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Recently, a great deal of interest has been focused on developing sensors that can measure both pressure and light. However, traditional sensors are difficult to integrate into silicon (Si)-based integrated circuits. Therefore, it is particularly important to design a sensor that operates on a new principle. In this paper, junction piezotronic transistor (JPT) arrays based on zinc oxide (ZnO) nanowire are demonstrated. And the JPT arrays show high spatial resolution pressure and light mapping with 195 dpi. Because ZnO nanowires are arranged vertically above the p-type Si channel's center of the transistor, the width of the heterojunction depletion region is constricted by the positive piezoelectric potential generated by strained ZnO. In addition, photogenerated charge carriers can be created in the Si channel when JPT is stimulated by light, which increases its electrical conductivity. Consequently, the external pressure and light distribution information can be obtained from the variation in the output current of the device. The prepared JPT arrays can be compatible with Si transistors, which make them highly competitive and make it possible to incorporate both pressure and light sensors into large integrated circuits. This work will contribute to many applications, such as intelligent clothing, human–computer interaction, and electronic skin. [ABSTRACT FROM AUTHOR]

Li3VO4, as a promising intercalation-type anode material for lithium-ion batteries, features a desired discharge potential (ca. 0.5-1.0 V vs. Li/Li+) and a good theoretical storage capacity (590 mAh g−1 with three Li+ inserted). However, the poor electrical conductivity of Li3VO4 hinders its practical application. In the present work, various amounts of oxygen vacancies were introduced in Li3VO4 through annealing in hydrogen to improve its conductivity. To elucidate the influence of oxygen vacancies on the electrochemical performances of Li3VO4, the surface energy of the resulting material was measured with an inverse gas chromatography method. It was found that Li3VO4 annealed in pure hydrogen at 400 °C for 15 min exhibited a much higher surface energy (60.7 mJ m−2) than pristine Li3VO4 (50.6 mJ m−2). The increased surface energy would lower the activation energy of phase transformation during the charge-discharge process, leading to improved electrochemical properties. As a result, the oxygen-deficient Li3VO4 achieved a significantly improved specific capacity of 495 mAh g−1 at 0.1 Ag−1 (381 mAh g−1 for pristine Li3VO4) and retains 165 mAh g−1 when the current density increases to 8 Ag−1. [ABSTRACT FROM AUTHOR]

V2(PO4)O/C is a promising new anode material for lithium ion batteries with excellent electrochemical properties, synthesized by a facile one pot hydrothermal method, followed by a two-step calcination process. The composite can deliver a reversible capacity of 445 mA h g−1, 409 mA h g−1 and 382 mA h g−1 at 1.0, 1.5 and 2.0 A g−1. The capacity retentions of V2(PO4)O/C cycled at 1 and 5 A g−1 for 200 cycles are 90% and 80%, respectively. The excellent electrochemical properties are mainly attributed to the following three factors: (1) face-sharing [VO6] octahedral arrays endow the crystal with a high intrinsic electronic conductivity; (2) the good lithium ion diffusion coefficient of the material contributes for reducing electrochemical and concentration polarization in the charge–discharge process; and (3) porous microstructure and nanoscale particles not only permit effective contact between the electrolyte and active material, but also provide more space to accommodate volume change during the discharge/charge processes. The results in this study provide convincing evidence that V2(PO4)O/C has significant research value for future practical applications. [ABSTRACT FROM AUTHOR]

Inorganic lead halide perovskite (CsPbX3, X = Cl, Br, I) NWs (NWs) have been employed in lasers due to their intriguing attributes of tunable wavelength, low threshold, superior stability, and easy preparation. However, current CsPbX3 NW lasers usually work in a multi-mode modal, impeding their practical applications in optical communication due to the associated false signaling. In this work, high-performance single-mode lasing has been demonstrated by designing and fabricating coupled cavities in the high-quality single-crystal CsPbBr3 NWs via the focused ion beam (FIB) milling approach. The single-mode laser shows a threshold of 20.1 μJ cm-2 and a high quality factor of ∼2800 profiting from the Vernier effect, as demonstrated by the experiments and finite-different time-domain (FDTD) simulations. These results demonstrate the promising potentials of the CsPbX3 NW lasers in optical communication and integrated optoelectronic devices.