In this study, we present a novel surface-enhanced Raman scattering (SERS) substrate based on porous silicon microcavities (PSiMCs) decorated with silver nanoparticles (AgNPs) for ultra-sensitive molecule detection. This substrate utilizes a dual enhancement mechanism: the localized surface plasmon resonance (LSPR) of AgNPs and the optical resonance of the PSiMC structure, which together create intense electromagnetic hot spots and prolong photon–molecule interactions. The porous architecture provides a large surface area for uniform nanoparticle distribution and efficient analyte adsorption. The AgNP/PSiMC substrate demonstrates an impressive detection limit of 1.0 × 10⁻¹³ M for rhodamine101 and 1.0 × 10⁻¹⁰ M for methyl parathion, outperforming many previously reported SERS platforms. Furthermore, the substrate exhibits excellent signal uniformity (RSD ≈ 6.14%) and long-term stability, retaining over 50% signal intensity after 28 days. These results underscore the potential of AgNP/PSiMCs as highly efficient, reproducible, and scalable SERS platforms for trace-level chemical and environmental sensing applications.

The Po Nagar Towers (Thap Ba) complex, an iconic heritage site of Cham culture and a nationally recognized special relic, has stood in Nhatrang, Vietnam, for over a thousand years. We report here a preliminary analysis of original ancient Cham bricks from the Po Nagar Towers using a combination of appropriate characterization techniques, including X-ray fluorescence (XRF), X-ray diffraction (XRD), Raman micro-spectroscopy, thermal dilatometry, compressive strength testing, and water sorption. Mechanical properties and firing temperatures of the ancient bricks have been determined to support the discussion on the likely technology used to make them. Specifically, they were made from clay, sand, plagioclases/feldspar, and grog mixed with intentionally added carbon precursor (charcoal powder), then fired at temperatures between 800 °C and 1000 °C to form lightweight bricks with a mass density of 1.3–1.6 kg/dm³ and an open porosity of 18–25%. The ancient Cham bricks have their texture and porosity to meet the requirements of the thin rubbing joint technique in tower construction and to contribute to the carvability and durability of Cham towers. A comparison is made with the bricks for tower restoration during the 2000s.

In this paper, we report a simple yet efficient method for rapid and high-performance SERS substrate fabrication by a combination of cold plasma and laser treatment. Our analysis reveals that cold plasma pre-treatment significantly reduced surface roughness, transforming 200 nm spikes into an almost perfectly uniform surface, while enhancing the substrate’s surface energy by lowering the water contact angle from 59° to 0°, all achieved within just 30 s of 0.9-mW plasma treatment, while 15-min green-laser treatment facilitated more uniform deposition of AuNPs across the entire treated area, effectively creating the SERS substrates. The combined treatments result in enhancement of the Raman intensity (11 times) and consistency over the whole area of the SERS substrates, and their reusability (up to 10 times). The fabricated SERS substrates exhibit a significant enhancement factor of approximately 3 × 10⁸ with R6G, allowing detection down to a concentration of 10⁻¹² M. We demonstrate the application of these SERS substrates by detecting amoxicillin—an antibiotic used worldwide to treat a diversity of bacterial infections—in a dynamic expanded linear range of seven orders (from 10⁻³ to 10⁻⁹ M) with high reliability (R² = 0.98), and a detection limit of 9 × 10⁻¹⁰ M. Our approach to high-performance SERS substrate fabrication holds potential for further expansion to other metallic NPs like Ag, or magnetic NPs (Fe₃O₄).

Polydopamine (PDA) is an emerging biomimetic material that stimulates the distinctive physicochemical properties of the blue mussel byssus. In this study, we report a rapid and facile method for the decoration of gold nanoparticles (AuNPs) onto the mussel-inspired polydopamine nanospheres (PDA NSs) via cold atmospheric plasma treatment. After 10 min of plasma treatment, AuNPs with a size of 10.3 ± 2.0 nm were formed on the surface of PDA NSs. This reaction was performed without the need for any additional reducing agents, thereby eliminating the use of harsh chemicals during the process. The synthesized AuNP-decorated PDA nanohybrids (PDA-Au) exhibit effective catalytic activity for the decoloration of Rhodamine B, with a pseudo-first-order rate constant of 1.405 min⁻¹. The green synthesis approach in this work highlights the potential of plasma-assisted methods for decorating biomimetic materials with metallic nanoparticles for catalytic and environmental applications.

Ternary I-III-VI chalcopyrite-type nanocrystals (NCs) range among the most important alternative materials to Cd-based NCs. Within this materials family, AgInSe2 (AISe) presents a narrower bandgap than widely studied AgInS2 (AIS), making it more suitable for numerous applications. At present, it remains a long-standing challenge to directly synthesize high-quality AISe core and AISe/ZnS core/shell NCs in aqueous solution at atmospheric pressure. In this work, we describe their synthesis using glutathione and citric acid as dual stabilizers. First, to form AISe core NCs, the Se precursor is injected into a solution containing the Ag and In complexes at 96 °C for 20 min. In the second step, the AISe/ZnS core/shell structure is created by growing the ZnS shell on the AISe NCs surface at 90 °C for 60 min. The synthesized AISe and AISe/ZnS core/shell NCs are characterized using X-ray diffraction, transmission electron microscopy, and UV-Vis absorption and photoluminescence for optical spectroscopies. After the growth of the ZnS shell, AISe/ZnS core/shell NCs exhibit higher photostability and emit intense luminescence at a wavelength of 680 nm with an impressive quantum yield (QY) of 30 %, which represents a threefold higher than the AISe core NCs. These properties make the aqueous soluble AISe/ZnS core/shell NCs favorable candidates for lighting, displays, and biological imaging applications.