Contact Electrification Induced Multicolor Self‐Recoverable Mechanoluminescent Elastomer for Wearable Smart Light‐Emitting Devices

Abstract

Wearable smart light‐emitting devices whose luminescence can respond to human motions have attracted extensive attention. However, the present electroluminescence‐based devices always require power supply and electronic sensors, which makes them inconvenient to use. In this work, the contact electrification induced multicolor mechanoluminescent (ML) Gd3Ga5O12:A (A = Eu3+, Tb3+, Bi3+)/polydimethylsiloxane (PDMS) elastomers are presented. It is revealed that the contact electrification arising from interaction between phosphor and PDMS polymer under mechanics directly excites emission levels, resulting in the self‐recoverable ML not requiring pre‐irradiation and the ultrastrong ML much stronger than that of piezoelectric sulfides. The unique ML mechanism of the elastomers can be understood well according to a proposed electron‐cloud model. Based on the fabric threads processed by the multicolor ML elastomers, some typical wearable smart light‐emitting devices with unique feature of mechanics–photon conversion are designed. It is demonstrated that the devices can emit light sensitively in response to human motions for interactive clothing decoration or dynamic anticounterfeiting, and can quantitatively display real‐time or dynamic stress distributions of body or muscle for human motion monitoring. Therefore, the contact electrification induced multicolor non‐preirradiation ML elastomers are significantly promising for applications in wearable smart light‐emitting devices.

Multimode-Responsive Luminescence of Er3+ Single-Activated CaF2 Phosphor for Advanced Information Encryption

“…Compared to CaF 2 :Er 3+ @ER composite film, noticeable deformation and recovery occur when rubbing the CaF 2 :Er 3+ @PDMS elastomer film. A separation and contact process between CaF 2 :Er 3+ particles and the polymer matrix are also generated simultaneously, resulting in the overlap and separation of their atomic electron cloud , The PDMS could accept electrons after the PDMS film after being rubbed with the CaF 2 :Er 3+ block (Figure S9), indicating the generation of charge in the process of rubbing the CaF 2 :Er 3+ @PDMS elastomer film. In this case, contact electrification should contribute to the ML generation of CaF 2 :Er 3+ @PDMS elastomer film.…”

“…However, when directly grounding CaF 2 :Er 3+ phosphors or rubbing CaF 2 :Er 3+ @epoxy resin (ER) composite film does not produce detectable ML emission although there is certainly local piezoelectric field near the defects or dopants, as shown in Figure e. Therefore, it cannot be assumed that the ML emission of the CaF 2 :Er 3+ sample surely originates from a piezoelectric-induced mechano-luminescence. ,, …”

“…Therefore, it cannot be assumed that the ML emission of the CaF 2 :Er 3+ sample surely originates from a piezoelectric-induced mechano-luminescence. 28,29,33 Notably, the ML behavior of CaF 2 :Er 3+ samples appears to be highly influenced by the polymer matrix. Particularly, green ML emission can be observed by the naked eye when rubbing the elastomer films of the CaF 2 :Er 3+ sample mixed with a certain flexible polymer matrix, such as polyurethane (PU) and PDMS.…”

Application convenient and energy-saving mechano-optics of Er3+-doped X2O2S (X = Y/Lu/Gd) for thermometry

“…Upon external mechanical stimuli, for instance, extruding, bending, stretching, and pressing, mechanoluminescent materials are able to emit luminescence. 1–12 This means that some mechanical actions that are thriftless in our daily life or even in industry production can be collected and recycled in the form of light. This is awfully fascinating, especially considering that we are now facing a new round of grievous energy crisis.…”

Visualized Stress-Temperature Sensor with the Zinc Sulfide and Perovskite Glass Ceramics Composite

“…The stress-temperature sensors, which relay information on both mechanical and thermal stimuli, have indeed garnered attention in various fields including mechanical engineering, manufacturing, smart skin, and structural analysis. − These sensors enable us to maneuver effectively and safely within our surrounding environment. , Among the different sensing materials available, luminescent material offering the advantages of transmitting information through optical signals, providing visualization, reliability and fast response. − Particularly, mechanoluminescence (ML) materials have the ability to convert mechanical stimulation into visible light emission. − This unique property makes them ideal for stress-temperature sensors as they allow for remote control, self-powering, and the ability to visualize stress distribution. − Therefore, dual-modal stress-temperature sensors based on ML materials are attracting great interest. For example, Pan et al developed a multifunctional stress and temperature sensor using CaZnOS/Er.…”