研究目的
To demonstrate an ultrafast laser-ablated hierarchically patterned silver nanoparticle/graphene oxide (AgNP/GO) hybrid surface-enhanced Raman scattering (SERS) substrate for highly sensitive and reproducible detection of an explosive marker 2,4-dinitrotoluene (2,4-DNT).
研究成果
The hierarchical laser-patterned AgNP/GO hybrid structure demonstrated remarkable enhancement in the SERS intensity even at ultralow analyte concentration, showing good stability and high sensitivity up to picomolar (pM) concentration range with a Raman intensity enhancement of ～1010 for 2,4-DNT. The generic SERS sensor thus fabricated has immense potential to be used as a portable explosive detector, owing to its sensing specificity and sensitivity.
研究不足
The technical and application constraints of the experiments include the need for precise control of laser ablation parameters to achieve uniform distribution of AgNPs and the potential for oxidation of AgNPs without GO coating.
1：Experimental Design and Method Selection
Ultrafast laser ablation in air with pulse energies of 25, 50, and 100 μJ was used to fabricate a hierarchical laser-patterned silver sheet (Ag?S). Multiple laser pulses at a wavelength of 800 nm and a pulse repetition rate of 50 fs at 1 kHz were directly focused on Ag?S to produce and deposit AgNPs onto Ag?S.
2：Sample Selection and Data Sources
An Ag sheet (Ag?S) target of 1 mm thickness was used for the multiline ablation. The surface morphology of ablated Ag?S was evaluated using atomic force microscopy, optical pro?lometry, and ?eld emission scanning electron microscopy (FESEM).
3：List of Experimental Equipment and Materials
Femtosecond laser ampli?er (Ti:sapphire, LIBRA, Coherent), Ag target (Ag?S) of 1 mm thickness, pristine graphite powder, 2,4-DNT, concentrated sulfuric acid (H2SO4), potassium permanganate (KMnO4), hydrogen peroxide (H2O2).
4：Experimental Procedures and Operational Workflow
Laser ablation experiments were performed with three different pulse energies of 25, 50, and 100 μJ. The laser pulses were scanned across Ag?S at a speed of 0.1 mm/s. GO was spin-coated onto the AgNPs produced by ultrafast ablation on Ag?S.
5：Data Analysis Methods
Selected area Raman mapping was performed to understand the intensity and size distribution of AgNPs on Ag?S. The SERS Raman intensity of Ag?S, AgNPs, and 2,4-DNT explosive marker was recorded with a Raman spectrometer.
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