Abstract: A dispersion that includes water and a light-emitting body dispersed in the water. The light-emitting body contains a nanoparticle of a AgInSe compound semiconductor, and a film to which hydrophilicity is imparted by ultrasonic irradiation on a surface of the nanoparticle. The film has a double structure having a first organic molecular film containing an alkylthiol and a second organic molecular film composed mainly of a fatty acid. The light-emitting body has an emission quantum yield of 10% or more, an emission intensity peak wavelength in the range of 650 to 1000 nm, and a half-width ?H of 100 nm or less at the emission intensity peak wavelength.

Abstract: A light emitter is formed from nanoparticles including a compound semiconductor containing an Ag component, In component, and Se component. The peak wavelength of the emission intensity falls within the range of 700 to 1400 nm, and the half-value width ?H for the peak wavelength is 100 nm or less. The light emitted is configured to emit strong light in the near-infrared region, and which is capable of detecting biological information, and is preferred for bioimaging.

Abstract: A light emitter is formed from nanoparticles including a compound semiconductor containing an Ag component, In component, and Se component. The peak wavelength of the emission intensity falls within the range of 700 to 1400 nm, and the half-value width ?H for the peak wavelength is 100 nm or less. The light emitted is configured to emit strong light in the near-infrared region, and which is capable of detecting biological information, and is preferred for bioimaging.