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With high sensitivity at single molecule level, surface-enhanced Raman scattering (SERS) is considered as an ultrasensitive optical detection technology with broad application prospects in lots of fields. However, the complicated fabrication and unaffordable price of SERS substrate are still a roadblock on the way to be widely used in industry. In this work, the SERS spectra on a commercial laser engraved Teflon (PTFE) film with engraved microarray are investigated. The wettability of film surface modulated by laser engraving make the microarray have the ability to decrease the contact area on film surface while water evaporation. The SEM image of the engraved area points out the micro/nanostructures generated engraving process is crucial to its superhydrophobic property. The probing molecules (i.e., methylene blue and rhodamine6G) were utilized to investigate with the limit of detection (1 × 10−14 M). Furthermore, the biomolecule (bovine serum albumin) was used to demonstrate its benefits in biological applications. The measured intensities of Raman spectra on this PTFE with laser engraved microarray demonstrate its potential value for a SERS substrate. Our work on this simple, cheap SERS substrate with high sensitivity has a great commercial value and plenty of application in lots of fields. Electronic supplementary material The online version of this article (10.1186/s11671-018-2658-3) contains supplementary material, which is available to authorized users.

Benefiting from the induced image charge on metal film, the light energy is confined on a film surface under metal nanoparticle dimer, which is called electromagnetic field redistribution. In this work, electromagnetic field distribution of metal nanoparticle monomer or dimer on graphene is investigated through finite-difference time-domain method. The results point out that the electromagnetic field (EM) redistribution occurs in this nanoparticle/graphene hybrid system at infrared region where light energy could also be confined on a monolayer graphene surface. Surface charge distribution was analyzed using finite element analysis, and surface-enhanced Raman spectrum (SERS) was utilized to verify this phenomenon. Furthermore, the data about dielectric nanoparticle on monolayer graphene demonstrate this EM redistribution is attributed to strong coupling between light-excited surface charge on monolayer graphene and graphene plasmon-induced image charge on dielectric nanoparticle surface. Our work extends the knowledge of monolayer graphene plasmon, which has a wide range of applications in monolayer graphene-related film. Electronic supplementary material The online version of this article (10.1186/s11671-018-2535-0) contains supplementary material, which is available to authorized users.

In this paper, we investigate the structural and electronic properties of zigzag silicene nanoribbons (ZSiNRs) with edge-chemistry modified by H, F, OH, and O, using the ab initio density functional theory method and local spin-density approximation. Three kinds of spin polarized configurations are considered: nonspin polarization (NM), ferromagnetic spin coupling for all electrons (FM), ferromagnetic ordering along each edge, and antiparallel spin orientation between the two edges (AFM). The H, F, and OH groups modified 8-ZSiNRs have the AFM ground state. The directly edge oxidized (O1) ZSiNRs yield the same energy and band structure for NM, FM, and AFM configurations, owning to the same s p 2 hybridization. And replacing the Si atoms on the two edges with O atoms (O2) yields FM ground state. The edge-chemistry-modified ZSiNRs all exhibit metallic band structures. And the modifications introduce special edge state strongly localized at the Si atoms in the edge, except for the O1 form. The modification of the zigzag edges of silicene nanoribbons is a key issue to apply the silicene into the field effect transistors (FETs) and gives more necessity to better understand the experimental findings.