Superhydrophobic surfaces via controlling the morphology of ZnO micro/nano complex structure

ZnO micro/nano complex structure films, including reticulate papillary nodes, petal-like and flake-hole, have been self-assembled by a hydrothermal technique at different temperatures without metal catalysts. The wettability of the above film surfaces was modified with a simple coating of heptadecafluorodecyltrimethoxy-silane in toluene. After modifying, the surface of ZnO film grown at 50℃ was converted from superhydrophilic with a water contact angle lower than 5° to superhydrophobic with a water contact angle of 165° Additionally, the surface of reticulate papillary nodes ZnO film grown at 100 ℃ had excellent superhydrophobicity, with a water contact angle of 173° and a sliding angle lower than 2° Furthermore, the water contact angle on the surface of petal-like and flake-hole ZnO films grown at 150℃ and 200℃ were found to be 140° and 120°, respectively. The wettability for the samples was found to depend strongly on the surface morphology which results from the growth temperature.

Localized in‑situ deposition:a new dimension to control in fabricating surface micro/nano structures via ultrafast laser ablation

Controllable fabrication of surface micro/nano structures is the key to realizing surface functionalization for various applications.As a versatile approach,ultrafast laser ablation has been widely studied for surface micro/nano structuring.Increasing research eforts in this feld have been devoted to gaining more control over the fabrication processes to meet the increasing need for creation of complex structures.In this paper,we focus on the in-situ deposition process following the plasma formation under ultrafast laser ablation.From an overview perspective,we frstly summarize the diferent roles that plasma plumes,from pulsed laser ablation of solids,play in diferent laser processing approaches.Then,the distinctive in-situ deposition process within surface micro/nano structuring is highlighted.Our experimental work demonstrated that the in-situ deposition during ultrafast laser surface structuring can be controlled as a localized micro-additive process to pile up secondary ordered structures,through which a unique kind of hierarchical structure with fort-like bodies sitting on top of micro cone arrays were fabricated as a showcase.The revealed laser-matter interaction mechanism can be inspiring for the development of new ultrafast laser fabrication approaches,adding a new dimension and more fexibility in controlling the fabrication of functional surface micro/nano structures.

Energy barrier for configurational transformation of graphene nanoribbon on nanotube

A graphene nanoribbon （GNR） has two basic configurations when winding on the outer surface of a carbon nanotube （CNT）： helix and scroll. Here the transformation between the two configurations is studied utilizing molecular dynamics simulations. The energy barrier during the transformation as well as its relationship with the interfacial energy and the radius of CNT are investigated. Our work offers further insights into the formation of desirable helix/scroll of GNR winding on nanotubes or nanowires, and thus can enable novel design of potential graphene-based electronics.

Controlled Synthesis of SnO_2 with Hierarchical Micro/Nano Structure

Preparing SnO2 with hierarchical micro/nano structures by hydrothermal, coordination, templating and electrochemical deposition methods and their mechanisms are investigated. The result shows that the echinus-like SnO2 prepared by Method 1 is a typical Ostwald mechanism that develops from internally to externally. The cabbage-like SnO2 by Method 2 is produced with oxalic acid as complexing agent to set-up precursor of SnO2, and then precursors are bocked around the body that is around the body being bocked. The nest-like SnO2 by Method 3 is controlled by citric acid as coordinator for the nucleation as well as the grow rate and setup process. Spongy-like SnO2 by Method 4 is produced using PST as template, PST is be infiltered into SnO2 precursor by gravity and capillary and treated thermally to form a multiporous structure. The petal-like SnO2 by Method 5 is formed with crystal deposition emergence due to oxidation-reduction reactions of two electrodes in an electric field. XRD analyses shows that the five results are all pure phase SnO2. It provides basic data for SnOE industrial application.

Construction of Zn-incorporated Micro/Nano Hierarchical Structure Coatings on Tantalum

Tantalum(Ta)alloys have been widely used as bone repair materials duc to their excellent biocompatibility.In present work,zinc(Zn)incorporated ceramic coatings with micro/nano hierarchical structure were successfully fabricated on Ta by micro-arc oxidation and hydrothermal treatment.The content of Zn ions is about(1.35士0.3)wt%.Cortex-like rough morphology(Ra:1.504μm)with irregular vermiform slots can be clearly observed on the surface of Ta.More importantly,the coatings resembling the structure of natural bone can release Zn,Ca,and P ions in a controlled and sustained manner.The corrosion resistance ofTa is greatly improved after functionalized with ceramic coatings,confirming by potentiodynamic polarization tests.The bonding strength between the coatings and substrates can be up to 18.9 N.Furthermore,the surface of MAOs-HT@Ta is covered by bonelike apatite after immersed in Simulated Body Fluid(SBF)for three weeks,showing excellently bioactivity.These results suggest that the innovative Zn-incorporated micro/nano hierarchical coatings on Ta may be used as promising candidates for orthopedic implants.

Research progress in improving the performance of PEDOT:PSS/Microand Nano-textured Si heterojunction for hybrid solar cells

Silicon-based hybrid solar cells(HSCs),especially PEDOT:PSS/Si HSC,have attracted the interest of researchers because they combine the advantages of organic and inorganic materials.A high quality PEDOT:PSS/Si heterojunction is the key to the good performance of PEDOT:PSS/Si HSC.However,as generally requisite to enhance light absorption for HSCs,Si Micro/Nano structures will reduce the interface contact quality between PEDOT:PSS and Si surface.The inferior interface contact quality will limit the separation efficiency of the photogenerated carriers.In this paper,we summarize the research progress in improving the interface contact between Si Micro/Nano structures and PEDOT:PSS film from three aspects:the optimization of Si Micro/Nano structures aimed to improve the fluid properties of PEDOT:PSS solution,the material modification of PEDOT:PSS and interface modification with the purpose to enlarge the heterojunction area and improve the electrical contact,and the specific deposition process of PEDOT:PSS solution developed to achieve the high filling rate of PEDOT:PSS on Si Micro/Nano structures.The insight of this paper is helpful for the preparation of high-quality heterojunction,which is vitally important for the development of high efficiency PEDOT:PSS/Si HSCs.

Effective strategy to achieve a metal surface with ultralow reflectivity by femtosecond laser fabrication

An effective and simple method is proposed for fabricating the micro/nano hybrid structures on metal surfaces by adjusting femtosecond laser fluence,scanning interval,and polarization.The evolution of surface morphology with the micro/nano structures is discussed in detail.Also,the mechanism of light absorption by the micro/nano hybrid structures is revealed.Compared with the typical periodic light-absorbing structures,this type of micro/nano hybrid structures has an ultralow average reflectivity of 2%in the 250–2300 nm spectral band and the minimum 1.5%reflectivity in UV band.By employing this method,large areas of the micro/nano hybrid structures with high consistency could be achieved.

Progress of passive daytime radiative cooling technologies towards commercial applications

Global warming has become one of the major environmental problems facing mankind in the 21st century,The existing refrigeration technology of buildings,like air conditioning,consumes a lot of energy.Passive daytime radiative cooling technology works without consuming energy.nor emitting carbon dioxide and other greenhouse gases.This review summarizes the development of daytime passive radiative cooling technologyfrom the basic principles,structure and materials of radiative coolers;analyses and evaluates the various existing radiative coolers.The core of radiative cooling lies in the combination of multi-scale micro/nano structures.The cooler reflects sunlight thus preventing the building from being heated up;while allows the building toradiate its own heat out thus being cooled down;meanwhile maintains the temperature difference by the heat insulation effect ofthe porous structure in theflm.The common challenges and potential solutions for the commercialization of radiative cooling technologies are analyzed,which may promote the applications of the technology in the near future.

Multishelled CuO/Cu_(2)O induced fast photo-vapour generation for drinking water

Solar thermal interfacial water evaporation is proposed as a promising route to address freshwater scarcity,which can reduce energy consumption and have unlimited application scenarios.The large semiconductor family with controllable bandgap and good chemo-physical stability are considered as good candidates for photo-evaporation.However,the evaporation rate is not satisfactory because the rational control of nano/micro structure and composition is still in its infancy stage.Herein,by systemically analyzing the photo-thermal evaporation processes,we applied the hollow multishelled structure(HoMS)into this application.Benefiting from the multishelled and hierarchical porous structure,the light absorption,thermal regulation,and water transport are simultaneously optimized,resulting in a water evaporation rate of 3.2 kg·m^(-2)·h^(-1),which is among the best performance in solar-vapour generation.The collected water from different water resources meets the World Health Organization standard for drinkable water.Interestingly,by using the CuO/Cu_(2)O system,reactive oxygen species were generated for water disinfection,showing a new route for efficient solar-vapour generation and a green way to obtain safe drinking water.