The trivalent ytterbium (Yb³⁺) ion has been extensively used as an emitter in short-wave infrared (SWIR) lasers, a sensitizer to activate other lanthanide ions for up-conversion luminescence, and a spectral converter in Ln³⁺-Yb³⁺ doubly doped quantum cutting phosphors. Here we report a new function of the Yb³⁺ ion—as an efficient emitting center for SWIR persistent luminescence. We have developed the first real SWIR persistent phosphor, MgGeO₃:Yb³⁺, which exhibits very-long persistent luminescence at around 1000 nm for longer than 100 h. The MgGeO₃:Yb³⁺ phosphor is spectrally transparent to visible/near-infrared light (~400–900 nm) and is a promising ultraviolet-to-SWIR spectral convertor. The MgGeO₃:Yb³⁺ phosphor also exhibits a photostimulated persistent luminescence capability, where the SWIR persistent emission in an ultraviolet-light pre-irradiated sample can be rejuvenated by low-energy light (white or red light) stimulation. The MgGeO₃:Yb³⁺ phosphor is expected to have promising applications in biomedical imaging, night-vision surveillance and photovoltaics.

A novel drug delivery system, containing functional Fe₃O₄, CdTe@ZnS QDs, doxorubicin and a chitosan matrix, was designed via a polymer crosslinking method.