Semiconductor nanoparticle assembly, semiconductor nanoparticle assembly dispersion liquid, semiconductor nanoparticle assembly composition, and semiconductor

A semiconductor nanoparticle aggregate that is an aggregate of core/shell type semiconductor nanoparticles including a core including In and P and a shell having one or more layers, in which a peak wavelength of an emission spectrum of the semiconductor nanoparticle aggregate is from 605 nm to 655 nm and a full width at half maximum of the emission spectrum is 43 nm or less. For each semiconductor nanoparticle, (1) an average value of a full width at half maximum of an emission spectrum is 28 nm or less, (2) a standard deviation of a peak wavelength of the emission spectrum is 10 nm or more and 30 nm or less, and (3) a standard deviation of the full width at half maximum of the emission spectrum is 12 nm or less.