Self‐Recoverable and NIR‐I to NIR‐II Tunable Broadband Mechanoluminescence of Cr³⁺‐Doped Antimonate Double Perovskites

Abstract Mechanoluminescence (ML), which generates an optical response to external mechanical stimuli, shows promise for high‐end stress sensing, flexible optoelectronic skin, dynamic mechanical visualization, and anti‐counterfeiting applications. Near‐infrared (NIR) light possesses the advantages of high tissue penetration capability and can be absorbed by certain organic molecules, thus NIR‐ML materials have potential applications in biomechanics imaging, nondestructive composition analysis, etc. However, their practical applications are limited by the emission wavelengths and bandwidths of the NIR‐ML materials. In this study, a series of double perovskites A 2 MSbO 6 :Cr 3+ (A = Sr, Ba; and M = Ga, Sc) is reported with self‐recoverable NIR‐ML emissions. By modulating the composition, the ML emission coverage are tuned from NIR‐I to NIR‐II (700 nm to over 1200 nm), and adjusted the full width at half maximum of the emission to 163 nm. In addition, under ultrasonic stimulation, these A 2 MSbO 6 :Cr 3+ ML materials emitted NIR light, with the NIR light from Sr 2 ScSbO 6 :Cr 3+ penetrating 5 mm of beef tissue. This study expands the library of NIR‐ML light sources and the ML spectral range, thereby promoting new applications of NIR‐ML materials.