Quantum dot security inks
First Claim
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1. A security ink, comprising:
- a liquid medium; and
a plurality of quantum dots disposed in said medium which, upon excitation with a light source, exhibit a quantum yield greater than 30%, and a photoluminescence which has at least one lifetime of more than 40 nanoseconds but less than 1 millisecond and which varies by at least 5% across the emission spectrum of the quantum dots.
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Abstract
A security ink is provided which includes a liquid medium having a plurality of quantum dots disposed therein. Upon excitation with a suitable light source, the ink exhibits a quantum yield greater than 30%, and a photoluminescence which has a lifetime of more than 40 nanoseconds and which varies by at least 5% across the emission spectrum of the quantum dots. Also disclosed are apparatuses for using the same for anti-counterfeit or authentication purposes, which uniquely identifying the presence of photoluminescent materials by spectrally resolving their photoluminescence lifetime.
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Citations
21 Claims
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1. A security ink, comprising:
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a liquid medium; and a plurality of quantum dots disposed in said medium which, upon excitation with a light source, exhibit a quantum yield greater than 30%, and a photoluminescence which has at least one lifetime of more than 40 nanoseconds but less than 1 millisecond and which varies by at least 5% across the emission spectrum of the quantum dots. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification