This paper reports the effects of the aspect ratio of zinc oxide (ZnO) nanowires on the performance of ZnO-nanowirebased dye-sensitized solar cells (DSSCs). ZnO nanowire-structured photoanodes can improve the efficiency of the electron collection of DSSCs, but their performances significantly depend on the aspect ratio of component nanowires and their array structures. The aspect ratio of nanowires has been successfully regulated by controlling the supersaturation degree of solutions, that is, simply by changing the molar ratio of Zn(II)/NH 3 . A highly oriented, single crystalline, long ZnO nanowire with a fine aligning structure was obtained with an aspect ratio of about 100-120 (diameter: 120-150 nm, length: 14 µm). The main crystalline phase measured by X-ray diffraction and Raman scattering was proven to be wurtzite-type ZnO, whereas the appearance of another phase was also detected. The films show a transmittance of about 60% in the visible light region and optical band gaps at around 3.2 eV. An overall conversion efficiency of about 1.7% was obtained, which is almost three times of that we reported previously. The present research points out a possible way to improve ZnO-based DSSCs by engineering a nanostructured electrode.

Flexible pressure sensors have attracted increasing interest because of their potential applications on wearable sensing devices for human−machine interface connections, but challenges regarding material cost, fabrication robustness, signal transduction, sensitivity improvement, detection range, and operation convenience still need to be overcome. Herein, with a simple, low-cost, and scalable approach, a flexible and wearable pressure-sensing device fabricated by utilizing filter paper as the solid support, poly(3,4-ethylenedioxythiophene) to enhance conductivity, and silver nanoparticles to provide a rougher surface is introduced. Sandwiching and laminating composite material layers with two thermoplastic polypropylene films lead to robust integration of sensing devices, where assembling four layers of composite materials results in the best sensitivity toward applied pressure. This practical pressure-sensing device possessing properties such as high sensitivity of 0.119 kPa −1 , high durability of 2000 operation cycles, and an ultralow energy consumption level of 10 −5 W is a promising candidate for contriving point-of-care wearable electronic devices and applying it to human−machine interface connections.

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