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Surface-enhanced Raman scattering (SERS) is a promising, sensitive, and label-free molecule detection scheme. However, uniformity and reproducibility of signal enhancement have remained elusive, making quantitative evaluation difficult. In this work, we propose a simple fabrication approach to quantitative SERS sensors that satisfies all the sought-after characteristics: a gold hole-sphere nanogap SERS substrate that is uniform, reproducible, sensitive, large, and cost-effective. Here, we achieve a sensing uniformity of 4.2% averaged over 4 points throughout the entire 6-in. substrate and a SERS enhancement of 4.6 × 108. Our approach provides for gap control in the vertical direction, thus granting very precise control with subnanometer accuracy and the statistical distribution of nanospheres in plane. This combination enables a remarkably uniform and reproducible SERS sensitivity over the entire substrate. The SERS spectra from DNA bases are also measured and their corresponding peaks are well defined down to 10 pM concentration. The proposed approach should be a key to quantitative SERS. [ABSTRACT FROM AUTHOR]

Ultrasensitive nanomechanical instruments, including the atomic force microscope (AFM)1-4 and optical and magnetic tweezers5-8, have helped shed new light on the complex mechanical environments of biological processes. However, it is difficult to scale down the size of these instruments due to their feedback mechanisms9, which, if overcome, would enable high-density nanomechanical probing inside materials. A variety of molecular force probes including mechanophores10, quantum dots11, fluorescent pairs12,13 and molecular rotors14-16 have been designed to measure intracellular stresses; however, fluorescence-based techniques can have short operating times due to photo-instability and it is still challenging to quantify the forces with high spatial and mechanical resolution. Here, we develop a compact nanofibre optic force transducer (NOFT) that utilizes strong near-field plasmon-dielectric interactions to measure local forces with a sensitivity of

Here, highly transparent nanocomposite films with an adjustable refractive index were fabricated through stable dispersion of ZrO2 (n = 2.16) nanoparticles (NPs) subjected to surface modification with SiO2 (n = 1.46) in polydimethylsiloxane (PDMS) (n = 1.42) using the Stöber method. ZrO2 NPs (13.7 nm) were synthesized using conventional hydrothermal synthesis, and their surface modification with SiO2 (ZrO2@SiO2 NPs) was controlled by varying the reaction time (3–54 h). The surface modification of the NPs was characterized using Fourier-transform infrared spectroscopy, dynamic light scattering, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and ellipsometry. The surface modification was monitored, and the effective layer thickness of SiO2 varied from 0.1 nm to 4.2 nm. The effective refractive index of the ZrO2@SiO2 NPs at λ = 633 nm was gradually reduced from 2.16 to 1.63. The 100 nm nanocomposite film was prepared by spin-coating the dispersion of ZrO2@SiO2 NPs in PDMS on the coverslip. The nanocomposite film prepared using ZrO2@SiO2 NPs with a reaction time of 18 h (ZrO2@SiO2-18h-PDMS) exhibited excellent optical transparency (Taverage = 91.1%), close to the transparency of the coverslip (Taverage = 91.4%) in the visible range, and an adjustable refractive index (n = 1.42–1.60) as the NP content in the film increased from 0 to 50.0 wt%. [ABSTRACT FROM AUTHOR]

Incorporating noble‐metal plasmonic nanoparticles (NPs) enhances the optoelectronic properties of perovskite solar cells (PSCs) but at a higher cost. In this work, the overlooked potential of refractory plasmonic materials is highlighted as a cost‐effective alternative additive in PSC research. This investigation aims to stimulate interest in this area by showcasing the theoretical and practical impacts of TiN plasmonic NPs when integrated into PSCs. TiN plasmonic NPs present a cost‐effective yet underexplored option. This study explores the impact of TiN NPs on PSCs through theoretical and experimental approaches. Finite‐difference time‐domain (FDTD) optical simulations and empirical data indicate that TiN NPs increase absorption and reduce reflectance in PSCs, driven by surface plasmon resonance and the significant growth of perovskite grains from 450 to 1400 nm. These NPs also regulate the perovskite crystallization rate by adsorbing DMF/DMSO, fostering larger grain formation. Improved band alignment and decreased trap states enhance charge transport and diminish non‐radiative recombination losses. As a result, PSC efficiency with optimal TiN NP concentration increased from 19.07% to 21.37%. Additionally, TiN‐enhanced PSCs display better stability, retaining 98.1% of their original PCE after 31 days under ambient conditions. [ABSTRACT FROM AUTHOR]

A newly developed nanopatterned broadband antireflective (AR) coating was fabricated on the front side of a glass/indium tin oxide/perovskite solar cell (PSC) by depositing a single interference layer onto a two-dimensional (2D)-patterned moth-eye-like nanostructure. The optimized developed AR nanostructure was simulated in a finite-difference time domain analysis. To realize the simulated developed AR nanostructure, we controlled the SiO 2 moth-eye structure with various diameters and heights and a MgF 2 single layer with varying thicknesses by sequentially performing nanosphere lithography, reactive ion etching, and electron-beam evaporation. Optimization of the developed AR nanostructure, which has a 100 nm-thick MgF 2 film coated onto the SiO 2 moth-eye-like nanostructure (diameter 165 nm and height 400 nm), minimizes the reflection loss throughout the visible range. As a result, the short-circuit current density ( J SC ) of the newly AR-coated PSC increases by 11.80%, while the open-circuit voltage ( V OC ) remains nearly constant. Therefore, the power conversion efficiency of the newly developed AR-decorated PSC increases by 12.50%, from 18.21% for a control sample to 20.48% for the optimum AR-coated sample. These results indicate that the newly developed MgF 2 /SiO 2 AR nanostructure can provide an advanced platform technology that reduces the Fresnel loss and therefore increases the possibility of the commercialization of glass-based PSCs.