Fig. 4. In-situ growth strategy.

a Schematic diagram of synthetic process of UCNPs@Bi@SiO₂ nanocomposites⁴¹. b Schematic illustration of preparation of NaYF₄:Yb/Er@CS@Mⁿ⁺S nanocomposites⁴³. c Schematic illustration of designing NaLnF₄@Cu_2-xS theranostic nanoplatform⁴⁷. a Reprinted with permission from ref. ⁴¹ Copyright 2019, American Chemical Society. b Reprinted with permission from ref. ⁴³ Copyright 2020, The Royal Society of Chemistry. c Reprinted with permission from ref. ⁴⁷ Copyright 2019, John Wiley and Sons