Nanoporous Pt thin films were prepared by simultaneous deposition of Pt and Si and subsequent dealloying of Si out of the PtxSi1−x films. The x values were easily controlled in the range of 0.10 to 0.90 by the distances between the sample position and the target positions and by the plasma power for the targets. With a roughness factor of around 40, the nanoporous Pt films showed enough sensitivity, selectivity, and detection limit for glucose and interfering species. Multiple nanoporous Pt films with similar roughness factors were easily fabricated using this method, which showed good enough and similar performance to other reported glucose sensors, suggesting a simple and quality controlled manufacturing method for nanoporous Pt films as nonenzymatic glucose sensors.
29 November 2022 in Journal of Alloys and Compounds
Structural colors with tunable properties have several applications in the beautification of mobile devices, surface decoration, art and color filters. Herein, we propose an asymmetric F−P cavity design to systematically tune structural colors by changing the thickness of the top metal and intermediate insulator. In this study, Cu and Si3N4 were chosen as the top metal and intermediate insulator layers, respectively, various reflection colors being realized on the Cu surface. Various capping layers—that is, SiO2, polymethyl methacrylate (PMMA), and a commercially available clear coat named ProtectaClear—were used to protect the Cu surface from scratching and oxidation. PMMA coatings can protect Cu from corrosive environments without degradation of the color quality. The colors can be tuned by controlling the thickness of either the metal or intermediate insulator layers, and vivid structural colors—including orange, bright orange, red, purple, violet, light blue, green-yellow, and yellow-green—can be printed. The colors obtained can be attributed to thin-film interference.
Structural colors with tunable properties have extensive applications in surface decoration, arts, absorbers, and optical filters. Planar structures have more advantages over other forms studied to date due to their easy manufacturability. Metal‐insulator‐metal‐based structures are one of the known methods to fabricate structural colors where colors can be tuned mainly by the thickness of the intermediate lossless insulator layer. However, generating colors by MIM structure requires a thin metallic layer on top, and the top metals’ abrasiveness and/or oxidation may degrade the colors quickly. Thus, we propose a lossy dielectric layer to replace the top metallic layer as a solution to ensure the structure’s durability by preventing scratches and oxidation. Herein, CrON/Si 3 N 4 /Metal structures have been studied where theoretical investigations suggest that highly saturated colors can be generated in the lossy‐lossless dielectric structures. Experimental data validated such simulations by revealing a range of vivid colors. Furthermore, these structures can easily achieve strong light absorption (SLA) even for a thick top layer of ∼100 nm. The colors realized by these structures are appeared due to a combination of the interference effect of the asymmetric Fabry–Perot cavity structure and the absorption rate in the CrO x N
1−
x layer.
Blue-light-emitting ZnSe core (C) and ZnSe/ZnS core/shell (C/S) quantum dots (QDs) were synthesized with phosphine-free precursors by a thermal decomposition method in paraffin oil solvent and applied to QD-converted light-emitting diodes (LEDs). The optical properties of the synthesized ZnSe C and ZnSe/ZnS C/S QDs were characterized by absorption spectroscopy and photoluminescence spectroscopy. Additionally, the quantum efficiency of the QDs was investigated. Their structural properties were studied with X-ray crystallography and transmission electron microscopy. The ZnSe/ZnS C/S QDs showed deep-blue light peaking at 425 nm. The blue-light-emitting ZnSe/ZnS C/S QDs were used as color-converting materials for near-ultraviolet LED-pumped blue LEDs and combined with yellow-light-emitting Zn-Cu-In-S/ZnS C/S QDs to fabricate white LEDs. The white LEDs showed warm white light [(CIE x, CIE y) = (0.4088, 0.3987)], Tc = 3488 K, and Ra = 61.2]. The results indicate that the ZnSe/ZnS C/S QDs have good potential for white light application after further improvements to their optical properties.