abstract |
An upconverting pigment dispersion includes an upconverting pigment, such as a β-NaYF 4 crystal doped with at least one of Erbium, Ytterbium or Thulium. The upconverting pigment dispersion is aqueous and, thus, includes water. A dispersant is added to increase the stability of the upconverting pigment of the dispersion. |