Zuobao Yang

Superior thoroughly mesoporous ternary hybrid photocatalysts of TiO2/WO3/g-C3N4 nanofibers for visible-light-driven hydrogen evolution

A novel and highly efficient visible-light-driven photocatalyst with robust stability, made up of thoroughly mesoporous TiO2/WO3/g-C3N4 ternary hybrid nanofibers, has been fabricated through a foaming-assisted electrospinning process followed by a solution dipping process. These fibers, without the assistance of a noble metal, yielded a high visible-light-driven photocatalytic H2 release rate of ∼286.6 μmol h−1, which was 65 times greater than that displayed by the pure TiO2 counterparts.

Highly Efficient Photocatalytic Hydrogen Evolution in Ternary Hybrid TiO2/CuO/Cu Thoroughly Mesoporous Nanofibers

Development of novel hybrid photocatalysts with high efficiency and durability for photocatalytic hydrogen generation is highly desired but still remains a grand challenge currently. In the present work, we reported the exploration of ternary hybrid TiO2/CuO/Cu thoroughly mesoporous nanofibers via a foaming-assisted electrospinning technique. It is found that by adjusting the Cu contents in the solutions, the unitary (TiO2), binary (TiO2/CuO, TiO2/Cu), and ternary (TiO2/CuO/Cu) mesoporous products can be obtained, enabling the growth of TiO2/CuO/Cu ternary hybrids in a tailored manner. The photocatalytic behavior of the as-synthesized products as well as P25 was evaluated in terms of their hydrogen evolution efficiency for the photodecomposition water under Xe lamp irradiation. The results showed that the ternary TiO2/CuO/Cu thoroughly mesoporous nanofibers exhibit a robust stability and the most efficient photocatalytic H2 evolution with the highest release rate of ∼851.3 μmol g(-1) h(-1), which was profoundly enhanced for more than 3.5 times with respect to those of the pristine TiO2 counterparts and commercial P25, suggesting their promising applications in clean energy production.

Enhanced field emission of p-type 3C-SiC nanowires with B dopants and sharp corners

Field emission with a low turn-on field and high stability is very important and highly desired for the practical application of nanostructures in electron emitters. In the present study, we report the growth of p-type 3C-SiC nanowires with B dopants and sharp corners created via the catalyst-assisted pyrolysis of a polymeric precursor. The morphologies, structures and field emission (FE) properties of the resultant SiC nanowires were investigated. FE measurements suggest that the B-doped SiC nanowires have excellent FE performance with a low turn-on field of 1.35 V μm−1 and a high field enhancement factor of ∼4895. More importantly, the current emission fluctuation of B-doped nanowires with an applied field of 1.88 V μm−1 at 200 °C could be improved to ∼11% from ∼22% of the undoped counterparts, suggesting that the high-temperature FE stability of SiC nanowires could be significantly enhanced by the B dopants. The excellent FE performances could be attributed to the special p-type triangular prism-like nanostructures with B dopants and numerous sharp corners on the prism edges, which could reduce the effective work function and remarkably increase the emission site density.

Efficient ultraviolet photodetectors based on TiO2 nanotube arrays with tailored structures

Recently, ultraviolet (UV) photodetectors based on TiO2 semiconductors have attracted intensive attention, due to their wide applications in environmental and biological research, optical communication, astronomical investigations and missile launch detection. However, there still remain material- and fabrication-related obstacles in realizing highly efficient UV photodetectors. Here, we reported the exploration of the efficient UV photodetectors based on the highly ordered TiO2 nanotube arrays (TNAs). The TNAs were prepared by a two-step anodic oxidation with tailored tube lengths and wall thicknesses, and then transplanted to a transparent FTO substrate to construct a front-illuminated photodetector. The as-assembled photodetectors exhibit a satisfactory stability and wavelength selectivity with a high photocurrent, photo-to-dark current ratio and responsivity up to 1395 μA, 10730 and 176.3 A W−1 under the UV illumination of 350 nm (45 μW cm−1) at a given bias of 2 V with TiO2 tube length of 14.7 μm, respectively, suggesting their promising applications in efficient UV photodetectors.

Superior Photodetectors Based on All-Inorganic Perovskite CsPbI3 Nanorods with Ultrafast Response and High Stability

Currently, one-dimensional all-inorganic CsPbX3 (X = Br, Cl, and I) perovskites have attracted great attention, owning to their promising and exciting applications in optoelectronic devices. Herein, we reported the exploration of superior photodetectors (PDs) based on a single CsPbI3 nanorod. The as-constructed PDs had a totally excellent performance with a responsivity of 2.92 × 103 A·W-1 and an ultrafast response time of 0.05 ms, respectively, which were both comparable to the best ones ever reported for all-inorganic perovskite PDs. Furthermore, the detectivity of the PDs approached up to 5.17 × 1013 Jones, which was more than 5 times the best one ever reported. More importantly, the as-constructed PDs showed a high stability when maintained under ambient conditions.

Current emission from P-doped SiC nanowires with ultralow turn-on fields

In the present work, we reported the current emission from P-doped SiC nanowire field emitters, which were synthesized via catalyst-assisted pyrolysis of polysilazane precursors. Directed by F–N theory for enhanced field emission (FE) behaviors, the emitters were grown into nanostructures with two desired characteristics, namely with an ultrahigh aspect ratio as well as incorporated P dopants, which brought profound enhancements to the field enhancement factor (β) and turn-on field (Eto). The as-grown SiC nanowires (SiCNWs) exhibit an aspect ratio over 1500 with a uniform spatial distribution of P dopants. The FE measurements exhibit that the SiCNWs possessed a field enhancement factor up to 11657 and an ultralow Eto of 0.47 V μm−1, which was little achieved among the reported studies. The current emission fluctuations are ∼±4.0% over 5 h, suggesting their good electron emission stability. We mainly attributed the totally excellent FE performances to the ultra-high aspect ratio and the incorporated P dopants of the obtained SiCNWs, which could synergistically cause a significant increase of the field enhancement factor and a decrease of the work function.

Enhancing the Performance of Quantum Dot Light-Emitting Diodes Using Room-Temperature-Processed Ga-Doped ZnO Nanoparticles as the Electron Transport Layer

Colloidal ZnO nanoparticle (NP) films are recognized as efficient electron transport layers (ETLs) for quantum dot light-emitting diodes (QD-LEDs) with good stability and high efficiency. However, because of the inherently high work function of such films, spontaneous charge transfer occurs at the QD/ZnO interface in such a QD-LED, thus leading to reduced performance. Here, to improve the QD-LED performance, we prepared Ga-doped ZnO NPs with low work functions and tailored band structures via a room-temperature (RT) solution process without the use of bulky organic ligands. We found that the charge transfer at the interface between the CdSe/ZnS QDs and the doped ZnO NPs was significantly weakened because of the incorporated Ga dopants. Remarkably, the as-assembled QD-LEDs, with Ga-doped ZnO NPs as the ETLs, exhibited superior luminances of up to 44 000 cd/m2 and efficiencies of up to 15 cd/A, placing them among the most efficient red-light QD-LEDs ever reported. This discovery provides a new strategy for fabricating high-performance QD-LEDs by using RT-processed Ga-doped ZnO NPs as the ETLs, which could be generalized to improve the efficiency of other optoelectronic devices.

Enhanced visible-light responsive photocatalytic activity of N-doped TiO2 thoroughly mesoporous nanofibers

Improving the photocatalytic efficiency of TiO2 semiconductor is crucially important and highly desired for its practical applications. In the present work, aiming to broaden the photoresponse window and limit the photocatalyst aggregation, we reported the exploration of N-doped TiO2 thoroughly mesoporous nanofibers with high purity in morphology via a foaming-assisted electrospinning strategy. The foaming agents and urea were introduced in the raw materials to create the mesopores and incorporate the N dopants into the conventional solid TiO2 nanofibers, respectively, which could be accomplished simultaneously over one-step calcination process. The synergetic combination of N dopants and one-dimensional mesoporous nanostructure allow the TiO2 fibers to exhibit significantly enhanced visible-light photocatalytic activity toward the Rhodamine B and hydrogen evolution, as compared to those of N-doped solid and intrinsic thoroughly mesoporous counterparts, suggesting their promising applications in water purification and energy supply.

Fabrication of highly oriented 4H-SiC gourd-shaped nanowire arrays and their field emission properties

The growth of highly oriented one-dimensional (1D) nanoarrays is critically important and highly desired, since it is one of the fundamental issues to push forward their applications in field emitters. In the current work, we reported the large-scale fabrication of highly oriented 4H-SiC gourd-shaped nanowire arrays with numerous sharp knots around the wire surface, which could be an ideal structural configuration for the exploration of emitters. The nanoarrays were prepared via an electrochemical anodic oxidation process assisted by pulsed voltage at room temperature (RT) and under atmospheric pressure. The formation of the gourd-shaped nanowires was mainly ascribed to the applied pulsed voltage, which caused the etching reaction, happened periodically and made the fluctuation of the diameters. Their measured field emission (FE) characteristics disclosed that the gourd-shaped SiC nanowire arrays had a low turn-on field of 0.95 V μm−1, implying their good FE performances. The current emission fluctuations at RT and 200 °C are measured to be ∼±2.1 and ±2.8%, respectively, suggesting that they are robust to be serviced at high temperatures.

Photodetectors with ultra-high detectivity based on stabilized all-inorganic perovskite CsPb0.922Sn0.078I3 nanobelts

Although significant progress has been made in the development of all-inorganic CsPbI3 (X = Br, Cl and I) perovskites, some crucial points typically concerning their stability and toxicity due to the presence of Pb are yet to be addressed. In the present study, we report the growth of qualified all-inorganic CsPbI3 perovskite nanobelts with high yield and purity via a solvothermal route; herein, Sn has been incorporated to substitute Pb to reduce the toxicity of these nanobelts. XPS analyses showed that the Sn-doped CsPbI3 nanobelts were substantially stabilized and exhibited satisfied stability for up to 15 days when maintained under air conditions. The as-constructed photodetectors (PDs) based on a single CsPb0.922Sn0.078I3 nanobelt displayed overall excellent performance with an ultrahigh detectivity of up to 6.43 × 1013 Jones, which was comparable to the best values of all-inorganic perovskite PDs reported to date.