Quantum dot light-emitting diode (QLED) and preparation method therefor, and display

The invention discloses a quantum dot light-emitting diode (QLED) and a preparation method therefor, and a display, and aims to block electron injection in the QLED, strengthen carrier injection balance in the QLED, improve optical output efficiency and resistance to water and oxygen erosion of a device in the QLED, and improve the luminance, working efficiency and service life of the QLED. The invention provides the QLED, wherein the QLED comprises a first electrode layer, a second electrode layer, a hole transport layer arranged between the first electrode layer and the second electrode layer, a quantum dot light-emitting layer arranged between the hole transport layer and the second electrode layer, an electron transport layer arranged between the quantum dot light-emitting layer and the second electrode layer, and an electron buffer layer arranged between the electron transport layer and the second electrode layer.