Smart Mechanoluminescent Phosphors: A Review of Strontium‐Aluminate‐Based Materials, Properties, and Their Advanced Application Technologies

Abstract

Mechanoluminescence, a smart luminescence phenomenon in which light energy is directly produced by a mechanical force, has recently received significant attention because of its important applications in fields such as visible strain sensing and structural health monitoring. Up to present, hundreds of inorganic and organic mechanoluminescent smart materials have been discovered and studied. Among them, strontium‐aluminate‐based materials are an important class of inorganic mechanoluminescent materials for fundamental research and practical applications attributed to their extremely low force/pressure threshold of mechanoluminescence, efficient photoluminescence, persistent afterglow, and a relatively low synthesis cost. This paper presents a systematic and comprehensive review of strontium‐aluminate‐based luminescent materials’ mechanoluminescence phenomena, mechanisms, material synthesis techniques, and related applications. Besides of summarizing the early and the latest research on this material system, an outlook is provided on its environmental, energy issue and future applications in smart wearable devices, advanced energy‐saving lighting and displays.

Fabrication and characterizations of Eu2+‐Dy3+ co‐doped SrAl2O4 ceramics with persistent luminescence

“…Based on the earlier reports 1,41,54,55 and the results obtained in this work, the energy band diagram of (Sr 0.97 Eu 0.01 Dy 0.02 )Al 2 O 4 PersL ceramics was constructed to illustrate the persistent luminescence mechanism in the (Sr 0.97 Eu 0.01 Dy 0.02 )Al 2 O 4 PersL ceramics (Figure 8). The energy band diagram for (Sr 0.97 Eu 0.01 Dy 0.02 )Al 2 O 4 PersL ceramics is composed of the relevant parts of the energy‐level schemes of the Eu 2+ , Dy 3+ , as well as the CB and valence band with the main trapping levels in the SrAl 2 O 4 host materials.…”

Dehydration-Triggered Afterglow Transition in a Mellitate-Based Coordination Polymer

“…Long persistent luminescence (LPL) materials, also known as long afterglow materials, can be excited by visible or ultraviolet (UV) light and can maintain long-lasting luminescence after removing the light source. − Therefore, LPL materials have found applications in various fields such as safety signs, luminescent coatings, light-storage materials, biological imaging, and anti-counterfeiting. − LPL materials mainly include inorganic, organic, and metal–organic materials. − Coordination polymers are a kind of metal–organic material, possessing a highly ordered network structure constructed by coordination interactions between metal ions (or clusters) and organic ligands . With both inorganic and organic units, coordination polymers provide a platform not only for manipulating the metal species and valence states for optimization of trap energy levels and luminescent metal centers , but also to improve the luminescence efficiency and lifetime of the organic component through the interactions of crystallization induction, halogen, host–guest doping, H-aggregation, etc. − …”

“…20−24 To construct single-component LPL coordination polymers, the following points need to be noted. (1) The selection of appropriate metal ions: metal ions in the d 10 closed shell configuration (such as Zn 2+ , Cd 2+ , etc.) can reduce the luminescence quenching caused by d−d transition, which is conducive to stabilizing the excitation states of organic ligands.…”

Programming Positive Mechanofluorescence in Liquid Crystalline Elastomers

“…Thanks to this phenomenon, carbazole-containing LSCEs can be exploited as optical mechanotransducers, i.e., materials capable of detecting mechanical stimuli and converting them into processable optical signals . As a whole, materials that modulate their emission of light upon the application of forces and other external stimuli have sparked a great interest recently because of their widespread applications. − …”