Designing stimuli-responsive and color-tunable indicators via the coexistence of dual emitting centers

Rare earth-doped luminescent materials have been widely applied in various fields, both in scientific research and practical applications. Recently, motivated by the demand for advanced smart platforms with multicolor and stimuli-responsiveness properties, the design of a single matrix containing a variety of emitting centers has become a trend in the development of luminescent materials. In this study, the design of a smart platform upon the combination of trivalent bismuth and lanthanides ions (Ln3+) in a LuNbO4 fergusonite-type matrix is reported. Importantly, it is found that such Bi3+/Ln3+ co-activated niobates exhibit multiple stimuli-responsiveness and noteworthy color-tunability. Lastly, we demonstrate the possible application of color-changeable indicators for information readouts via luminescent inks using LuNbO4:Bi3+/Ln3+. This work not only offers guidance for developing color tunable and stimuli-responsive inorganic luminescent materials, but also presents great promise in fields from information security, anticounterfeiting, and optical sensing to smart platforms and beyond.