Nanoparticles monolayer formation by spin coating is considered to be a simple, fast and inexpensive nanopatteming technique However, the parameters that govern the overall growth process in this technique are not com...Nanoparticles monolayer formation by spin coating is considered to be a simple, fast and inexpensive nanopatteming technique However, the parameters that govern the overall growth process in this technique are not completely quantified and techniques for the controlled and continuous growth of close packed monolayer particle arrays without defects need to be developed. In this paper, an ordered particle array formation process is analyzed theoretically, employing material flux balance and parti- cle-subjected forces balance, based on the film thickness model of spin coating and evaporation rate law. A series of experi- ments were conducted using silica particle suspensions with various particle volume fractions and different spin speeds. The results show that the spin speed should match the particle volume fraction to meet the requirements of material flux and particles movement in order to obtain a close packed monolayer film. The formation mechanism of fabrication defects involving particle agglomeration and uncontrollable voids were analyzed qualitatively based on crystal growth theory, and validation experiments were performed. The formation of highly uniform close-packed monolayer films was demonstrated and the condi- tion requirements for achieving monolayer nanoparticles array with good quality presented.展开更多
Three-dimensional(3D)nanoarchitectures have offered unprecedented material performances in diverse applications like energy storages,catalysts,electronic,mechanical,and photonic devices.These outstanding performances ...Three-dimensional(3D)nanoarchitectures have offered unprecedented material performances in diverse applications like energy storages,catalysts,electronic,mechanical,and photonic devices.These outstanding performances are attributed to unusual material properties at the nanoscale,enormous surface areas,a geometrical uniqueness,and comparable feature sizes with optical wavelengths.For the practical use of the unusual nanoscale properties,there have been developments for macroscale fabrications of the 3D nanoarchitectures with process areas over centimeter scales.Among the many fabrication methods for 3D structures at the nanoscale,proximity-field nanopatterning(PnP)is one of the promising techniques that generates 3D optical holographic images and transforms them into material structures through a lithographic process.Using conformal and transparent phase masks as a key factor,the PnP process has advantages in terms of stability,uniformity,and reproducibility for 3D nanostructures with periods from 300 nm to several micrometers.Other merits of realizing precise 3D features with sub-100 nm and rapid processes are attributed to the interference of coherent light diffracted by phase masks.In this review,to report the overall progress of PnP from 2003,we present a comprehensive understanding of PnP,including its brief history,the fundamental principles,symmetry control of 3D nanoarchitectures,material issues for the phase masks,and the process area expansion to the wafer-scale for the target applications.Finally,technical challenges and prospects are discussed for further development and practical applications of the PnP technique.展开更多
Functionalization of silicon substrate surfaces with a stable monolayer for resisting non-specific adsorption of proteins has attracted great interest,since it is directly relevant to the development of miniature,sili...Functionalization of silicon substrate surfaces with a stable monolayer for resisting non-specific adsorption of proteins has attracted great interest,since it is directly relevant to the development of miniature,silicon-based biosensors and implantable microdevices,such as silicon-neuron interfaces.This brief review summarizes our contribution to the development of robust monolayers grown by surface hydrosilylation on atomically flat,hydrogen-terminated silicon surfaces.The review also outlines our strategy and progress on the fabrication of single molecule patterns on such monolayer platforms.展开更多
The morphology of linear polybutadiene physisorbed on freshly cleaved mica from a dilute polymer solution is investigated through atomic force microscopy.A fine-structure study shows that the monolayer morphology in a...The morphology of linear polybutadiene physisorbed on freshly cleaved mica from a dilute polymer solution is investigated through atomic force microscopy.A fine-structure study shows that the monolayer morphology in air(after rapid solvent evaporation)depends strongly on the molecular weight(Mw)of the linear polymer,the adsorbed amount,and the conformation adopted by the adsorbed polymer chains under good solvent conditions.The dependence of the observed polymer structure on Mw is most significant for samples with high surface density,where the intermolecular interactions among the adsorbed polymers are important.For high surface density,the adsorbed polymers tend to aggregate and minimize unfavorable contacts with air for all of the different Mw samples,leading to an isotropic structural pattern.These structural phenomena with increasing surface density are explained on the basis of the intermolecular interactions of the adsorbed polymers under good solvent conditions,and after the abrupt solvent evaporation corresponding to poor solvent conditions.The experimental observations are further discussed using the results obtained from molecular dynamics simulations of a simple coarse-grained model.展开更多
To unlock the full potential of PSCs,machine learning(ML)was implemented in this research to predict the optimal combination of mesoporous-titanium dioxide(mp-TiO_(2))and weight percentage(wt%)of phenyl-C_(61)-butyric...To unlock the full potential of PSCs,machine learning(ML)was implemented in this research to predict the optimal combination of mesoporous-titanium dioxide(mp-TiO_(2))and weight percentage(wt%)of phenyl-C_(61)-butyric acid methyl ester(PCBM),along with the current density(J_(sc)),open-circuit voltage(V_(oc)),fill factor(ff),and energy conversion efficiency(ECE).Then,the combination that yielded the highest predicted ECE was selected as a reference to fabricate PCBM-PSCs with nanopatterned TiO_(2)layer.Subsequently,the PCBM-PSCs with nanopatterned TiO_(2)layers were fabricated and characterized to further understand the effects of nanopatterning depth and wt%of PCBM on PSCs.Experimentally,the highest ECE of 17.338%is achieved at 127 nm nanopatterning depth and 0.10 wt%of PCBM,where the J_(sc),V_(oc),and ff are 22.877 mA cm^(-2),0.963 V,and 0.787,respectively.The measured J_(sc),V_(oc),ff,and ECE values show consistencies with the ML prediction.Hence,these findings not only revealed the potential of ML to be used as a preliminary investigation to navigate the research of PSCs but also highlighted that nanopatterning depth has a significant impact on J_(sc),and the incorporation of PCBM on perovskite layer influenced the V_(oc)and ff,which further boosted the performance of PSCs.展开更多
A method is presented for nano-patterning a diffraction grating on human hair with a focused ion beam. Strands of brown hair are patterned with hyperbolas and Archimedean spirals whose pitches range from 540 nm to 104...A method is presented for nano-patterning a diffraction grating on human hair with a focused ion beam. Strands of brown hair are patterned with hyperbolas and Archimedean spirals whose pitches range from 540 nm to 1040 nm. Exposure of the hair strands to white light at various incident angles demonstrates that light of varying wavelengths is diffracted by the diffraction gratings. The diffraction causes the brown strands of hair to reflect light from the entire range of visible light.展开更多
In this paper, microphase behavior of an ABC triblock copolymer, polystyrene-block-poly（2-vinylpyridine）-block- poly（ethylene oxide）, namely PS-b-P2VP-b-PEO, was systematically studied during spin-coating and solv...In this paper, microphase behavior of an ABC triblock copolymer, polystyrene-block-poly（2-vinylpyridine）-block- poly（ethylene oxide）, namely PS-b-P2VP-b-PEO, was systematically studied during spin-coating and solvent vapor annealing based on various parameters, including the types of the solvent, spin speed and thickness. The morphological features and the microdomain location of the different blocks were characterized by atomic force microscope （AFM） and high resolution transmission electron microscopy （HRTEM）. With increasing thickness, the order-order transition from nanopores array to the pattern of nanostripes was observed due to microdomain coarsening. These processes of pattern transformation were based on the selectivity of toluene for different blocks and on the contact time between solvent molecules and the three blocks. This work provides different templates for preparation of gold nanoparticle array on silicon wafer, which can be adopted as an active surface-enhanced Raman scattering （SERS） substrate for poly（3-hexylthiophene） （P3HT）.展开更多
The development of nanoelectronics and nanotechnologies has been boosted significantly by the emergence of 2D materials because of their atomic thickness and peculiar properties,and developing a universal,precise patte...The development of nanoelectronics and nanotechnologies has been boosted significantly by the emergence of 2D materials because of their atomic thickness and peculiar properties,and developing a universal,precise patterning technology for single-layer 2D materials is critical for assembling nanodevices.Demonstrated here is a nanomachining technique using electrical breakdown by an AFM tip to fabricate nanopores,nanostrips,and other nanostructures on demand.This can be achieved by voltage scanning or applying a constant voltage while moving the tip.By measuring the electrical current,the formation process on single-layer materials was shown quantitatively.The present results provide evidence of successful pattern fabrication on single-layer MoS2,boron nitride,and graphene,although further confirmation is still needed.The proposed method holds promise as a general nanomachining technology for the future.展开更多
A novel two-dimensional nanopattemed TiO2 thin film has been synthesized through the interaction between cationic Gemini surfactant molecules and the prepared TiO2 colloid nanoparticles with average diameters of 8 nm ...A novel two-dimensional nanopattemed TiO2 thin film has been synthesized through the interaction between cationic Gemini surfactant molecules and the prepared TiO2 colloid nanoparticles with average diameters of 8 nm by controlling the surface pressure of the monolayer. TEM photographs from the formed Gemini-TiO2 composite monolayer confirm that the prepared TiO2 film is of a branch nanopattern.展开更多
Bacterial adhesion is a critical process in many fields,such as implant infections,microbiologically influenced corrosion and bioelectricity generation in microbial fuel cells.During bacterial adhesion,the contact are...Bacterial adhesion is a critical process in many fields,such as implant infections,microbiologically influenced corrosion and bioelectricity generation in microbial fuel cells.During bacterial adhesion,the contact area between the attached bacteria and the patterned surface plays an important role.In this study,different surface topographies and treatments were employed to simulate three circumstances with different contact areas.A nanostripe structure with a period of 576.9 nm and a height of 203.5 nm was fabricated on pure titanium by femtosecond laser ablation.Bacteria in liquid attached to the peaks of the nanostripe structure and were stretched on the two adjacent nanostripes.Compared with the polished surface,the contact area between bacteria and the nanostripe surface was reduced to 50%,resulting in a reduction(about 50%)in the coverage rate of attached bacteria.In addition,the nanostripe surface was a hydrophobic surface with a water contact angle(WCA)of 112.1°,and the surface potential of the nanostripe surface was higher than that of the polished surface.However,the surface potential and wettability of the nanostripe surface played a minor role in the bacterial adhesion due to the reduced contact area.Upon drying,the attached bacteria on the nanostripe surface sank into the valley region and the contact area was about 40%larger than that on the polished surface.The lateral strength of bacterial adhesion on nanostripe surfaces was higher than that on polished surfaces,due to the larger contact area.Upon applying a lateral force of 10.0 nN,the percentage of bacteria remaining on the nanostripe surface(31.1%)was higher than that on the polished surface(11.9%).Hence,the bacterial adhesion on the nanopatterned surface was mainly determined by the contact area.The in-depth exploration of the relation between bacterial adhesion on the nanopatterned surface and the contact area enables the rational surface designs of biomaterials to regulate bacterial adhesion.展开更多
As a well-known natural protein biomaterial,silk fibroin(SF)has shown broad application prospects in typical biomedical fields.However,the mostly used SF from Bombyx mori silkworm lacks specific cell adhesion sites an...As a well-known natural protein biomaterial,silk fibroin(SF)has shown broad application prospects in typical biomedical fields.However,the mostly used SF from Bombyx mori silkworm lacks specific cell adhesion sites and other bioactive peptide sequences,and there is still significant room for further improvement of their biological functions.Therefore,it is crucial to develop a facile and effective modification strategy for this widely researched biomaterial.In this study,the SF electrospun scaffold has been chosen as a typical SF biomaterial,and air plasma etching has been adopted as a facile nanopattern modification strategy to promote its biological functions.Results demonstrated that the plasma etching could feasibly and effectively create nano-island-like patterns on the complex surface of SF scaffolds,and the detailed nanopattern features could be easily regulated by adjusting the etching time.In addition,the mesenchymal stem cell responses have illustrated that the nanopattern modification could significantly regulate corresponding cell behaviors.Compared with the non-etched scaffold,the 10min-etched scaffolds(10E scaffold)significantly promoted stem cell proliferation and osteogenic differentiation.Moreover,10E scaffold has also been confirmed to effectively accelerate vascularization and ectopic osteogenesis in vivo using a rat subcutaneous implantation model.However,the mentioned promoting effects would be weakened or even counteracted with the increase of etching time.In conclusion,this facile modification strategy demonstrated great application potential for promoting cell proliferation and differentiation.Thus,it provided useful guidance to develop excellent SF-based scaffolds suitable for bone and other tissue engineering.展开更多
The atomic edge structure of graphene governs its unique electronic properties with applications in nanoscale electronics and optoelectronics.To fully realize its potential,it is critical to develop a precision etchin...The atomic edge structure of graphene governs its unique electronic properties with applications in nanoscale electronics and optoelectronics.To fully realize its potential,it is critical to develop a precision etching process producing graphene edges along desired directions.Here,we present a novel approach utilizing scanning probe lithography(SPL)facilitated by a mechanochemical atomic attrition process.This technique enables the fabrication of nanopatterns in single-layer graphene from graphene edges,precisely along the crystallographic orientation of zigzag(ZZ)and armchair(AC)edges,without inducing mechanical damage to the surrounding area.Density functional theory(DFT)calculations revealed that the dissociation of CC bonds by the SPL probe is mediated by the formation of interfacial bridge bonds between the graphene edge and the reactive silica surface.This SPL-based mechanochemical etching method enables the construction of various nanodevice structures with specific edge orientations,which allows the exploitation of their electronic properties.展开更多
Non-planar morphology is a common feature of devices applied in various physical fields,such as light or fluid,which pose a great challenge for surface nano-patterning to improve their performance.The present study pr...Non-planar morphology is a common feature of devices applied in various physical fields,such as light or fluid,which pose a great challenge for surface nano-patterning to improve their performance.The present study proposes a discretely-supported nanoimprint.lithography(NIL)technique to fabricate nanostructures on the extremely non-planar surface,namely high-spatial-frequency stepped surface.The designed discretely imprinting template implanted a discretely-supported intermediate buffer layer made of sparse pillars arrays.This allowed the simultaneous generation of air-cushion-like buffer and reliable support to the thin structured layer in the template.The resulting low bending stiffness and distributed concentrated load of the template jointly overcome the contact difficulty with a stepped surface,and enable the template to encase the stepped protrusion as tight as possible.Based on the proposed discretely-supported NIL,nanostructures were fabricated on the luminous interface of light emitting diodes chips that covered with micrometer step electrodes pad.About 96%of the utilized indium tin oxide transparent current spreading layer surface on top of the light emitting diode(LED)chips was coated with nanoholes array,with an increase by more than 40%in the optical output power.The excellent ability of nanopatterning a non-planar substrate could potentially lead innovate design and development of high performance device based on discretely-supported NIL.展开更多
Protein adsorption onto polymer surfaces is a very complex and ubiquitous phenomenon whose integrated process impacts essential applications in our daily lives such as food packaging materials,health devices,diagnosti...Protein adsorption onto polymer surfaces is a very complex and ubiquitous phenomenon whose integrated process impacts essential applications in our daily lives such as food packaging materials,health devices,diagnostic tools,and medical products.Increasingly,novel polymer materials with greater chemical intricacy and reduced dimensionality are used for various applications involving adsorbed proteins on their surfaces.Hence,the nature of protein-surface interactions to consider is becoming much more complicated than before.A large body of literature exists for protein adsorption.However,most of these investigations have focused on collectively measured,ensemble-averaged protein behaviors that occur on macroscale and chemically unvarying polymer surfaces instead of direct measurements at the single protein or sub-protein level.In addition,interrogations of protein-polymer adsorption boundaries in these studies were typically carried out by indirect methods,whose insights may not be suitably applied for explaining individual protein adsorption processes occurring onto nanostructured,chemically varying polymer surfaces.Therefore,an important gap in our knowledge still exists that needs to be systematically addressed via direct measurement means at the single protein and sub-protein level.Such efforts will require multifaceted experimental and theoretical approaches that can probe multilength scales of protein adsorption,while encompassing both single proteins and their collective ensemble behaviors at the length scale spanning from the nanoscopic all the way to the macroscopic scale.In this review,key research achievements in nanoscale protein adsorption to date will be summarized.Specifically,protein adsorption studies involving polymer surfaces with their defining feature dimensions and associated chemical partitions comparable to the size of individual proteins will be discussed in detail.In this regard,recent works bridging the crucial knowledge gap in protein adsorption will be highlighted.New findings of intriguing protein surface assembly behaviors and adsorption kinetics unique to nanoscale polymer templates will be covered.Single protein and sub-protein level approaches to reveal unique nanoscale protein-polymer surface interactions and protein surface assembly characteristics will be also emphasized.Potential advantages of these research endeavors in laying out fundamentally guided design principles for practical product development will then be discussed.Lastly,important research areas still needed to further narrow the knowledge gap in nanoscale protein adsorption will be identified.展开更多
This paper presents a novel technique to fabricate metallic nanowires in selective areas on a Si substrate.Thermoplastic drawing of viscous metallic glass from cavities etched in Si can produce metallic nanowires.The ...This paper presents a novel technique to fabricate metallic nanowires in selective areas on a Si substrate.Thermoplastic drawing of viscous metallic glass from cavities etched in Si can produce metallic nanowires.The length and diameter of nanowires can be controlled by adjusting the drawing conditions without changing the Si mold.A thin metal shadow mask is stacked above the Si mold during thermoplastic drawing to fabricate the nanowires only in specific locations.The mask restricts the flow of metallic glass to predefined shapes on the mask,resulting in the formation of nanowires in selected areas on Si.An Al foil-based mask made by a benchtop vinyl cutter is used to demonstrate the proof-of-concept.Even a simple Al foil mask enables the positioning of metallic nanowires in selective areas as small as 200μm on Si.The precision of the vinyl cutter limits the smallest dimensions of the patterned areas,which can be further improved by using laser-fabricated stencil masks.Results show that a single row of metallic glass nanowires can be patterned on Si using selective thermoplastic drawing.Controllable positioning of metallic nanowires on substrates can enable new applications and characterization techniques for nanostructures.展开更多
We present measurements of the in situ, microscopic architecture of a self- assembled bilayer at the interface between a regularly nanopatterned surface and an aqueous sub-phase using neutron reflectometry. The substr...We present measurements of the in situ, microscopic architecture of a self- assembled bilayer at the interface between a regularly nanopatterned surface and an aqueous sub-phase using neutron reflectometry. The substrate is patterned with a rectangular array of nanoscale holes. Because of the high quality of the pattern, using neutron reflectometry, we are able to map the surface-normal density distribution of the patterned silicon, the penetration of water into the pattern, and the distribution of a deposited film inside and outside of the etched holes. In this stud; 1,2-dilauroyl-sn-glycero-3-phosphocholine （DLPC） single bilayers were deposited on the hydrophilic patterned surface. For bilayers deposited either by vesicle fusion （VF） or by the Langmuir-Schaefer （L-S） technique, the most consistent model found to fit the data shows that the lipids form bilayer coatings on top of the substrate as well as the bottoms of the holes in an essentially conformal fashion. However, while there is a single bilayer on the unetched silicon surface, the lipids coating the bottoms of the holes form a complex bimodal structure consistent with a rough surface produced by the etching process. This study provides insight into film transfer both outside and inside regular nanopatterned features.展开更多
Nanofabrication of two-dimensional materials through mechanical machining is normally influenced by not only process parameters such as load and velocity but also intrinsic properties such as strength and thickness.He...Nanofabrication of two-dimensional materials through mechanical machining is normally influenced by not only process parameters such as load and velocity but also intrinsic properties such as strength and thickness.Herein,we examined the effects of graphene oxide(GO)film thickness on nanofabrication on the plane surfaces and at the step edges using scanning probe microscope lithography.The material removal of GO initiates at the load above a critical value,which strongly depends on film thickness and locations.With the increase in film thickness,the critical load decreases monotonically on the plane surfaces but increases gradually at the step edges.Further,the critical load for the GO monolayer at the step edges is at least 25 times lower than that on the plane surfaces,and the gap decreases to around 3 times when GO thickness increases to four layers.Then,mechanical nanofabrication initiating from the GO step edge allows producing various nanopatterns under extremely low loads around 1 nN.Finally,the GO nanostructures are deoxidized by annealing at 800°C in high-purity argon to restore their highly functionalized conjugated structures,which are supported by X-ray diffraction and Raman characterizations.This work provides a novel approach to fabricating graphene-like nanostructures by deoxidizing GO after nanofabrication,which holds significant potential for applications in graphene-based devices.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.51375381,51575427 and 51675422)the 2015 Overall Planning Innovation Project Foundation of Shaanxi Province(Grant No.2015KTCQ01-36)
文摘Nanoparticles monolayer formation by spin coating is considered to be a simple, fast and inexpensive nanopatteming technique However, the parameters that govern the overall growth process in this technique are not completely quantified and techniques for the controlled and continuous growth of close packed monolayer particle arrays without defects need to be developed. In this paper, an ordered particle array formation process is analyzed theoretically, employing material flux balance and parti- cle-subjected forces balance, based on the film thickness model of spin coating and evaporation rate law. A series of experi- ments were conducted using silica particle suspensions with various particle volume fractions and different spin speeds. The results show that the spin speed should match the particle volume fraction to meet the requirements of material flux and particles movement in order to obtain a close packed monolayer film. The formation mechanism of fabrication defects involving particle agglomeration and uncontrollable voids were analyzed qualitatively based on crystal growth theory, and validation experiments were performed. The formation of highly uniform close-packed monolayer films was demonstrated and the condi- tion requirements for achieving monolayer nanoparticles array with good quality presented.
基金supported by Creative Materials Discovery Program through the National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT(No.2020M3D1A1110522).
文摘Three-dimensional(3D)nanoarchitectures have offered unprecedented material performances in diverse applications like energy storages,catalysts,electronic,mechanical,and photonic devices.These outstanding performances are attributed to unusual material properties at the nanoscale,enormous surface areas,a geometrical uniqueness,and comparable feature sizes with optical wavelengths.For the practical use of the unusual nanoscale properties,there have been developments for macroscale fabrications of the 3D nanoarchitectures with process areas over centimeter scales.Among the many fabrication methods for 3D structures at the nanoscale,proximity-field nanopatterning(PnP)is one of the promising techniques that generates 3D optical holographic images and transforms them into material structures through a lithographic process.Using conformal and transparent phase masks as a key factor,the PnP process has advantages in terms of stability,uniformity,and reproducibility for 3D nanostructures with periods from 300 nm to several micrometers.Other merits of realizing precise 3D features with sub-100 nm and rapid processes are attributed to the interference of coherent light diffracted by phase masks.In this review,to report the overall progress of PnP from 2003,we present a comprehensive understanding of PnP,including its brief history,the fundamental principles,symmetry control of 3D nanoarchitectures,material issues for the phase masks,and the process area expansion to the wafer-scale for the target applications.Finally,technical challenges and prospects are discussed for further development and practical applications of the PnP technique.
基金supported by the Welch Foundation grant E-1498NSF CAREER Award (CTS-0349228 to CC)+1 种基金grant DMR-0706627NIH R21 HD058985
文摘Functionalization of silicon substrate surfaces with a stable monolayer for resisting non-specific adsorption of proteins has attracted great interest,since it is directly relevant to the development of miniature,silicon-based biosensors and implantable microdevices,such as silicon-neuron interfaces.This brief review summarizes our contribution to the development of robust monolayers grown by surface hydrosilylation on atomically flat,hydrogen-terminated silicon surfaces.The review also outlines our strategy and progress on the fabrication of single molecule patterns on such monolayer platforms.
基金the EPSRCDTA and the Institute of Materials and Processes,School of Engineering at the University of Edinburgh.
文摘The morphology of linear polybutadiene physisorbed on freshly cleaved mica from a dilute polymer solution is investigated through atomic force microscopy.A fine-structure study shows that the monolayer morphology in air(after rapid solvent evaporation)depends strongly on the molecular weight(Mw)of the linear polymer,the adsorbed amount,and the conformation adopted by the adsorbed polymer chains under good solvent conditions.The dependence of the observed polymer structure on Mw is most significant for samples with high surface density,where the intermolecular interactions among the adsorbed polymers are important.For high surface density,the adsorbed polymers tend to aggregate and minimize unfavorable contacts with air for all of the different Mw samples,leading to an isotropic structural pattern.These structural phenomena with increasing surface density are explained on the basis of the intermolecular interactions of the adsorbed polymers under good solvent conditions,and after the abrupt solvent evaporation corresponding to poor solvent conditions.The experimental observations are further discussed using the results obtained from molecular dynamics simulations of a simple coarse-grained model.
基金supported by the“Human Resources Program in Energy Technology”of the Korea Institute of Energy Technology Evaluation and Planning(KETEP),which received financial resources from the Ministry of Trade,Industry&Energy,Republic of Korea(No.20204010600470)the Korea Evaluation Institute of Industrial Technology(KEIT)and the Ministry of Trade,Industry&Energy(MOTIE)of the Republic of Korea(No.20018608)Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(No.2022R1I1A1A01064236)
文摘To unlock the full potential of PSCs,machine learning(ML)was implemented in this research to predict the optimal combination of mesoporous-titanium dioxide(mp-TiO_(2))and weight percentage(wt%)of phenyl-C_(61)-butyric acid methyl ester(PCBM),along with the current density(J_(sc)),open-circuit voltage(V_(oc)),fill factor(ff),and energy conversion efficiency(ECE).Then,the combination that yielded the highest predicted ECE was selected as a reference to fabricate PCBM-PSCs with nanopatterned TiO_(2)layer.Subsequently,the PCBM-PSCs with nanopatterned TiO_(2)layers were fabricated and characterized to further understand the effects of nanopatterning depth and wt%of PCBM on PSCs.Experimentally,the highest ECE of 17.338%is achieved at 127 nm nanopatterning depth and 0.10 wt%of PCBM,where the J_(sc),V_(oc),and ff are 22.877 mA cm^(-2),0.963 V,and 0.787,respectively.The measured J_(sc),V_(oc),ff,and ECE values show consistencies with the ML prediction.Hence,these findings not only revealed the potential of ML to be used as a preliminary investigation to navigate the research of PSCs but also highlighted that nanopatterning depth has a significant impact on J_(sc),and the incorporation of PCBM on perovskite layer influenced the V_(oc)and ff,which further boosted the performance of PSCs.
文摘A method is presented for nano-patterning a diffraction grating on human hair with a focused ion beam. Strands of brown hair are patterned with hyperbolas and Archimedean spirals whose pitches range from 540 nm to 1040 nm. Exposure of the hair strands to white light at various incident angles demonstrates that light of varying wavelengths is diffracted by the diffraction gratings. The diffraction causes the brown strands of hair to reflect light from the entire range of visible light.
基金supported by the National Natural Science Foundation of China(Nos.51273048 and 51203025)Natural Science Foundation of Guangdong Province(No.S2012040007725)
文摘In this paper, microphase behavior of an ABC triblock copolymer, polystyrene-block-poly（2-vinylpyridine）-block- poly（ethylene oxide）, namely PS-b-P2VP-b-PEO, was systematically studied during spin-coating and solvent vapor annealing based on various parameters, including the types of the solvent, spin speed and thickness. The morphological features and the microdomain location of the different blocks were characterized by atomic force microscope （AFM） and high resolution transmission electron microscopy （HRTEM）. With increasing thickness, the order-order transition from nanopores array to the pattern of nanostripes was observed due to microdomain coarsening. These processes of pattern transformation were based on the selectivity of toluene for different blocks and on the contact time between solvent molecules and the three blocks. This work provides different templates for preparation of gold nanoparticle array on silicon wafer, which can be adopted as an active surface-enhanced Raman scattering （SERS） substrate for poly（3-hexylthiophene） （P3HT）.
基金supported by the National Natural Science Foundation of China(Grant Nos.12075191,12388101,and 12241201)the Fundamental Research Funds for the Central Universities(Grant No.D5000230120)the Natural Science Basic Research Program of Shaanxi Province(Grant No.2023-JC-YB-541).
文摘The development of nanoelectronics and nanotechnologies has been boosted significantly by the emergence of 2D materials because of their atomic thickness and peculiar properties,and developing a universal,precise patterning technology for single-layer 2D materials is critical for assembling nanodevices.Demonstrated here is a nanomachining technique using electrical breakdown by an AFM tip to fabricate nanopores,nanostrips,and other nanostructures on demand.This can be achieved by voltage scanning or applying a constant voltage while moving the tip.By measuring the electrical current,the formation process on single-layer materials was shown quantitatively.The present results provide evidence of successful pattern fabrication on single-layer MoS2,boron nitride,and graphene,although further confirmation is still needed.The proposed method holds promise as a general nanomachining technology for the future.
基金supported by the National Natural Science Foundation of China(No.20473057)Shanghai Nanotechnology Promotion Center(No.0352nm094,No.0452nm088).
文摘A novel two-dimensional nanopattemed TiO2 thin film has been synthesized through the interaction between cationic Gemini surfactant molecules and the prepared TiO2 colloid nanoparticles with average diameters of 8 nm by controlling the surface pressure of the monolayer. TEM photographs from the formed Gemini-TiO2 composite monolayer confirm that the prepared TiO2 film is of a branch nanopattern.
基金financial support from the National Nat-ural Science Foundation of China(Nos.52071028 and 52003028)the Beijing Nova Program(2022 Beijing Nova Program Cross Coop-eration Program No.20220484178).
文摘Bacterial adhesion is a critical process in many fields,such as implant infections,microbiologically influenced corrosion and bioelectricity generation in microbial fuel cells.During bacterial adhesion,the contact area between the attached bacteria and the patterned surface plays an important role.In this study,different surface topographies and treatments were employed to simulate three circumstances with different contact areas.A nanostripe structure with a period of 576.9 nm and a height of 203.5 nm was fabricated on pure titanium by femtosecond laser ablation.Bacteria in liquid attached to the peaks of the nanostripe structure and were stretched on the two adjacent nanostripes.Compared with the polished surface,the contact area between bacteria and the nanostripe surface was reduced to 50%,resulting in a reduction(about 50%)in the coverage rate of attached bacteria.In addition,the nanostripe surface was a hydrophobic surface with a water contact angle(WCA)of 112.1°,and the surface potential of the nanostripe surface was higher than that of the polished surface.However,the surface potential and wettability of the nanostripe surface played a minor role in the bacterial adhesion due to the reduced contact area.Upon drying,the attached bacteria on the nanostripe surface sank into the valley region and the contact area was about 40%larger than that on the polished surface.The lateral strength of bacterial adhesion on nanostripe surfaces was higher than that on polished surfaces,due to the larger contact area.Upon applying a lateral force of 10.0 nN,the percentage of bacteria remaining on the nanostripe surface(31.1%)was higher than that on the polished surface(11.9%).Hence,the bacterial adhesion on the nanopatterned surface was mainly determined by the contact area.The in-depth exploration of the relation between bacterial adhesion on the nanopatterned surface and the contact area enables the rational surface designs of biomaterials to regulate bacterial adhesion.
基金supported by the International Cooperation Fund of the Science and Technology Commission of Shanghai Municipality(22520711900)National Natural Science Foundation of China(52273125,52173031)+2 种基金the Fundamental Research Funds for the Central Universities(2232024D-01)the Basic Research Project of the Science and Technology Commission of Shanghai Municipality(21JC1400100)the Oriental Talent Plan(Leading Talent Program,no.152).
文摘As a well-known natural protein biomaterial,silk fibroin(SF)has shown broad application prospects in typical biomedical fields.However,the mostly used SF from Bombyx mori silkworm lacks specific cell adhesion sites and other bioactive peptide sequences,and there is still significant room for further improvement of their biological functions.Therefore,it is crucial to develop a facile and effective modification strategy for this widely researched biomaterial.In this study,the SF electrospun scaffold has been chosen as a typical SF biomaterial,and air plasma etching has been adopted as a facile nanopattern modification strategy to promote its biological functions.Results demonstrated that the plasma etching could feasibly and effectively create nano-island-like patterns on the complex surface of SF scaffolds,and the detailed nanopattern features could be easily regulated by adjusting the etching time.In addition,the mesenchymal stem cell responses have illustrated that the nanopattern modification could significantly regulate corresponding cell behaviors.Compared with the non-etched scaffold,the 10min-etched scaffolds(10E scaffold)significantly promoted stem cell proliferation and osteogenic differentiation.Moreover,10E scaffold has also been confirmed to effectively accelerate vascularization and ectopic osteogenesis in vivo using a rat subcutaneous implantation model.However,the mentioned promoting effects would be weakened or even counteracted with the increase of etching time.In conclusion,this facile modification strategy demonstrated great application potential for promoting cell proliferation and differentiation.Thus,it provided useful guidance to develop excellent SF-based scaffolds suitable for bone and other tissue engineering.
基金supported by the National Natural Science Foundation of China(Nos.52122507,52350411,and 12002289)the National Key R&D Program of China-Young Scientist Program(No.2023YFB3405500)+1 种基金The Independent Project of State Key Laboratory of Rail Transit Vehicle System(No.2023TPL-T04)Seong H.Kim was supported by the National Science Foundation of the USA(No.CMMI-1912199).
文摘The atomic edge structure of graphene governs its unique electronic properties with applications in nanoscale electronics and optoelectronics.To fully realize its potential,it is critical to develop a precision etching process producing graphene edges along desired directions.Here,we present a novel approach utilizing scanning probe lithography(SPL)facilitated by a mechanochemical atomic attrition process.This technique enables the fabrication of nanopatterns in single-layer graphene from graphene edges,precisely along the crystallographic orientation of zigzag(ZZ)and armchair(AC)edges,without inducing mechanical damage to the surrounding area.Density functional theory(DFT)calculations revealed that the dissociation of CC bonds by the SPL probe is mediated by the formation of interfacial bridge bonds between the graphene edge and the reactive silica surface.This SPL-based mechanochemical etching method enables the construction of various nanodevice structures with specific edge orientations,which allows the exploitation of their electronic properties.
基金financed by the National Key R&D Program of China(No.2017YFB1102900)the Natural Science Foundation of China(No.51805422)+1 种基金the China Postdoctoral Science Foundation(No.2019M653592)the Basic Research Program of Natural Science of Shaanxi Province of China(No.2019JLM-5).
文摘Non-planar morphology is a common feature of devices applied in various physical fields,such as light or fluid,which pose a great challenge for surface nano-patterning to improve their performance.The present study proposes a discretely-supported nanoimprint.lithography(NIL)technique to fabricate nanostructures on the extremely non-planar surface,namely high-spatial-frequency stepped surface.The designed discretely imprinting template implanted a discretely-supported intermediate buffer layer made of sparse pillars arrays.This allowed the simultaneous generation of air-cushion-like buffer and reliable support to the thin structured layer in the template.The resulting low bending stiffness and distributed concentrated load of the template jointly overcome the contact difficulty with a stepped surface,and enable the template to encase the stepped protrusion as tight as possible.Based on the proposed discretely-supported NIL,nanostructures were fabricated on the luminous interface of light emitting diodes chips that covered with micrometer step electrodes pad.About 96%of the utilized indium tin oxide transparent current spreading layer surface on top of the light emitting diode(LED)chips was coated with nanoholes array,with an increase by more than 40%in the optical output power.The excellent ability of nanopatterning a non-planar substrate could potentially lead innovate design and development of high performance device based on discretely-supported NIL.
基金D.H.C.,T.X,and J.T.acknowledge financial support on this work by the National Science Foundation(NSF Award Nos.CHE1404658,CHE1903857)from the Macromolecular,Supramolecular and Nanochemistry Program under the Division of Chemistry.J.H.acknowledges the NSF support from the Independent Research/Development(IR/D)program while serving at the National Science Foundation.
文摘Protein adsorption onto polymer surfaces is a very complex and ubiquitous phenomenon whose integrated process impacts essential applications in our daily lives such as food packaging materials,health devices,diagnostic tools,and medical products.Increasingly,novel polymer materials with greater chemical intricacy and reduced dimensionality are used for various applications involving adsorbed proteins on their surfaces.Hence,the nature of protein-surface interactions to consider is becoming much more complicated than before.A large body of literature exists for protein adsorption.However,most of these investigations have focused on collectively measured,ensemble-averaged protein behaviors that occur on macroscale and chemically unvarying polymer surfaces instead of direct measurements at the single protein or sub-protein level.In addition,interrogations of protein-polymer adsorption boundaries in these studies were typically carried out by indirect methods,whose insights may not be suitably applied for explaining individual protein adsorption processes occurring onto nanostructured,chemically varying polymer surfaces.Therefore,an important gap in our knowledge still exists that needs to be systematically addressed via direct measurement means at the single protein and sub-protein level.Such efforts will require multifaceted experimental and theoretical approaches that can probe multilength scales of protein adsorption,while encompassing both single proteins and their collective ensemble behaviors at the length scale spanning from the nanoscopic all the way to the macroscopic scale.In this review,key research achievements in nanoscale protein adsorption to date will be summarized.Specifically,protein adsorption studies involving polymer surfaces with their defining feature dimensions and associated chemical partitions comparable to the size of individual proteins will be discussed in detail.In this regard,recent works bridging the crucial knowledge gap in protein adsorption will be highlighted.New findings of intriguing protein surface assembly behaviors and adsorption kinetics unique to nanoscale polymer templates will be covered.Single protein and sub-protein level approaches to reveal unique nanoscale protein-polymer surface interactions and protein surface assembly characteristics will be also emphasized.Potential advantages of these research endeavors in laying out fundamentally guided design principles for practical product development will then be discussed.Lastly,important research areas still needed to further narrow the knowledge gap in nanoscale protein adsorption will be identified.
基金The authors would like to thank the financial support from National Science Foundation(NSF)through CMMI CAREER Award#1921435.
文摘This paper presents a novel technique to fabricate metallic nanowires in selective areas on a Si substrate.Thermoplastic drawing of viscous metallic glass from cavities etched in Si can produce metallic nanowires.The length and diameter of nanowires can be controlled by adjusting the drawing conditions without changing the Si mold.A thin metal shadow mask is stacked above the Si mold during thermoplastic drawing to fabricate the nanowires only in specific locations.The mask restricts the flow of metallic glass to predefined shapes on the mask,resulting in the formation of nanowires in selected areas on Si.An Al foil-based mask made by a benchtop vinyl cutter is used to demonstrate the proof-of-concept.Even a simple Al foil mask enables the positioning of metallic nanowires in selective areas as small as 200μm on Si.The precision of the vinyl cutter limits the smallest dimensions of the patterned areas,which can be further improved by using laser-fabricated stencil masks.Results show that a single row of metallic glass nanowires can be patterned on Si using selective thermoplastic drawing.Controllable positioning of metallic nanowires on substrates can enable new applications and characterization techniques for nanostructures.
文摘We present measurements of the in situ, microscopic architecture of a self- assembled bilayer at the interface between a regularly nanopatterned surface and an aqueous sub-phase using neutron reflectometry. The substrate is patterned with a rectangular array of nanoscale holes. Because of the high quality of the pattern, using neutron reflectometry, we are able to map the surface-normal density distribution of the patterned silicon, the penetration of water into the pattern, and the distribution of a deposited film inside and outside of the etched holes. In this stud; 1,2-dilauroyl-sn-glycero-3-phosphocholine （DLPC） single bilayers were deposited on the hydrophilic patterned surface. For bilayers deposited either by vesicle fusion （VF） or by the Langmuir-Schaefer （L-S） technique, the most consistent model found to fit the data shows that the lipids form bilayer coatings on top of the substrate as well as the bottoms of the holes in an essentially conformal fashion. However, while there is a single bilayer on the unetched silicon surface, the lipids coating the bottoms of the holes form a complex bimodal structure consistent with a rough surface produced by the etching process. This study provides insight into film transfer both outside and inside regular nanopatterned features.
基金supported by the National Natural Science Foundation of China(Nos.52350411,52122507 and 52235004)Sichuan Science and Technology Program(2023NSFSC1988 and 2023YFSY0004)the Fundamental Research Funds for the Central University(No.2682021ZTPY095).
文摘Nanofabrication of two-dimensional materials through mechanical machining is normally influenced by not only process parameters such as load and velocity but also intrinsic properties such as strength and thickness.Herein,we examined the effects of graphene oxide(GO)film thickness on nanofabrication on the plane surfaces and at the step edges using scanning probe microscope lithography.The material removal of GO initiates at the load above a critical value,which strongly depends on film thickness and locations.With the increase in film thickness,the critical load decreases monotonically on the plane surfaces but increases gradually at the step edges.Further,the critical load for the GO monolayer at the step edges is at least 25 times lower than that on the plane surfaces,and the gap decreases to around 3 times when GO thickness increases to four layers.Then,mechanical nanofabrication initiating from the GO step edge allows producing various nanopatterns under extremely low loads around 1 nN.Finally,the GO nanostructures are deoxidized by annealing at 800°C in high-purity argon to restore their highly functionalized conjugated structures,which are supported by X-ray diffraction and Raman characterizations.This work provides a novel approach to fabricating graphene-like nanostructures by deoxidizing GO after nanofabrication,which holds significant potential for applications in graphene-based devices.
