Surface-Enhanced Raman Spectroscopy via Hybridization of Block Copolymer Nanostructure and Graphene Oxide

Abstract

From past to present, a demand for various tools and their substrates for effective detection in biosensors or cell monitoring has been intensified. Among many methods, Raman spectroscopy has its strength in simple and rapid procedure. However, Raman spectroscopy shows poor detection limit on extremely low concentrated probe solution, requiring the research on intensifying the Raman signal. To overcome this shortcoming, surface-enhanced Raman spectroscopy (SERS) through surface modification has been extensively studied. Block copolymer (BCP) nanolithography, a bottom-up technique, is an adequate tools to fabricate a uniform array of subsequent metal nanoparticles (NPs). The BCP nanolithography has become one of the most important tools to generate numerous nanogaps, or plasmonic hot spots, between nanoaprticles owing to the strength mentioned above. However, a trade-off relationship between narrowing the gap size to get stronger enhancement and locating probe molecules at the hot spots proposed a demand for some novel techniques that helps probe molecules to penetrate into narrow hot spots. In this paper, the author proposed an idea of introducing π-π interaction to help probe molecules to locate at hot spots based on the fact that most probe molecules have π conjugation in their molecular structure. Since graphene oxide (GO) is a 2-D material and contains numerous π conjugations at the same time, there can be various enhancing behaviors with GO. The author fabricated Au@GO@AuNPs to enhance the Raman signal and checked the uniformity.