Tactile sensing, which can reflect the displacement of touch, is considered to be an essential function for electronic skin to mimic natural skin. Here we report a novel tactile sensor with good sensitivity, excellent durability and fast response based on highly flexible and transparent conductor layers. The tactile device is simple in terms of structure consisting of a pair of compliant conductive plates, which were adhered to graphene films (GFs) on the surface layer of the polyethylene terephthalate (PET) substrate, and a transparent elastic adhesive sandwiched between the electrodes. The as-assembled tactile sensors can reflect one-dimensional (1D) touch tactile. And the resistance of the device is linearly related to the tactile of touch. Notably, the rate of resistance change is up to 420% when the displacement is changed by 25 mm. The tactile sensor features a high sensitivity of 0.143 mm−1, a long lifetime of 14 000 cyclic loading tests, and a fast response of 0.3 ms. Furthermore, the electrical signals of the tactile sensors are almost irrelevant to the interference signals such as vertical displacement, stress magnitude, stress acting area and bending strain. This rational design of innovative materials and devices presents great potential for electronic devices to completely replace the unique tough sensing properties of human skin.

Tactile sensing, which can reflect the displacement of touch, is considered to be an essential function for electronic skin to mimic natural skin. Here we report a novel tactile sensor with good sensitivity, excellent durability and fast response based on highly flexible and transparent conductor layers. The tactile device is simple in terms of structure consisting of a pair of compliant conductive plates, which were adhered to graphene films (GFs) on the surface layer of the polyethylene terephthalate (PET) substrate, and a transparent elastic adhesive sandwiched between the electrodes. The as-assembled tactile sensors can reflect one-dimensional (1D) touch tactile. And the resistance of the device is linearly related to the tactile of touch. Notably, the rate of resistance change is up to 420% when the displacement is changed by 25 mm. The tactile sensor features a high sensitivity of 0.143 mm−1, a long lifetime of 14 000 cyclic loading tests, and a fast response of 0.3 ms. Furthermore, the electrical signals of the tactile sensors are almost irrelevant to the interference signals such as vertical displacement, stress magnitude, stress acting area and bending strain. This rational design of innovative materials and devices presents great potential for electronic devices to completely replace the unique tough sensing properties of human skin.

Interface/surface properties play an important role in the development of most electronic devices. In particular, nanowires possess large surface areas that create new challenges for their optoelectronic applications. Here, we demonstrated that the piezoelectric field and UV laser illumination modulate the surface potential distribution of a bent ZnO wire by the Kelvin probe force microscopy technology. Experiments showed that the surface potential distribution was changed by strain. The difference of surface potential between the outer/inner sides of the ZnO wire increased with increasing strain. Under UV laser illumination, the difference of surface potential between the outer/inner sides of the ZnO wire increased with increasing strain and illumination time. The origin of the observed phenomenon was discussed in terms of the energy band diagram of the bent wire and adsorption/desorption theory. It is suggested that the change of surface potential can be attributed to the uneven distribution of the carrier density across the wire deduced by the piezoelectric effect and surface adsorption/desorption of oxygen ions. This study provides an important insight into the surface and piezoelectric effects on the surface potential and can help optimize the performance of electronic and optoelectronic devices.

Study of the service behavior of nanomaterials is very important for real applications of nanodevices. In this paper, the dissolving behavior of ZnO wire in HCl solution was investigated, the preferential etching plane and electrical properties upon the treatment were also discussed in detail. The smaller diameter wire resulted in a more pronounced corrosion rate due to the higher specific surface area. The detailed morphological study demonstrated that the ZnO wire had a preferential etching plane {101} in the HCl solution. The etching also strongly reduced the electrical properties of ZnO wires. These results may provide valuable guidance for designing nanodevices based on ZnO micro/nano wires.

We demonstrate for the first time the corrosion behavior of ZnO micro/nanowires under stress. The influence of the piezoelectric effect on the corrosion of ZnO micro/nanowires in acidic and alkaline environments was investigated. The two sides of the bent ZnO micro/nanowires have a significantly different corrosion rate while strain-free ZnO micro/nanowires remain the same. Corrosion behaviors of individually bent ZnO microwires (MWs) have been clearly observed under various strains estimated using the local curvature model. The corrosion phenomena of bent ZnO MWs in acidic and alkaline environments were different. The outer surface of the wire attracts free hydroxide ions and the inner one attracts hydrogen ions from the solution which promotes the chemical reaction due to the effect of the piezoelectric potential which is generated by strain. The experimental results indicated that the corrosion rate is quite sensitive to strain, which provides a recommendation for the design and evaluation of nanodevices that serve in extreme environments.

•A self-powered Schottky barrier UV photodetector based on 1-D ZnO is fabricated.•For the first time we investigate the local irradiation effects of UV detector.•Irradiating both the junctions and ZnO can optimize the performance of the device.A self-powered metal-semiconductor-metal (MSM) UV photodetector was successfully fabricated based on Ag/ZnO/Au structure with asymmetric Schottky barriers. This exhibits excellent performance compared to many previous studies. Very high photo-to-dark current ratio (approximately 105–106) was demonstrated without applying any external bias, and very fast switching time of less than 30 ms was observed during the investigation. Opposite photocurrent direction was generated by irradiating different Schottky diodes in the fabricated photodetector. Furthermore, the device performance was optimized by largely irradiating both the ZnO microwire (MW) junctions. Schottky barrier effect theory and O2 adsorption–desorption theories were used to investigate the phenomenon. The device has potential applications in self-powered UV detection field and can be used as electrical power source for electronic, optoelectronic and mechanical devices.

We report the fabrication of CdS quantum dot sensitized solar cells with ZnO nanowire arrays as the photoanodes. The influences of precursor solution temperature and sensitizing cycles on the performance of CdS quantum dots sensitized ZnO nanowires solar cells were studied. Successive ionic layer adsorption and reaction (SILAR) method was applied to deposit CdS quantum dots on the surface of ZnO nanowire arrays for assembling ZnO/CdS electrodes. The results of scanning electron microscopic (SEM), X-ray diffraction (XRD) patterns and UV–vis absorption spectroscopy indicated that the ZnO nanowires electrodes were well-covered with CdS quantum dots. The temperature of the ethanol sensitizing solutions significantly influenced the performance of ZnO/CdS electrodes by affecting the rate of deposition reaction and the penetration ability of ethanol solution. The CdS quantum dots sensitized ZnO-based solar cells exhibited a short-circuit current density (Jsc) of 3.1 mA/cm2, an open-circuit voltage (Voc) of 0.55 V and a photovoltaic conversion efficiency of 0.72%, which is much higher than that reported in literatures, under the illumination of one sun (AM 1.5, 100 mW/cm2) when the temperature of the ethanol solutions was 60 °C and ZnO arrays were sensitized for seven times.

Recently, self-powered devices based on a p–n heterojunction have been widely reported, but there are few reports about self-powered UV detectors based on a single ZnO microwire/p-Si film with double heterojunctions. Compared with the common p–n heterojunction type devices, the fabricated devices with double heterojunctions based on a single n-type ZnO microwire and a p-type Si film exhibited excellent electrical performance such as an ideal rectification behaviour and a low turn-on voltage. At zero bias, the fabricated device can deliver a photocurrent of 71 nA, a high photosensitivity of about 3.17 × 103 under UV light (0.58 mW cm−2) illumination and a fast rising and falling time of both less than 0.3 s. Furthermore, the photocurrent increased with the rising of the optical intensity at low power intensities. The physical mechanism has been explained by energy band diagrams.