Semiconductor nanoparticles, semiconductor nanoparticle dispersion and optical member

Semiconductor nanoparticles having a core/shell structure including at least, In, P, Zn, Se, S and a halogen, wherein

• the core comprises In, P, Zn, and S,
• the shell comprises Zn, S, and Se, at least the core comprises the halogen,
• contents of P, Zn, Se, S and the halogen, in terms of molar ratio with respect to In, are as follows:
• 0.05 to 0.95 for P,
• 0.50 to 15.00 for Zn,
• 0.50 to 5.00 for Se,
• 0.10 to 15.00 for S, and
• 0.10 to 1.50 for the halogen, and
• a sum total of a number of moles of Se and a number of moles of S in the semiconductor nanoparticles is larger than a number of moles of Zn in the semiconductor nanoparticles.