Fabrication of Robust, Anti-reflective, Transparent Superhydrophobic Coatings with a Micropatterned Multilayer Structure.

Transparent superhydrophobic coatings with mechanical stability, self-cleaning function, and anti-reflective property have drawn much attention due to the great potential in a variety of real-world applications. In this work, we develop an ingenious approach to construct micropatterned transparent superhydrophobic coatings with a multilayer structure (water contact angle ∼153.6°, sliding angle ∼3.2°). A micropatterned ultraviolet-cured resist frame facilitates durability, while the modified silica nanoparticles, which are housed within the micro-cavities and bonded by an epoxy-based adhesive, impart superhydrophobicity. The micropatterned multilayer surface could endure sandpaper abrasion while maintaining satisfactory hydrophobicity. The prepared surfaces also retain the excellent water repellency after water jet impact, acid submerging, and mechanical bending, suggesting that they are sustainable in the case of adverse conditions and can be integrated with objects with non-flat geometries. Further, the superhydrophobic coatings exhibit an anti-reflection property while preserving high transparency. Taken together, we envision that the design strategies here can offer a practicable route to produce transparent superhydrophobic coatings for diverse outdoor applications.

Factors influencing the working temperature of quantum dot light-emitting diodes.

Quantum dot light-emitting diodes (QLEDs) possess huge potential in display due to their outstanding optoelectronic performance; however, serve degradation during operation blocks their practical applications. High temperature is regarded as one of major factors causing degradation. Therefore, a systematical study on the working temperature of QLEDs is very essential and urgent for the development of high stable QLEDs. In this work, different influence factors such as the electro-optic conversion efficiency (EOCE), voltage, current density, active area, substrate size, substrate type and sample contact are discussed in detail on the working temperature of QLEDs. The research results show that the working temperature of general QLEDs under normal operation conditions is usually smaller than 75 °C when the ambient temperature is 25 °C. However, temperature of QLEDs working under extreme conditions, such as high power or small substrate size, will exceed 100 °C, resulting in irreversible damage to the devices. Moreover, some effective measures to reduce the working temperature are also proposed. The analysis and discussion of various influencing factors in this work will provide guidance for the design of stable QLEDs and help them work at a safer temperature.

SnO2-Modified Two-Dimensional CuO for Enhanced Electrochemical Reduction of CO2 to C2H4.

Electrochemical reduction of CO2 was a widespread method for CO2 conversion into valuable chemical fuel. C2H4 is an important product from CO2 reduction. However, conversion of CO2 into the hydrocarbon C2H4 faced large energy barriers. Herein, we, for the first time, achieve a high efficiency for electrochemical conversion of CO2 to C2H4 on a tin-modified CuO. By modifying with Sn, we obtained a related low onset potential of C2H4 as positive as -0.8 V versus RHE and a high Faradaic efficiency of C2H4 as high as 22% at -1.0 V (vs RHE). According to density functional calculation, the Sn dopant mainly enriched the electron density of CuO, while it was electron-poor in the Sn dopants. The rate of CO2 reduction can be enhanced on Cu nanosheets with higher electron density. We believed that this work would promote the development of two-dimensional catalysts for CO2 conversion and deepen the understanding of doping on CO2 reduction.

Construction of 1D/2D α-Fe2O3/SnO2 Hybrid Nanoarrays for Sub-ppm Acetone Detection.

Exhaled acetone is one of the representative biomarkers for the noninvasive diagnosis of type-1 diabetes. In this work, we have applied a facile two-step chemical bath deposition method for acetone sensors based on α-Fe2O3/SnO2 hybrid nanoarrays (HNAs), where one-dimensional (1D) FeOOH nanorods are in situ grown on the prefabricated 2D SnO2 nanosheets for on-chip construction of 1D/2D HNAs. After annealing in air, ultrafine α-Fe2O3 nanorods are homogenously distributed on the surface of SnO2 nanosheet arrays (NSAs). Gas sensing results show that the α-Fe2O3/SnO2 HNAs exhibit a greatly enhanced response to acetone (3.25 at 0.4 ppm) at a sub-ppm level compared with those based on pure SnO2 NSAs (1.16 at 0.4 ppm) and pure α-Fe2O3 nanorods (1.03 at 0.4 ppm), at an operating temperature of 340°C. The enhanced acetone sensing performance may be attributed to the formation of α-Fe2O3-SnO2 n-n heterostructure with 1D/2D hybrid architectures. Moreover, the α-Fe2O3/SnO2 HNAs also possess good reproducibility and selectivity toward acetone vapor, suggesting its potential application in breath acetone analysis.

Porous GaN Submicron Rods for Gas Sensor with High Sensitivity and Excellent Stability at High Temperature.

Highly porous GaN submicron rods have been synthesized successfully by a facile hydrothermal method and heat treatment under controlled atmosphere. The morphology and size of the hydrothermal products are tailorable by adjusting the concentration of precursor solutions. Upon calcination in air, the nanorod-assembled GaOOH submicron rods are converted into bundlelike Ga2O3 and into porous GaN submicron rods under an ammonia flow. Gas-sensing characterization demonstrates that the sensors based on porous GaN exhibit high sensitivity and fast response to ethanol vapor, as well as excellent stability and reliability at high temperature. The highly porous GaN submicron rods with a large specific surface area, small grain size, and high length-to-diameter ratio show better response to ethanol. A possible sensing enhancement mechanism is also proposed. This study provides a promising route for the novel synthesis of GaN submicron rods for high-performance gas sensors.

NiO nanoparticle-decorated SnO2 nanosheets for ethanol sensing with enhanced moisture resistance.

In a high relative humidity (RH) environment, it is challenging for ethanol sensors to maintain a high response and excellent selectivity. Herein, tetragonal rutile SnO2 nanosheets decorated with NiO nanoparticles were synthesized by a two-step hydrothermal process. The NiO-decorated SnO2 nanosheet-based sensors displayed a significantly improved sensitivity and excellent selectivity to ethanol gas. For example, the 3 mol% NiO-decorated SnO2 (SnO2-3Ni) sensor reached its highest response (153 at 100 ppm) at an operating temperature of 260 °C. Moreover, the SnO2-3Ni sensor had substantially improved moisture resistance. The excellent properties of the sensors can be attributed to the uniform dispersion of the NiO nanoparticles on the surface of the SnO2 nanosheets and the formation of NiO-SnO2 p-n heterojunctions. Considering the long-term stability and reproducibility of these sensors, our study suggests that the NiO nanoparticle-decorated SnO2 nanosheets are a promising material for highly efficient detection of ethanol.