Electroluminescent device comprising a target film comprising a small molecular layer and a large molecular layer and method for fabricating the same, display panel and display device

Abstract

An electroluminescent device and a display device are disclosed. The electroluminescent device includes a hole inject layer, a hole transport layer, an electroluminescent layer, an electron transport layer, and an electron inject layer. At least one of the hole inject layer, the hole transport layer, the electron transport layer, and the electron inject layer is a target film including a small molecular layer and a large molecular layer which are arranged in a stacked manner, and the small molecular layer has a thickness larger than that of the large molecular layer.

What is claimed is: 
     
         1 . An electroluminescent device, comprising a hole inject layer, a hole transport layer, an electroluminescent layer, an electron transport layer, and an electron inject layer, wherein at least one of the hole inject layer, the hole transport layer, the electron transport layer, and the electron inject layer is a target film comprising a small molecular layer and a large molecular layer which are arranged in a stacked manner, and the small molecular layer has a thickness larger than that of the large molecular layer. 
     
     
         2 . The electroluminescent device of  claim 1 , wherein the electron transport layer is the target film. 
     
     
         3 . The electroluminescent device of  claim 2 , wherein a LUMO energy level of the small molecular layer and a LUMO energy level of the large molecular layer increase in an electron transport direction in the electroluminescent device. 
     
     
         4 . The electroluminescent device of  claim 3 , wherein a molecular layer of the electron transport layer away from the electroluminescent layer has the LUMO energy level of 2.6 eV, and a molecular layer of the electron transport layer close to the electroluminescent layer has the LUMO energy level of 2.8 eV. 
     
     
         5 . The electroluminescent device of  claim 3 , wherein a molecular layer of the electron transport layer away from the electroluminescent layer has the LUMO energy level of 2.5 eV, and a molecular layer of the electron transport layer close to the electroluminescent layer has the LUMO energy level of 2.7 eV. 
     
     
         6 . The electroluminescent device of  claim 2 , wherein a molecular layer of the electron transport layer close to the electroluminescent layer has a cross-linked network structure. 
     
     
         7 . The electroluminescent device of  claim 6 , wherein the cross-linked network structure comprises cross-linking groups. 
     
     
         8 . The electroluminescent device of  claim 1 , wherein the target film comprises at least one small molecular layer and at least one large molecular layer, and the small molecular layer and the large molecular layer are arranged alternately. 
     
     
         9 . The electroluminescent device of  claim 1 , wherein the large molecular layer of the target film is closer to the electroluminescent layer than the small molecular layer of the target film. 
     
     
         10 . The electroluminescent device of  claim 1 , wherein the small molecular layer of the target film is closer to the electroluminescent layer than the large molecular layer of the target film. 
     
     
         11 . The electroluminescent device of  claim 1 , wherein the large molecular layer comprises a large molecule and the small molecular layer comprises a small molecule, a relative molecular mass of the large molecule of the large molecular layer ranges from several thousands to several millions, and a relative molecular mass of the small molecule of the small molecular layer is smaller than five hundreds. 
     
     
         12 . The electroluminescent device of  claim 1 , wherein the hole transport layer has a cross-linked network structure. 
     
     
         13 . The electroluminescent device of  claim 1 , wherein the hole inject layer has a cross-linked network structure. 
     
     
         14 . The electroluminescent device of  claim 1 , wherein the electroluminescent layer has a cross-linked network structure. 
     
     
         15 . The electroluminescent device of  claim 1 , wherein the hole transport layer comprises at least two molecular layers that are arranged alternately, a molecular layer of the at least two molecular layers away from the electroluminescent layer has a HOMO energy level of 4.6 eV, and a molecular layer of the at least two molecular layers close to the electroluminescent layer has a HOMO energy level of 4.76 eV. 
     
     
         16 . The electroluminescent device of  claim 1 , wherein the hole transport layer comprises at least two molecular layers that are arranged alternately, a molecular layer of the at least two molecular layers away from the electroluminescent layer has a HOMO energy level of 5.1 eV, and a molecular layer of the at least two molecular layers close to the electroluminescent layer has a HOMO energy level of 5.7 eV. 
     
     
         17 . The electroluminescent device of  claim 1 , wherein a material for the large molecular layer is polythiophene or polyaniline, and a material for the small molecular layer is ethylenedioxythiophene or triphenylamine. 
     
     
         18 . The electroluminescent device of  claim 1 , further comprising a first electrode and a second electrode, wherein a material for the first electrode and a material for the second electrode are both tin indium oxide, a material for the electron transport layer is tungsten oxide, a material for the electron inject layer is molybdenum oxide, and a material for the hole inject layer is vanadium oxide. 
     
     
         19 . The electroluminescent device of  claim 1 , wherein the electroluminescent device is an organic light emitting diode device or a quantum dot light emitting diode device. 
     
     
         20 . A display device comprising:
 a substrate; and   a plurality of electroluminescent devices of  claim 1  on the substrate.