Quantum dots and a composite and a display device including the quantum dots. The quantum dots comprise a semiconductor nanocrystal core comprising indium and phosphorous, and optionally zinc, a semiconductor nanocrystal shell disposed on the semiconductor nanocrystal core, the first semiconductor nanocrystal shell comprising zinc, selenium, and sulfur, wherein the quantum dots are configured to exhibit a maximum photoluminescence peak in a green light wavelength region, and in an ultraviolet-visible (UV-Vis) absorption spectrum of the quantum dots, a ratio A450/Afirst, of an absorption value at 450 nm to an absorption value at a first excitation peak is greater than or equal to about 0.7, and a valley depth (VD) defined by the following equation is greater than or equal to about 0.4:

(Absfirst−Absvalley)/Absfirst=VD



wherein, Absfirst is an absorption value at the first absorption peak wavelength and Absvalley is an absorption value at a lowest point of the valley adjacent to the first absorption peak, and
wherein the maximum photoluminescence peak of the quantum dots has a full width at half maximum of less than or equal to 40 nanometers.