Unlike conventional bulk or film materials, one-dimensional (1D) semiconducting zinc oxide (ZnO) nanostructures exhibit excellent photoelectric properties including ultrahigh intrinsic photoelectric gain, multiple light confinement, and subwavelength size effects. Compared with polycrystalline thin films, nanowires usually have high phase purity, no grain boundaries, and long-distance order, making them attractive for carrier transport in advanced optoelectronic devices. The properties of one-dimensional nanowires—such as strong optical absorption, light emission, and photoconductive gain—could improve the performance of light-emitting diodes (LEDs), photodetectors, solar cells, nanogenerators, field-effect transistors, and sensors. For example, ZnO nanowires behave as carrier transport channels in photoelectric devices, decreasing the loss of the light-generated carrier. The performance of LEDs and photoelectric detectors based on nanowires can be improved compared with that of devices based on polycrystalline thin films. This article reviews the fabrication methods of 1D ZnO nanostructures—including chemical vapor deposition, hydrothermal reaction, and electrochemical deposition—and the influence of the growth parameters on the growth rate and morphology. Important applications of 1D ZnO nanostructures in optoelectronic devices are described. Several approaches to improve the performance of 1D ZnO-based devices, including surface passivation, localized surface plasmons, and the piezo-phototronic effect, are summarized.
It has been gradually realized that the sustainable electronic devices are of great prospects for sustainable applications in electronic technology products. From another point of view, a device with multiple physical performances would be a potential candidate for next generation multifunctional electronics. In this report, a flexible memory device based on sweet potato skin (SPS) was demonstrated, which presented a stable memory performance over 500 cycles and a large switching resistance ratio, and the current-voltage (I-V) hysteretic loop accompanied by capacitance effect and negative differential resistance state. In order to carry out detailed mechanism analysis, two materials (ITO or Ti) with different work functions as the bottom electrode and Ag as the top electrode were used to prepare two memristive devices. It can be confirmed that the conductive behavior obeys Schottky emission and direct tunneling at low voltage region, while it follows the hopping conduction at high voltage region. In a word, the selected SPS, a sustainable waste material, can be employed to prepare bioelectronic devices, which has a potential application value in green electronic products.
14 July 2018 in Physical Chemistry Chemical Physics
An electronic cell that possesses synchronously multi-physical properties is of great importance in the applications of multifunctional electronic devices. In this study, an overwhelming coexistence of negative differential resistance (NDR) effect and resistive switching (RS) memory behavior at room temperature was observed based on Ag/Cu2ZnSnSe4 (CZTSe)/Mo devices. The long retention time of ∼104 s and high HRS/LRS resistance ratio of ∼215 can be achieved, indicating that our devices possess excellent resistance random access memory (RRAM). Moreover, strong NDR behavior was observed at room temperature, which provides a great potential application in advanced electronic devices. Finally, the combined physical model of conductive filament and Schottky barrier reinstallment is demonstrated to explain the coexistence phenomenon. Thus, in this, study we propose a new strategy for preparing a multifunctional electronic device with multiple physical attributes in the future.
In recent years, rare-earth metals with triply oxidized state, lanthanide ions (Ln3+), have been demonstrated as dopants, which can efficiently improve the optical and electronic properties of metal halide perovskite materials. On the one hand, doping Ln3+ ions can convert near-infrared/ultraviolet light into visible light through the process of up-/down-conversion and then the absorption efficiency of solar spectrum by perovskite solar cells can be significantly increased, leading to high device power conversion efficiency. On the other hand, multi-color light emissions and white light emissions originated from perovskite nanocrystals can be realized via inserting Ln3+ ions into the perovskite crystal lattice, which functioned as quantum cutting. In addition, doping or co-doping Ln3+ ions in perovskite films or devices can effectively facilitate perovskite film growth, tailor the energy band alignment and passivate the defect states, resulting in improved charge carrier transport efficiency or reduced nonradiative recombination. Finally, Ln3+ ions have also been used in the fields of photodetectors and luminescent solar concentrators. These indicate the huge potential of rare-earth metals in improving the perovskite optoelectronic device performances.