Fabrication of flexible paper-based Surface-enhanced Raman scattering substrate from Au nanocubes monolayer for trace detection of crystal violet on shell

Surface-enhanced Raman scattering (SERS) substrate is the key to SERS technology and it is still a basic focus to fabricate desirable SERS substrates offering multiple advantages of strong Raman enhancement and good reproducibility and portability. A flexible paper-based SERS substrate were fabricated involving the use of Au nanocubes (NCs) monolayer. Au NCs were generated with tunable size in the range of 24 to 63 nm through seed-mediated growth method. The effect of support on SERS properties of Au NCs–assembled monolayer was systemically explored. As a result, more excellent SERS performance could be obtained by assembling Au NCs on the filter paper. Besides, the influence of Au NCs' size on SERS-enhanced effect of paper-based substrate was also investigated. Our results clearly indicated that paper-based substrate with 39 nm Au NCs possessed the optimal SERS enhancement. This SERS substrate exhibited high sensitivity with enhancement factor (EF) up to 9.75 × 10 7 and demonstrated good uniformity and time stability. Furthermore, based on this superior paper-based SERS substrate with advantage of powerful sample extraction performance, the measurement of crystal violet (CV) on shell surface were successfully carried out with detection limit down to 2.17 × 10 −7 M. And linear quantification were achieved in the range from 5 × 10 −5 to 5 × 10 −7 M. To sum up, the as-prepared SERS substrate is applicable for on-site detection and analysis of CV on various shell surfaces.