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The rapid development of electrical skin and wearable electronics raises the requirement of stretchable strain sensors. In this study, an active fiber-based strain sensor (AFSS) is fabricated by coiling a fiber-based generator around a stretchable silicone fiber. The AFSS shows the sensitive and stable performance and has the ability to detect the strain up to 25%, which is also demonstrated to detect finger motion states. It may play an essential role in future self-powered sensor system. [ABSTRACT FROM AUTHOR]

Metasurface holograms, with the capability to manipulate spatial light amplitudes and phases, are considered next-generation solutions for holographic imaging. However, conventional fabrication approaches for meta-atoms are heavily dependent on electron-beam lithography (EBL), a technique known for its expensive and time-consuming nature. In this paper, a polarization-insensitive metasurface hologram is proposed using a cost-effective and rapid nanoimprinting method with titanium dioxide (TiO2) nanoparticle loaded polymer (NLP). Based on a simulation, it has been found that, despite a reduction in the aspect ratio of meta-atoms of nearly 20%, which is beneficial to silicon master etching, NLP filling, and the mold release processes, imaging efficiency can go up to 54% at wavelength of 532 nm. In addition, it demonstrates acceptable imaging quality at wavelengths of 473 and 671 nm. Moreover, the influence of fabrication errors and nanoimprinting material degradation in terms of residual layer thickness, meta-atom loss or fracture, thermal-induced dimensional variation, non-uniform distribution of TiO2 particles, etc., on the performance is investigated. The simulation results indicate that the proposed device exhibits a high tolerance to these defects, proving its applicability and robustness in practice. [ABSTRACT FROM AUTHOR]

Purpose: By investigating the thermal-mechanical interaction between the through silicon via (TSV) and the Cu pad, this study aimed to determine the effect of electroplating defects on the upper surface protrusion and internal stress distribution of the TSV at various temperatures and to provide guidelines for the positioning of TSVs and the optimization of the electroplating process. Design/methodology/approach: A simplified model that consisted of a TSV (100 µm in diameter and 300 µm in height), a covering Cu pad (2 µm thick) and an internal drop-like electroplating defect (which had various dimensions and locations) was developed. The surface overall deformation and stress distribution of these models under various thermal conditions were analyzed and compared. Findings: The Cu pad could barely suppress the upper surface protrusion of the TSV if the temperature was below 250 ?. Interfacial delamination started at the collar of the TSV at about 250 ? and became increasingly pronounced at higher temperatures. The electroplating defect constantly experienced the highest level of strain and stress during the temperature increase, despite its geometry or location. But as its radius expanded or its distance to the upper surface increased, the overall deformation of the upper surface and the stress concentration at the collar of the TSV showed a downward trend. Originality/value: Previous studies have not examined the influence of the electroplating void on the thermal behavior of the TSV. However, with the proposed methodology, the strain and stress distribution of the TSV under different conditions in terms of temperature, dimension and location of the electroplating void were thoroughly investigated, which might be beneficial to the positioning of TSVs and the optimization of the electroplating process. [ABSTRACT FROM AUTHOR]

On page 1798, J. Zhou and colleagues present two kinds of pretreated cotton threads that are entangled to form an double helixes‐structure generator. The generator is then coiled around a silicone fiber to form an active fiber‐based strain sensor which shows sensitive and stable performance and has the ability to detect human body motions. This indicates potential applications in future self‐powered healthy monitor systems by detecting the mechanical deformation of the human body and surrounding environment. [ABSTRACT FROM AUTHOR]

• The influence of annealing temperature on the n- region was thoroughly evaluated. • Junction depths were calculated through simulations and validated with experiments. • The transport rate of interstitials was determined by the 1D model and validated. • Reannealing experiments resulted in the pn junction moving back. • The diffusion coefficient of vacancies was determined and validated. The n− region is crucial to the performance of n-on-p HgCdTe devices. However, the underlying mechanisms governing its formation process remain insufficiently elucidated in current literature. In this work, the influence of annealing temperature on the n− region formation process was investigated systematically through experiments and one-dimensional (1D) simulation. The two key parameters, the transport rate of interstitials (Tr I) and the diffusion coefficient of vacancies (D V) were determined through the 1D model, and their accuracy was validated by experiments. The determination of Tr I and D V allows for more flexible and precise optimization of the n− region in HgCdTe, thereby providing valuable guidance for cost-effective, high performance, and reliable preparation of HgCdTe detectors. [ABSTRACT FROM AUTHOR]

Self-powered and wearable electronics, which are away from the problems of batteries, can provide the sustainable and comfortable interactive service for people. In this work, cellular polypropylene piezoelectret, which is with excellent physical and electrical properties, is utilized to build the human body energy harvesting and self-powered human health monitoring systems. The cellular polypropylene piezoelectret flexible generator can reach a maximum peak power density of ≈52.8 mW m−2. Simultaneously, self-powered human body biological signals detecting sensors are demonstrated to detect the human physiological signals, such as coughing action and arterial pulses. This study strongly indicates the great compatibility and potential applications in human healthy monitoring may pave a new developing way for portable and wearable electronics systems. [ABSTRACT FROM AUTHOR]

The cellular piezoelectret generator (CPG) has drawn considerable attention as an emerging flexible energy harvester because of its advantages of a simple structure, easy assembly, a low cost, and eco-friendliness. To facilitate practical applications, an initial theoretical study of CPGs is presented in this work, in which the output characteristics of CPGs can be optimized through an appropriate choice of parameters, including the electret dielectric permittivity, device structure, polarization process, and external load. A good agreement with experimental results is achieved, verifying the validity of the theoretical study. The reported theory offers a complete interpretation of the dynamic working mechanism of CPGs and provides significant guidance for the design of a CPG with enhanced yield. [ABSTRACT FROM AUTHOR]