“…Lanthanide-doped luminescent nanocrystals, as a distinctive type of fluorescence materials, exhibit exceptional optical properties such as superior optical stability, narrowband emission, and nonphotobleaching [1,2], which make them highly promising for various applications including biosensors [3,4], multicolour displays [5], lasers [6,7], encoding [8,9], and anticounterfeiting [10][11][12][13]. However, the absorption cross-section (usually ranging from 10 À21 to 10 À19 cm 2 ) of trivalent lanthanide ions is typically small due to the forbidden 4f-4f transition, resulting in the relatively low luminescence brightness [14,15].…”