A broadband near-infrared nanoemitter powered by mechanical action

The rapid development of near-infrared (NIR) spectroscopic techniques has greatly promoted the discovery of novel luminescent materials as broadband NIR light sources. However, conventional phosphors are typically powered by electricity, which may aggravate the ever-increased energy demands of humanity. Herein, we report a new class of Ga2O3:Cr3+ nanophosphors that can continuously emit broadband NIR light under mechanical action through self-recoverable mechanoluminescence (ML). We show that the ML intensity and profile can be deliberately tuned by local crystal-site engineering through rare-earth and indium substituting. By controlling the dopant concentration of In3+ along with Yb3+ co-doping, highly tunable light emission over a broad range of 650–1,100 nm is realized with a record large full width at half maximum (FWHM) of 267 nm. Our findings enrich the library of NIR light sources with the feature of sustainable photon production, which raises new possibilities for advanced sensing and spectroscopy studies.