A new class of battery-free, mechanically powered, piezoelectric Ca₅Ga₆O₁₄:Tb³⁺ phosphors with self-recoverable luminescence

Abstract

A new class of Ca5Ga6O14:Tb3+ mechanoluminescent phosphors with trap-independent, self-recoverable mechanoluminescence and a low mechanical stimulus threshold are reported, whose properties originate from piezoelectricity of the host with giant piezoelectric coefficients.

Bioinspired Bimodal Mechanosensors with Real‐Time, Visualized Information Display for Intelligent Control

“…[ 37 ] Notably, Figure 2g and Figure S8 and Video S2 (Supporting Information) show the ML intensity decreases slowly after external force releasing and the afterglow time of ML is ≈3.29 s (the elapsed times are given in each image). Compared with recently reported ML systems, [ 13,15,21,22,26,27,37–40 ] our bimodal mechanosensor exhibits higher force sensitive and lower trigger pressure threshold (Table S1, Supporting Information). Based on the advantages of high sensitivity and spatial resolution, long afterglow, power‐free, the as‐prepared panel could easily detect local tiny pressure and track the trace of it.…”

“…[12] However, with the defects of high stress threshold (typically more than 1 N), weak intensity, and insufficient sensitivity, most ML sensors consisting of inorganic phosphors (e,g, ZnS: Cu and SrAl 2 O 4 :Eu 2+ ) are to date difficult to achieve real-time and high-resolution imaging. [13,14] To address the challenge, great efforts have been devoted to improving the mechano-sensing performance, such as the synthesis of new efficient ML phosphors, [15][16][17] doping nano particles (like SiO 2 , Al 2 O 3 , In 2 O 3 , and ZrO 2 ) for stress concentration, [18,19] and optimizing the architectures of ML sensors. [20] These strategies have improved luminous intensity and response sensitivity to some extent.…”

Principles, properties, and sensing applications of mechanoluminescence materials

“…Ca 5 Ga 6 O 14 : Tb 3+ features self-healing ML and a low mechanical stimulation threshold, which can be used in battery-free, energy saving ML materials. 110 It is known from the above that the ML mechanism of centrosymmetric materials is related to local piezoelectricity, which is caused by local structural deformation near defects or impurities in the crystal. The tribo-induced electric field also affects the release and recombination of charge carriers trapped in these materials.…”

Multicolor Mechanoluminescence in Sr2Ga2GeO7: Pr3+ for Stress Sensing and Anticounterfeiting

“…Any subtle difference can lead to a change in the local environment, for that different activators have different responses to the changes in crystal field intensity. [ 8 ] In contrast, single‐ion doping is relatively simple, which can achieve stable and excellent luminescence performances with better reproducibility for large‐scale application. [ 9 ] At present, the development of multicolor ML materials based on single doping has become a research focus, but the development is quite limited.…”