A semiconductor nanocrystal particle represented by Chemical Formula 1 and having a full width at half maximum (FWHM) of less than or equal to about 30 nanometers (nm) in the emission wavelength spectrum is provided: AxA′(3+α−x)D(2+β)E(9+γ).   Chemical Formula 1 In Chemical Formula 1, A is a first metal including Rb, Cs, or a combination thereof, A′ is an organic substance derived from an ammonium salt, an organic material derived from an organic ligand, or an organic material including a combination thereof, D is a second metal including Sb, Bi, or a combination thereof E is Cl, Br, I, or a combination thereof, 1 0, −1