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In this work, 3D periodic "grid-type" CuO/Cu2O layers were fabricated on a copper sheet using laser processing techniques, and the laser processing parameters were optimized for favorable ZnO nanowire growth. It was found that ZnO nanowires could be successfully prepared to form a CuO-Cu2O-ZnO heterojunction structure without an extra catalyst or seed layer coating, which could be attributed to the copper oxide active sites induced via laser texturing. ZnO nanowires on laser textured "grid-type" copper substrates demonstrated an effective piezocatalytic performance with different morphologies and the generation of abundant reactive oxygen species in the CuO-Cu2O-ZnO catalytic system, providing a fundamental mechanism for the degradation of organic dye in water. This simple and low-cost method could provide a useful guide for the large-scale efficient and versatile synthesis of immobilized piezoelectric catalysts. [ABSTRACT FROM AUTHOR]

Flexible vibration sensors applied to acoustic recognition have been studied for using as skin-like electronics. However, the development of vibration sensors to recognise the human voice accurately with stable frequency response, high sensitivity and flexible/conformable form factor has proved to be a major challenge. A flexible capacitive acoustic sensor made of convex array microstructured polydimethylsiloxane film has been proposed to detect the acoustic range of human beings. Performances in the voice response range, including sensitivity, detection limit and dynamic response, were explored and delivered an excellent result due to its unique air void structures. The sensor with such a dielectric layer exhibited high sensitivity (at least 2.01 kPa−1 under 1.06 Pa), wide strength range (0–833.33 kPa), low detection limit (~0.14 Pa) and good cyclic stability (>2000 cycles of different pressures). Our device is suitable for several promising voice-recognition applications, such as home automation, remote control systems and vocal healthcare. [ABSTRACT FROM AUTHOR]

Abstract: Self‐cleanable surface‐enhanced Raman scattering (SERS) spectroscopy affords a promising route toward environment‐friendly biosensors for point‐of‐care diagnostics. It is of great importance to develop recyclable SERS substrates driven by a photocatalytic decomposition process, especially in the visible range. In this work, inspired by the hedgehog‐like structures, a broadband visible‐light‐driven photocatalytic SERS platform with the CuO nanowires (NWs)/Cu2O hetero‐nanostructures as the backbone is demonstrated. Via employing the approach of nanosecond laser ablation on Cu sheet coupled with subsequent thermal oxidation, the formed hedgehog‐like, high‐density, and dual‐scale micro/nanostructures not only demonstrate enhanced broadband visible‐light‐absorption capability even extended to the near infrared range but also exhibit boosted interfacial adhesion with favorable stability. Such phenomena imply that the binary oxidized Cu composites decorated with metallic nanoparticles can serve as high‐performance SERS substrates with superior recyclability. Under the visible light illumination, the as‐fabricated ternary Ag/CuO NWs/Cu2O composites can be self‐cleaned by photocatalytic degradation of adsorbates, thus leading to recyclable SERS substrates, which can preserve more than 85% SERS activity after seven cycles' measurement. These results pave a new path to realize reusable SERS substrates in the applications of remote and resource‐limited environments toward next‐generation green biosensors. [ABSTRACT FROM AUTHOR]