The disclosure provides a precursor solution, a perovskite solar cell and a preparation method thereof. The solute of the precursor solution includes a metal halide, the solvent of the precursor solution is an organic solvent, and the precursor solution contains nanobubbles, which have a diameter not more than 1000 nm, and the zeta potential of the precursor solution does not exceed −20 mV. The method of preparing the precursor solution includes: (1) preparing an organic solvent containing nanobubbles; (2) dissolving a solute in the organic solvent containing nanobubbles. The precursor solution of the disclosure has a very low zeta potential, and the nanobubbles can exist stably in the organic solvent(s) for up to one month. When comparing with traditional methods for preparing the precursor solution of the perovskite cells, the method for preparing the precursor solution of the disclosure can effectively improve the stability, reproducibility and solubility of the metal halide in the organic solvent(s).

An object of the present invention is to provide a luminescent particle having an emission maximum wavelength in a long wavelength range of 680 nm or longer and exhibiting a high quantum yield; and a compound having an emission maximum wavelength in a long wavelength range of 680 nm or longer and exhibiting a high quantum yield in the particles. According to the present invention, provided is a luminescent particle containing at least one kind of compound represented by Formula (1) (definitions of substituents in the formula are as set forth in the description) and a particle.

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An object of the present invention is to provide a luminescent particle having an emission maximum wavelength in a long wavelength range of 680 nm or longer and exhibiting a high quantum yield; and a compound having an emission maximum wavelength in a long wavelength range of 680 nm or longer and exhibiting a high quantum yield in the particles. According to the present invention, provided is a luminescent particle containing at least one kind of compound represented by Formula (1) (definitions of substituents in the formula are as set forth in the description) and a particle. ##STR00001##

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, strontium iodide, and cesium bromide; 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.

An optically emissive material and, in particular, materials for use in single photon generation technologies, have multiple excited energy states that have different decay rates and can emit photons with different properties. A primary excitation radiation source is configured to apply primary radiation to an optically emissive material to excite the optically emissive material into a primary excited state. A secondary excitation radiation source is configured to apply secondary radiation to a thermal contribution material to generate thermal energy in the thermal contribution material. The thermal contribution material is physically configured to transfer thermal energy to the optically emissive material and excite the optically emissive material from the primary excited state to a secondary excited state for dynamic control of the emission rate, or emitted photon properties, of the optically emissive material.

An optically emissive material and, in particular, materials for use in single photon generation technologies, have multiple excited energy states that have different decay rates and can emit photons with different properties. A primary excitation radiation source is configured to apply primary radiation to an optically emissive material to excite the optically emissive material into a primary excited state. A secondary excitation radiation source is configured to apply secondary radiation to a thermal contribution material to generate thermal energy in the thermal contribution material. The thermal contribution material is physically configured to transfer thermal energy to the optically emissive material and excite the optically emissive material from the primary excited state to a secondary excited state for dynamic control of the emission rate, or emitted photon properties, of the optically emissive material.

The method for producing light-emitting particles each having a surface layer containing Si on a surface of a semiconductor nanocrystal particle composed of a metal halide includes the steps of: forming the semiconductor nanocrystal particle and a poly-siloxane bond from a solution containing a raw material for the semiconductor nanocrystal particle, a silane compound A having a binding group and a hydrolyzable silyl group, and a solvent, to obtain a precursor particle; mixing the precursor particle, a polymer B containing a structural unit having a basic group and a solvophilic structural unit, and a solvent to obtain a mixture; and adding a silane compound C having a hydrolyzable silyl group to the mixture to obtain a light-emitting particle having a layer containing the polymer B and a polymer of the silane compound C on a surface of the precursor particle.

A method for synthesizing nanoparticles with a predetermined size at high or full yield comprises mixing a first precursor material comprising a first compound comprising a halide moiety and a metal or a metalloid, a second precursor material comprising a second compound comprising a polyatomic nonmetal, and a solvent. The method further comprises heating the mixture to colloidally form nanoparticles comprising the polyatomic nonmetal and the metal or metalloid. The halide moiety is selected such as to colloidally form the nanoparticles in a predetermined size range that is at least partially determined by this halide moiety.

An object of the present invention is to provide a luminescent particle having an emission maximum wavelength in a long wavelength range of 680 nm or longer and exhibiting a high quantum yield; and a compound having an emission maximum wavelength in a long wavelength range of 680 nm or longer and exhibiting a high quantum yield in the particles. According to the present invention, provided is a luminescent particle containing at least one kind of compound represented by Formula (1) (definitions of substituents in the formula are as set forth in the description) and a particle.

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Provided are a light-emitting device, a lighting appliance, and a lighting fixture that emit light that tends to promote melatonin secretion. The light-emitting device, the lighting appliance, and the lighting fixture include a light-emitting element having an emission peak wavelength in a range of 400 nm to 490 nm and a first phosphor having an emission peak wavelength in a range of 570 nm to 680 nm. The emitted light has a correlated color temperature that is 1950 K or less, an average color rendering index Ra that is 40 or greater, a full width at half maximum of an emission spectrum indicating a maximum emission intensity in an emission spectrum of the light-emitting device that is 110 nm or less, and a melanopic ratio MR derived from Equation (1) that is 0.233 or less.