Nanosculptured tungsten oxide: High-efficiency SERS sensor for explosives tracing

• Published in: Journal of hazardous materials Vol. 476; p. 135171
• Main Authors: Shvalya, Vasyl, Olenik, Jaka, Vengust, Damjan, Zavašnik, Janez, Štrbac, Jelena, Modic, Martina, Baranov, Oleg, Cvelbar, Uroš
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 05.09.2024
• Subjects: Explosives; Nanoplasmonics; Plasma cleaning; SERS; Tungsten oxide; Tungsten oxide; Nanoplasmonics; Explosives; SERS; Plasma cleaning
• ISSN: 0304-3894; 1873-3336; 1873-3336
• DOI: 10.1016/j.jhazmat.2024.135171

The accurate and rapid identification of explosives and their toxic by-products is an important aspect of safety protocols, forensic investigations and pollution studies. Herein, surface-enhanced Raman scattering (SERS) is used to detect different explosive molecules using an improved substrate design by controllable oxidation of the tungsten surface and deposition of Au layers. The resulting furrow-like morphology formed at the intersection of the tungsten Wulff facets increases nanoroughness and improves the SERS response by over 300 % compared to the untreated surface. The substrate showed excellent reproducibility with a relative standard deviation of less than 15 % and a signal recovery of over 95 % after ultrafast Ar/O2 plasma cleanings. The detection limit for the "dried on a surface" measurement case was better than 10−8 M using the moving scanning regime and an acquisition time of 10 s, while for the "water droplets on a surface" scenario the LoD is 10−7, which is up to 2 orders of magnitude better than the UV-Vis spectroscopy method. The substrates were successfully used to classify the molecular fingerprints of HMX, Tetryl, TNB and TNT, demonstrating the efficiency of a sensor for label-free SERS screening in the practice of monitoring traces of explosives in the water medium. [Display omitted] •Controlled “micro to nano” patterning increases the sensitivity by over 300 %.•Rapid “no waste” plasma mild cleaning under 100 s for SERS sensor reuse.•Robust surface with no damage signs after cleaning with 95 % signal recovery.•A high 106 enhancement and low RSD < 15 % for reliable explosives traces sensing.