Supplementary Materialsnn9b09508_si_001

Supplementary Materialsnn9b09508_si_001. sensing in 3D. Being a proof-of-principle, we successfully determine in one experiment the layer-specific glass transition temperatures of a bilayer polymer thin film of poly(methyl methacrylate), PMMA, and poly(methyl methacrylate)/poly(methacrylic acid), P(MMA-MAA). Our work thus demonstrates a strategy for nanoplasmonic sensor design and utilization to simultaneously probe local chemical or physical processes at spatially different locations. In a wider perspective, it stimulates further development of sensors that employ multiple detection elements to generate distinct and spectrally individually addressable LSPR modes. LSPR peaks within the visible to near-infrared (NIR) spectral range (their near-fields, we also fabricated an identical metasurface with the bottom disk and cone structure but without the top disk. As shown in Figure ?Figure11d, the extinction spectrum of such a system is identical for the short wavelength range where the top disk LSPR peak is lacking. In other words, removing (or adding) the top disk from (to) the 3D structure does not alter the optical response of the bottom disk. Also, increasing the spatial separation between bottom and top disk to 100 nm only leads to the modification of the very best disk LSPR maximum (because of smaller size), whereas the response of underneath disk continues to be, for useful purpose, unchanged (Shape S1). This contrasts reported instances of combined systems, where spectral features that rely on the non-negligible coupling power and not just for the constituent antennas could Formoterol hemifumarate be noticed36,37 (discover also Shape S1 where we shorten Formoterol hemifumarate the length between your disks to 60 nm). Furthermore, FDTD simulations of an individual 3D nanostructure reproduce accurately the experimental observations and therefore further corroborate having less near-field coupling between your disks (Shape ?Shape11e). We remember that Rabbit Polyclonal to PEX3 the LSPR peak in the simulation can be broader compared to the experimental one, unlike what one expects because of the size variant in specific nanostructures in ensemble measurements. We recall how the optical response of our amorphous arrays (quasi-random with short-range purchase) Formoterol hemifumarate depends upon the single-particle response which, nevertheless, can be modified from the stochastically spread fields by additional nanoparticles.38,39 The magnitude and sign from the stochastic interference from the scattered fields using the incident one are dependant on the particle minimum center-to-center distance (see Figure S3 for our metasurface). These total bring about the reddish colored or blue change from the single-particle resonance placement, broadening or narrowing from the maximum width, and corresponding modification from the amplitude.40,41 This interaction may be the origin of most the differences between your simulated and experimental response, whereas additional factors result from utilizing a tabulated permittivity for Ag which is probable near, however, not exactly add up to, experiments aswell a geometrical difference Formoterol hemifumarate between your modeling and test. Having founded the metasurface nanoarchitecture therefore, we consider assessing Formoterol hemifumarate the Ag antennas for useful sensing applications now. As an initial step to allow this, we address the actual fact that Ag can be susceptible to oxidation by implementing among the ideas of indirect nanoplasmonic sensing,42 when a slim coating film can be put on the sensing framework to be able to protect it from the surroundings and permit software also in challenging chemical environments aswell as at high temps. Furthermore, software of such a slim layer also provides a chemically uniform surface, which is of importance in sensing applications where the interaction between the sensor surface and analyte is critical for the behavior of the latter. Here, we choose Si3N4 as the coating material due to its low permeability toward oxygen and its high temperature stability.43 Specifically, employing plasma-enhanced chemical vapor deposition (PE-CVD), we apply a conformal 10 nm thin Si3N4 coating on the entire metasurface (Figure ?Figure22a), which still preserves its distinguishable LSPR peaks (Figure S2). Open in a separate window Figure 2 Coating of the 3D metasurface and its stability. (a) False-colored SEM image of a 3D sensor plasmonic metasurface coated with a 10 nm Si3N4 layer (violet). Also shown is the to-scale schematic of the coated sensor. Scale bar is 200 nm. Wavelength-resolved temporal evolution of optical extinction of (b) uncoated and (c) Si3N4-coated 3D sensors as a function of increasing temperature up to 600 C under constant flow of 2% O2 in Ar. The dashed lines denote the spectral peak maximum, peak, of the bottom and top disks. For the uncoated sensor, the bottom and top disk LSPR peaks vanish around 500 and 550 C, respectively, due to complete oxidation. Extended 2 h exposure to 2% O2 in Ar at 600 C is also shown for the (d) uncoated and (e) coated sensors. Evidently, the Si3N4 coating excellently protects the Ag nanodisks from oxidation at extremely severe conditions even. (f,g) Space temperatures extinction spectra of the uncoated and covered metasurface, respectively, before.