Porous Tungsten Nitride: A Sensitive SERS Substrate with High Stability

In surface-enhanced Raman spectroscopy detection, the structure of the Raman scattering substrate is critical to the sensitivity and stability of the detector. In this study, W₁₈O₄₉ ultrafine nanowire bundles are used as precursors to synthesize porous tungsten nitride (WN) through a nitriding treatment. As a typical transition metal nitride (TMN), these porous WN exhibit a strong localized surface plasmon resonance effect in the visible region, with a resonance peak centered at 672 nm. Significantly, WN as a substrate for detection of typical dyes exhibit strong Raman enhancement signals. In particular, the detection sensitivity for R6G has been significantly improved, with the lowest detectable concentration reaching an impressive 1 × 10^-10 M, and the maximum enhancement factor is up to 1.62 × 10⁷. Moreover, they even can maintain the detection performance in a variety of harsh environments, showing outstanding corrosion resistance, and oxidation resistance, which is not available on traditional noble metal and semiconductor Raman substrates.