A quantum dot light-emitting device comprising a first electrode and a second electrode , a quantum dot layer between the first electrode and the second electrode, a first electron transport layer and a second electron transport layer disposed between the quantum dot layer and the second electrode, wherein the second electron transport layer is disposed between the quantum dot layer and the first electron transport layer, and each of the first electron transport layer and the second electron transport layer comprise an inorganic material, wherein a lowest unoccupied molecular orbital (LUMO) energy level of the second electron transport layer is shallower than a lowest unoccupied molecular orbital (LUMO) energy level of the first electron transport layer, and a lowest unoccupied molecular orbital (LUMO) energy level of the quantum dot layer is shallower than a lowest unoccupied molecular orbital (LUMO) energy level of the second electron transport layer, wherein the first electron transport layer comprises a first metal oxide nanoparticle, and the second electron transport layer comprises a second metal oxide nanoparticle, the second metal oxide nanoparticle being different from the first metal oxide nanoparticle, provided that when the first metal oxide nanoparticle includes zinc, the second metal oxide nanoparticle does not include zinc; and wherein the LUMO energy level is measured by ultraviolet photoelectron spectroscopy. a first electrode and a second electrode , a quantum dot layer between the first electrode and the second electrode, a first electron transport layer and a second electron transport layer disposed between the quantum dot layer and the second electrode, wherein the second electron transport layer is disposed between the quantum dot layer and the first electron transport layer, and each of the first electron transport layer and the second electron transport layer comprise an inorganic material, wherein a lowest unoccupied molecular orbital (LUMO) energy level of the second electron transport layer is shallower than a lowest unoccupied molecular orbital (LUMO) energy level of the first electron transport layer, and a lowest unoccupied molecular orbital (LUMO) energy level of the quantum dot layer is shallower than a lowest unoccupied molecular orbital (LUMO) energy level of the second electron transport layer, energy level of the second electron transport layer is shallower than a lowest unoccupied molecular orbital (LUMO) energy level of the first electron transport layer, and a lowest unoccupied molecular orbital (LUMO) energy level of the quantum dot layer is shallower than a lowest unoccupied molecular orbital (LUMO) energy level of the second electron transport layer, wherein the first electron transport layer comprises a first metal oxide nanoparticle, and the second electron transport layer comprises a second metal oxide nanoparticle, the second metal oxide nanoparticle being different from the first metal oxide nanoparticle, provided that when the first metal oxide nanoparticle includes zinc, the second metal oxide nanoparticle does not include zinc; and wherein the LUMO energy level is measured by ultraviolet photoelectron spectroscopy. <EOS>