Engineering SERS-active substrates: design and characterization of advanced structures

We investiga ted the crea tion of SERS-a ctive hiera rchica l substra tes ba sed on self-a ssembled na nospheres (HSNs). We demonstra te how the “hiera rchica l” a pproa ch could be systema tica lly exploited to extend the SERS hotspots into the third dimension, by enha ncing the hot-spots spa tia l density a nd intensity. The proposed hiera rchica l substra tes ta ke a dva ntage of the single la yer hexa gona l closed pa cked a rra y na nospheres (CPA). An a dditiona l la yer of upper na nospheres to obtain dense a nd intense hot spots pa ttern is employed. To predict the SERS performa nce a nd to identify the promising a rchitectures, a numerica l a na lysis is ca rried out, offering design criteria, a n overview of the opera ting mecha nisms and conditions tha t a ffect the SERS beha vior of substra tes. We fa brica ted HSNs by using a self-a ssembling a pproa ch a nd the prelimina ry results reported. The results highlight tha t HSNs ca n be used a s cost-effective SERS substra tes with better performa nce tha n simpler single-la yer CPA configura tions.