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Mechanical luminescence (ML) is the conversion of mechanical energy into light energy when a material is subjected to a force. It is challenging to develop ML materials with tunable luminescent properties by single ion doping, which have broad application prospects in the fields of stress sensing and dynamic signature anticounterfeiting. In this study, a Pr3+ doped Sr2Ga2GeO7 tunable ML material is reported. Due to the traps resulting from unequal substitution of Pr3+–Sr2+ in [SrO6] heptahedra, the deep/shallow traps redistribution occurs towards a multicolor ML from red to green. In addition, even after continuous friction sliding force (15 N), the ML intensities can be recovered after ultraviolet pre‐irradiation, indicating that Sr2Ga2GeO7: Pr3+ has excellent ML emission stability. Based on thermoluminescence analysis, potential PersL and ML mechanisms are further elaborated by a lattice engineering (trap regulation) strategy. In all, the development of single‐ion doped multicolor ML materials may have crucial research value and show a variety of potential applications in the fields of anticounterfeiting and information encryption. [ABSTRACT FROM AUTHOR]

Inorganic lead halide perovskite quantum dots (CsPbX3 QDs (X = Cl, Br, or I)) have attracted more and more attention due to their high absorption coefficient, narrow emission band, high quantum efficiency, and tunable emission wavelength. However, CsPbX3 QDs are decomposed when exposed to bright light, heat, moisture, etc., which leads to severe luminous attenuation and limits their commercial application. In this paper, CsPbBr3@glass materials were successfully synthesized by a one-step self-crystallization method, including melting, quenching and heat treatment processes. The stability of CsPbBr3 QDs was improved by embedding CsPbBr3 QDs into zinc-borosilicate glass. Then, the CsPbBr3@glass was combined with polyurethane (PU) to form a flexible composite luminescent film CsPbBr3@glass@PU. This strategy enables the transformation of rigid perovskite quantum dot glass into flexible luminescent film materials and further improves the photoluminescence quantum yield (PLQY) from 50.5% to 70.2%. The flexible film has good tensile properties, and its length can be strained 5 times as long as the original length. Finally, a white LED was encapsulated by combining CsPbBr3@glass@PU film and red phosphor K2SiF6:Mn4+ with a blue LED chip. The good performance of the obtained CsPbBr3@glass@PU film indicates that it has potential application in flexible liquid crystal displays (LCDs) as a backlight source. [ABSTRACT FROM AUTHOR]

Mechanoluminescence (ML) materials have found potential applications in information storage, anti‐counterfeiting, and stress sensing. Conventional stress sensing based on absolute ML intensity is prone to significant mistakes owing to the unpredictability of measurement surroundings. However, implementing a ratiometric ML sensing technique may considerably ameliorate this issue. In this study, a single activator‐doped gallate material (LiGa5O8:Pr3+) is proposed to determine the relationship between the ML intensity and the change in local positional symmetry that occurs when the material is subjected to stress. The sensing reliability of the ML intensity ratio under different factors (Force; Content; Thickness and Materials) is systematically analyzed, where the factor that has the greatest effect on the proportional ML is the concentration, with the ML intensity asymmetry ratio decreasing from 1.868 to 1.300 varying concentration at constant stress. The colour‐resolved visualization of stress sensing is further realized, which opens a new path for a ratiometric ML‐based strategy to improve the reliability of stress sensing. [ABSTRACT FROM AUTHOR]

Luminous properties play an essential role in phosphor-converted white light-emitting diodes for high-quality illumination, where the self-reducing behavior of doped activators and their excellent thermal stability have received significant attention. Here, we prepared NaY9Si6O26:Mn2+ red phosphors by a high-temperature solid-state reaction method, which achieved self-reduction of Mn4+ → Mn2+ and excellent thermal stability (luminous intensity at 420 K is 98% of that at room temperature) under ambient conditions. First-principles calculations and X-ray photoelectron spectroscopy elucidated a self-reduction mechanism from Mn4+ to Mn2+. The defect types were calculated in conjunction with thermoluminescence, verifying that the low thermal quenching properties originated from the transfer of electrons from the defect energy level to the Mn2+ excited state center induced by the cationic vacancy defect, which suppressed the luminescence loss from thermal quenching. In this work, the effect of defects on luminescence properties is highlighted and the further exploration of defect control is stimulated, opening up a new avenue for new types of highly thermally stable materials. [ABSTRACT FROM AUTHOR]

Mechanoluminescence (ML) materials, which can emit light under external mechanical stimuli, have attracted wide attention in diverse applications such as displays, anti-counterfeiting and 3D signatures. However, weak ML intensity and limited ML regulation methods are still limiting the development of ML materials. In this study, a series of Li0.997YGeO4:0.5% Bi3+,xTb3+ samples are synthesized by a high temperature solid-state reaction method. Based on photoluminescence (PL), crystal structures, ML, persistent luminescence (PersL), diffuse reflectance (DR) spectra and thermoluminescence (TL) analysis, the inherent relationship between PL, PersL and ML is further clarified in detail. The existence of abundant trap sites created by the vacancy of Li+ ions and the Bi3+ → Tb3+ energy transfer can improve the ML properties of phosphors. These excellent materials can open up a new approach for enhancing the ML intensity and expand the application of ML materials in the anti-counterfeiting fields. [ABSTRACT FROM AUTHOR]