Adaptive solid-state luminescent phosphors
AssigneeBoard of Supervisors of Louisiana State University and Agricultural and Mechanical College
InventorJames Anthony Dorman
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Abstract
The absorbance or emission wavelength of composite materials comprising a transition metal doped shell disposed over a rare earth doped core and a functionalizable group on the surface of the transition metal doped shell can change upon subjection to a carboxylic acid. This method of changing the absorbance or emission wavelength of a composite material can be used to identify counterfeit currency using an ink comprising a composite material.
Claims20
A composite material comprising:
- a rare earth doped core;
- a transition metal doped shell disposed over the core;
- and
- a functionalizable group on the surface of the transition metal doped shell.
A method of changing the absorbance or emission spectrum of a nanoparticle, the method comprising:
- providing a nanoparticle having a rare earth doped core, a transition metal doped shell, and at least one surface functionalizable group;
- and
- treating the nanoparticle with at least one carboxylic acid;
- wherein the absorbance or emission spectrum of the nanoparticle is changed upon treatment with the carboxylic acid.
A method of identifying counterfeit currency, the method comprising the steps of:
- providing an ink having a core-shell nanoparticle with surface functionalizable groups;
- applying the ink during the minting of authentic currency;
- treating a currency sample with a solution comprising a carboxylic acid;
- and
- exposing the currency sample to UV light;
- wherein the treatment with carboxylic acid changes the emission wavelength of the core-shell nanoparticle.
Dependencies are inferred from the claim text.