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In this work, a simple, controllable and mass-produced microcrack technique for stretchable strain sensors is presented. Specifically, the conductive layer (hydroxylated MWCNTs) and the flexible substrate (Ecoflex) of fiber strain flexible sensors are modified based on proton irradiation defect engineering. The evolution of defects in sensitive materials and the density of microcracks in flexible substrates are controlled by controlling the irradiation fluence during the irradiation process. In particular, when the irradiation fluence is 1 × 1014 p cm−2, the gauge factor (GF) of the fiber strain sensor is as high as 1274.8, and the response time and recovery time are reduced by 49.4% and 45.1%, respectively. At the same time, the microcracked structure does not fracture easily under a large strain, the maximum strain being 800%. In addition, fiber strain flexible sensors can also be used to detect biomechanical signals in different scenarios. This simple and efficient microcrack technique opens up a new prospect for the fabrication of high-performance stretchable strain sensors. [ABSTRACT FROM AUTHOR]

Dislocations are important for their effects on the chemical, electrical, magnetic, and transport properties of oxide materials, especially for electrochemical devices such as solid fuel cells and resistive memories, but these effects are still under-studied at the atomic level. We have developed a quantum mechanical/molecular mechanical (QM/MM)-based multiscale simulation program to reveal the diffusion properties of protons on 〈100〉 edge dislocations in BaZrO3 perovskite oxide. We find that the large free space and the presence of hydrogen bonds in the dislocation core structure lead to significant trapping of protons. The diffusion properties of protons in dislocation cores were investigated, and no evidence of pipeline diffusion was found from the calculated migration energy barriers, which not only did not accelerate ion diffusion but rather decreases the conductivity of ions. The proton diffusion properties of Y-doped BaZrO3 (BZY), with a dislocation core structure (BZY-D) and with a grain boundary structure (BZY-GB) were also compared. In all three structures, local lattice deformation occupies an essential part in the proton transfer and rotation processes. The change in bond order is calculated and it is found that the interaction with oxygen and Zr ions during proton transfer and rotation controls the energy barrier for local lattice deformation of the O–B–O motion, which affects the proton diffusion in the structure. Our study provides insight into proton diffusion in dislocations in terms of mechanical behavior, elucidates the origin of the energy barrier associated with proton diffusion in dislocations, and provides guidance for the preparation and application of proton conductors. [ABSTRACT FROM AUTHOR]

Zintl phase Mg3Sb2, which has ultra-low thermal conductivity, is a promising anisotropic thermoelectric material. It is worth noting that the prediction and experiment value of lattice thermal conductivity (κ) maintain a remarkable difference, troubling the development and application. Thus, we firstly included the four-phonon scattering processes effect and performed the Peierls–Boltzmann transport equation (PBTE) combined with the first-principles lattice dynamics to study the lattice thermal transport in Mg3Sb2. The results showed that our theoretically predicted κ is consistent with the experimentally measured, breaking through the limitations of the traditional calculation methods. The prominent four-phonon scatterings decreased phonon lifetime, leading to the κ of Mg3Sb2 at 300 K from 2.45 (2.58) W m−1 K−1 to 1.94 (2.19) W m−1 K−1 along the in (cross)-plane directions, respectively, and calculation accuracy increased by 20%. This study successfully explains the lattice thermal transport behind mechanism in Mg3Sb2 and implies guidance to advance the prediction accuracy of thermoelectric materials. [ABSTRACT FROM AUTHOR]

Controllable and stable 1T phase MoS2 nanosheets (MoS2 NSs) were obtained by 1 MeV electron irradiation for the first time, and the hydrogen evolution reaction (HER) performance was improved. We propose that the synergistic effect of electron excitation and vacancy formation, and mechanical strain are the main factors causing the phase transition from the 2H to 1T phase in MoS2 NSs induced by electron irradiation. It was found that the irradiation-induced defects in the catalysts could provide abundant active sites, while 1T phase MoS2 NSs with excellent electrical conductivity would greatly improve the interfacial charge transfer rate, which is beneficial for improving the catalytic performance. In addition, the appropriate irradiation fluence is the key factor to improve the HER performance of MoS2 NSs. Therefore, the application of the electron irradiation method provides a new strategy to enhance the HER performance of MoS2 NSs. [ABSTRACT FROM AUTHOR]

Zintl phase Mg 3 Sb 2 , which has ultra-low thermal conductivity, is a promising anisotropic thermoelectric material. It is worth noting that the prediction and experiment value of lattice thermal conductivity ( κ ) maintain a remarkable difference, troubling the development and application. Thus, we firstly included the four-phonon scattering processes effect and performed the Peierls-Boltzmann transport equation (PBTE) combined with the first-principles lattice dynamics to study the lattice thermal transport in Mg 3 Sb 2 . The results showed that our theoretically predicted κ is consistent with the experimentally measured, breaking through the limitations of the traditional calculation methods. The prominent four-phonon scatterings decreased phonon lifetime, leading to the κ of Mg 3 Sb 2 at 300 K from 2.45 (2.58) W m -1 K -1 to 1.94 (2.19) W m -1 K -1 along the in (cross)-plane directions, respectively, and calculation accuracy increased by 20%. This study successfully explains the lattice thermal transport behind mechanism in Mg 3 Sb 2 and implies guidance to advance the prediction accuracy of thermoelectric materials.

Dislocations are important for their effects on the chemical, electrical, magnetic, and transport properties of oxide materials, especially for electrochemical devices such as solid fuel cells and resistive memories, but these effects are still under-studied at the atomic level. We have developed a quantum mechanical/molecular mechanical (QM/MM)-based multiscale simulation program to reveal the diffusion properties of protons on 〈100〉 edge dislocations in BaZrO 3 perovskite oxide. We find that the large free space and the presence of hydrogen bonds in the dislocation core structure lead to significant trapping of protons. The diffusion properties of protons in dislocation cores were investigated, and no evidence of pipeline diffusion was found from the calculated migration energy barriers, which not only did not accelerate ion diffusion but rather decreases the conductivity of ions. The proton diffusion properties of Y-doped BaZrO 3 (BZY), with a dislocation core structure (BZY-D) and with a grain boundary structure (BZY-GB) were also compared. In all three structures, local lattice deformation occupies an essential part in the proton transfer and rotation processes. The change in bond order is calculated and it is found that the interaction with oxygen and Zr ions during proton transfer and rotation controls the energy barrier for local lattice deformation of the O-B-O motion, which affects the proton diffusion in the structure. Our study provides insight into proton diffusion in dislocations in terms of mechanical behavior, elucidates the origin of the energy barrier associated with proton diffusion in dislocations, and provides guidance for the preparation and application of proton conductors.