An upconversion single molecule probe is provided that includes a core having a nanoparticle seed crystal, where the nanoparticle seed crystal is an upconversion seed crystal, a first shell enveloping the core, and a second shell enveloping the first shell.

Synthesizing upconverting nanoparticles includes heating a precursor solution comprising one or more rare earth salts, an alkali metal salt or alkaline earth salt, and a solvent comprising a plasticizer in a microwave reactor to yield a product mixture, and cooling the product mixture to yield the upconverting nanoparticles. Core-shell upconverting nanoparticles are synthesized by combining the upconverting nanoparticles with a precursor solution comprising one or more rare earth salts, an alkali metal salt or alkaline earth salt, and a solvent comprising a plasticizer to yield a nanoparticle mixture, heating the nanoparticle mixture in a microwave reactor to yield a product mixture, and cooling the product mixture to yield the core-shell upconverting nanoparticles.

A lighting device includes a light source and a photoconversion layer including a perovskite compound represented by Formula 1. The perovskite compound absorbs at least part of light emitted from the light source and emits light having a different wavelength range from the absorbed light:

[A][B][X].sub.3  <Formula 1>

In Formula 1, A is at least one monovalent organic cation, at least one a monovalent inorganic cation, or any combination thereof, B is at least one divalent inorganic cation, and X is at least one monovalent anion.

A nanophosphor in accordance with one exemplary embodiment of the present disclosure includes a fluoride-based nanoparticle co-doped with Ce.sup.3+ and one selected from a group consisting of Tb.sup.3+, Eu.sup.3+ and a combination thereof. The nanophosphor may be excited by a single wavelength of ultraviolet rays to emit various colors of green, yellow, orange, red and the like, and exhibit high photostability without photoblinking. The nanophosphor may be utilized as a bio imaging contrast agent, a transparent display device, an anti-counterfeit code and the like.

Embodiments relate generally to lanthanide nanocrystals as ultraviolet downconverters.

An anti-counterfeiting yarn includes a uniformly distributed up-conversion fluorescent material and a polymer, wherein the up-conversion fluorescent material comprises a maximum weight percent of about 1.8%. A method of preparing an anti-counterfeiting yarn includes mixing functional polymer chips containing up-conversion fluorescent material with polymer chips not containing up-conversion fluorescent material in a ratio such that the fluorescent material is uniformly distributed in the mixture, melting the mixture, extruding the melt into filaments, and producing anti-counterfeiting yarn through spinning and drawing the filaments.

The disclosure relates to a scintillator material for a radiation detector. In an embodiment, the scintillator material can include a crystalline alkaline-earth metal halide comprising at least one alkaline-earth metal selected from Mg, Ca, Sr, Ba, said alkaline-earth metal halide being doped with at least one dopant that activates the scintillation thereof other than Sm.sup.2+, and co-doped with Sm.sup.2+, said alkaline-earth metal halide comprising at least one halogen selected from Br, Cl, I.

Monodisperse particles having: a single pure crystalline phase of a rare earth-containing lattice, a uniform three-dimensional size, and a uniform polyhedral morphology are disclosed. Due to their uniform size and shape, the monodisperse particles self assemble into superlattices. The particles may be luminescent particles such as down-converting phosphor particles and up-converting phosphors. The monodisperse particles of the invention have a rare earth-containing lattice which in one embodiment may be an yttrium-containing lattice or in another may be a lanthanide-containing lattice. The monodisperse particles may have different optical properties based on their composition, their size, and/or their morphology (or shape). Also disclosed is a combination of at least two types of monodisperse particles, where each type is a plurality of monodisperse particles having a single pure crystalline phase of a rare earth-containing lattice, a uniform three-dimensional size, and a uniform polyhedral morphology; and where the types of monodisperse particles differ from one another by composition, by size, or by morphology. In a preferred embodiment, the types of monodisperse particles have the same composition but different morphologies. Methods of making and methods of using the monodisperse particles are disclosed.

New methods and assays for multiplexed detection of analytes using phosphors that are uniform in morphology, size, and composition based on their unique optical lifetime signatures are described herein. The described assays and methods can be used for imaging or detection of multiple unique chemical or biological markers simultaneously in a single assay readout.

An upconversion single molecule probe is provided that includes a core having a nanoparticle seed crystal, where the nanoparticle seed crystal is an upconversion seed crystal, a first shell enveloping the core, and a second shell enveloping the first shell.