Invisible luminescent inks and luminescent films based on lanthanides for anti-counterfeiting

Synthesis of SrF2:Yb:Er ceramic precursor powder by co-precipitation from aqueous solution with different fluorinating media: NaF, KF and NH4F

“…50 The synthesis methods developed are scalable 51 and can be used to obtain nanoparticles in industrial volumes. The nanoparticles obtained can be used to increase the efficiency of solar panels, 35,[52][53][54][55][56] in anticounterfeiting, 57 in the production of thin optical films for anti-reflective protective coatings on glass, 58 in 2D/3D monitors, 59 in bioimaging, 33 pressure and temperature sensors, 60 and in plastic sorting. 61 The physicochemical regularities revealed confirmed the possibility of synthesising precursor powders for laser ceramics using the method of precipitation from aqueous solutions.…”

Effect of the fluorinating agent type (NH4F, NaF, KF) on the particle size and emission properties of SrF2:Yb:Er luminophores

“…1 The maximum theoretical quantum yields for upconversion luminescence are 50%, 33.33% and 25% for two-, three-and four-photon processes, respectively. [2][3][4] In order to be used in nanothermometry, 5,6 up-conversion lasers, 7 dosimeters, 8 bioimaging, [9][10][11][12][13] solar panel efficiency enhancement, [14][15][16][17][18][19][20] anticounterfeiting, [21][22][23] vacuum measurement, 24 and laser cooling, 25 powders with particle sizes in the range of tens of nanometres to tens of microns are required, including those with a core-shell structure. The powders generally have a lower up-conversion PLQY due to the increase in surface area, which is the source of luminescence quenching.…”

Dual-mode luminescence anti-counterfeiting and white light emission of NaGdF4:Ce,Eu,Tb/carbon dot hydrophilic nanocomposite ink

“…Li et al designed and synthesized hyaluronic acid (HA)–lanthanide (Tb 3+ , Eu 3+ ) composite anti-counterfeit luminescent materials with different luminescent colors and successfully constructed the luminescence pattern. 7 With the illumination of a handheld ultraviolet lamp, the encrypted information can be read quickly.…”