Synergistic piezoelectricity enhanced BaTiO_(3)/polyacrylonitrile elastomer-based highly sensitive pressure sensor for intelligent sensing and posture recognition applications

Designing stretchable and skin-conformal self-powered sensors for intelligent sensing and posture recognition is challenging.Here,based on a multi-force mixing and vulcanization process,as well as synergistically piezoelectricity of BaTiO_(3)and polyacrylonitrile,an all-in-one,stretchable,and self-powered elastomer-based piezo-pressure sensor(ASPS)with high sensitivity is reported.The ASPS presents excellent sensitivity(0.93 V/104 Pa of voltage and 4.92 nA/104 Pa of current at a pressure of 10-200 kPa)and high durability(over 10,000 cycles).Moreover,the ASPS exhibits a wide measurement range,good linearity,rapid response time,and stable frequency response.All components were fabricated using silicone,affording satisfactory skinconformality for sensing postures.Through cooperation with a homemade circuit and artificial intelligence algorithm,an information processing strategy was proposed to realize intelligent sensing and recognition.The home-made circuit achieves the acquisition and wireless transmission of ASPS signals(transmission distance up to 50 m),and the algorithm realizes the classification and identification of ASPS signals(accuracy up to 99.5%).This study proposes not only a novel fabrication method for developing self-powered sensors,but also a new information processing strategy for intelligent sensing and recognition,which offers significant application potential in human-machine interaction,physiological analysis,and medical research.

Large electrical strain in lead-free K_(0.5)Na_(0.5)NbO_(3)-based ceramics by heterovalent doping

Heterovalent doped(K_(0.48-0.07)xNa_(0.52-0.43)xBi_(0.5)x)(Nb_(0.95-0.95x)Sb_(0.05-0.05x)Zrx)O_(3)ceramics were fabricated using conventional solid-state reaction.Then,the phase structures,dielectric,ferroelectric,and electricstrain properties were investigated.The compositions were tuned to be located at polymorphic phase boundary with increasing heterovalent Bi3t and Zr4t doping levels.A large strain of 0.19%was obtained at relatively low electric fields of 30 kV/cm in the composition of x=0.04.The normalized large-signal d33*values were approximately 633 pm/V under a low driving electric field of 30 kV/cm,which were comparable or larger than the values reported for other lead-free families.The large strains obtained can be attributed to the formation of nanodomains and high-density domain walls,which were confirmed by the observations of domain morphology using transmission electron microscopy(TEM)technique.Excellent temperature stability of the strain properties of the x=0.04 sample could be ascribed to the sluggish behaviour for the local structural heterogeneity in heterovalent-ion doped KNN ceramic.Theoretical simulations revealed that the Zr^(4t)produce the local stress at the BO6 octahedra and Bi3t could yield off-centering of AO12 ployhedron due to the nature of Bi 6s lone pair electrons,which induced lattice expansion and local distortions in the sample.The local displacements are strongly anisotropic in heterovalent-ion doped system.It is believed that random local fields exist in these compositions owing to the eixstence of charge distribution.Such heterovalent doping of Bi^(3t)and Zr^(4t)could destory simultaneously the orthorhombic symmetry and the short-range ferroelecctric order,leading to the formation of complex nanodomains and local structral hetergenenity.Heterovalent doping may,therefore,offer a new avenve to design novel K0.5Na0.5NbO3(KNN)-based materials for their mutifunctional applications.

纸基碳纳米管薄膜/叉指结构的超灵敏宽量程压力传感器（英文）

柔性压力传感器因其在可穿戴设备和人机交互界面中的潜在应用而备受关注.特别是在实际应用中,人们对具有高灵敏度、宽测量范围和低成本的压力传感器有很大需求.基于此,我们研制出了一种测量范围宽的超灵敏压力传感器.该传感器是以碳纳米管(CNT)均匀溶液直接喷在纸表面作为敏感材料,用光刻技术制成的叉指电极为结构.由于CNT大的比表面积、纸的多孔结构以及CNT与叉指电极有效接触的协同作用,压力传感器实现了从0到140 kPa的宽测量范围,并在15,000个测试周期内表现出良好的稳定性.对于纸基碳纳米管薄膜/叉指状结构(PCI)压力传感器,敏感材料与叉指电极之间的连接区域在较小的压力范围内占主导地位,而敏感材料的内部变化在大的压力区域起主导作用.此外PCI压力传感器不仅具有2.72 kPa-1(直到35 kPa)的高灵敏度,还可以检测小重量,如一颗绿豆(约8 Pa).当压力传感器贴附到人体表面时,可以监测生理信号,如手腕运动、脉搏跳动和语音识别.此外,压力传感器的阵列能够识别空间压力分布,有望实际应用于人机交互界面.

A high-performance, single-electrode and stretchable piezotriboelectric hybrid patch for omnidirectional biomechanical energy harvesting and motion monitoring

Triboelectric nanogenerators(TENGs)have recently drawn much attention in the field of biomechanical energy harvesting and motion monitoring.However,the electrode stretchability and contact-separation model induced complicated packed structure remain a problem that heavily affects output performance during various human movements and requires to be urgently addressed.Here,a single-electrode piezotriboelectric hybrid nanogenerator(SEP-TENG)integrated with stretchable liquid-metal metal electrodes is reported,which simultaneously achieves outstanding energy harvesting performance and skincomfort human motion monitoring.A polarized piezoelectric BaTiO_(3)/silicon rubber(SR)composites film is served as the effective negative tribomaterial,benefiting from the improved dielectric constant and piezoelectric charge transfer,the optimized SEP-TENG generates a high peak power density of 5.7 W/m^(2) while contacted with human skin.Besides,owing to the ultralow Young's modulus of the SR encapsulation layer and tribo-piezoelectric hybrid layer,the homogeneous integrated multilayer composite serves no break till a 745%elongation,promoting that the SEP-TENG could effectively harvest biomechanical energy and realize stable power supplying for wearable electronics even under large deformation state.Furthermore,the SEP-TENG could comfortably attach to the finger joints and collect bending energy.This work provides a novel design methodology for a single-electrode TENG to realize omnidirectional biomechanical energy harvesting and motion monitoring.

Stretchable and skin-conformal piezo-triboelectric pressure sensor for human joint bending motion monitoring

Stretchable,skin-conformal,and self-powered wearable pressure sensors have garnered significant attention for use in human joint bending motion monitoring.Here,a piezo-triboelectric pressure sensor(P-TPS)based on triboelectric nanogenerator and piezoelectric nanogenerator is demonstrated.The P-TPS can generate an enhanced electrical output by coupling the dual-mode triboelectrification and piezoelectric effect.The P-TPS shows high sensitivity(voltage=0.3 V/kPa;current=4.3 nA/kPa;pres-sure range=0-200 kPa),high linearity,and good stability.Furthermore,it demonstrates a wide mea-surement range(0-800 kPa),table frequency response,and fast response time.Additionally,all components of the P-TPS are fabricated using flexible and stretchable materials,affording satisfactory stretchability and excellent skin conformality.Owing to their ability to self-power,they can be attached to the outside of joints to monitor human joint bending movements in real time.Hence,this study provides a novel method of using a stretchable and skin-conformal piezo-triboelectric nanogenerator with high electrical performance as a self-powered pressure sensor,which offers significant potential in personalized recognition,medical research,and human machine interface.

低电场下耐疲劳La掺杂PbZrO3薄膜的储能特性及温度稳定性研究

为了满足恶劣环境下低功耗脉冲功率器件的需求,具有超高储能密度和温度稳定性的静电储能电容器受到广泛关注.本研究在较低的电场激励作用和极宽的温度范围内获得了高储能性能的反铁电薄膜.采用溶胶^-凝胶法制备了La掺杂的Pb Zr O3薄膜,在~800 k V cm^-1电场下,室温下可释放储能密度34.87 J cm^-3,储能效率为59.23%.此外,该储能特性具有优良的温度稳定性(210°C下储能密度为27.98 J cm^-3)、抗疲劳特性(3×10^9次循环后无明显疲劳)以及频率稳定性(储能密度:39.78–29.32 J cm^-3;储能效率:61.03%–44.95%)(测试频率10–5000 Hz,电场为~900 k V cm^-1).反铁电薄膜储能性能提升主要是由于La Ni O3缓冲层以及掺杂产生铅空位而引起的高极化值(Pmax约为103.7μC cm^-2)和较低的剩余极化(Pr^7μC cm^-2),为脉冲功率器件在低功耗系统中的应用奠定了研究基础.