Ratiometric mechanoluminescence in single Pr³⁺‐activated LiGa₅O₈

Abstract

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.

A Bifunctional Luminescent Whitening and Sensing Material Based on Photoluminescence and Mechanoluminescence

“…Consequently, it can make the fabric appear much whiter and brighter, which is called photoluminescence (PL) whitening. − Moreover, it has been found that without any preirradiation, some materials such as ZnS: Cu/Mn 2+ can emit intense light under mechanical stimuli, including friction, stretching, compression, or impact, and their brightness is quantitatively related to the applied stress, which is called mechanoluminescence (ML) sensing. − Accordingly, the PL whitening and ML sensing materials can utilize natural sunlight or ubiquitous mechanical energy in daily life to generate light emissions, avoiding the requirement of an artificial irradiation source. Therefore, these materials show great advantages in energy conservation and environmental protection. − However, the PL whitening and ML sensing effects have never been simultaneously observed in a single material.…”

Sharp-to-Broad Band Energy Transfer in Lithium Aluminate and Gallate Phosphors for SWIR LED

“…The spinel-like structured and crystalline matrix of LiGa 5 O 8 can be doped with various rare earth and transition metal ions, which impart the desired NIR luminescence upon excitation. These doped phosphors exhibit sharp emission lines characteristic of the f – f or d – d transitions of the activator ions in six-coordination sites such as Cr 3+ , Ni 2+ , Tm 3+ , and Pr 3+ . − Recent literature highlights the occurrence of energy transfer between Cr 3+ (broadband emission) and Ni 2+ (broadband emission) . However, the mechanism underlying the energy transfer from sharp-band to broadband emission remains inadequately addressed.…”

Effect of Eu3+ doping on the structural, optical, and photoluminescent properties of LiGa5O8 phosphor

“…The study of persistent luminescence in lithium gallate has also been explored. Wu et al 17 studied the mechano-luminescence properties of Pr 3+ -doped lithium gallate, finding it suitable for stress sensing. They assessed its reliability under various conditions, such as varying force, sample content, and thickness.…”