Ubiqd, Inc.

Los Alamos National Security, LLC

Triad National Security, LLC

Hunter McDaniel

Matthew R Bergren

Karthik Ramasamy

Victor I Klimov

Chloe Castañeda

Nikolay S Makarov

The present disclosure relates generally to nanoparticle formulations, and more specifically to nanoparticle and ligands used for imparting low-pH solubility in a range of solvents, including photoluminescent materials such as quantum dots.

Low-pH nanoparticles and ligands

An optical element is provided which includes an optical fiber, and a plurality of fluorophores disposed inside the optical fiber. The fluorophores have a quantum yield greater than 50%, and emit a spectrum of light having a maximum intensity at wavelengths within the range of 400 nm to 2000 nm.

Fiber-coupled broadband light source

An optical element is provided which comprises a plurality of fluorophores disposed in a medium. The fluorophores have a quantum yield greater than 50% and an absorption spectrum with a maximum intensity at wavelengths less than 400 nm, and emit a spectrum of light having a maximum intensity at wavelengths within the range of 400 nm to 1200 nm. The optical element is at least partially transparent over the visible region of the spectrum. The optical element is especially useful as a window or other optical component of a greenhouse structure.

Luminescent optical elements for agricultural applications

A method is provided for verifying the authenticity of an article which bears a security mark. The method includes irradiating the security mark with a time-varying light source, ascertaining at least one portion of the emissions spectrum of the irradiated security mark with at least one photodetector, determining the photoluminescence lifetime of the security mark by monitoring the time or frequency response of the photodetector, and verifying the authenticity of the article only if the security mark exhibits a photoluminescence which has a lifetime that falls within the range of appropriate values for each portion of the photoluminescence spectrum for which the photoluminescence lifetime of said security mark was ascertained.

Authentication of quantum dot security inks

Low-PH nanoparticles and ligands

Disclosed herein are embodiments of a composition comprising a polymer or sol-gel and one or more nanocrystals. The composition is useful as a luminescent solar concentrator. The nanocrystals are dispersed in the polymer or sol-gel matrix so as to reduce or substantially prevent nanocrystal-to-nanocrystal energy transfer and a subsequent reduction in the emission efficiency of the composition. In some embodiments, the polymer matrix comprises an acrylate polymer. Also disclosed herein is a method for making the composition. Devices comprising the composition are disclosed. In some cases the polymer is the waveguide, in others the polymer is applied as a coating on a waveguide. In some examples, the device is a window.

Colorless luminescent solar concentrators using colloidal semiconductor nanocrystals

Common approaches to retroreflectors rely on absorptive materials that waste light energy that could be utilized for visibility. Disclosed photoluminescent retroreflectors filter reflected light, like traditional colored retroreflectors, but down-convert photons of the wrong color into a glow visible from more directions. The glow enables visibility for more observers or observers whose light source is far from their line of sight. The color of the glow can be adjusted by choice of luminescent material as a design feature or safety purpose. Certain embodiments utilize photoluminescent additives within a retroreflector while other embodiments utilize a photoluminescent coating on top of a pre-made retroreflector. An exemplary photoluminescent material for these optical devices is CuInZnSquantum dots.

Photoluminescent retroreflector

A fluorescent liquid penetrant is provided which includes a liquid medium having a plurality of fluorophores disposed therein. Upon excitation with a suitable light source, the penetrant exhibits a quantum yield greater than 40% (or in some embodiments, greater than 90%). In some embodiments, the fluorophore is a low-toxicity quantum dot. In some embodiments, the fluorophore has significantly reduced self-absorption, which allows for surface discontinuity depth measurement. Also disclosed are apparatuses for using these fluorescent liquid penetrants for non-destructive testing purposes. In some embodiments, these tests include measuring the depth of a discontinuity by analyzing photoluminescence intensity and/or photoluminescence peak position shift.

Fluorescent liquid penetrants and methods of nondestructive testing

Methods of authenticating security inks

Common approaches to synthesizing alloyed quantum dots employ high-cost, air-sensitive phosphine complexes as the selenium precursor. Disclosed quantum dot synthesis embodiments avoid these hazardous and air-sensitive selenium precursors. Certain embodiments utilize a combination comprising a thiol and an amine that together reduce and complex the elemental selenium to form a highly reactive selenium precursor at room temperature. The same combination of thiol and amine acts as the reaction solvent, stabilizing ligand, and sulfur source in the synthesis of quantum dot cores. A non-injection approach may also be used. The optical properties of the quantum dots synthesized by this new approach can be finely tuned for a variety of applications by controlling size and/or composition of size and composition. Further, using the same approach, a shell can be grown around a quantum dot core that improves stability, luminescence efficiency, and may reduce toxicity.

Synthesis of quantum dots

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.

Growing community of inventors

Los Alamos, NM, United States of America

Hunter McDaniel