Advanced Sensor Research最新文献

Smart Monitoring Hydrogel Sensors

In article 2400003, Hong Zhang, Yang Luo, and co-workers report advancements in smart hydrogel sensors for health monitoring and early warning. Leveraging the biocompatible properties of hydrogels, these sensors facilitate continuous, precise monitoring of various physiological parameters. The review highlights the mechanisms of these sensors, their benefits for medical diagnostics, and directions for future research. It also explores their potential in various medical scenarios, such as disease monitoring and management, underscoring the need for further clinical validation.

Integrated Microwave Photonic Sensors

Sensors stand as pivotal cornerstones of technologies. In article 2300145, Xiaoke Yi and co-workers demonstrate integrated microwave photonic sensors using microresonators for ultra-sensitive, high-resolution, and rapid detection. These compact sensors, enhanced through integration techniques and artificial intelligence, offer great potential across various applications, representing a significant advancement in modern sensing technologies.

Deformation-Insensitivity

Flexible sensor array using kirigami structural and soft-hinge design enables deformation-insensitive pressure detection. The sensitivity of sensor is enhanced by the modification with micropillars on conductive rubber. Characterization tests verify the almost negligible effects to sensor caused by 40% stretching and 180° bending interferences. The proposed sensor array is capable of functioning on the deformable surfaces with stable detection signals. More details can be found in article 2400012 by Yancheng Wang and co-workers.

Mechanical energy harvesters have recently emerged as promising options for self-powering sensors and small electronic devices. In this work, aluminum ferrite (AlFeO₃)/PVDF hybrid perovskite electrospun nanofiber-based tribo-enhanced piezoelectric nanogenerators (TPENGs) are developed for energy harvesting. The as-fabricated TPENG achieves an average voltage output of 52.3 V and an average current output of 1.23 µA. Additionally, the power density of the TPENG is calculated to be 0.085 W.m⁻² at an 80 MΩ external resistance load. A 3D-printed device is fabricated, containing nylon fabric (tribo-positive) as a rotor attached to printed fins, while six (AlFeO₃)/PVDF hybrid perovskite electrospun nanofiber piezoelectric nanogenerators (PENGs) wrapped with Kapton tape (tribo-negative) serve as the stator. The three printed fins of the device are moved by a string-based pulley, generating an open circuit voltage of 200 V and a short circuit current of 4.5 µA. The as-fabricated 3D-printed device with TPENGs is used to power small electronics (e.g., LEDs and watch) and an exercise setup, allowing patients to generate power by pulling the attached string, thereby estimating the level of impairment. Integrating energy harvesting into rehabilitation motivates patients to move impaired body parts, enhancing TPENG's application in healthcare as a practical and engaging tool for patient rehabilitation.

Interactive Wood

Sensors fabricated directly onto wooden surfaces allow to detect humidity and temperature changes or monitor the curing of varnishes. They enable structural integrity monitoring in construction or turn furniture into interactive touch panels, all in a sustainable fashion. More details can be found in article number 2400010 by Martin Kaltenbrunner and co-workers.

The use of hydrogen as an energy carrier will require low-cost, low-power hydrogen sensors. Toward this goal, penta-twinned palladium nanowires (Pd NWs) are synthesized and fabricated sensors from them by drop-casting. Pd NWs drop-cast onto an interdigitated electrode (IDE) gave a response of 0.3% to 1 vol.% H₂, with response and recovery times of 12 and 20 s, respectively. However, they exhibited a negative response (decreased resistance) at low H₂ concentrations. Pd NWs on a paper substrate provided a tenfold higher response to 1 vol.% H₂, with response and recovery times of 10 s each, but still exhibited negative response at low H₂ concentration. Exposing the Pd NW-on-paper sensor to ozone-generating UV light degraded the PVP used in Pd NW synthesis, eliminating the reverse sensing response, and providing a response of 5% to 1 vol.% H₂, with response and recovery times of 15 s. This allowed reliable H₂ detection down to 100 ppm H₂. Finally, coating the Pd NWs with a small amount of Pt (<5%) reduced the response and recovery times to 5 s by catalyzing H₂ dissociation. This work provides a path to low-cost sensors to enable the safe use of H₂ as an energy carrier.

Coupling surface plasmon resonance (SPR) sensing with electrochemistry (EC) is a promising analytical strategy to obtain information about interfacial phenomena in heterogeneous reactions. Typical EC-SPR sensors utilize a metal film both as the plasmonic material and as the working electrode. In this configuration, the eigenmodulation of the plasmonic properties of the metal film under applied potential results in a background signal, which hampers the unambiguous interpretation of the sensor response due to redox reactions. Here, a new strategy is presented to overcome this disadvantage by using a van der Waals heterostructure (vdW-HS) as the working electrode. The vdW-HS comprises of a graphene / hexagonal boron nitride (hBN) stack on a gold film of a standard SPR sensor. It is shown here that the background signal is completely suppressed enabling the unambiguous analysis of SPR sensor response due to electrochemical reactions. It is further observed that the potential dependent plasmonic signals are not just a reproduction of the electrochemical current and subtle differences can be traced back to the diffusive nature of the redox active species. Finally, it is demonstrated that EC-SPR can be used as a complementary method to distinguish if the electrochemical response is mainly surface-bound or due to diffusion.