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The Influence of Laser Ablation Parameters on the Holes Structure of Laser Manufactured Graphene Paper Microsieves
摘要： The graphene paper microsieves can be applied in the ?ltration of biological ?uids or separation of solid particles from exploitation ?uids. To produce graphene paper microsieves for speci?c applications, good control over fabrication should be achieved. In this study, a laser ablation method using a picosecond laser was applied to fabricate graphene paper microsieves. Holes in the microsieves were drilled using pulsed laser radiation with a pulse energy from 5 to 100 μJ, a duration of 60 ps, a wavelength of 355 nm, and a repetition rate of 1 kHz. The impact method was applied using 10 to 100 pulses to drill one hole. To produce holes of a proper diameter which could separate biological particles of a certain size (≥10 μm), optimum parameters of graphene paper laser ablation were de?ned using the MATLAB software taking into account laser pulse energy, repetition rate, and a desired hole diameter. A series of structural tests were carried out to determine the quality of an edge and a hole shape. Experimental results and Laguerre–Gauss calculations in MATLAB were then compared to perform the analysis of the distribution of di?raction fringes. Optimum experimental parameters were determined for which good susceptibility of the graphene paper to laser processing was observed.
关键词： laser manufacturing,graphene paper,picosecond laser,graphene paper microsieves,laser ablation
更新于2025-09-23 15:19:57
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Variable densification of reduced graphene oxide foam into multifunctional high-performance graphene paper
摘要： Super-flexible, electrically and thermally conductive graphene-based papers are in great demand in the fields of electronics and supercapacitors. However, the applications of graphene-based papers are limited either by their brittleness, small scale, or by their unsatisfactory thermal conductivity. Conventionally, such papers are fabricated by vacuum-assisted filtration, direct evaporation, electrospray coating, or wet spinning. Here we propose a novel strategy, namely, direct densification of reduced graphene oxide foam, to fabricate large-scale multifunctional graphene papers. The graphene paper density could be adjusted by applying different loads. The densities of the graphene papers varied from 0.32 g cm?3 to 1.85 g cm?3. The thermal conductivity, tensile stress, electrical conductivity and electromagnetic interface shielding effectiveness increased with an increase in the density of the graphene paper. When the density of the graphene paper reached 1.85 g cm?3, the tensile stress was up to 50.4 MPa with strain of 4%, the thermal conductivity was 1103 W m?1 K?1 at room temperature and there was high electrical conductivity of 1.1 × 10? S m?1, as well as an electromagnetic interference (EMI) shielding effectiveness of 77.2 dB. Our new strategy is very promising in terms of controlling the thickness, density, and size of graphene paper.
关键词： graphene paper,densification,EMI shielding,electrical conductivity,thermal conductivity
更新于2025-09-19 17:15:36
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Laser and thermal dewetting of gold layer onto graphene paper for non-enzymatic electrochemical detection of glucose and fructose
摘要： Electrochemical non-enzymatic detections of glucose and fructose were based on gold nanoparticles (AuNPs) onto graphene paper. Electrodes based on AuNPs have been obtained inducing dewetting, by thermal (furnace) or by laser, of sputter deposited 8 nm-thick Au layer onto graphene paper. The electrodes were characterized by Scanning Electron Microscopy, Micro Raman Spectroscopy, X-ray Diffraction, Rutherford back-scattering Spectroscopy and Cyclic Voltammetry. The main difference exhibited by thermal and laser dewetting processes lies in the size and shape of the resulting gold nanoparticles. Laser dewetting originates smaller particles than that obtained by thermal dewetting. The particles are almost spherical and mainly localized onto graphene nanoplatelets. The size of AuNPs is in the ranges 10–150 nm. Electrodes obtained by thermal process present gold nanostructures characterized by faceted AuNPs. Typical sizes are in the range of 20–40 and 200–400 nm. The electrocatalytic activity toward glucose and fructose oxidation in alkaline phosphate buffer solution are presented and discussed. Glucose was detected at a potential of 0.17 V (laser dewetting) or 0.19 V (thermal dewetting) vs SCE, which corresponds to the intense peak of two electrons oxidation. Fructose was detected at potential of 0.4 V vs SCE. Sensitivity up to 1240 μA mM?1 cm?2 for glucose detection was obtained. The resulting analytical performances for glucose and fructose detection are very promising since comparable to the actual state of art for nanostructured gold electrodes which are, however, produced by complex multi-steps wet processes and/or enzymes.
关键词： Glucose,Gold nanoparticles,Graphene paper,Fructose electrochemical detection
更新于2025-09-12 10:27:22