Biomimetic piezoelectric mobile acoustic sensor is fabricated for exceptional accuracy of AI-based biometric authentication.

After a piezoelectric inkjet printhead jets the first droplet, the actuating membrane still vibrates, creating residual vibrations in the ink channel, which can degrade the inkjet printhead performance. For suppressing these vibrations, an optimized actuating voltage waveform with two pulses must be obtained, of which the first pulse is used for jetting and the second pulse is used to suppress the residual vibrations. In this study, the pressure history within the ink channel of a recirculating piezoelectric inkjet printhead was first acquired using lumped element modeling. Then, for suppressing residual vibrations, a bipolar voltage waveform was optimized via analysis of the tuning time ($t_{\mathrm{t}}$ ), dwell time ($t_{\mathrm{d}2}$), rising time ($t_{\mathrm{r}2}$), falling time ($t_{\mathrm{f}2}$), and voltage amplitude of the second pulse. Two voltage waveforms, Waveform 01 and Waveform 02, were optimized thereafter. In Waveform 01, $t_{\mathrm{t}}=2 \mathsf{\mu }\mathrm{s}, t_{\mathrm{d}2}=2 \mathsf{\mu }\mathrm{s}$, and $t_{\mathrm{r}2}$ and $t_{\mathrm{f}2}=1 \mathsf{\mu }\mathrm{s}$ were finalized as the optimal parameters; in the case of another waveform, the optimal parameters of $t_{\mathrm{d}2}$, $t_{\mathrm{r}2}$, and $t_{\mathrm{f}2}$ were found to be $4$, $1$, and $1 \mathsf{\mu }\mathrm{s}$, respectively. The optimal voltage amplitude of the second pulse was found to be 1/3 the amplitude of the first pulse. On the basis of our analysis, the tuning time in Waveform 01 is the most sensitive parameter, and the performance yielded is even poorer than that yielded by standard waveform, if not optimized. Therefore, the other waveform is recommended for the suppression of residual vibrations.

Bio-inspired near-sensor computing, which integrates sensing and processing functions, presents a promising strategy to enhance efficiency and reduce latency in such applications. Here, we introduce tactile sensory nerve systems with biologically realistic energy efficiency, utilizing starfish-inspired capacitive pressure sensors integrated with flexible memristors. These starfish-inspired sensors, with their high aspect ratio (~3) and stress-focusing, hourglass-shaped dielectric microstructures, enable highly sensitive tactile detection across a broad pressure range, effectively mimicking the properties of human skin. Artificial tactile sensory nerves, which integrate the capacitive sensor with a flexible memristor exhibiting synaptic plasticity, function reliably as energy-efficient near-sensor computing systems by bio-realistically transducing mechanical stimuli into transient electrical signals. The developed system operates as both an artificial nociceptor and a tactile near-sensor computing unit, with energy consumption approaching biological levels at approximately 140 pJ and 2.2 fJ, respectively. This neuro-inspired localized computing strategy offers a physical platform for advanced smart user interface applications.

Building‐integrated photovoltaics (BIPVs) have gained significant attention by promising renewable electricity without concerns of additional space, environmental damage, and maintenance problems. However, silicon‐based BIPVs generally limit aesthetic appearance due to their monotonous dark blue modules. In addition, maintaining performance is challenging because BIPV modules are easily contaminated by particulate matter, hindering practical applicability. In this study, a solution‐based process of functional nanoparticles (NPs) is employed to fabricate large‐area colored films with self‐cleaning properties. The stable and robust NPs comprising inorganic‐based fluorinated silica (F‐SiO₂) NPs and silica‐coated gold (Au@SiO₂) NPs are synthesized for self‐cleaning and aesthetic integration, respectively. The NPs are then self‐assembled into a hierarchical structure with the aid of a silicone‐based binder over a large area (1 m²) using customized convective‐assembly equipment, resulting in tunable colored hydrophobic and super‐hydrophobic surfaces. Finally, they are applied on the front glass of BIPV modules of a 3 kW solar system on a constant over 1 year, with a system energy efficiency of ≈89.5%. Moreover, the colored glass modules show excellent stability after damp heat (85 °C/85%) and accelerated weathering tests. Hence, they are expected to be utilized as a functional colored film for sustainable BIPVs.

Tactile sensation plays a crucial role in human interaction with the environment, facilitating the perception of various physical stimuli such as pressure, texture and temperature through the skin. Mimicking human tactile perception, the development of flexible tactile sensors has seen significant growth, significantly expanding their applicability in robotics, medical devices and wearable technology. This paper reviews recent advances in flexible tactile sensor technology, with a focus on the development of multifunctional sensors capable of detecting multiple types of tactile stimuli simultaneously. Unlike traditional rigid sensors, flexible tactile sensors integrate the sensitivity and elasticity of human skin, enabling them to adapt to different surfaces and detect a wider range of stimuli.

The dissipation of excessive heat in high-power light-emitting diodes (LEDs) is essential for maintaining luminous efficiency, color stability, and device lifetime. While the incorporation of thermal vias in substrates is commonly used to improve heat dissipation, increasing their number is difficult in the limited area due to fabrication constraints. In this study, we use finite element analysis to investigate the effects of thermal via configurations on LED performance, including variations in the number of vias, spacing between vias, and their misalignment relative to the LED, arising from manufacturing tolerances. We found that the reduction in LED temperature saturated beyond a certain number of vias. Moreover, heat reduction can be further enhanced by optimizing the spacing between vias under a fixed number of vias. Based on these findings, the design of via configurations can achieve both fabrication feasibility and effective heat dissipation in high-power LEDs.