Graphene quantum dots modified W18O49 as SERS substrate for MB detection

Surface-enhanced Raman scattering (SERS) as a sensitive detection method had attracted tremendous attention. Graphene quantum dots (GQDs) were synthesized by a top–down approach, and the W 18 O 49 samples were prepared by a solvothermal method with WCl 6 as the tungsten source. The size of prepared GQDs presented a size of 10 nm and a topographic height of 1.5 nm, corresponding to 1–3 layers of graphene sheets. There were two different lattice fringes of 0.34 nm and 0.378 nm matched with the (002) and (010) lattice planes of GQDs and W 18 O 49 , respectively. After the modification of GQDs, the band gap energy of W 18 O 49 was narrowed, and the separation and electron transport capability of W 18 O 49 were improved due to the existence of GQDs. In this work, the detection sensitivity of SERS was effectively improved by chemical and electromagnetic field enhancement when W 18 O 49 /GQDs composites were used as SERS substrates. Therefore, it will be an effective way to improve the SERS performance of W 18 O 49 by modifying GQDs.