Preparation and Photoelectric Properties of Patterned Ag Nanoparticles on FTO/Glass Substrate by Laser Etching and Driving Layer Strategy

An effective method based on laser etching and driving layer strategy was proposed to prepare patterned Ag nanoparticles(Ag NPs)on fluorine-doped tin oxide(FTO)/glass substrate and thus to enhance the photoelectric properties.This method successively included depositing an aluminum-doped zinc oxide(AZO)driving layer,laser etching,depositing an Ag layer,furnace annealing and laser removal.Different AZO and Ag layer thicknesses were adopted,and the surface morphology,crystal structure and photoelectric properties were investigated.An Ag NPs/FTO/glass sample without an AZO driving layer was prepared for comparison.It was found that furnace annealing of the Ag layer combined with the AZO driving layer,rather than that without the AZO driving layer,was more conducive to generating patterned Ag NPs.Using a 20-nmthick AZO layer and a 150-nm-thick Ag layer led to the formation of uniformly distributed Ag NPs being aligned along the laser-etched grooves to form a pattern.The as-obtained sample had the best comprehensive photoelectric property with an average transmittance of 79.95%,a sheet resistance of 7.11Ω/sq and the highest figure of merit of 1.50×10^(-2)Ω^(-1),confirming the feasibility of the proposed method and providing enlightenment for related researches of transparent conductive oxide-based films.

Improvement of laser damage thresholds of fused silica by ultrasonic-assisted hydrofluoric acid etching

Polished fused silica samples were etched for different durations by using hydrofluoric（HF） acid solution with HF concentrations in an ultrasonic field. Surface and subsurface polishing residues and molecular structure parameters before and after the etching process were characterized by using a fluorescence microscope and infrared（IR） spectrometer, respectively. The laser induced damage thresholds（LIDTs） of the samples were measured by using pulsed nanosecond laser with wavelength of 355 nm. The results showed that surface and subsurface polishing residues can be effectively reduced by the acid etching process, and the LIDTs of fused silica are significantly improved. The etching effects increased with the increase of the HF concentration from 5 wt.% to 40 wt.%. The amount of polishing residues decreased with the increase of the etching duration and then kept stable. Simultaneously, with the increase of the etching time, the mechanical strength and molecular structure were improved.

Fabrication of Through Micro-hole Arrays in Silicon Using Femtosecond Laser Irradiation and Selective Chemical Etching

We demonstrate a method of fabricating through micro-holes and micro-hole arrays in silicon using femtosecond laser irradiation and selective chemical etching. The micro-hole formation mechanism is identified as the chemical reaction of the femtosecond laser-induced structure change zone and hydrofluoric acid solution. The morphologies of the through micro-holes and micro-hole arrays are characterized by using scanning electronic microscopy, The effects of the pulse number on the depth and diameter of the holes are investigated. Honeycomb arrays of through micro-holes fabricated at different laser powers and pulse numbers are demonstrated.

A novel method for fabricating polydimethylsiloxane microfluidic chip master molds

We proposed a novel method of fabricating polydimethylsiloxane (PDMS) microfluidic chip polymer master molds in this paper. The method mainly includes two steps. First, a stainless steel slice was laser etched to form a metal model. Then, the organic solution of poly(methyl methacrylate) (PMMA) was casted onto the metal model to fabricate the PMMA master which subsequently would be used to fabricate PDMS chips. We systematically researched different laser parameters influencing the surface status of microchannels and obtained optimized etching parameters. We investigated and optimized the organic solution composition of PMMA while casting chip masters, and developed a method to form fine polymer masters using two different viscosity solutions to cast the model in turn, and studied the repeatable replication. Then, we investigated physical performance of this chip and evaluated the practicability by analyzing Rhodamine B. Compared with present methods, the proposed method does not need photolithography on photoresistant and chemical etching. The entire fabricating progress is simple, fast, low-cost and can be controlled easily. Only several minutes are required to make a metal model, 3 hours for a PMMA master, and one day for PDMS chips.

Fabrication of Micro/Nano-textured Titanium Alloy Implant Surface and Its Infl uence on Hydroxyapatite Coatings

We put forward a protocolcombining laser treatment and acid etching to obtain multiscale micro/nano-texture surfaces of titanium alloy implant.Firstly,the operationalparameters of the laser were optimized to obtain an optimum current.Secondly,the laser with the optimum operationalparameters was used to fabricate micro pits.Thirdly,multiple acid etching was used to clean the clinkers of micro pits and generate submicron and nanoscale structures.Finally,the bioactivity of the samples was measured in a simulated body fluid.The results showed that the micropits with a diameter of 150 μm and depth of 50 μm were built successfully with the optimized working current of 13 A.In addition,submicron and nanoscale structures,with 0.5-2 μm microgrooves and 10-20 nm nanopits,were superimposed on micro pits surface by multiple acid etching.There was thick and dense HA coating only observed on the multiscale micro/nano-textured surface compared with polished and micro-textured surface.This indicated that the multiscale micro/nano-texture surface showed better ability toward HA formation,which increased the bioactivity of implants.

One-step modification method of a superhydrophobic surface for excellent antibacterial capability

In this study,micro/nanostructures are fabricated on the surface of 3Cr13 stainless steel via laser etching,and a superhydrophobic coating with silver nanoparticles(AgNPs)is prepared by utilizing the reduction–adsorption properties of polydopamine(PDA).We investigate the effect of soaking time from the“one-step method”on the reduction of nano-Ag,surface wettability,and antibacterial properties.Scanning electron microscopy is performed to analyze the distribution of nano-Ag on the surface,whereas X-ray energy dispersive spectroscopy and X-ray photoelectron spectroscopy are used to analyze the crystal structures and chemical compositions of different surfaces.Samples deposited with PDA on their surface are soaked in a 1H,1H,2H,2H-perfluorodecyltriethoxysilane water–alcohol solution containing AgNO3 for 3 h.Subsequently,a“one-step method”is used to prepare low-adhesion superhydrophobic surfaces containing AgNPs.As immersion progresses,more AgNPs are deposited onto the surface.Compared with the polished surface,the samples prepared via the“one-step method”show significant antibacterial properties against both gram-negative Escherichia coli and gram-positive Staphylococcus aureus.The antibacterial properties of the surface improve as immersion progresses.

Comparison of Physical Isolation on Large Active Area Perovskite Solar Cells

To reduce the quadratic scaling of the series resistance(R)and sheet resistance(Rs)of the devices,physi-cal isolation of the large area devices into small pieces has been proven to be a reliable and cost-efficient patterning technique.In this paper,we got an interesting result that the physical isolation did not show obvious effct on the photovoltaic performance of perovskite solar cells(PSCs)when fixing the active area.Three different isolation types,unetched ITO,etched ITO,and laser etching whole devices,have been induced to investigate the physical isolation roles.The results show that the electrons and holes could be collected efficiently in active area for all the isolation types.The proposed mechanism illustrates that the nonradiative recombination and recombination of electrons and hole in inactive area do not influence the performance of devices.This work may open a new way for the commer-cialization of PSCs by reducing the complex process and the etching costs.

Highly sensitive torsion sensor based on triangular-prism-shaped long-period fiber gratings

We propose and investigate a compact optical fiber sensor that aims to measure the torsion in both amount and direction with high sensitivity.This sensor is configured by a triangular-prism-shaped long-period fiber grating,which is fabricated by the high frequency CO_(2) laser polished method.The unique design of the triangular-shaped structure breaks the rotational symmetry of the optical fiber and provides high sensitivity for torsion measurement.In preliminary experiments,the torsion response of the sensor achieves a good stability and linearity.The torsion sensitivity is 0.54 nm/(rad/m),which renders the proposed structure a highly sensitive torsion sensor.