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.

Scintillator materials, as well as related systems, and methods of detection using the same, are described herein. The scintillator material composition may comprise a Tl-based scintillator material. For example, the composition may comprise a thallium-based halide. Such materials have been shown to have particularly attractive scintillation properties and may be used in a variety of applications for detection radiation.

The present disclosure discloses, in one arrangement, a scintillator material made of a metal halide with one or more additional group-13 elements. An example of such a compound is Ce:LaBr.sub.3 with thallium (Tl) added, either as a codopant or in a stoichiometric admixture and/or solid solution between LaBr.sub.3 and TlBr. In another arrangement, the above single crystalline iodide scintillator material can be made by first synthesizing a compound of the above composition and then forming a single crystal from the synthesized compound by, for example, the Vertical Gradient Freeze method. Applications of the scintillator materials include radiation detectors and their use in medical and security imaging.

An upconversion nanoparticle includes at least one host selected from LiYF.sub.4, NaY, NaYF.sub.4, NaGdF.sub.4, and CaF.sub.3, at least one sensitizer selected from Sm.sup.3+, Nd.sup.3+, Dy.sup.3+, Ho.sup.3+, and Yb.sup.3+ doped in the at least one host, and at least one activator selected from Er.sup.3+, Ho.sup.3+, Tm.sup.3+, and Eu.sup.3+ doped in the at least one host. The upconversion nanoparticle is designed using a calculation from first principles to absorb light in the near-infrared wavelength range whose stability is ensured. Further, a hyaluronic acid-upconversion nanoparticle conjugate, in which the upconversion nanoparticle as described above is bonded to hyaluronic acid, is provided to be used in various internal sites with a hyaluronic acid receptor, particularly enables targeting, and increases an internal retention period and biocompatibility thereof.

Provided are a core-multishell upconversion nanophosphor capable of being excited by 800±20 nm, 980±20 nm, and 1530±20 nm near-infrared (NIR) light to emit various colors including green, red, blue, and combinations thereof, and a transparent polymer composite including the upconversion nanophosphor. A crystalline shell may be formed between the red, green, and blue emission layers to enable emission of pure red, green, or blue light, and be further formed on an outermost surface to provide a color-tunable and high-brightness upconversion nanophosphor.

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.

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.

Disclosed herein is a material, comprising a first metal halide that is operative to function as a scintillator; where the first metal halide excludes cesium iodide (ScI), strontium iodide (SrI.sub.2), cesium bromide (CsBr), thallium doped cesium iodide (CsI:Tl), europium doped strontium iodide (SrI.sub.2:Eu), europium doped barium iodide (BaI.sub.2;EU), cerium doped strontium iodide (SrI.sub.2:Ce), cerium doped barium iodide (BaI.sub.2:Ce), cerium doped lanthanum bromide (LaBr.sub.3:Ce), and cerium doped lutetium iodide (LuI.sub.3:Ce); and a surface layer comprising a second metal halide that is disposed on a surface of the first metal halide; where the second metal halide has a lower water solubility than the first metal halide.

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.

The present disclosure relates to down-shifting nanophosphors, a method for preparing the same, and a luminescent solar concentrator (LSC) using the same. The down-shifting nanophosphors according to an embodiment of the present disclosure include a core including NaYF.sub.4 nanocrystals doped with neodymium (Nd) and ytterbium (Yb), and further include a neodymium (Nd)-doped crystalline shell surrounding the core, or further include a NaYF.sub.4 crystalline shell surrounding the crystalline shell. Therefore, the down-shifting nanophosphors efficiently absorb near infrared rays with a wavelength range of 700-900 nm and efficiently emit near infrared rays with a wavelength range of 950-1050 nm. In addition, the down-shifting nanophosphors according to an embodiment of the present disclosure has a size of 60 nm or less, and thus can be applied to manufacture transparent LSC films with ease and can realize transparent solar cell modules having high near infrared ray shifting efficiency.