Quantum dot device and quantum dots

An electroluminescent device, comprising

• a first electrode and a second electrode facing each other,
• an emission layer disposed between the first electrode and the second electrode, the emission layer comprising quantum dots, and
• wherein the quantum dots comprise
• a first semiconductor nanocrystal comprising a zinc chalcogenide, and
• a second semiconductor nanocrystal comprising zinc, sulfur, and selenium,
• wherein the quantum dots do not comprise cadmium,
• wherein the quantum dots are configured to emit blue light having a maximum photoluminescent peak wavelength in a range of greater than or equal to about 440 nanometers and a quantum yield of the quantum dots is greater than or equal to 60%,
• wherein the quantum dots have an average value of solidity of greater than or equal to about 0.85, and
• wherein the zinc chalcogenide comprises zinc, selenium, and tellurium.