A series of novel phenomena such as optical nonlinear enhancement effect, transmission enhancement, orientation effect, high sensitivity to refractive index, negative refraction and dynamic regulation of low threshold can be generated by the control of surface plasmon (SP) with metal micro-nano structure and metal/material composite structure. The application of SP in nano-photonics, super-resolution imaging, energy, sensor detection, life science, and other fields shows an important prospect. Silver nanoparticles are one of the commonly used metal materials for SP because of their high sensitivity to refractive index change, convenient synthesis, and high controllable degree of shape and size. In this review, the basic concept, fabrication, and applications of silver-based surface plasmon sensors are summarized.
The application of flexible electronics in the field of communication has made the transition from rigid physical form to flexible physical form. Flexible electrode technology is the key to the wide application of flexible electronics. However, flexible electrodes will break when large deformation occurs, failing flexible electronics. It restricts the further development of flexible electronic technology. Flexible stretchable electrodes are a hot research topic to solve the problem that flexible electrodes cannot withstand large deformation. Flexible stretchable electrode materials have excellent electrical conductivity, while retaining excellent mechanical properties in case of large deformation. This paper summarizes the research results of flexible stretchable electrodes from three aspects: material, process, and structure, as well as the prospects for future development.
The piezoelectric effect refers to a physical phenomenon where piezoelectric materials generate an electric field when subjected to mechanical stress or undergo mechanical deformation when subjected to an external electric field. This principle underlies the operation of piezoelectric sensors. Piezoelectric sensors have garnered significant attention due to their excellent self-powering capability, rapid response speed, and high sensitivity. With the rapid development of sensor techniques achieving high precision, increased mechanical flexibility, and miniaturization, a range of flexible electronic products have emerged. As the core constituents of piezoelectric sensors, flexible piezoelectric composite materials are commonly used due to their unique advantages, including high conformability, sensitivity, and compatibility. They have found applications in diverse domains such as underwater detection, electronic skin sensing, wearable sensors, targeted therapy, and ultrasound diagnostics for deep tissue. The advent of flexible piezoelectric composite materials has revolutionized the design concepts and application scenarios of traditional piezoelectric materials, playing a crucial role in the development of next-generation flexible electronic products. This paper reviews the research progress on flexible piezoelectric composite materials, covering their types and typical fabrication techniques, as well as their applications across various fields. Finally, a summary and outlook on the existing issues and future development of these composite materials are provided.
Low-dimensional piezoelectric and quantum piezotronics are two important branches of low-dimensional materials, playing a significant role in the advancement of low-dimensional devices, circuits, and systems. Here, we firstly propose a solid-phase sintering and vapor-liquid-solid growth (SS-VLS-like) method of preparing a quantum-sized oxide material, i.e., black phosphorus (BP)@MgO quantum dot (QD) crystal with a strong piezoelectric response. Quantum-sized MgO was obtained by Mg slowly released from MgB2 within the confinement of a nanoflake BP matrix. Since the slow release of Mg only grows nanometer-sized MgO to hinder the further growth of MgO, we added a heterostructure matrix constraint: nanoflake BP. With the BP as the matrix confinement, MgO QDs embedded in the BP@MgO QD crystals were formed. These crystals have a layered two-dimensional (2D) structure with a thickness of 11 nm and are stable in the air. In addition, piezoresponse force microscopy (PFM) images show that they have extremely strong polarity. The strong polarity can also be proved by polarization reversal and a simple pressure sensor.
Acceleration sensors are tools for detecting acceleration and serve purposes like fault monitoring and behavior recognition. It is extensively employed in a variety of industries, including aerospace, artificial intelligence, biology, and many more. Among these, one of the major research hotspots and challenges is the development of low-energy, self-powered, miniature, mass-produced sensors. Due to its capacity to perceive human behavior and identify errors, the flexible acceleration sensor offers a distinct advantage in the use of flexible and miniaturized sensing systems. This review analyzes the current state of piezoelectric flexible acceleration sensors’ applications in the areas of sensitive materials, processing technology, and device structure and briefly summarizes the fundamental properties of these sensors. Additionally, it ends with a prognosis for the future growth of flexible piezoelectric acceleration sensors.
Highly crystalline Bi2Te3based compounds with small grain size were successfully synthesized by flash sintering (FS) method in 10 s at room temperature under suitable current density using Bi, Te and Se powders. The instantaneously generated local Joule heat at grain boundary is regarded as the main reason for the rapid completion of chemical reaction and crystallization. By combining FS synthesis method with spark plasma sintering (SPS), Bi2Te3based bulk materials with high relative density were fabricated in 10 min. Suitably prolonging sintering temperature and holding time in SPS process can decrease carrier concentration and phonon thermal conductivity, while increasing carrier mobility. Hence, the sample prepared at 753 K for 3 min shows 20% higherZTvalue than that of the sample prepared at 723 K for 3 min. Compared with common zone melting or powder metallurgy methods taking several hours by complex operation, this method is time-saving and low cost.