UCNPs were modified by F127, a nonionic surfactant, to endow them with good colloidal properties.
Pickering emulsions stabilized by NaYF4:Yb/Tm UCNPs exhibited good stability and uniform shape.
Versatile CS/NaYF4:Yb/Tm HMs were fabricated by the gelling of Pickering emulsion droplets.
The CS/NaYF4:Yb/Tm HMs preserved good upconversion luminescent property.