Understanding the Enhancement Mechanism of ZnO Nanorod-based Piezoelectric Devices through Surface Engineering

Recent advances in MXene-based composites for piezoelectric sensors

Piezoelectric sensors are crucial in medical, industrial, and consumer electronics applications, yet their performance and sensitivity often fall short due to the limitations in current piezoelectric materials. To address these deficiencies, significant research has been directed towards developing composite materials that enhance piezoelectric properties by integrating piezoelectric materials with various fillers. MXenes, a novel class of 2D transition metal carbides/nitrides, exhibit remarkable properties such as high electrical conductivity, mechanical strength, and chemical stability. These characteristics, along with a high surface area and hydrophilicity, make MXenes an ideal additive for preparing piezoelectric composites with improved properties. Despite existing reviews on MXenes in sensor applications, only a few have systematically explored their role in piezoelectric sensors. This review provides a comprehensive analysis of MXene-based piezoelectric sensors, examining the impact of different composites on piezoelectric properties, synthesis methods, structural designs, and application areas. While promising, challenges such as scalability, reproducibility, and environmental stability must be addressed to fully realize the potential of MXene-based composites. This comprehensive analysis highlights the advancements, opportunities for further development, and the transformative potential of MXenes in the next generation of high-performance, multifunctional piezoelectric sensors.

Flexible Lead-Free Piezoelectric Ba0.94Sr0.06Sn0.09Ti0.91O3/PDMS Composite for Self-Powered Human Motion Monitoring

Piezoelectric wearable electronics, which can sense external pressure, have attracted widespread attention. However, the enhancement of electromechanical coupling performance remains a great challenge. Here, a new solid solution of Ba_1-xSr_xSn_0.09Ti_0.91O₃ (x = 0.00~0.08) is prepared to explore potential high-performance, lead-free piezoelectric ceramics. The coexistence of the rhombohedral phase, orthorhombic phase and tetragonal phase is determined in a ceramic with x = 0.06, showing enhanced electrical performance with a piezoelectric coefficient of d₃₃~650 pC/N. Furthermore, Ba_0.94Sr_0.06Sn_0.09Ti_0.91O₃ (BSST) is co-blended with PDMS to prepare flexible piezoelectric nanogenerators (PENGs) and their performance is explored. The effects of inorganic particle concentration and distribution on the piezoelectric output of the composite are systematically analyzed by experimental tests and computational simulations. As a result, the optimal V_OC and I_SC of the PENG (40 wt%) can reach 3.05 V and 44.5 nA, respectively, at 138.89 kPa, and the optimal sensitivity of the device is up to 21.09 mV/kPa. Due to the flexibility of the device, the prepared PENG can be attached to the surface of human skin as a sensor to monitor vital movements of the neck, fingers, elbows, spine, knees and feet of people, thus warning of dangerous behavior or incorrect posture and providing support for sports rehabilitation.