Compared with atmospheric plasma spraying,LPS is more suitable for preparing functional coatings with micro-nano structure.Micro-nano structured coatings are mainly classified into hierarchical-structure and binary-structure.The present study reviews the preparation technology,structural characteristics,functional properties,and potential applications of LPS coatings with a micro-nano structure.The micro-nano structured coatings obtained through tailoring the structure will present excellent performances.

Flexible Triboelectric Nanogenerator from Micro-nano Structured Polydimethylsiloxane

Triboelectric nanogenerator（TENG） can convert mechanical energy to electrical energy through contact electrification and electrostatic induction. Single-friction-surface triboelectric nanogenerator（STENG） extends poten- tial application because a finger can be used as one friction surface in the contact electrification. In this work, a fully flexible STENG has been made, consisting of polydimethylsiloxane（PDMS） with micro-nano structures on its ob- serve side and a flexible electrode on its reverse side. The femtosecond laser ablation was introduced to make micro-nano structures on PDMS and Ag nanowires（Ag NWs） were embedded in PDMS to serve as flexible induction electrode. It has been demonstrated that the energy conversion efficiency increases greatly because of the existing micro-nano structures on PDMS. Further, the mechanism of STENG was proved. Owing to the fully flexible charac- teristics in both the electrode and PDMS, STENG works well when it is adhered on any subject, for example, on clothes by tape.

Structure induced wide range wettability:Controlled surface of micro-nano/nano structured copper films for enhanced interface

The wettability of materials used in the production of devices employed in various technological domains have attracted significant attentions.Therefore,it is important to design the surfaces of these materials such that they can provide the required surface free energy and simplify the interfacial structure.Herein,various Cu films with a highly controllable surface wettability and a wide range of contact angles ranging from 6°to 152°were fabricated,and the corresponding mechanism was discussed.A wide range of wettability was realized by controlling the surface structure of the Cu film.The nanogap structure of the vertical nanowire-array film led to a high surface free energy.Similarly,the oblique nanowirearray film increased the surface free energy;however,the surface free energy was dependent on the size of the nanowires rather than on the nanogaps owing to the crystallinity of the film.Additionally,cluster-nanowire-array films were designed to realize a wettability transition from hydrophilicity to hydrophobicity with a constant surface free energy.The Cu foam possessed a superhydrophilic surface owing to its high porosity,whereas the cluster-nanoparticle structure possessed a superhydrophobic surface.In addition,we noted that the structure-induced wettability played an important role in tuning the semiconductor and metal interfacial stress and simplifying the interfacial structure.Furthermore,the outstanding electrical conductivity of the Cu films indicates its promising potential as an electrode.The structure-induced wettability proposed in this study can be applied for a wide range of materials,particularly for films used for advanced applications.

Osteogenic and antibacterial ability of micro-nano structures coated with ZnO on Ti-6Al-4V implant fabricated by two-step laser processing

The biological performance of Ti-6Al-4V implant is primarily determined by their surface properties.However,traditional surface modification methods,such as acid etching,hardly make improvement in their osseointegration ability and antibacterial capacity.In this study,we prepared a multi-scale composite structure coated with zinc oxide(ZnO)on Ti-6Al-4V implant by an innovative technology of two-step laser processing combined with solution-assistant.Compared with the acid etching method,the physicochemical properties of surface significantly improved.The in vitro results showed that the particular dimension of micro-nano structure and the multifaceted nature of ZnO synergistically affected MC3T3-E1 osteogenesis and bacterial activities:(1)The surface morphology showed a‘contact guidance'effect on cell arrangement,which was conducive to the adhesion of filopodia and cell spreading,and the osteogenesis level of MC3T3-E1 was enhanced due to the release of zinc ions(Zn^(2+));(2)the characterization of bacterial response revealed that periodic nanostructures and Zn^(2+)released could cause damage to the cell wall of E.coli and reduce the adhesion and aggregation of S.aureus.In conclusion,the modified surface showed a synergistic effect of physical topography and chemical composition,making this a promising method and providing new insight into bone defect repairment.

Micro-nano structured VNb_(9)O_(25)anode with superior electronic conductivity for high-rate and long-life lithium storage

The oxygen vacancies and micro-nano structure can optimize the electron/Li+migration kinetics in anode materials for lithium batteries(LIBs).Here,porous micro-nano structured VNb_(9)O_(25)composites with rich oxygen vacancies were reasonably prepared via a facile solvothermal method combined with annealing treatment at 800℃for 30 h(VNb_(9)O_(25)-30 h).This micro-nano structure can enhance the contact of active material/electrolyte,and shorten the Li+diffusion distance.The introduction of oxygen vacancies can further boosts the intrinsic conductivity of VNb_(9)O_(25)-30 h for achieving excellent LIB performance.The as-prepared VNb_(9)O_(25)-30 h anode showed advanced rate capability with reversible capacity of 122.2 m A h g^(-1)at 4 A g^(-1),and delivered excellent capacity retention of~100%after 2000 cycles.Meanwhile,VNb_(9)O_(25)-30 h provides unexpected long-cycle life(i.e.,reversible capacity of 165.7 m A h g^(-1)at 1 A g^(-1)with a high capacity retention of 85.6%even after 8000 cycles).Additionally,coupled with the Li Fe PO4 cathode,the Li Fe PO4//VNb_(9)O_(25)-30 h full cell delivers superior LIB properties with high reversible capacities of 91.6 m A h g^(-1)at 5 C for 1000 cycles.Thus,such reasonable construction method can assist in other high-performance niobium-based oxides in LIBs.

Biomimetic Photonic Structures with Tunable Structural Colours： From Natural to Biomimetic to Applications

Natural photonic structure with tunable structural colours is one of the most miraculous structures which always catches our eyes. However, the application of artificial photonic structures is limited. Moreover, because of the ability of tunable colours, photonic structure is the excellent candidate for many fields, such as sensor, bioassay, anti-counterfeiting, optical components, photocatalytic, fibers and fabrics. Considering the superior tunable optical property and other excellent performance such as robust mechanical strength, wettability, there are new domains and novel routes for this material that deserve us to explore. In this review, some natural photonic structures are discussed. Some novel fabrication methods and applications will be mentioned in this article. Furthermore, this review provides an insight and outlook for the photonic material with tunable eolours focusing on fabrication, design and applications.

新型陶瓷基复合超疏水涂层的制备及其性能

为了研究开发新型超疏水涂层的制备方法,改善涂层的结构与性能,以Al_2O_3-40%TiO_2(AT40)、PFA(全氟烷氧基乙烯基醚共聚物)粉末为原始材料,采用大气等离子喷涂(APS)技术,并调整电流、氩气流量等喷涂参数,在铝合金基体表面制备了两种不同的AT40/PFA复合超疏水涂层。利用相对应的测试仪器及分析手段对喷涂态涂层的相组成、显微结构、摩擦系数及基本性能等进行了表征分析。结果表明,两种涂层的相组成均为C_(20)F_(42)、Al_2TiO_5及少量的γ-Al_2O_3、α-Al_2O_3相;涂层表面均为圆形和椭圆形的粒状突起结构,其中突起结构的表面均存在类似荷叶表面结构的二元微纳米乳突结构,其表面粗糙度为9.3μm和12.41μm;所得涂层具有良好的综合性能,与水的静态接触角均达到了150°以上,滚动角为4～5°;在其他参数不变的情况下,随着电流的增大及氩气流量的减小,涂层中的陶瓷相含量增加,涂层的粗糙度、摩擦系数、显微硬度及结合强度均增大。

Fabrication of diamond ultra-fine structures by femtosecond laser

A 400 nm femtosecond laser was used to ablate the surface of a high-pressure and high-temperature diamond,and subwavelength surface micro structures with a period of 100 nm were achieved. A variety of micro-nano composite surface structures were prepared by changing the polarization direction and laser scanning direction.By dynamically adjusting the laser polarization and the laser scanning tracks, a maskless direct writing fabrication of micro-nano complex structures was realized. The micro-nano patterning on an ultra-hard and super-stabile diamond provides a new idea for the preparation of friction reducing surfaces, nano imprint transfer templates, surface enhanced Raman scattering test substrates, and micro-nano optical structures.

Bioinspired Functional Surfaces for Medical Devices

Medical devices are a major component of precision medicine and play a key role in medical treatment,particularly with the rapid development of minimally invasive surgery and wearable devices.Their tissue contact properties strongly affect device performance and patient health(e.g.,heat coagulation and slipperiness on surgical graspers).However,the design and optimization of these device surfaces are still indistinct and have no supporting principles.Under such conditions,natural surfaces with various unique functions can provide solutions.This review summarizes the current progress in natural functional surfaces for medical devices,including ultra-slipperiness and strong wet attachment.The underlying mechanisms of these surfaces are attributed to their coupling effects and featured micronano structures.Depending on various medical requirements,adaptable designs and fabrication methods have been developed.Additionally,various medical device surfaces have been validated to achieve enhanced contact properties.Based on these studies,a more promising future for medical devices can be achieved for enhanced precision medicine and human health.

Transition metal carbonate anodes for Li-ion battery: fundamentals,synthesis and modification

Even though transition metal carbonates(TMCs, TM = Fe, Mn, Co, Ni etc.), show high theoretical capacities, rich reserves and environmental friendliness as anodes for lithium-ion batteries(LIBs), they suffer from sluggish electronic/ionic conductivities and huge volume variation, which severely deteriorate the rate capacities and cycling performances. Understanding the intrinsic reaction mechanism and further developing ideal TMC-based anode with high specific capacity, excellent rate capabilities, and longterm cycling stability are critical for the practical application of TMCs. In this review, we firstly focus on the fundamental electrochemical energy-storage mechanisms of TMCs, in terms of conversionreaction process, pseudocapacitance-type charge storage, valence change for charge storage and catalytic conversion mechanisms. Based on the reaction mechanisms, various modification strategies to improve the electrochemical performance of TMCs are summarized, covering:(i) micro-nano structural engineering, in which the influence factors on the morphology are discussed, and multiple architectures are listed;(ii) elemental doping, in which the intrinsic mechanisms of metal/nonmetal elements doping on the electrochemical performance are deeply explored;(iii) multifunctional compositing strategies, in which the specific affections on structure, electronic conductivity and chemo-mechanical stability are summarized.Finally, the key challenges and opportunities to develop high-performance TMCs are discussed and some solutions are also proposed. This timely review sheds light on the path towards achieving cost-effective and safe LIBs with high energy density and long cycling life using TMCs-based anode materials.