Linfeng Hu

An Optimized Ultraviolet-A Light Photodetector with Wide-Range Photoresponse Based on ZnS ZnO Biaxial Nanobelt

A novel 1D/1D nanocomposite-based photodetector is successfully fabricated from high-crystalline ZnS/ZnO biaxial nanobelts for the first time. Optimized performance of the ZnS/ZnO nanobelt photodetector is much better than that of pure ZnS or ZnO nanostructures, with a wide-range UV-A light photoresponse, high sensitivity, and very fast response speed.

ZnS nanostructure arrays: a developing material star.

Semiconductor nanostructure arrays are of great scientific and technical interest because of the strong non-linear and electro-optic effects that occur due to carrier confinement in three dimensions. The use of such nanostructure arrays with tailored geometry, array density, and length-diameter-ratio as building blocks are expected to play a crucial role in future nanoscale devices. With the unique properties of a direct wide-bandgap semiconductor, such as the presence of polar surfaces, excellent transport properties, good thermal stability, and high electronic mobility, ZnS nanostructure arrays has been a developing material star. The research on ZnS nanostructure arrays has seen remarkable progress over the last five years due to the unique properties and important potential applications of nanostructure arrays, which are summarized here. Firstly, a survey of various methods to the synthesis of ZnS nanostructure arrays will be introduced. Next recent efforts on exploiting the unique properties and applications of ZnS nanostructure arrays are discussed. Potential future directions of this research field are also highlighted.

Low‐Dimensional Nanostructure Ultraviolet Photodetectors

Low-dimensional (LD) nanostructures are ideal systems for constructing high-performance photodetectors due to their tailored geometries, high surface-area-to-volume ratios and rationally designed surfaces. This article provides a brief summary about recent progress on LD nanostructures based visible-light-blind ultraviolet photodetectors. The current challenges and an outlook on the future developments of this research field are summarized and highlighted.

High‐Performance NiCo2O4 Nanofilm Photodetectors Fabricated by an Interfacial Self‐Assembly Strategy

Photon detection in visible light or ultraviolet region shows widespread applications including environmental and biological research, sensors, missile launch, and detection. [ 1 ] In recent years, the use of nanostructured materials in photodetectors is an emerging research topic due to their high surface-to-volume ratios and rationally designed surfaces. [ 2 ] A large number of photodetectors using semiconductor nanostructures as the building blocks have been reported in the last several years. [ 3 ] In particular, the interest in developing high-performance photodetectors has culminated in the realization of individual lowdimensional nanostructured photodetectors fabricated using a top-down approach. [ 4–9 ] Although the individual-nanostructurebased photodetectors exhibit high quantum effi ciency, the top-down approach usually requires a complex and costly lithography process including organic fi lm coating, exposure, metal evaporation, and lift-off. Technologically, if the nanostructures could be assembled in a thin-fi lm form, the metal electrodes could be easily deposited on the fi lm using a hand-operable metal microwire as a mask, and, additionally, the performances of such a thin-fi lm photodetector would be optimized due to the integration of a large number of individual nanostructures. However, compared with the individual-nanostructure-based devices, the reports of nanofi lm photodetectors are comparatively rare, [ 10 ] which is mainly due to the challenge in the fabrication of high-quality nanofi lms that are used as the key sensing elements of devices. Traditional methods for nanofi lm fabrication, such as chemical vapor deposition, atomic layer deposition, and molecular beam epitaxy, require a fairly wellcontrolled environment and sophisticated pieces of equipment with high operating costs. [ 11 ] Therefore, it is very desirable to develop a novel and simple route to fabricate a high-performance nanofi lm photodetector. Solution-based self-assembly is a powerful bottom-up approach for the fi lm fabrication due to low cost and low environmental impact. Most recently, a novel oil/water interface self-assembly has been reported as an effective strategy for the assembly of various nanostructures such as nanoparticles, [ 12 ]

Stacking‐Order‐Dependent Optoelectronic Properties of Bilayer Nanofilm Photodetectors Made From Hollow ZnS and ZnO Microspheres

Innovative bilayer nanofilms composed of semiconducting ZnS and ZnO hollow microspheres are successfully fabricated by an oil-water interfacial self-assembly strategy. The photocurrent of the bilayer film-based photodetectors is dependent on the stacking orders of the building blocks. The optimal optoelectronic properties of the ZnS(up)/ZnO(down) device are much better than those of the monolayer-film based device.

One-dimensional inorganic semiconductor nanostructures: A new carrier for nanosensors

One-dimensional (1D) inorganic semiconductor nanostructures have witnessed an explosion of interest over the last decade because of advances in their controlled synthesis and unique property and potential applications. A wide range of gases, chemicals, biomedical nanosensors, and photodetectors have been assembled using 1D inorganic semiconductor nanostructures. The high-performance characteristics of these nanosensors are particularly attributable to the inorganic semiconducting nanostructure high surface-to-volume ratio (SVR) and its rationally designed surface. In this review, we provide a brief summary of the state-of-the-art research activities in the field of 1D inorganic semiconductor nanostructure-based nanosensors. Some perspectives and the outlook for future developments in this area are presented.

Heteroepitaxial Growth of GaP/ZnS Nanocable with Superior Optoelectronic Response

We demonstrate the controlled growth of coaxial nanocables composed of GaP/ZnS core-shell structures by a facile chemical vapor deposition method. Structural analysis confirms that the cubic GaP (111) plane and wurtzite ZnS (0001) plane present close similarities in terms of hexagonal-arranged atomic configuration with small in-plane lattice mismatch, and the ZnS shell is epitaxially grown on the (100) plane of the cubic GaP core. Compared with the unitary ZnS nanobelts, the GaP/ZnS coaxial nanocables exhibit improved optoelectronic properties such as high photocurrent and excellent photocurrent stability. This approach opens up new strategy to boost the performance of ZnS-based photodetectors.

Nickel Cobaltite Nanostructures for Photoelectric and Catalytic Applications

Bimetallic oxide nickel cobaltite (NiCo2 O4 ) shows extensive potential for innovative photoelectronic and energetic materials owing to their distinctive physical and chemical properties. In this review, representative fabrications and applications of NiCo2 O4 nanostructures are outlined for photoelectronic conversion, catalysis, and energy storage, aiming to promote the development of NiCo2 O4 nanomaterials in these fields through an analysis and comparison of their diverse nanostructures. Firstly, a brief introduction of the spinel structures, properties, and morphologies of NiCo2 O4 nanomaterials are presented. Then, the advanced progress of NiCo2 O4 nanomaterials for both photoelectronic conversion and energy fields is summarized including such examples as solar cells, electrocatalysis, and lithium ion batteries. Finally, further prospects and promising developments of NiCo2 O4 nanomaterials in these significant fields are proposed.

Band Gap Tunable Zn2SnO4 Nanocubes through Thermal Effect and Their Outstanding Ultraviolet Light Photoresponse

This work presents a method for synthesis of high-yield, uniform and band gap tunable Zn2SnO4 nanocubes. These nanocubes can be further self-assembled into a series of novel nanofilms with tunable optical band gaps from 3.54 to 3.18 eV by simply increasing the heat treatment temperature. The Zn2SnO4 nanocube-nanofilm based device has been successfully fabricated and presents obviously higher photocurrent, larger photocurrent to dark current ratio than the previously reported individual nanostructure-based UV-light photodetectors, and could be used in high performance photodetectors, solar cells, and electrode materials for Li-ion battery.

Pseudocapacitance-tuned high-rate and long-term cyclability of NiCo2S4 hexagonal nanosheets prepared by vapor transformation for lithium storage

The high conductivity of bimetallic thiospinel NiCo2S4 endows energy storage devices with very fascinating performance. However, the unsatisfactory rate capability and long-term cyclability of this material series significantly limit their large-scale practical applications such as in electric vehicles and hybrid electric vehicles. Herein, we successfully synthesized NiCo2S4 hexagonal nanosheets with a large lateral dimension of ∼1.35 μm and a thickness of ∼30 nm through a vapor transformation method. The dynamic transformation process of the NiCo2S4 polycrystalline nanosheets from NiCo-hydroxide has been revealed in detail. Originating from their two-dimensional thin-sheet structure with a high aspect ratio, the induced extrinsic capacitive contribution as high as 91% makes them an ideal candidate for high-capacity and high-rate lithium-ion anodes. The NiCo2S4 nanosheets deliver a reversible capacity of 607 mA h g−1 upon 800 cycles at a current density of 2 A g−1. This outstanding long cycle performance sheds light on the structural design of electrode materials for high-rate lithium-ion batteries.