The photodegradation of organic pollutants using metal oxide-based catalysts has drawn great attention as an effective method for wastewater treatment. In this study, zinc oxide nanoparticles (ZnO NPs) and zinc oxide/copper oxide nanocomposites (ZnO/CuO NCs) were fabricated using the leaf extract of Croton macrostachyus as a nontoxic, natural reducing and stabilizing agent. The synthesized samples were characterized by employing X-ray diffraction, microscopic, spectroscopic, and electrochemical methods. The results confirmed the successful synthesis of ZnO NPs and ZnO/CuO NCs with well-defined crystalline structures and morphologies. The prepared samples were tested for the photodegradation of methylene blue (MB) dye under visible light irradiation. Compared to ZnO NPs, ZnO/CuO NCs showed greatly improved photocatalytic performances, particularly with the sample prepared with the 20 mol % Cu precursor (97.02%). The enhancement could be related to the formed p-n heterojunction, which can suppress the recombination of charge carriers and extend the photoresponsive range. A theoretical study of the photocatalytic activity of ZnO/CuO NCs against MB dye degradation was also conducted by using COMSOL Multiphysics software. The results of the simulation are in reasonable agreement with those of the experiment. This study contributes to the development of sustainable and effective photocatalytic materials that are suitable for application in environmental remediation, particularly in the treatment of wastewater.

Plasmonic molecules, which are geometrically well-defined plasmonic metal nanoparticle clusters, have attracted significant attention due to their enhancement of light–matter interactions owing to a stronger electric field enhancement than that by single particles. High-resolution lithography techniques provide precise positioning of plasmonic nanoparticles, but their fabrication costs are excessively high. In this study, we propose a lithography-free, self-assembly fabrication method, termed the dual-dewetting process, which allows the control of the size and density of gold nanoparticles. This process involves depositing a gold thin film on a substrate and inducing dewetting through thermal annealing, followed by a second deposition and annealing. The method achieves a uniform distribution of particle size and density, along with increased particle density, across a 6-inch wafer. The superiority of the method is confirmed by a 30-fold increase in the signal intensity of surface-enhanced Raman scattering following the additional dewetting with an 8 nm film, compared to single dewetting alone. Our findings indicate that the dual-dewetting method provides a simple and efficient approach to enable a variety of plasmonic applications through efficient plasmonic molecule large-area fabrication.

Sunhwa Gu, Damun Heo, Vanna Chrismas Silalahi, Hojae Lee, and Jong-Min Lee. Applied Science and Convergence Technology 2025;34:87-92. https://doi.org/10.5757/ASCT.2025.34.3.87

Bacteriophages demonstrate a remarkable ability to adhere to host surfaces, thus improving their chances of reproduction. These viral entities demonstrate extreme interface properties through their highly specific and periodic peptide receptors, surpassing any manmade surface in terms of variability and adhesiveness. This intriguing quality has led to investigations into biohybrid nanostructures, wherein bacteriophages are combined with inorganic substances. Among them, cesium lead halide (CsPbI₃) perovskite quantum dots (PQDs) are promising emissive materials, with their optical characteristics being vital for the advancement of light-emitting and optoelectronic apparatuses. In this study, we explored the integration of M13 bacteriophages (phages) with CsPbI₃ PQDs. Our observations indicated that the photoluminescence of CsPbI₃ + M13 phage was amplified 7.7-fold compared to pure CsPbI₃, the lifetime of the quantum dots extended from 40.47 ns to 53.32 ns and enhanced the stability. Simulations and experimental results both demonstrate the significant role of M13 bacteriophages in achieving enhanced optical properties for PQDs. These findings confirm the significant contribution of M13 phages to enhancing the optical attributes in PQDs, laying the groundwork for innovative optoelectronic applications.