Search

Solar‐driven water evaporation and valuable fuel generation is an environmentally friendly and sustainable way for clean water and energy production. However, a few bottlenecks for practical applications are high‐cost, low productivity, and severe sunlight angle dependence. Herein, solar evaporation with enhanced photocatalytic capacity that is light direction insensitive and of efficiency breakthrough by virtue of a three‐dimensional (3D) photothermal catalytic spherical isotopic evaporator is demonstrated. A homogeneous layer of microfluidic blow spun polyamide nanofibers loaded with efficient light absorber of polypyrrole nanoparticles conformally wraps onto a lightweight, thermal insulating plastic sphere, featuring favorable interfacial solar heating and efficient water transportation. The 3D spherical geometry not only guarantees the omnidirectional solar absorbance by the light‐facing hemisphere, but also keeps the other hemisphere under shadow to harvest energy from the warmer environment. As a result, the light‐to‐vapor efficiency exceeds the theoretical limit, reaching 217% and 156% under 1 and 2 sun, respectively. Simultaneously, CO2 photoreduction with generated steam reveals a favorable clean fuels production rate using photocatalytic spherical evaporator by secondary growth of Cu2O nanoparticles. Finally, an outdoor demonstration manifests a high evaporation rate and easy‐to‐perform construction on‐site, providing a promising opportunity for efficient and decentralized water and clean fuel production. [ABSTRACT FROM AUTHOR]

Quantum dots (QDs) have gained extensive attention owing to their outstanding photoelectric properties. However, the fast and continuous synthesis of QDs remains a challenge. Herein, for the first time, we develop a magnetothermal microfluidic technique (MMT) to rapidly synthesize CdSe and CdSe@ZnS QDs with higher optical performance and continuous production. The as-prepared CdSe@ZnS QDs exhibit relatively high photoluminescence quantum yields (PL QYs) (∼70%). Meanwhile, by manipulating the fluid rate and reaction temperature of the MMT, the emission wavelengths can be tuned in the visible region from 515 to 625 nm. Furthermore, the red emissive CdSe@ZnS QDs are used as fluorescent conversion materials in a backlight display, which shows a wide color gamut around 112%. Our purpose is to highlight a new powerful platform of the MMT for rapid, accurate, and continuous fabrication of photoluminescent nanomaterials, which will guide the substantial progress of backlight displays and light emitting diodes (LEDs). [ABSTRACT FROM AUTHOR]

The stability and electronic structures of AlN nanowires with and without N-vacancy are investigated using firstprinciples calculations. We find that there is an inverse correlation between formation energy and diameter in ideal AlN nanowires. After calculating the formation energies of N-vacancy at different sites in AlN nanowires with different diameters, we find that the N-vacancy prefers to stay at the surface of the nanowires and it is easier to fabricate them under Al-rich conditions. Through studying the electronic properties of AlN nanowires with N-vacancies, we further find that there are two isolated bands in the deep part of the band gap, one of them is fully occupied and the other is half occupied. The charge density indicates that the half-fully occupied band arises from the Al at the surface, and this atom becomes an active centre. [ABSTRACT FROM AUTHOR]

Highlights: [•] IO branches are different with the increase of aluminum concentration. [•] IO phonons in high frequency range increase linearly. [•] IO phonons in low frequency range do not increase linearly. [•] The electron-IO phonon coupling in high frequency range increase linearly. [•] The electron-IO phonon coupling in higher aluminum concentration range is stronger. [Copyright &y& Elsevier]

Solar-driven water evaporation and valuable fuel generation is an environmentally friendly and sustainable way for clean water and energy production. However, a few bottlenecks for practical applications are high-cost, low productivity, and severe sunlight angle dependence. Herein, solar evaporation with enhanced photocatalytic capacity that is light direction insensitive and of efficiency breakthrough by virtue of a three-dimensional (3D) photothermal catalytic spherical isotopic evaporator is demonstrated. A homogeneous layer of microfluidic blow spun polyamide nanofibers loaded with efficient light absorber of polypyrrole nanoparticles conformally wraps onto a lightweight, thermal insulating plastic sphere, featuring favorable interfacial solar heating and efficient water transportation. The 3D spherical geometry not only guarantees the omnidirectional solar absorbance by the light-facing hemisphere, but also keeps the other hemisphere under shadow to harvest energy from the warmer environment. As a result, the light-to-vapor efficiency exceeds the theoretical limit, reaching 217% and 156% under 1 and 2 sun, respectively. Simultaneously, CO 2 photoreduction with generated steam reveals a favorable clean fuels production rate using photocatalytic spherical evaporator by secondary growth of Cu 2 O nanoparticles. Finally, an outdoor demonstration manifests a high evaporation rate and easy-to-perform construction on-site, providing a promising opportunity for efficient and decentralized water and clean fuel production., (© 2021 The Authors. Advanced Science published by Wiley-VCH GmbH.)

ZnO Quantum dots with particle sizes about 5 nm were prepared by sol-gel method, the research about the photo luminescence(PL)/photoluminescence excitation(PLE) spectrum and the fluorescence lifetime indicated that the green emissions can be divided into two parts which were attributed to different transit mechanisms. The higher energy green emission was due to the electrons transit from conduction band to oxygen vacancies while the lower energy green emission was assigned to the electrons transit from the shallow donor levels which enhanced the green emission to the oxygen vacancies and the shallow donor levels was also the reason why the green emission reach strongest intensity when the excitation energy was a little lower than the band gap energy. While the blue emission can be explained by the electrons transiting from Zinc intervals to the valence band. The two mechanisms of green emission are first highlighted and should be considered in the optical application.