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) Gd 3 Ga 5 O 12 :A (A = Eu 3+ , Tb 3+ , Bi 3+ )/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.