The invention provides a
quantum dot electroluminescent device and a preparation method thereof. The
quantum dot electroluminescent device comprises a first
electrode layer; a
quantum dot light emitting layer disposed on the surface of the first
electrode layer; a functional layer disposed on a surface of the
quantum dot light emitting layer remote from the first
electrode layer, the functional layer includes a first sub-functional layer, a second sub-functional layer and a third sub-functional layer stacked in sequence, the second sub-functional layer comprises an
electron transport material,the
band gap widths of the materials corresponding to the first and third sub-functional
layers are larger than that of the
electron transport material, the highest occupied
molecular orbital energylevels of the materials corresponding to the first and third sub-functional
layers are smaller than that of the
electron transport materials, and the lowest unoccupied
molecular orbital energy levelsof the materials corresponding to the first and third sub-functional
layers are larger than that of the electron transport materials, respectively. A second electrode layer disposed on a surface of the functional layer remote from the
quantum dot light emitting layer. By adoption of the
quantum dot electroluminescent device, while balanced carrier injection is realized, the material applicabilityis improved.