Polymer microparticles spatially and spectrally encoded using upconversion nanocrystals (UCN) are described for labeling of articles and tissues. UCN having spectrally distinguishable emission spectra are disposed in different portions of an encoding region of each microparticle.

The invention generally relates to materials and methods for creating and/or utilizing upconverting luminescence. More particularly, the invention relates to novel compositions (e.g., nanoparticles) and related methods of preparation and use that enable upconverting luminescence with an efficient excitation optimized at about 800 nm. A unique class of cascade sensitized tri-doped UCNPs with a biocompatiable 800 nm excitable property are disclosed herein, for example, tri-doped -NaYF.sub.4:Nd, Yb, Er (Tm)/NaYF.sub.4UCNPs, which employ Nd.sup.3+ as 800 nm photon sensitizer and Yb.sup.3+ as bridging ions, having strong green or blue upconversion emissions without photobleaching.

A method of fracturing multiple productive zones of a subterranean formation penetrated by a wellbore is disclosed. The method comprises injecting a fracturing fluid into each of the multiple production zones at a pressure sufficient to enlarge or create fractures in the multiple productive zones, wherein the fracturing fluid comprises an upconverting nanoparticle that has a host material, a dopant, and a surface modification such that the upconverting nanoparticle is soluble or dispersible in water, a hydrocarbon oil, or a combination thereof; recovering a fluid from one or more of the multiple production zones; detecting the upconverting nanoparticle in the recovered fluid by exposing the recovered fluid to an excitation radiation having a monochromatic wavelength; and identifying the zone that produces the recovered fluid or monitoring an amount of water or oil in the produced fluid by measuring an optical property of the upconverting nanoparticle in the recovered fluid.

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.

Lanthanide double perovskite nanocrystals are described. The nanocrystals display high energy luminescence, making them useful in a variety of light-emitting materials and devices. Methods of preparing the lanthanide double perovskite nanocrystals using a hot injection method are also described.

A method of fracturing multiple productive zones of a subterranean formation penetrated by a wellbore is disclosed. The method comprises injecting a fracturing fluid into each of the multiple production zones at a pressure sufficient to enlarge or create fractures in the multiple productive zones, wherein the fracturing fluid comprises an upconverting nanoparticle that has a host material, a dopant, and a surface modification such that the upconverting nanoparticle is soluble or dispersible in water, a hydrocarbon oil, or a combination thereof; recovering a fluid from one or more of the multiple production zones; detecting the upconverting nanoparticle in the recovered fluid by exposing the recovered fluid to an excitation radiation having a monochromatic wavelength; and identifying the zone that produces the recovered fluid or monitoring an amount of water or oil in the produced fluid by measuring an optical property of the upconverting nanoparticle in the recovered fluid.

The invention presents a near-infrared photothermal coupling curing non-oxide ceramic slurry, along with its preparation method and application. The ceramic slurry consists of various raw materials, with weight fractions as follows: non-oxide ceramic powder (40?90 parts), photosensitive resin (0.5?20 parts), photosensitive monomer (1?40 parts), photoinitiator (0.25?4 parts), thermal initiator (0.25?4 parts), additive (0.75?5 parts), and up-conversion luminescent material (0.5?4 parts). The non-oxide ceramic powders can include Si.sub.3N.sub.4, TiN, BN, AlN, SiC, WC, TiC, ZrC, TiB.sub.2, and ZrB.sub.2. By combining the photochemical and photothermal dual curing system using near-infrared up-conversion, this invention addresses the issue of insufficient curing encountered in single photocuring or thermal curing processes. Moreover, by incorporating near-infrared light source-driven additive manufacturing, it enables rapid prototyping of high-solid-content non-oxide ceramic slurry, ultimately allowing for the fabrication of high-fidelity non-oxide ceramic structures.

A near infrared-II region (NIR-II) fluorescent rare earth nanoprobe (RENP) test strip and its preparation method are disclosed. The NIR-II fluorescent RENP test strip includes a sample pad, a conjugation pad, a nitrocellulose (NC) membrane, an absorbent pad and a plastic backing. The sample pad, conjugation pad, NC membrane, absorbent pad are superimposed on the plastic backing successively along a horizontal direction. Detection antibodies labeled RENPs are immobilized on the conjugation pad; capture antibodies set as a test line and quality control antibodies set as a control line are sprayed on the NC membrane. RENPs with NIR-II luminescence are selected as an efficient fluorescent probe, and its excellent optical properties make the prepared test strip possesses excellent detection sensitivity, good accuracy, high stability and favorable repeatability. Meanwhile, preparation process of test strip is also simple and controllable, which is suitable for scale production.

A scintillation crystal can include Ln.sub.(1-y)RE.sub.yX.sub.3, wherein Ln represents a rare earth element, RE represents a different rare earth element, y has a value in a range of 0 to 1, and X represents a halogen. In an embodiment, RE is Ce, and the scintillation crystal is doped with Sr, Ba, or a mixture thereof at a concentration of at least approximately 0.0002 wt. %. In another embodiment, the scintillation crystal can have unexpectedly improved linearity and unexpectedly improved energy resolution properties. In a further embodiment, a radiation detection system can include the scintillation crystal, a photosensor, and an electronics device. Such a radiation detection system can be useful in a variety of radiation imaging applications.

The invention generally relates to materials and methods for creating and/or utilizing upconverting luminescence. More particularly, the invention relates to novel compositions (e.g., nanoparticles) and related methods of preparation and use that enable upconverting luminescence with an efficient excitation optimized at about 800 nm. A unique class of cascade sensitized tri-doped UCNPs with a biocompatiable 800 nm excitable property are disclosed herein, for example, tri-doped -NaYF.sub.4:Nd, Yb, Er (Tm)/NaYF.sub.4UCNPs, which employ Nd.sup.3+ as 800 nm photon sensitizer and Yb.sup.3+ as bridging ions, having strong green or blue upconversion emissions without photobleaching.