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Cr3+-doped Sr3Ga2Ge4O14:0.03Cr3+ (SGGO:0.03Cr3+) phosphor was synthesized via a high-temperature solid-phase method. Considering the tunable structure of SGGO, Ga3+ ions in the matrix were substituted with In3+ ions at a certain concentration. The tuned phosphor produced a red-shifted emission spectrum, with its luminescence intensity at 423 K maintained at 63% of that at room temperature; moreover, the internal quantum efficiency increased to 65.60%, and the external quantum efficiency correspondingly increased to 21.94%. On this basis, SGIGO:0.03Cr3+ was encapsulated into a pc-LED, which was applied in non-destructive testing (NDT) experiments, successfully realizing the recognition of water and anhydrous ethanol, proving its potential application in the field of NDT. [ABSTRACT FROM AUTHOR]

Fibers are added to foam concrete to improve its mechanical properties. Despite several studies about the performance of fiber-reinforced foam concretes, the mechanism of fiber reinforcement in foam concretes is not understood. In this research, the microstructural properties of Polyvinyl alcohol (PVA) fiber-reinforced foam concretes were quantitatively analyzed with different fiber sizes and fiber contents. The relationship between different parameters was investigated to understand how and why fibers influence the microstructural properties of foam concrete. In addition, a regression model was developed to analyze how fibers influence the compressive strength and which parameters have the highest impact on the compressive strength. The results show that the mechanism of reinforcement is different in high-density and low-density foam concretes. In high-density foam concrete, fiber distribution had a dominant impact on the compressive strength, but the pore structure did not show much influence on the strength. However, in low-density foam concrete, fiber distribution significantly influenced pore structure, and an improved pore structure provided higher compressive strength. The size of fibers significantly affects fiber reinforcement efficiency. The large-diameter fibers outperformed small-diameter fibers in improving the compressive strength of high-density foam concrete. In contrast, the small-diameter fibers showed better reinforcement efficiency in low-density foam concrete. By optimizing the PVA fiber size and content, the compressive strength of low-density and high-density foam concretes can be improved by 45.3% and 15.5%, respectively. [ABSTRACT FROM AUTHOR]

Long persistent luminescence (LPL) materials have been widely applied and investigated in the fields of night‐safe, bio‐fluorescent labeling, and optical anti‐counterfeiting because of their unique properties of delayed luminescence. In this work, the focus of this research is to significantly improve the LPL properties of Li2Zn0.9992Ge3O8:0.08%Cr3+ by adjusting the ratio of Li+/Zn2+. On the one hand, when Li+:Zn2+ < 2:1 (Li1.97Zn1.0292Ge3O8:0.08%Cr3+), a deep‐red LPL is produced in the 650–900 nm band for more than 50 h, which is 2.5 times longer than that without regulation. From another perspective, when Li+:Zn2+ > 2:1 (Li2.01Zn0.9892Ge3O8:0.08%Cr3+), the intensity of LPL is enhanced about four times compared to unregulated. The relationship between traps and LPL was comprehensively investigated by analyzing thermoluminescence spectra. Biological tissue penetration experiments were performed and a set of anti‐counterfeit labels was designed. This research will provide guidance for the design of a novel persistent phosphor for the desired trap depth. [ABSTRACT FROM AUTHOR]

Non‐contact ratiometric luminescence thermometry continues to gain popularity over decades due to its fascinating features of high accuracy, fast response, and simplicity. In this regard, rational design of optical thermometers with ultrahigh relative sensitivity and low temperature resolution has become a cutting‐edge topic. Herein, a luminescence intensity ratio thermometric method depending on the emission line at 698 nm (peak 1) and the emission bands at 713 and 721 nm (peaks 2 and 3) of Li1.97Zn1.0292Ge3O8:0.08%Cr3+ is proposed. As temperature elevates from 50 to 300 K, the 698 nm emission line undergoes an 84‐fold increase while the 713 and 721 nm emission bands show the opposite decline trend. This fascinating feature enables high relative sensitivity of 13.09% K−1 and low temperature resolution of 0.032 K, which are superior to most of the reported optical thermometers. This work is expected to provide more insights for designing excellent and reliable optical thermometers by employing Cr3+ activated luminescent materials. [ABSTRACT FROM AUTHOR]