Uniform Nanostructures Research Articles

The formation of uniform straw-like β-FeOOH nanostructures with superior catalytic performance for the degradation of Rhodamine B

In this work, uniform straw-like akaganeite (β-FeOOH) nanostructures with superior catalytic performance were successfully prepared via a facile hydrothermal method. The as-prepared uniform straw-like β-FeOOH nanostructures were characterized by various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Visible (UV-vis) spectroscopy, UV-vis diffused reflection spectra (UV-vis DRS), and X-ray photoelectron spectroscopy (XPS). The optical property of β-FeOOH was investigated and the catalytic activity of β-FeOOH was also systematically evaluated in a Fenton process for the degradation of Rhodamine B (RhB). Based on the experimental results and analysis, it could be concluded that the as-prepared β-FeOOH nanostructures exhibited wide absorption wavelength range which was approximately 200–680 nm. The degradation efficiency of RhB reached 90% and the color of RhB solutions transformed from fresh pink to colorless after 9 h.

Topographically designed hybrid nanostructures via nanotransfer printing and block copolymer self-assembly.

Nanotransfer printing (nTP) has attracted much attention due to its high pattern resolution, simple process, and low processing cost for useful nanofabrication. Here, we introduce a thermally assisted nTP (T-nTP) process for the effective fabrication of various periodic three-dimensional (3D) nanosheets, such as concavo-convex lines, spine lines, square domes, and complex multi-line patterns. The T-nTP method allows continuous nanoscale 3D patterns with functionality to be transferred onto both rigid and flexible substrates by heat without any collapse of uniform convex nanostructures with nanochannels. We also show the pattern formation of multi-layered hybrid structures consisting of two or more materials by T-nTP. Furthermore, the formation of silicon oxide nanodots (0D) within a printed metallic nanowave structure (3D) can be achieved by the combined method of T-nTP and the self-assembly of poly(styrene-b-dimethylsiloxane) (PS-b-PDMS) block copolymers. Moreover, we demonstrate how to obtain well-defined oxide-metal hybrid nanostructures (0D-in-3D) through the spontaneous accommodation of PDMS spheres in the confined spaces of an Au-wave nanotemplate. This approach is applicable during the nanofabrication of various high-resolution devices with complex geometrical nanopatterns.

Inch-Scale Ball-in-Bowl Plasmonic Nanostructure Arrays for Polarization-Independent Second-Harmonic Generation.

Second-harmonic generation (SHG) in plasmonic nanostructures has been investigated for decades due to their wide applications in photonic circuit, quantum optics and biosensing. Development of large-scale, uniform, and efficient plasmonic nanostructure system with tunable modes is desirable for their feasible utilizations. Herein, we design an efficient inch-scale SHG source by a solution-processed method instead of traditional high-cost processes. By assembling the gold nanoparticles with the porous anodic alumina templates, multiresonance in both visible and near-infrared regions can be achieved in hexagonal plasmonic nanostructure arrays, which provide strong electric field enhancement at the gap region. Polarization-independence SHG radiation has been realized owing to the in-plane isotropic characteristic of assembled unit. The tilt-angle dependent and angle-resolved measurement showed that wide-angle nonlinear response is achieved in our device because of the gap geometry of ball-in-bowl nanostructure with nonlinear emission electric dipoles distributed on the concave surface, which makes it competitive in practical applications. Our progress not only makes it possible to produce uniform inch-scale nonlinear arrays through low-cost solution process; and also advances the understanding of the SHG radiation in plasmonic nanostructures.

Integrated EC-SERS Chip with Uniform Nanostructured EC-SERS Active Working Electrode for Rapid Detection of Uric Acid.

Toxemia of pregnancy is a very dangerous disease for pregnant women. The mortality rate of toxemia of pregnancy is close to 10% to 15%. Early detection of pregnancy toxemia is to monitoring uric acid concentration in urine. The current mainstream method for detecting uric acid requires an enzyme (urate oxidase), which needs to be stored in a low-temperature environment, and the method requires complex chemical steps, which takes a longer time and more samples. In this study, we propose an integrated miniature three-electrode electrochemical surface-enhanced Raman spectroscopy chip (EC-SERS chip) suitable for rapid EC-SERS detection applications. The integrated microfluidic reservoir on the chip makes it easy to use, which is very suitable for rapid detection applications. The SERS active working electrode for the proposed integrated EC-SERS chip is a nanocone array polycarbonate (PC) substrate decorated with an evenly distributed and tightly packed array of gold nanospheres. It showed good uniformity and can be easily reproduced. The integrated EC-SERS chip is very small compared to the traditional electrochemical cell, which reduces the sample volume required for the testing. In addition, the chip is for one-time use only. It eliminates the need to clean electrochemical cells for reuse, thereby reducing the possibility of contamination and inaccurate detection. Various low-concentration Rhodamine 6G (R6G) solutions were tested to verify the performance of the developed EC-SERS chip. Experimental results showed that the proposed EC-SERS chip has a strong enhancement factor of up to 8.5 × 106 and a very good EC-SERS uniformity (the relative standard deviation of EC-SERS intensity is as low as 1.41%). The EC-SERS chip developed has been further tested for the detection of uric acid in synthetic urine. The results showed that the EC-SERS signal intensity has a highly linear relationship with the logarithm of the uric acid concentration in synthetic urine, which indicates that the developed EC-SERS chip is suitable for the quantitative detection of uric acid in synthetic urine. Therefore, the developed EC-SERS chip is very promising to be used in routine and early diagnosis of pregnancy toxemia and may be used in many other medical tests, food safety, and biotechnology applications.

Self-Directed Self-Assembly of 3D Tailored Block Copolymer Nanostructures.

Directed self-assembly (DSA) of block copolymers (BCPs) provides a powerful tool to fabricate various 2D nanostructures. However, it still remains a challenge to extend DSA to make uniform and complex 3D nanostructures through BCP self-assembly. In this paper, we introduce a method to fabricate various nanostructures in 3D and test it using simulations. In particular, we employ dissipative particle dynamics (DPD) simulation to demonstrate that uniform multilayer nanostructures can be achieved by alternating the stacking of two "orthogonal" BCPs films, AB copolymer film and AC copolymer film, without the need to cross-link or etch any of the components. The assembly of a new layer occurs on top of the previous bottom layer, and thus the structural information from the substrate is propagated upward in the film, a process we refer to as self-directed self-assembly (SDSA). If this process is repeated many times, one can have tailored multilayer nanostructures. Furthermore, the natural (bulk) phases of the block copolymers in each layer do not need to be the same, so one can achieve complex 3D assemblies that are not possible with a single-phase 3D system. This method in conjunction with grapho (or chemo) epitaxy is able to evolve a surface pattern into a 3D nanostructure. Here we show several examples of nanostructures fabricated by this process, which include aligned cylinders, spheres on top of cylinders, and orthogonal nanomeshes. Our work should be useful for creating complex 3D nanostructures using self-assembly.

Different Modes of Deformation of Soft Triangular Honeycombs at the Sub-5nm Scale.

Patterning on the sub-5nm length scale is a contemporary challenge for further miniaturization of microelectronic circuits. Here, the first soft self-assembled triangular patterns are reported showing transitions between regular and two different kinds of isosceles (acute and obtuse angled) triangles on this length scale, formed by liquid crystalline honeycombs of polyphilic block molecules involving a fluorinated oligo(para-phenylene ethynylene) core. The type of formed triangular pattern depends on the degree and position of fluorination and on temperature. They are the first soft honeycombs combining tilted and nontilted organizations in a uniform nanostructure, where the tilted molecules in only one or two sides of the triangular prismatic cells dominate the shape and the size of the morphology.

Achieving Purely-Organic Room-Temperature Aqueous Phosphorescence via a Two-Component Macromolecular Self-Assembly Strategy.

Manipulation of supramolecular behaviors and aggregation states represents an important topic in devising intriguing photofunctional systems. Here we report a two-component macromolecular self-assembly strategy for achieving aqueous room-temperature phosphorescence (RTP) in purely organic systems. Amphiphilic triblock copolymers are used to modulate the self-assembly of planar RTP molecules in aqueous solution, leading to the formation of sheet-like RTP objects with well-defined morphology, uniform crystalline nanostructures and excellent aqueous dispersity. In contrast, the addition of the planar RTP molecules into aqueous medium only leads to precipitation and quenching of RTP properties. Powder X-ray diffraction and single-crystal X-ray diffraction studies reveal that the amphiphilic triblock copolymers can assist supramolecular columnar packing of the planar RTP molecules where multiple non-covalent interactions stabilize the triplet excited states. Interestingly, it is found that luminescent signals of the sheet-like RTP objects can be extracted from strong fluorescent environments by phosphorescence mode and emission lifetime measurement.

(Invited) In-Situ Monitoring of Luminescence and Oxidation of Porous Silicon in Liquid Electrolytes with Photoconduction

Silicon can be made porous by electrochemical (anodization) etching in hydrofluoric acid (HF). This is the most controlled and used technique for the preparation of porous silicon (PSi). The porous structure depends on several factors, such as silicon resistivity and type, as well as HF concentration and anodization current. In the case of lightly-doped p-type silicon, uniform sponge-like nano-structures can be formed. This type of PSi layer is characterized in particular by its porosity and thickness. PSi is interesting for a variety of properties, some related to quantum confinement in its nanostructure, such as luminescence and porosity-dependent optical absorption, refractive index and surface area. It has potential applications in optoelectronics, photovoltaics, medicine and sensing.Recently, we have made use of the particular behavior of PSi photoconduction in an electrolyte: when PSi is illuminated, only the charge carriers photogenerated in the Si substrate contribute to the measured photocurrent, and thus, the photocurrent is a measure of the optical transmission of PSi. This behavior allowed us to measure the PSi optical constants for various optical wavelengths and PSi porosities in situ in HF and thus for the most pristine form of PSi and avoiding all the problems related to the drying and handling of high-porosity PSi free-standing layers1. We have also used the photoconduction to study the chemical etching of PSi in HF. We could monitor the etching as it proceeded and developed a model that allowed us to derive the HF-dependent etching rates and the absorption coefficient of PSi for a large range of porosities not explored so far, from as-prepared to close to 100% porosity (PSi fully dissolved)2. Finally, we have also made use of the photoconduction technique to understand the photoetching of PSi in HF by monochromatic light.3 In this paper, we use the photoconduction technique to monitor the evolution of different types of oxidation processes of PSi in acid solutions. The photoluminescence is also acquired in-situ. The different oxidation processes studied here are: chemical oxidation in different solutions, photo-assisted oxidation by monochromatic light, and electrochemical oxidation. The photoconduction technique allowed for a good understanding of the oxidation progress and the evolution of the oxidation rates over reaction time. Moreover, the monitoring of the photoluminescence, coupled to the in-situ derivation of the optical absorption provides a way to optimize the reaction time for achieving maximum luminescence efficiency.An example is shown in Fig. 1. It shows the photocurrent (at 405 nm illumination)-time plot for a 5-μm thick PSi layer of initial porosity 68% oxidized in H2SO4 0.5M. The photocurrent, signature of the optical absorption, increases as the oxidation progresses since the formed oxide is transparent at the 405 nm light. Here, the oxidation does not proceed up to full PSi oxidation, therefore the photocurrent does not reach full saturation. The photoluminescence was also recorded and reached its maximum at ~ 65 h (blue star on the plot). 1 B. Gelloz, H. Fuwa, and L. H. Jin, Ecs Journal of Solid State Science and Technology 5 (3), P190 (2016). 2 B. Gelloz, K. Ichimura, H. Fuwa, E. Kondoh, and L. Jin, Ecs Journal of Solid State Science and Technology 6 (1), R1 (2017). 3 B. Gelloz, H. Fuwa, E. Kondoh, and L. Jin, Ecs Journal of Solid State Science and Technology 7 (12), P730 (2018). Figure 1

Designing of Ag2S Nanowires from a Single‐Source Molecular Precursor [(PPh3)2AgS2P(OiPr)2] for Hydrogen Evolution Reaction

AbstractIn the present study, we illustrated a facile fabrication of large scale ultra‐thin silver sulfide (Ag2S) nanowires (NWs) and its promising application in hydrogen evolution reaction (HER). Ultra‐thin and highly uniform Ag2S nanostructures were fabricated from single‐source precursor [(PPh3)2AgS2P(OiPr)2], and characterized by utilizing various structural and imaging techniques. Large‐scale monodispersed ultra‐thin single‐crystalline Ag2S nanowires were generated via n‐decylboronic acid induced thermal decomposition of the single precursor in the presence of octadecyl amine and oleyl amine mixture under anaerobic conditions. We explored the catalytic activities of Ag2S nanowires for HER which showed an overpotential of−88 mV at 10 mA/cm2 and the corresponding Tafel slope was found to be 52 mV dec−1.

Nanostructures with good photoelectric properties fabricated by femtosecond laser and secondary sputtering on ITO films

The fabrication of uniform and intact nanostructures on semiconductor thin films is an essential process to alleviate the many electronic defects that are usually present. In this study, nanostructures with good photoelectric properties were fabricated on ITO films by direct laser irradiation and secondary sputtering. A Nd:YLF femtosecond laser system, with a wavelength of 800 nm and a repetition rate of 1 kHz based on pulse regenerative amplification, was used. Laser-induced periodic surface structures with different fluences and scan speeds were studied. With a fluence of 1.86 J cm −2 , a scan speed of 1.1 mm s −1 , a scan spacing of 4.5 μm, and a focused laser spot of 18.5 μm, a large area of uniform nanostructures with little damage are obtained under optimized parameters. The transmittance increases by up to 21%, and the sheet resistance increases more than 10 times. A definite thickness of the ITO thin film was sputtered by secondary sputtering to improve the electrical conductivity, and the heights of nanostructures can be exactly controlled. Compared with the untreated surface of ITO films, the transmittance increases by 19% and the sheet resistance decreases to less than 1.6 times with the optimal nanostructure height of 90 nm. This method to fabricate nanostructures can greatly improve the photoelectric properties without any complex processing and expensive cost, which can be greatly used in a wide area of the industry application. • Large-area LIPSSs with good photoelectric properties are obtained on ITO thin films by an accurate controllability method. • Large-area LIPSSs with little damage are obtained under optimized parameters. The transmittance increases by up to 21%. • The height of LIPSSs can be exactly controlled by the secondary sputtering, and the electrical conductivity can be improved. • The transmittance increases by 19% and the sheet resistance changes little (about 1.6 times) with the optimum LIPSSs.

Batch preparation of gold nanoparticles with highly uniform morphology and tunable plasmonic properties

The plasmonic properties of individual metallic nanostructures are of great importance for application in surface science, materials science, and nanophotonics. Herein, being facilitated with a home-made flow device and pulsed laser irradiation, we proposed a batch preparation protocol towards spherical Au nanoparticles (Au NPs) and cage shell entrapped spherical core nanoparticles (Au@cAu NPs) with highly uniform morphology and a tunable size distribution. The Fano resonance behavior exhibited by the effective interaction between spherical Au NPs and the silicon surface has great potential for the design of ultrasensitive optical sensing devices. In comparison with the spherical Au NP, the individual Au@cAu NP displayed not only a red-shifted and broadened localized surface plasmon resonance (LSPR) scattering peak, but also a higher electromagnetic field enhancement. Therefore, the Au@cAu NPs offer a better choice for plasmonic enhancement-based applications in the red and near-infrared region. In general, the current work provides a new and easy method for the large-scale preparation of gold-based uniform nanostructures, and offers an avenue to understand the interference of different plasmon modes in plasmonic systems, which has potential applications in surface science.

Ultrasensitive microfluidic electrochemical immunosensor based on electrodeposited nanoporous gold for SOX-2 determination

An ultrasensitive and portable microfluidic electrochemical immunosensor for SOX-2 cancer biomarker determination was developed. The selectivity and sensitivity of the sensor were improved by modifying the microfluidic channel. This was accomplished through a physical-chemical treatment to produce a hydrophilic surface, with an increased surface to volume/ratio, where the anti-SOX-2 antibodies can be covalently immobilized. A sputtered gold electrode was used as detector and its surface was activated by using a dynamic hydrogen bubble template method. As a result, a gold nanoporous structure (NPAu) with outstanding properties, like high specific surface area, large pore volume, uniform nanostructure, good conductivity, and excellent electrochemical activity was obtained.SOX-2 present in the sample was bound to the anti-SOX-2 immobilized in the microfluidic channel, and then was labeled with a second antibody marked with horseradish peroxidase (HRP-anti-SOX-2) like a sandwich immunoassay. Finally, an H2O2 + catechol solution was added, and the enzymatic product (quinone) was reduced on the NPAu electrode at +0.1 V (vs. Ag). The current obtained was directly proportional to the SOX-2 concentration in the sample. The detection limit achieved was 30 pg mL−1, and the coefficient of variation was less than 4.75%. Therefore, the microfluidic electrochemical immunosensor is a suitable clinical device for in situ SOX-2 determination in real samples.

Periodic Microstructures Fabricated by Laser Interference with Subsequent Etching

Periodic nanostructures have wide applications in micro-optics, bionics, and optoelectronics. Here, a laser interference with subsequent etching technology is proposed to fabricate uniform periodic nanostructures with controllable morphologies and smooth surfaces on hard materials. One-dimensional microgratings with controllable periods (1, 2, and 3 μm) and heights, from dozens to hundreds of nanometers, and high surface smoothness are realized on GaAs by the method. The surface roughness of the periodic microstructures is significantly reduced from 120 nm to 40 nm with a subsequent inductively coupled plasma (ICP) etching. By using laser interference with angle-multiplexed exposures, two-dimensional square- and hexagonal-patterned microstructures are realized on the surface of GaAs. Compared with samples without etching, the diffraction efficiency can be significantly enhanced for samples with dry etching, due to the improvement of surface quality.

Uniform Mesoporous CoCO3 Nanospindles on Graphite Nanosheets for Highly Efficient Lithium Storage

AbstractAs anodes for lithium‐ion batteries, CoCO3 has a much higher specific capacity than graphite and can meet the urgent demands of electric vehicles and portable electronics. However, reported CoCO3 anodes are of micrometer‐sized morphology (0.4–10 µm) that severely limits long‐term and rate performances (in particular >2.0 A g−1) due to intrinsically low conductivity and high volume expansion. Mesoporous materials have uniform open mesopores to offer sufficient solid/electrolyte contact, rapid Li+ transport, and large pore volume. However, it is still challenging to prepare uniform mesoporous CoCO3 nanostructures. This work reports a urea–NH4HCO3–ethylene glycol (EG) solvothermal system to fabricate uniform mesoporous CoCO3 nanospindles and concurrently composite with multilayered graphite nanosheets. The obtained mesoporous CoCO3 has a specific surface area of 143.7 m2 g−1, 12.4 times that of commercial CoCO3. The preparation mechanism is studied in‐depth, where urea, NH4HCO3, EG, and crystal water play essential and respective roles. The synergistic effect of the mesopore and graphite nanosheets facilitates long‐term cycling stability (1465 mAh g−1 after 450 cycles at 200 mA g−1 with 101.1% capacity retention) and high‐rate performance (1033 mAh g−1 at 2.0 A g−1). The essential roles of mesopores and graphite nanosheets in boosting the kinetic change are investigated.

Facile Fabrication of Highly Uniform Tellurium Nanorods for Self‐Powered Flexible Optoelectronics

AbstractNanoscale tellurium (Te) materials are promising for advanced optoelectronics owing to their many intriguing properties. However, the facile fabrication of highly uniform 1D Te nanostructures has been a challenge. Herein, an electrochemical exfoliation method is developed to prepare uniform Te nanorod (NRs), which can form stable and high concentration suspension in organic solvents. The morphology of the Te NRs can be well tuned by the electrochemical exfoliation condition. Flexible photodetectors based on Te NRs show an excellent responsivity of 6.1 A W−1. The detectivity achieves 1.2 × 1011 Jones, which is the highest among Te‐based photodetectors. Moreover, self‐powered photodetectors based on Te NRs are successfully fabricated, which exhibits a responsivity of 3 µA W−1. This new method paves the way for the applications of Te NRs in self‐powered flexible optoelectronics.

Improvement of saw damage removal to fabricate uniform black silicon nanostructure on large-area multi-crystalline silicon wafers

The first step of preparing black silicon solar cells by Ag metal-assisted chemical etching method (Ag-MACE) is to remove the saw damage layer on the surface of diamond wire saw multi-crystalline silicon wafers. The usual way to do this is with a hot solution of KOH. However, the surface of silicon wafers processed in large quantities in this way will have many white spots and stains. These white spots and stains are the saw damage layer that have not been removed cleanly. They affect not only the appearance of the solar cells, but, most importantly, the subsequent uniform deposition of silver nanoparticles on the silicon wafers. An additive containing cyclodextrin and lignosulfonate has been developed in this work. This can remove effectively the saw damage layer and eliminate the white spots and stains on the surface of the silicon wafer. So as to improve the appearance of silicon wafer and make silver nanoparticles uniformly deposited on the surface of the whole silicon wafer. This additive has been proved to be very useful in improving solar cell efficiency, raising parallel resistance and reducing reverse leakage current and so on. Eventually, mass-produced solar cells made by Ag-MACE with this additive have a maximum efficiency of 19.49%, which is 0.46 percent absolutely higher than that without the additive.

Quasi-3D Plasmonic Nanowell Array for Molecular Enrichment and SERS-Based Detection.

We report on a quasi-three-dimensional (3D) plasmonic nanowell array with high structural uniformity for molecular detection. The quasi-3D plasmonic nanowell array was composed of periodic hexagonal Au nanowells whose surface is densely covered with gold nanoparticles (Au NPs), separated by an ultrathin dielectric interlayer. The uniform array of the Au nanowells was fabricated by nanoimprint lithography and deposition of Au thin film. A self-assembled monolayer (SAM) of perfluorodecanethiol (PFDT) was coated on the Au surface, on which Au was further deposited. Interestingly, the PFDT-coated Au nanowells were fully covered with Au NPs with an ultra-high density of 375 μm−2 rather than a smooth film due to the anti-wetting property of the low-energy surface. The plasmonic nanogaps formed among the high-density Au NPs led to a strong near-field enhancement via coupled localized surface plasmon resonance and produced a uniform surface-enhanced Raman spectroscopy (SERS) response with a small relative standard deviation of 5.3%. Importantly, the highly uniform nanostructure, featured by the nanoimprint lithography and 3D growth of densely-packed Au NPs, minimizes the spatial variation of Raman intensity, potentially providing quantitative analysis. Moreover, analyte molecules were highly concentrated and selectively deposited in nanowells when a water droplet containing the analyte was evaporated on the plasmonic substrate. The analyte formed a relatively thick overcoat in the nanowells near the triple line due to the coffee-ring effects. Combining 3D plasmonic nanowell substrates with molecular enrichments, highly sensitive detection of lactic acid was demonstrated. Given its combination of high sensitivity and signal uniformity, the quasi-3D plasmonic nanowell substrate is expected to provide a superior molecular detection platform for biosensing applications.

High rhodamine B and methyl orange removal performance of graphene oxide/carbon nanotube nanostructures

Novel three-dimensional (3D) graphene oxides (GOs) and carbon nanotubes (CNTs) nanostructures have been prepared via a facile freeze-drying method, aiming to obtain the uniform dispersed carbon-based nanostructures with high surface area. The subsequent N2 adsorption and desorption isotherms have confirmed the high BET surface area feature of the obtained products. Especially the GNT 1–5 sample, whose weight ratio of GOs: CNTs is 1:5, have showed a surface area of 257.6 m2/g. The organic dye removal experiments have demonstrated that the GNTs nanostructures display the ability to adsorb both cationic (Rhodamine B, RhB) and anionic (Methyl orange, MO) dyes in aqueous solution, and the maximum adsorption capacity can reach over 248.48 mg/g with RhB and 66.96 mg/g with MO. This study also reveals that the adsorption kinetics of both dyes follow the pseudo-second-order model, while the equilibrium during adsorption could be explained well by the Langmuir and Freundlich adsorption isotherm theory. Thus, the as-prepared 3D GNT nanostructures have shown great potential as a adsorbent to remove organic dyes in waste-water treatment.

Nanostructured Germanium with >99% Absorption at 300–1600 nm Wavelengths

AbstractNear‐infrared (NIR) sensors find numerous applications within various industry fields, including optical communications and medical diagnostics. However, the state‐of‐the‐art NIR sensors made of germanium (Ge) suffer from rather poor response, largely due to high reflection from the illuminated device surface. This work demonstrates a method to increase the sensitivity of Ge sensors by implementing nanostructures to the wafer surfaces. The absorbance of nanostructured Ge wafers is measured to be >99% in the whole UV–vis–NIR spectrum up to 1600 nm wavelength, which is a significant improvement to bare Ge wafers that reach absorption of only 63% in maximum. The process is shown to be capable of producing uniform nanostructures covering full 100 mm diameter substrates as well as wafers with etch mask openings of different sizes and shapes, which demonstrates its applicability to complementary metal oxide semiconductor (CMOS) sensor manufacturing. The results imply that nanostructured Ge has potential to revolutionize the sensitivity of Ge‐based sensors.

Controllable Subtractive Nanoimprint Lithography for Precisely Fabricating Paclitaxel-Loaded PLGA Nanocylinders to Enhance Anticancer Efficacy.

Nanoimprint lithography presents a new strategy for preparing uniform nanostructures with predefined sizes and shapes and has the potential for developing nanosized drug delivery systems. However, the current nanoimprint lithography is a type of an additive nanofabrication method that has limited potential due to its restricted template-dependent innate character. Herein, we have developed a novel subtractive UV-nanoimprint lithography (sUNL) for the scalable fabrication of PLGA nanostructures with variable sizes for the first time. sUNL can not only fabricate a variety of predefined nanostructures by simply utilizing different nanoimprint molds but also precisely prepare scalable nanocylinders with different length to diameter ratios. Particularly, sUNL can fabricate paclitaxel-loaded PLGA nanocylinders (PTX-PLGA NCs) with high drug-loading rate of 40% and long storage stability over a year. We demonstrate that PTX-PLGA NCs target clathrin- and caveolae-mediated cell transport pathways and display increased cellular uptake, in comparison to traditional PTX-loaded PLGA nanoparticles (PTX-PLGA NPs), leading to enhanced anticancer effects. Therefore, sUNL represents a promising nanofabrication method for efficiently developing predefined drug delivery systems.