Electroluminescent device and semiconductor nanoparticle

A population comprising

• a plurality of semiconductor nanoparticles comprising zinc, selenium, tellurium, and sulfur,
• wherein the semiconductor nanoparticles do not comprise cadmium,
• wherein in the semiconductor nanoparticles,
• a mole ratio of sulfur to tellurium is greater than or equal to about 1:1 and less than or equal to about 110:1,
• the semiconductor nanoparticles are configured to emit light having a maximum emission peak wavelength of greater than or equal to about 440 nanometers and less than or equal to about 580 nanometers,
• the semiconductor nanoparticles exhibit a quantum yield of greater than or equal to about 80%, and
• wherein a mole ratio of selenium to tellurium is greater than or equal to about 25:1-1:1 and less than or equal to about 117:1.

A semiconductor nanoparticle comprising

• a core comprising a first semiconductor nanocrystal comprising ZnTexS1-x, wherein x is greater than or equal to about 0.2 and less than or equal to about 0.5;
• and
• a shell disposed on the core, the shell comprising zinc and selenium,
• wherein
• in the semiconductor nanoparticle, a mole ratio of sulfur to tellurium is greater than or equal to about 0.5:1 and less than or equal to about 110:1, and
• the semiconductor nanoparticle is configured to emit light having a maximum emission peak wavelength of greater than or equal to about 440 nanometers and less than or equal to about 580 nanometers, and
• optionally wherein a mole ratio of selenium to tellurium is greater than or equal to about 1:1 and less than or equal to about 117:1.