Flexible piezoelectric nanogenerators (NGs) based on patterned growth of ZnO nanowires (PNWs) by the hydrothermal method are proposed for high-efficiency energy harvesting applications. The use of the PNWs in ZnO-based FPNGs results in a significant improvement in terms of the magnitude of the output currents of up to 6 times when compared with pristine ZnO NW-based FPNGs without patterned growth mode. The maximum output current was measured to be about 150 nA, which was enough to drive some micro/nanoelectronic devices. The improved output performance is mainly attributed to the patterned growth mode in FPNGs, which may significantly reduce the piezoelectric potential screening effect caused by free electrons in ZnO. This strategy may provide a highly promising platform as energy harvesting devices for viable industrial applications in portable/wearable nanodevices.

An efficient catalytic system was developed for the acetalization and ketalization of carbonyl compounds with polyhydric alcohols under mild solvent-free conditions. In the presence of 0.1 mol% CoCl 2 and 0.2 mol% dimethylglyoxime at 70 • C under 5 KPa pressure for 1 h, 95.3% conversion of cyclohexanone and 100% selectivity of the corresponding cyclic ketal could be obtained, where TOF reached as high as 953 h −1 . It is proposed that the in situ generated planartetracoordinate cobaloxime played the key role in the catalytic cycle and was responsible for the excellent catalytic performance.

Simultaneous growth of different kinds of aligned GaN nanostructures (i.e., nanowires, needles, pyramids and micro-rods) on a single substrate was firstly realized at a low temperature of 790 C by naturally changing the III/V ratio across the substrate via a coaxial pipeline configuration. The effects of substrate distance and growth pressure on nanostructure growth were investigated. The morphology variation from nanowires to micros-rods would be explained in terms of Ga species changing from the Ga element to GaN molecule in a hot-wall reactor. This work is helpful for on chip integration of different kinds of nanodevices on unusual substrates of low melting temperature.

The development of flexible photodetectors is believed to have great potential for future optoelectronic applications, such as biomedical imaging and smart wearable systems. Here the work proposes a simple and low-cost approach for integrating a flexible and wearable ZnO ultraviolet (UV) photodetector using polyester fabric as the platform for the first time. The ZnO nanowires coated polyester fabric was prepared by a low-temperature hydrothermal approach. They measured the performance of the photodetector in terms of I-V characteristics and time-resolved photocurrent. The results showed that the as-fabricated ZnO UV photodetector presented great reliability. Additionally, the working mechanism of the device was also discussed.