Ni and O co-modified MoS2 as universal SERS substrate for the detection of different kinds of substances

Surface-enhanced Raman scattering (SERS) has attracted extensive attention as an ultrasensitive detec-tion method. However, the poor biocompatibility and expensive synthesis cost of noble metal SERS sub-strates have become non-negligible factors that limit the development of SERS technology. Metal chalcogenide semiconductors as an alternative to noble metal SERS substrates can avoid these disadvan-tages, but the enhancement effect is lower than that of noble metal substrates. Here, we report a method to co-modify MoS2 by Ni and O, which improves the carrier concentration and mobility of MoS2. The SERS effect of the modified MoS2 is comparable to that of noble metals. We found that the improved SERS per-formance of MoS2 can be attributed to the following two factors: strong interfacial dipole-dipole inter-action and efficient charge transfer effect. During the doping process, the incorporation of Ni and O enhances the polarity and carrier concentration of MoS2, enhances the interfacial interaction of MoS2, and provides a basis for charge transfer. During the annealing process, the introduction of O atoms into the S defects reduces the internal defects of doped MoS2, improves the carrier mobility, and promotes the efficient charge transfer effect of MoS2. The final modified MoS2 as a SERS substrate realizes low- concentration detection of bilirubin, cytochrome C, and trichlorfon. This provides promising guidance for the practical inspection of metal chalcogenide semiconductor substrates.(c) 2022 Elsevier Inc. All rights reserved.

Automated summary

Surface-enhanced Raman scattering (SERS) is widely studied as an ultrasensitive detection method, but the poor biocompatibility and high synthesis cost of noble metal SERS substrates limit its development. Metal chalcogenide semiconductors have emerged as an alternative, but with lower enhancement effect. In this study, we improved MoS2 by co-modifying it with Ni and O, which enhanced the carrier concentration and mobility of MoS2. The SERS effect of the modified MoS2 was comparable to that of noble metals, and it enabled the low-concentration detection of various substances.