An Assisting Contact Electrification Strategy for Achieving Self‐Recoverable Mechanoluminescence

ABSTRACT Self‐recoverable mechanoluminescence (ML) is a unique property of materials that can stably emit light under repeated stress, enabling new applications in smart sensing, displays, and wearable devices. However, self‐recoverable ML is very rare and only observed in a few active phosphors excited by piezoelectricity or contact electrification. Herein, we present an assisting contact electrification strategy that can enable inactive phosphors inherently lacking ML to achieve self‐recoverable ML. A typical illustration demonstrates that commercially available LaPO ₄ : Tb ³⁺ , Ce ³⁺ phosphor lacks piezoelectrically excited ML. No ML of Tb ³⁺ is excited in polydimethylsiloxane (PDMS), apart from the ML of LaPO ₄ host. Accordingly, we introduce strongly electrifiable fluoride into PDMS to induce contact electrification, thereby successfully assisting in the excitation of self‐recoverable ML of Tb ³⁺ from the inactive LaPO ₄ : Tb ³⁺ , Ce ³⁺ . This case illustrates that, based on the assisting contact electrification strategy, the originally rare self‐recoverable ML may become a universal property of all phosphors.