Integrating Ultrastable Cyclic Mechanoluminescence and Zero‐Thermal‐Quenching Photoluminescence Unlocks Multifunctional Optical Applications

ABSTRACT Excellent stability is essential for multi‐stimuli‐responsive luminescent materials toward high‐performance multifunctional optoelectronics. However, integrating cyclic‐stable mechanoluminescence (ML) and thermally stable photoluminescence (PL) into a single chemically stable material remains a critical challenge. Herein, we present a novel narrow‐band green‐emitting Ba 0.79 Al 10.9 O 17.14 :0.25Mn 2+ (BAO:0.25Mn 2+ ) phosphor with rigid β ‑Al 2 O 3 ‑type structure, which exhibits a high internal quantum efficiency (IQE) of 60.3% and exceptional zero‐thermal‐quenching (ZTQ) PL behavior up to 523 K. This phosphor exhibits positive moisture resistance, preserving its PL intensity, IQE, and ZTQ feature even after immersion in water for 7 days. Particularly, the BAO:0.25Mn 2+ /polydimethylsiloxane (PDMS) elastomer demonstrates self‐recoverable and ultrastable cyclic ML without obvious degradation even after 15 000 rapid continuous stretching cycles. The ML is confirmed to originate from an interfacial triboelectric effect. By integrating narrow‐band emission, robust thermal and environmental PL stability, as well as superior cyclically stable and self‐recoverable ML within a single material platform, the BAO:0.25Mn 2+ phosphor demonstrates promising applications in wide‑gamut display backlighting, flexible fire‑safety indicators, optical encryption, and interactive pressure mapping. This study not only sheds new light on the integration of PL and ML, but also establishes a promising material platform for advanced multifunctional optical applications, laying a solid foundation for next‐generation intelligent luminescent materials and devices.