A quantum dot comprising a core comprising a first semiconductor nanocrystal comprising zinc, selenium, and optionally tellurium; and a shell disposed on the core and comprising a second semiconductor nanocrystal having a different composition from the first semiconductor nanocrystal, and comprising zinc and at least one of sulfur and selenium, wherein the shell comprises at least three branches extending from the core, wherein at least one of the branches has a length of greater than or equal to about 2 nm, the quantum dot emits blue light comprising a maximum emission peak at a wavelength of less than or equal to about 470 nm, a full width at half maximum (FWHM) of the maximum emission peak is less than about 35 nm, and the quantum dot does not comprise cadmium.