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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]

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) refers to the luminescence phenomenon that occurs when a material is under external mechanical stimuli. However, relying solely on stress information to obtain ML signals is prone to test errors in complex test conditions. In this work, a Tb3+/Eu3+‐doped Lu3Al2Ga3O12 multicolor ML material is reported, in which the ML color can be adjusted from white to red (CIE color coordinates: from (x = 0.313, y = 0.3293) to (x = 0.6183, y = 0.379)) by changing the Eu3+ concentration. In addition, LAGO: 0.25% Tb3+ and LAGO: 1.5% Eu3+ are physically mixed at different mass ratios, and the varied stimuli‐responsed emission characteristics of Tb3+ and Eu3+ ions are used to develop a stress and temperature dual sensing device. Stress and temperature information can be further reflected simultaneously through the blue/red emission ratio IR (ITb/IEu). As the temperature increases, the color changes from white to red (CIE color coordinates: from (x = 0.3259, y = 0.306) to (x = 0.4707, y = 0.3625)), and the relative temperature sensitivity (Sr) is as high as 1.209% K−1 at 298 K. This sensing device provides a new idea for potential structural safety monitoring, multi‐modal anti‐counterfeiting technology, etc. [ABSTRACT FROM AUTHOR]

An activator's selective occupation of a host is of great significance for designing high-quality white light-emitting diode phosphors, while achieving a full-spectrum single-phase white light emission phosphor is challenging. In this study, a boron phosphate solid-solution Na 2 Y 2 (BO 3 ) 2- x (PO 4 ) x O:0.005 Bi 3+ (NYB 2- x P x O:0.005 Bi 3+ ) white phosphor was designed by selectively occupying Bi 3+ activators in the mixed anionic groups. The substitutes of the anionic unit (BO 3 ) 3- by the (PO 4 ) 3- unit are supposed to force part of the Bi 3+ ion to enter the Na lattice site, which produces an intense orange-red emission peaked at 590 nm. In parallel, spectral tuning from blue to white light and an internal quantum efficiency of 56.42% was obtained, and the thermal stabile luminescence intensity remains at 94.2% of the initial intensity after four heating-cooling cycles from 30 to 210 °C (luminescent intensity is 83.6% of room temperature (RT) at 150 °C, with excellent thermal stability and recovery performance). Finally, an excellent color rendering index ( Ra = 90.8 and R9 = 85) was demonstrated for white light-emitting diode devices using only an NYB 1.5 P 0.5 O:0.005 Bi 3+ phosphor and a near-ultraviolet (n-UV) 365 nm LED chip. This work delves into the different selective occupancy of Bi 3+ ions and explores a new avenue for the design of phosphors for full-spectrum white light emission.