For sensitive and reproducible surface-enhanced Raman scattering (SERS)-based trace detection, a SERS platform with high concentration of homogeneously distributed hotspots is needed. Herein, we report a facile monolayer assembly of multispiked gold nanoparticles (MSGNPs) of various sizes over a large area. The assembly was achieved simply by tuning the concentration of MSGNPs in a suspension and subsequently drying it on a substrate under ambient conditions. A monolayer assembly for MSGNP sizes ranging from 150 to 640 nm has been demonstrated. The MSGNP assembly showed excellent sensitivity and uniformity of SERS-based trace detection, owing to the presence of high concentration of uniformly distributed interparticle and intraparticle hotspots. In particular, detection of 10 fM of a toxic dye, crystal violet, has been demonstrated. Moreover, ammonium nitrate, which is a commonly used material for homemade explosives, was detected at 1 μM level. The MSGNP-based SERS platforms have great potential for applications in sensitive and reliable toxin and explosive detection.

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Plasmonic interfaces are used as an alternative and highly effective light management technique for solar cells. Topdown approaches produce well-ordered and carefully designed plasmonic structures for tailor-made light management; however, they are costly, and their fabrication is time-consuming. Thus, their utilization for industrial-scale solar cells is not trivial. It has been shown that dewetting is a cost-and time-effective bottom-up approach for the fabrication of plasmonic interfaces, yet it lacks precise control of the surface coverage for optimum light management. Therefore, new strategies are actively sought. In this work, the spray coating technique is used to deposit plasmonic interfaces with polyol synthesized silver bipyramidal nanocubes onto industrial-scale monocrystalline silicon solar cells. Through a systematic study, the effect of surface coverage on cell performance is investigated, as it is essential to utilize the interface in well-controlled amounts for optimal light management. A relative increase in the photovoltaic conversion efficiency of 3.5−6.4% upon creating localized surface plasmon resonance-based plasmonic interfaces is demonstrated.

In this work, we demonstrate that a polished Si wafer surface can be converted to possess strong surface-enhanced Raman scattering (SERS) activity by spray coating of polyol synthesized colloidal silver...