OLED Device and Preparation Method Thereof, Display Substrate and Display Apparatus

Abstract

Provided is an OLED device, which includes a first electrode, a second electrode, and a first light emitting unit located between the first electrode and the second electrode. An absorption rate of the first electrode for blue light is greater than an absorption rate of the first electrode for red light, and the absorption rate of the first electrode for blue light is greater than an absorption rate of the first electrode for green light. The first light emitting unit includes a light emitting layer and a hole functional unit located between the first electrode and the light emitting layer. The hole functional unit at least includes at least two hole functional layers, and any hole functional layer includes a second functional layer for injecting holes and a third functional layer for transporting holes which are stacked along a direction away from the first electrode.

What is claimed is: 
     
         1 . An OLED device, comprising:
 a first electrode, a second electrode, and a first light emitting unit located between the first electrode and the second electrode, wherein   an absorption rate of the first electrode for blue light is greater than an absorption rate of the first electrode for red light, and the absorption rate of the first electrode for blue light is greater than an absorption rate of the first electrode for green light;   the first light emitting unit comprises a light emitting layer and a hole functional unit located between the first electrode and the light emitting layer; and   the hole functional unit comprises at least two hole functional layers, and any hole functional layer comprises a second functional layer for injecting holes and a third functional layer for transporting holes which are stacked along a direction away from the first electrode.   
     
     
         2 . (canceled) 
     
     
         3 . The OLED device of  claim 1 , wherein a difference between a lowest unoccupied molecular orbital (LUMO) energy level of the second functional layer adjacent to the first electrode and a work function of the first electrode is smaller than 1.6 eV. 
     
     
         4 - 5 . (canceled) 
     
     
         6 . The OLED device of  claim 1 , wherein, the first electrode is in direct contact with the second functional layer of one of the hole functional layers. 
     
     
         7 . The OLED device of  claim 1 , wherein, a thickness of the second functional layer is smaller than a thickness of the third functional layer. 
     
     
         8 . The OLED device of  claim 1 , wherein a thickness of the second functional layer in the hole functional layer close to the first electrode in the hole functional unit is smaller than a thickness of the second functional layer in the hole functional layer away from the first electrode in the hole functional unit. 
     
     
         9 . The OLED device of  claim 1 , wherein a thickness of the third functional layer in the hole functional layer close to the first electrode in the hole functional unit is smaller than a thickness of the third functional layer in the hole functional layer away from the first electrode in the hole functional unit. 
     
     
         10 . (canceled) 
     
     
         11 . The OLED device of  claim 1 , wherein the light emitting layer comprises a first light emitting layer, a second light emitting layer and a third light emitting layer which are sequentially stacked along the direction away from the first electrode, wherein the first light emitting layer and the second light emitting layer are in direct contact with each other, and a connection layer is disposed between the second light emitting layer and the third light emitting layer. 
     
     
         12 . The OLED device of  claim 11 , wherein the first light emitting layer is a red light emitting layer, the second light emitting layer is a green light emitting layer, and the third light emitting layer is a blue light emitting layer. 
     
     
         13 . The OLED device of  claim 1 , wherein the hole functional unit further comprises a first functional layer for transporting electrons, wherein the first functional layer is located between the first electrode and the at least two hole functional layers, and the first functional layer is in contact with the first electrode;
 the first functional layer comprises an electron transporting material doped with one or more of active metals and active metal compounds; and   an energy level difference between a lowest unoccupied molecular orbital (LUMO) energy level of the second functional layer and a highest occupied molecular orbital (HOMO) energy level of the third functional layer is smaller than 1 electron volt eV.   
     
     
         14 - 17 . (canceled) 
     
     
         18 . The OLED device of  claim 13 , wherein the hole functional layer further comprises a fourth functional layer located between the second functional layer and the third functional layer, wherein the fourth functional layer is a mixed layer comprising a hole injection material and a hole transporting material;
 an energy level difference between a HOMO energy level of the hole transporting material of the fourth functional layer and the LUMO energy level of the second functional layer is smaller than 1 eV, and an energy level difference between the HOMO energy level of the hole transporting material of the fourth functional layer and the HOMO energy level of the third functional layer is smaller than 1 eV.   
     
     
         19 - 20 . (canceled) 
     
     
         21 . The OLED device of  claim 13 , wherein the first functional layer comprises a first material layer in contact with the first electrode and a second material layer between the first material layer and the hole functional layer; the first material layer comprises a metal material, and the second material layer comprises an electron transporting material doped with one or more of an active metal and an active metal compound. 
     
     
         22 . The OLED device of  claim 1 , wherein the first light emitting unit further comprises at least one of: a hole transporting layer between the hole functional unit and the light emitting layer, an electron blocking layer between the light emitting layer and the hole transporting layer, an electron blocking layer between the light emitting layer and the hole functional unit, an electron transporting layer between the light emitting layer and the second electrode, an electron injection layer between the electron transporting layer and the second electrode, and a hole blocking layer located between the light emitting layer and the electron transporting layer. 
     
     
         23 . The OLED device of  claim 1 , further comprising: one or more second light emitting units located between the first light emitting unit and the second electrode; wherein adjacent light emitting units are connected through a connection layer; the first light emitting unit and the second light emitting unit emit light with different colors; and
 at least one of the second light emitting units comprises a light emitting layer and at least one of a hole injection layer, a hole transporting layer, an electron blocking layer, an electron transporting layer, an electron injection layer and a hole blocking layer.   
     
     
         24 . The OLED device of  claim 1 , wherein the first electrode is a reflective anode and the second electrode is a light-transmitting cathode. 
     
     
         25 . A display substrate, comprising the OLED device of  claim 1 . 
     
     
         26 . A display apparatus, comprising the display substrate of  claim 25 . 
     
     
         27 . A preparation method for an OLED device, comprising:
 forming a first electrode, a first light emitting unit and a second electrode on a substrate; wherein an absorption rate of the first electrode for blue light is greater than an absorption rate of the first electrode for red light, and the absorption rate of the first electrode for blue light is greater than an absorption rate of the first electrode for green light; and   forming the first light emitting unit, which comprises sequentially forming a hole functional unit and a light emitting layer;   wherein forming the hole functional unit comprises forming at least two hole functional layers on a side of the first electrode away from the substrate, and any hole functional layer comprises a second functional layer for injecting holes and a third functional layer for transporting holes which are stacked along a direction away from the first electrode.   
     
     
         28 . The preparation method of  claim 27 , wherein the first electrode is in direct contact with the second functional layer of one of the hole functional layers in the hole functional unit. 
     
     
         29 . The preparation method of  claim 27 , wherein the hole functional unit further comprises a first functional layer for transporting electrons in contact with the first electrode, wherein the first functional layer is located between the first electrode and the at least two hole functional layers; and
 the first functional layer comprises an electron transporting material doped with one or more of active metals and active metal compounds; an energy level difference between a lowest unoccupied molecular orbital (LUMO) energy level of the second functional layer and a highest occupied molecular orbital (HOMO) energy level of the third functional layer is smaller than 1 eV.   
     
     
         30 . The preparation method of  claim 29 , wherein the hole functional layer further comprises a fourth functional layer located between the second functional layer and the third functional layer, the fourth functional layer is a mixed layer comprising a hole injection material and a hole transporting material; and
 an energy level difference between a HOMO energy level of the hole transporting material of the fourth functional layer and the LUMO energy level of the second functional layer is smaller than 1 eV, and an energy level difference between the HOMO energy level of the hole transporting material of the fourth functional layer and the HOMO energy level of the third functional layer is smaller than 1 eV.