Ordered SnO₂ nanostructures were prepared as humidity sensors by nanosphere lithography with the magnetron sputtering technique. The X-ray diffraction patterns of SnO₂ nanostructures show that all intense diffraction peaks correspond to the crystallographic planes of SnO₂. The Atomic Force Microscope (AFM) mage shows that these SnO₂ nanostructures exhibited a classic honeycomb structure. The resistance of this sensor was measured to show that the resistance of the sensor decreases with an increase from lower relative humidity (RH) to higher RH. Additionally, the longest response/recovery time was 32 s/42 s for 11–96% RH. The hysteresis for the SnO₂ nanostructure sensor was <5%.

Lithium-sulfur (Li-S) batteries have received extensive attention due to their high theoretical specific capacity and theoretical energy density. However, their commercialization is hindered by the shuttle effect caused by the dissolution of lithium polysulfide. To solve this problem, a method is proposed to improve the performance of Li-S batteries using Ti₂N(Ti₂NS₂) with S-functional groups as the sulfur cathode host material. The calculation results show that due to the mutual attraction between Li and S atoms, Ti₂NS₂ has the moderate adsorption energies for Li₂S_x species, which is more advantageous than Ti₂NO₂ and can effectively inhibit the shuttle effect. Therefore, Ti₂NS₂ is a potential cathode host material, which is helpful to improve the performance of Li-S batteries. This work provides a reference for the design of high-performance sulfur cathode materials.

In order to realize the collection and utilization of low-frequency vibration energy, a multi-directional piezoelectric energy harvester is proposed, which consists of a lower circular arc beam and an upper L-shaped beam. Both the lower and upper beams can achieve multi-directional energy harvesting, and the upper L-shaped beam can also act as a mass block to reduce the resonant frequency. The structure of this energy harvester is optimized. Four different structures are studied with varying combination angles between the upper and lower layers to acquire data related to resonant frequency, vibration shape, stress distribution, open-circuit voltage, and output power. Additionally, the performance of each structure is comprehensively prepared and measured to verify its effectiveness. The optimal structure achieved a resonant frequency of 11 Hz and an output power of 57.1 μW at the optimal load resistance of 201 kΩ. Consequently, this work provides valuable reference for the study of low-frequency vibration energy harvesting technology.

Wide-range flexible pressure sensors are in difficulty in research while in demand in application. In this paper, a wide-range capacitive flexible pressure sensor is developed with the foaming agent ammonium bicarbonate (NH₄HCO₃). By controlling the concentration of NH₄HCO₃ doped in the polydimethylsiloxane (PDMS) and repeating the curing process, pressure-sensitive dielectrics with various porosity are fabricated to expand the detection range of the capacitive pressure sensor. The shape and the size of each dielectric is defined by the 3D printed mold. To improve the dielectric property of the dielectric, a 1% weight ratio of multi-walled carbon nanotubes (MWCNTs) are doped into PDMS liquid. Besides that, a 5% weight ratio of MWCNTs is dispersed into deionized water and then coated on the electrodes to improve the contact state between copper electrodes and the dielectric. The laminated dielectric layer and two electrodes are assembled and tested. In order to verify the effectiveness of this design, some reference devices are prepared, such as sensors based on the dielectric with uniform porosity and a sensor with common copper electrodes. According to the testing results of these sensors, it can be seen that the sensor based on the dielectric with various porosity has higher sensitivity and a wider pressure detection range, which can detect the pressure range from 0 kPa to 1200 kPa and is extended to 300 kPa compared with the dielectric with uniform porosity. Finally, the sensor is applied to the fingerprint, finger joint, and knee bending test. The results show that the sensor has the potential to be applied to human motion detection.

The growing demand from the extended reality and wearable electronics market has led to an increased focus on the development of flexible human-machine interfaces (HMI). These interfaces require efficient user input acquisition modules that can realize touch operation, handwriting input, and motion sensing functions. In this paper, we present a systematic review of triboelectric-based contact localization electronics (TCLE) which play a crucial role in enabling the lightweight and long-endurance designs of flexible HMI. We begin by summarizing the mainstream working principles utilized in the design of TCLE, highlighting their respective strengths and weaknesses. Additionally, we discuss the implementation methods of TCLE in realizing advanced functions such as sliding motion detection, handwriting trajectory detection, and artificial intelligence-based user recognition. Furthermore, we review recent works on the applications of TCLE in HMI devices, which provide valuable insights for guiding the design of application scene-specified TCLE devices. Overall, this review aims to contribute to the advancement and understanding of TCLE, facilitating the development of next-generation HMI for various applications.

The sensitivity of silicon nanopillar array for relative humidity (RH) with UV illumination was investigated in this work. The silicon nanopillar array was prepared by nanosphere lithography. Electrical measurements were performed on its sensing performance with and without UV irradiation. It was found that UV light improved the humidity sensitivity with different UV light wavelengths and power. The sensor response and recovery time were reduced. Furthermore, the turn-on threshold voltage and the operating voltage both decreased. These sensing characteristics can mainly be attributed to the electron-hole pairs generated by UV light. These electron-hole pairs promote the adsorption and desorption processes. The results indicate that silicon nanopillar array materials with UV irradiation might be competitive as novel sensing materials for fabricating humidity sensors with high performances.