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Radio frequency (RF) heating has been considered as a promising method for food pasteurization and disinfestations, materials and heating uniformity are the main considerations in developing and scaling-up RF treatment protocols. In this study, an experimentally validated model of corn seeds was developed to investigate its RF heating characteristics and effects of sample shape on heating uniformity. Results showed that hot spots distributed in the corners and edges but cold ones in the centre of the rectangular sample, which led to the concentration of electric field at the sample edges, thus increased their electric field intensity and loss power. Comparing the temperature distributions of corn samples in six shapes, the best heating uniformity was observed in the special round sample (round corners, edges and surfaces), its uniformity index was 0.04, as its special round surface made the direction of the electromagnetic field in the sample incline to the centre, and homogenized the electric field intensity and loss power density. The results provide an evidence for temperature prediction and uniformity improvement of corn seeds during RF heating.

With the continuous advancement of global industrialization, a large amount of organic and inorganic pollutants have been discharged into the environment, which is essential for human survival. Consequently, the issue of water environment pollution has become increasingly severe. Photocatalytic technology is widely used to degrade water pollutants due to its strong oxidizing performance and non-polluting characteristics, and BiVO4-based photocatalysts are one of the ideal raw materials for photocatalytic reactions. However, a comprehensive global analysis of the factors influencing the photocatalytic performance of BiVO4-based photocatalysts is currently lacking. Here, we performed a meta-analysis to investigate the differences in specific surface area, kinetic constants, and the pollutant degradation performance of BiVO4-based photocatalysts under different preparation and degradation conditions. It was found that under the loading condition, all the performances of the photocatalysts can be attributed to the single BiVO4 photocatalyst. Moreover, loading could lead to an increase in the specific surface area of the material, thereby providing more adsorption sites for photocatalysis and ultimately enhancing the photocatalytic performance. Overall, the construct heterojunction and loaded nanomaterials exhibit a superior performance for BiVO4-based photocatalysts with 136.4% and 90.1% improvement, respectively. Additionally, within a certain range, the photocatalytic performance increases with the reaction time and temperature. [ABSTRACT FROM AUTHOR]

Although cadmium (Cd)‐based nanocrystals have enabled high‐performance quantum‐dot light‐emitting diodes (QLEDs), their mass production is likely to be affected by environmental protection policies. Among all the potential Cd‐free candidates, Cu‐In‐Zn‐S (CIZS) nanocrystals (NCs) have attracted particular interests. Still, the performance of the corresponding LED is currently limited by imbalanced charge injection and luminescence quenching, which are both related to the ZnO‐based electron transporting layer (ETL). This work demonstrates that ZnO nanoparticles (NPs) doped with Sn, Mg (Zn1−x−ySnxMgyO), and passivated with Cl are promising to resolve the above issues. All‐solution‐processed QLEDs based on Cd‐free CIZS NCs are fabricated by using Zn0.9Sn0.1O NPs as the ETL, and the peak external quantum efficiency (EQEmax) was nearly twice that of ZnO (EQEmax = 1.74%). The main reason is that the incorporation of Sn can reduce the conductivity of ZnO by an order of magnitude. Combining the advantages of Zn0.9Sn0.1O, Zn0.8Sn0.1Mg0.1O@Cl NPs are designed by the co‐doping of Mg and Cl passivation. The EQEmax and current efficiency based on Zn0.8Sn0.1Mg0.1O and Zn0.8Sn0.1Mg0.1O@Cl as ETLs are further increased to 4.84%, 14.00 cd A−1 and 5.53%, 15.99 cd A−1, respectively. The positive effects of Mg ions can remarkably optimize energy level structure to balance charge injection, while Cl can further passivate defects. The findings offer a new guideline for developing Cd‐free light‐emitting diodes. [ABSTRACT FROM AUTHOR]

Investigating the effect of different phases on the optical performance is crucial for thermal sensing phosphor materials. Ba(2−x)SrxMgWO6:Er3+, Yb3+, K+ double perovskite phosphors were successfully prepared using a high-temperature solid-phase method. The dominant up-conversion luminescent (UCL) mechanism was deduced by analyzing the power-dependence spectra and energy level diagrams. By X-ray diffraction tests and tolerance factor calculations, it was demonstrated that the substitution of Sr2+ ions for Ba2+ ions led to the phase changing from cubic to tetragonal. The phase transition led to a decrease in the crystallographic symmetry of the compounds and changes in the optical thermometric properties. The optical temperature sensing properties were investigated using the fluorescence intensity ratio of thermally coupled energy levels (2H11/2 and 4S3/2 to the ground state energy level 4I15/2) of Er3+ ions in Ba2MgWO6, BaSrMgWO6 and Sr2MgWO6. The maximum absolute sensitivities obtained for Ba2MgWO6, BaSrMgWO6 and Sr2MgWO6 doped with 7% Er3+, 2% Yb3+ and 9% K+ were 6.77 × 10−4 K−1, 10.09 × 10−4 K−1 and 23.4 × 10−4 K−1, respectively. The comparison revealed that the phase transition caused an increase in the luminescence intensity and absolute sensitivity. This provides a useful pathway for modulating the subsequent thermometric performance. [ABSTRACT FROM AUTHOR]

A series of red-emitting BaLaLiWO6:Mn4+ (BLLW:Mn4+) phosphors were successfully synthesized by a high-temperature solid-state reaction method. The crystal structure and luminescence properties of the obtained samples were systematically investigated. The emission spectra exhibited a deep red emission band peaking at 716 nm with a full width at half-maximum (FWHM) of 44 nm under 340 nm excitation. The optimal Mn4+ molar concentration was about 1.2%. In addition, the luminescence mechanism was analyzed using a Tanabe Sugano energy level diagram. With the substitution of Sr for Ba, there was a red shift in the emission spectrum and a blue shift in the excitation spectrum. The emission intensity of BLLW:1.2%Mn4+ at 150 °C was about 22% of the initial value at room temperature. In contrast, the emission intensity of SrLaLiWO6:1.2%Mn4+ still maintained 79% of the initial emission intensity at room temperature at 150 °C. This was due to the fact that with the substitution of Sr for Ba, the W–O bond length gradually decreases, which gradually enhanced the crystal field strength of Mn4+. [ABSTRACT FROM AUTHOR]

The removal of chlorophenol (CP) contaminants from water is a great challenge owing to their natural robustness and the toxic chlorinated by-products generated in degradation processes. In this work, a series of three-dimensional nanoflower-like structured photocatalysts (CQDs/ZnIn2S4-x, x = 1, 2, or 3 wt%) were fabricated via a facile hydrothermal approach. Excellent photocatalytic abilities toward 4-CP degradation under Xe lamp irradiation were achieved over the as-prepared composites. The removal efficiency of total organic carbon for 4-CP on the optimized CQDs/ZnIn2S4-2 was 49.1%, which was 16.0% higher than that of ZnIn2S4. The presence of CQDs could not only be used to adjust controllable band structures for enhancing light absorption, but it could also serve as an electron acceptor to promote the transition of electron–hole pairs. Moreover, a possible degradation mechanism of 4-CP was also proposed according to the analyses of active species, electron paramagnetic resonance characterization, degradation products, and attacked sites. Overall, this work unveils a superior function of an efficient photocatalyst for refractory organic pollutants. [ABSTRACT FROM AUTHOR]

With the increasing demand for new inorganic functional materials, more and more attention is paid to rare earth ion doped luminescent materials. In this work, an Eu2+ doped Ba4La6O(SiO4)6 phosphor was synthesized by the high temperature solid-phase method. In the phosphor, two Ba2+ sites could be occupied by Eu2+ cations to provide two different kinds of coordination environments, resulting in broad emitting bands in the range of 450–630 nm and ultra-wide excitation bands in the range of 250–500 nm. The presence of two different Eu2+ emitting centers is verified by measuring the photoluminescence spectra and decay curves in Ba4La6O(SiO4)6 phosphors. The temperature dependence of emission intensity and full width at half maximum of Eu2+ in the range of 293–453 K were investigated systematically. The substitution of Ba2+ by Sr2+ can adjust the crystal field; thus, the luminous intensity was improved by 2.07 times and T50 was increased from 380 K to 453 K. Due to the Sr2+ ion doping, some of the Eu3+ ions cannot be reduced and remain in the trivalent state. In addition, by integrating the as-prepared Ba1.42Sr2.5La6O(SiO4)6:Eu phosphor, commercial blue and red phosphors, and a 385 nm LED chip, a white-LED lamp was made, which realized an applicable color rendering index (Ra = 94.6). For the Ba0.42Sr3.5La6O(SiO4)6 phosphor, the emission can be shifted from yellow to green and to yellow by excitation wavelength variation from 250 to 360 and 480 nm, which proves that the phosphor is a promising candidate for anti-counterfeiting applications. [ABSTRACT FROM AUTHOR]