WO2019095380A1 - Quantum-dot electroluminescent component, preparation method therefor, and display device - Google Patents

Abstract

A quantum-dot electroluminescent component (1) comprises a substrate (10), an anode layer (20), functional layers (30) and a cathode layer (40) that are sequentially stacked. The functional layers (30) comprise an electron transport layer (310), light emitting layers (320) and a hole transport layer (330) that are sequentially stacked. The electron transport layer (310) is disposed on one side of the cathode layer (40) adjacent to the substrate (10), and the hole transport layer (330) is disposed on one side of the anode layer (20) distant from the substrate (10). The light emitting layers (320) comprise a green light emitting layer (321), a first electron blocking layer (322), a second electron blocking layer (323), a red light emitting layer (324), and a blue light emitting layer (325). The green light emitting layer (321) is disposed on a surface of the hole transport layer (330) distant from the anode layer (20). The first electron blocking layer (322) and the second electron blocking layer (323) are disposed on surfaces of the green light emitting layer (321) distant from the hole transport layer (330) and do not completely cover the green light emitting layer (321), and the green light emitting layer (321) is a quantum-dot light emitting layer. The red light emitting layer (324) is disposed on a surface of the first electron blocking layer (322) distant from the green light emitting layer (321). The blue light emitting layer (325) is disposed on a surface of the second electron blocking layer (323) distant from the green light emitting layer (321). Also provided are a preparation method for the quantum-dot electroluminescent component (1), and a display device (2) comprising the quantum-dot electroluminescent component (1).

Description

Quantum dot electroluminescent device, preparation method thereof, and display device Technical field

The present invention relates to the field of optoelectronic technology, and in particular to a quantum dot electroluminescent device, a preparation method thereof, and a display device.

Background technique

With the continuous development of display technology, people have higher and higher requirements on the display quality of display devices. The color gamut currently available on the market for LCD TVs is between 68% and 72% according to the National Television Standards Committee standard, and thus cannot provide high-quality color effects. In order to improve the color gamut of LCD TVs, high color gamut backlight technology is becoming the focus of research in the industry. In order to display the color of nature more realistically, the display industry has proposed a new display color standard BT2020. At present, the method of realizing BT2020 mainly adopts a fresher luminescent material, wherein the quantum dot material has the advantages of concentrated luminescence spectrum, high color purity, and the illuminating color can be easily adjusted by the size, structure or composition of the quantum dot material. The color gamut and color reproduction capability of the display device can be effectively improved in the display device.

Summary of the invention

In view of this, the present invention provides a quantum dot electroluminescent device in order to realize an ultra-wide color gamut display that satisfies the BT2020 color gamut requirement, and the specific technical solutions are as follows:

A quantum dot electroluminescent device comprising a substrate, an anode layer, a functional layer and a cathode layer which are sequentially stacked, the functional layer comprising an electron transport layer, a light emitting layer and a hole transport layer, The electron transport layer is disposed on a side of the cathode adjacent to the substrate, the light emitting layer is disposed between the electron transport layer and the hole transport layer, and the hole transport layer is disposed on the anode layer away from the substrate One side

The light emitting layer includes a green light emitting layer, a first electron blocking layer, a second electron blocking layer, a red light emitting layer, and a blue light emitting layer; the green light emitting layer is disposed on a surface of the hole transport layer away from the anode layer The first electron blocking layer and the second electron blocking layer are disposed on a surface of the green light emitting layer away from the hole transport layer, and the first electron blocking layer and the second electron blocking layer are not completely covered a green light emitting layer, wherein the green light emitting layer is a quantum dot light emitting layer; the red light emitting layer is disposed on a surface of the first electron blocking layer away from the green light emitting layer, wherein the blue light emitting layer is disposed at The second electron blocking layer is away from the surface of the green light emitting layer.

Preferably, the LUMO energy level of the first electron blocking layer is higher than the LUMO energy level of the red light emitting layer by at least a first predetermined energy level, and the LUMO energy level of the second electron blocking layer is greater than the LUMO of the blue light emitting layer. The energy level is higher than at least the second predetermined energy level.

Preferably, the green light emitting layer further includes a hole transport type body.

Preferably, a region of the green light emitting layer that is not covered by the first electron blocking layer and the second electron blocking layer is a green light emitting region, and an area of the green light emitting region is smaller than an area of the red light emitting layer and An area smaller than an area of the blue light emitting layer, and an area of the red light emitting layer is smaller than an area of the blue light emitting layer to achieve light emission of the green light emitting region, the red light emitting layer, and the blue light emitting layer The difference in brightness is within the preset range.

Preferably, the first electron blocking layer and the second electron blocking layer are disposed on a surface of the green light emitting layer away from the hole transport layer and are spaced apart from each other.

Preferably, the green light emitting layer includes opposite first and second ends, and the first electron blocking layer and the second electron blocking layer are disposed adjacent to each other in the green light emitting layer away from the hole. A first end on the surface of the layer, the green light emitting region being disposed at a second end of the green light emitting layer away from the surface of the hole transport layer.

Preferably, the green light emitting layer includes opposite first and second ends, and the first electron blocking layer and the second electron blocking layer are disposed adjacent to each other in the green light emitting layer away from the hole. Floor The second end of the surface, the green light emitting region is disposed at a first end of the green light emitting layer on a surface away from the hole transport layer.

Preferably, the functional layer further includes a hole blocking layer disposed in the middle of the light emitting layer and the electron transport layer, and disposed on the red light emitting layer and the blue light emitting layer to emit light away from the green light The surface of the layer and the green light emitting layer are on the surface away from the hole transport layer.

Preferably, the hole blocking layer has a HOMO energy level lower than a HOMO energy level of the blue light emitting layer by a third predetermined energy level, and the hole blocking layer has a LUMO energy level of 2.8-3.0 eV.

Preferably, the red light emitting layer has a HOMO energy level of 5.2-5.4 eV, the red light emitting layer has a LOMO energy level of 2.9-3.1 eV, and the blue light emitting layer has a HOMO energy level of 5.6-6.0 eV. The blue light emitting layer has a LOMO energy level of 2.6-3.0 eV;

The HOMO level of the first electron blocking layer is between the energy levels of the hole transport layer and the red light emitting layer, and the LUMO level of the first electron blocking layer is 2.1-2.3 eV; The HOMO level of the electron blocking layer is between the energy levels of the hole transport layer and the blue light emitting layer, and the LUMO level of the second electron blocking layer is 2.1-2.3 eV.

Preferably, the functional layer further includes a hole injection layer disposed between the substrate and the hole transport layer.

Preferably, the functional layer further includes an electron injection layer disposed between the electron transport layer and the cathode layer.

The invention also provides a method for preparing a quantum dot electroluminescent device, the preparation method comprising:

Providing a substrate;

Forming an anode layer, a functional layer and a cathode layer on the surface of the substrate;

The method for forming the functional layer includes sequentially forming an electron transport layer, a light emitting layer, and a hole transport layer on a side of the anode layer away from the substrate, the light emitting layer being formed between the electron transport layer and the hole transport layer;

The method for forming the light emitting layer includes:

Forming a green light emitting layer on the surface of the hole transport layer away from the anode layer, the green light emitting layer being a quantum dot light emitting layer;

Forming a first electron blocking layer and a second electron blocking layer on a surface of the green light emitting layer away from the hole transport layer;

Forming a red light emitting layer on a surface of the first electron blocking layer away from the green light emitting layer;

A blue light emitting layer is formed on a surface of the second electron blocking layer away from the green light emitting layer.

Preferably, the green light-emitting layer is formed on the surface of the hole transport layer by a coating method.

Preferably, the first electron blocking layer, the second electron blocking layer, the red light emitting layer and the blue light emitting layer are formed by using a patterned mask technology.

The present invention also provides a display device comprising the quantum dot electroluminescent device of any one of claims 1-12.

The invention has the beneficial effects that the invention adopts the green light quantum dots to form the green sub-pixels, and the blue sub-pixels and the red sub-pixels prepared by the deep blue and deep red materials can realize the ultra-wide color gamut display satisfying the BT2020 color gamut requirement. .

DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings to be used in the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without paying for creative labor.

1 is a schematic cross-sectional view of a quantum dot electroluminescent device according to a first embodiment of the present invention.

2 is a schematic cross-sectional view of a quantum dot electroluminescent device according to a second embodiment of the present invention.

3 is a cross-sectional view of a quantum dot electroluminescent device according to a third embodiment of the present invention.

4 is a cross-sectional view of a quantum dot electroluminescent device according to a fourth embodiment of the present invention.

FIG. 5 is a flow chart of a method for fabricating a quantum dot electroluminescent device according to a fifth embodiment of the present invention.

FIG. 6 is a flow chart of a method for preparing a functional layer in a quantum dot electroluminescent device according to a fifth embodiment of the present invention.

FIG. 7 is a flow chart of a method for fabricating a light-emitting layer according to a fifth embodiment of the present invention.

FIG. 8 is a schematic diagram of a display device according to the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

Referring to FIG. 1, a first embodiment of the present invention provides a quantum dot electroluminescent device 1 comprising a substrate 10, an anode layer 20, a functional layer 30 and a cathode layer 40 which are sequentially stacked. The functional layer 30 includes an electron transport layer 310, a light emitting layer 320, and a hole transport layer 330. The electron transport layer 310 is disposed on a side of the cathode layer 40 adjacent to the substrate 10, and the light emitting layer 320 is disposed at Between the electron transport layer 310 and the hole transport layer 330, the hole transport layer 330 is disposed on a side of the anode layer 20 away from the substrate 10. The anode layer 20 is for providing holes, and the hole transport layer 330 is for transporting the holes to the light emitting layer 320. The cathode layer 40 is for providing electrons, and the electron transport layer 310 is for transmitting the electrons to the light emitting layer 320. The holes and the electrons are combined in the light emitting layer 320 to emit light.

The light emitting layer 320 includes a green light emitting layer 321, a first electron blocking layer 322, a second electron blocking layer 323, a red light emitting layer 324, and a blue light emitting layer 325. The green light emitting layer 321 is a quantum dot light emitting layer, and the quantum dot light emitting layer includes green light quantum dots.

In a further embodiment, the material of the green light quantum dot is ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, HgS, HgSe, HgTe, AlN, AlP, AlAs, GaN, GaP, GaAs, GaSb, GaSe, InN, InP , InAs, InSb, T1N, T1P, TlAs, T1Sb, PbS, PbSe, PbTe or a mixture thereof. Among them, CdSe and ZnSe are preferred from the viewpoint of common properties and optical properties. The material of the green light quantum dot is preferably a composite material, preferably CdSe/CdS, CdSe/ZnS, InP/ZnSTe, GaInP/ZnSTe, GaInP/ZnSSe, more preferably CdSe/ZnS.

In a further embodiment, the material of the red light emitting layer 324 is a deep red organic material. Preferably, it is a polystyrene quinoline (PPV-Q) material. Preferably, the material of the blue light emitting layer 325 is a dark blue organic material.

The first electron blocking layer 322 functions to block electrons from being transmitted from the red light emitting layer 324 to the green light emitting layer 321 . The second electron blocking layer 323 functions to block electrons from being transmitted from the blue light emitting layer 325 to the green light emitting layer 321 .

The green light emitting layer 321 is disposed on a surface of the hole transport layer 330 away from the anode layer 20. The first electron blocking layer 322 and the second electron blocking layer 323 are disposed on a surface of the green light emitting layer 321 away from the hole transport layer 330, and the first electron blocking layer 322 and the second electron blocking layer 323 The green light emitting layer 321 is not completely covered.

A region of the green light-emitting layer 321 that is not covered by the first electron blocking layer 322 and the second electron blocking layer 323 is a green light-emitting region 326.

The red light emitting layer 324 is disposed on a surface of the first electron blocking layer 322 away from the green light emitting layer 321 . Since the first electron blocking layer 322 has a function of blocking electron transport, electrons cannot pass through the red light emitting layer 324 to reach the green light emitting layer 321 and recombine with the holes transmitted from the hole transport layer 330. Therefore, although a part of the green light-emitting layer 321 is present under the red light-emitting layer 324, only red light of the red light-emitting layer 324 is emitted in this portion.

The blue light emitting layer 325 is disposed on the second electron blocking layer 323 away from the green light emitting layer 321 on the surface. By the same token, since the second electron blocking layer 323 has a function of blocking electron transport, electrons cannot pass through the blue light emitting layer 325 to reach the green light emitting layer 321 and recombine with the holes transmitted from the hole transport layer 330. Therefore, although a part of the green light-emitting layer 321 is present under the blue light-emitting layer 325, blue light of the blue light-emitting layer 325 is emitted only in this portion.

The green light emitting region 326, the red light emitting layer 324, and the blue light emitting layer 325 described above constitute three color sub-pixels of the quantum dot electroluminescent device 1.

In a further embodiment, the LUMO energy level of the first electron blocking layer 322 is higher than the LUMO energy level of the red light emitting layer 324 by at least a first predetermined energy level, and the LUMO energy level ratio of the second electron blocking layer 323 is The LUMO level of the blue light emitting layer 325 is higher than at least a second predetermined level. Wherein the LUMO energy level refers to the lowest Unoccupied Molecular Orbital (LUMO) energy level. The first predetermined energy level refers to a lowest energy level that the first electron blocking layer 322 can block electrons from passing through the first electron blocking layer 322 and is higher than the LUMO energy level of the red light emitting layer 324. . This will be explained below with further embodiments.

In a further embodiment, the first predetermined energy level is 0.3 eV. That is, assuming that the LUMO level of the red light-emitting layer 324 is 3.0 eV and the LUMO level of the first electron blocking layer 322 is 3.3 eV, the first electron blocking layer 322 can block electrons from passing through the first electron blocking. Layer 322 is combined with the holes. Assuming that the LUMO level of the red light-emitting layer 324 is 3.0 eV, and the LUMO level of the first electron blocking layer 322 is 3.2 eV, the LUMO level of the first electron blocking layer 322 is higher than the LUMO level of the red light-emitting layer 324. The output is only 0.2 eV, and the first predetermined energy level is 0.3 eV. At this time, the first electron blocking layer 322 is unable to block electrons, and the electrons will pass through the first electron blocking layer 322 to combine with the holes, thereby causing A portion of the green light-emitting layer 321 under the red light-emitting layer 324 emits green light, and the emitted green light is confused with the red light emitted by the red light-emitting layer 324, resulting in poor light-emitting effect.

Similarly, in a further embodiment, the second predetermined energy level is 0.3 eV. That is, it is assumed that the LUMO level of the blue light-emitting layer 325 is 3.0 eV, and the LUMO level of the second electron blocking layer 323 is 3.3 eV, then the second electron blocking layer 323 is capable of blocking electrons from passing through the second electron blocking layer 323 in combination with the holes. It is assumed that the LUMO level of the blue light-emitting layer 325 is 3.0 eV, and the LUMO level of the second electron blocking layer 323 is 3.2 eV, and the LUMO level of the second electron blocking layer 323 is higher than the LUMO level of the blue light-emitting layer 325. It is only 0.2eV, and the second predetermined energy level is 0.3eV. At this time, the second electron blocking layer 323 cannot block electrons, and the electrons will pass through the second electron blocking layer 323 to combine with the holes, which will result in A portion of the green light-emitting layer 321 under the blue light-emitting layer 325 emits green light, and the emitted green light is confused with the blue light emitted by the blue light-emitting layer 325, resulting in poor light-emitting effect.

In a further embodiment, the green light emitting layer 321 further includes a hole transport type body. The hole transport type body is used to increase the efficiency of transporting holes. The material of the hole transporting type main body may be 4,4',4"-tris-(N-(naphthylene-2-YL)-N-aniline) triphenylamine (2-TNATA for short), 4, 4 ',4"-tris(N-carbazole)triphenylamine (TCTA), 1,3,5-triphenylbenzene (TDAPB), 4'4"-tris(N,N-bisphenylamine) -triphenylamine (TDATA for short), N,N'-bis(3-naphthyl)-N,N'-diphenyl-1,1'-diphenyl-4,4'-diamine (abbreviated as NPB) , N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (TPD for short), s-(4-amino-2,2,6,6-tetramethyl Any one or more of piperidine) (abbreviated as s-TAD) and 4,4',4"-tris(3-methyl-phenylaniline)triphenylamine (abbreviated as m-MTDATA).

In a further embodiment, the area of the green light emitting layer 321 not covered by the first electron blocking layer 322 and the second electron blocking layer 323 is a green light emitting region 326, and the area of the green light emitting region 326 is smaller than the The area of the red light emitting layer 324 is smaller than the area of the blue light emitting layer 325, and the area of the red light emitting layer 324 is smaller than the area of the blue light emitting layer 325 to realize the green light emitting area 326, The difference in luminance of the red light emitting layer 324 and the blue light emitting layer 325 is within a preset range. It can be understood that, when the green light emitting layer 321 , the red light emitting layer 324 , and the blue light emitting layer 325 are different according to the performance difference or the amount of the light emitting materials, the green light emitting layer 321 , the red light emitting layer 324 , and the blue light emitting layer 325 are different. The area size relationship can be appropriately adjusted to meet the needs of the illuminating color gamut.

In a further embodiment, the first electron blocking layer 322 and the second electron blocking layer 323 are disposed at The green light emitting layer 321 is away from the surface of the hole transport layer 330 and spaced apart from each other. At this time, the green light-emitting region 326 is located between the first electron blocking layer 322 and the second electron blocking layer 323 as shown in FIG. Correspondingly, the red light emitting layer 324 and the blue light emitting layer 325 are located on both sides of the green light emitting region 326. Viewed from directly above the quantum dot electroluminescent device 1, the arrangement of the illuminating colors is red, green, and blue.

Referring to FIG. 2, in the second embodiment of the present invention, the green light emitting layer 321 includes a first end 3211 and a second end 3212 disposed opposite to each other. In this embodiment, it can be understood that the first end 3211 is the left end of the green light emitting layer 321 and the second end 3212 is the right end of the green light emitting layer 321 . The first electron blocking layer 322a and the second electron blocking layer 323a are juxtaposed adjacent to each other at a first end 3211 of the green light emitting layer 321 on a surface away from the hole transport layer 330. The green light emitting region 326a is disposed at a second end 3212 of the green light emitting layer 321 on a surface away from the hole transport layer 330. Correspondingly, the red light emitting layer 324 and the blue light emitting layer 325 are disposed on the left side of the green light emitting layer 321, and the green light emitting area 326a is disposed on the right side of the green light emitting layer 321. Viewed from directly above the quantum dot electroluminescent device 1, the arrangement of the luminescent colors is red, blue, and green.

Referring to FIG. 3 , in the third embodiment of the present invention, the green light emitting layer 321 includes a first end 3211 and a second end 3212 disposed opposite to each other. As in the second embodiment, in the present embodiment, it can be understood that the first end 3211 is the left end of the green light emitting layer 321 and the second end 3212 is the right end of the green light emitting layer 321 . The first electron blocking layer 322b and the second electron blocking layer 323b are juxtaposed adjacent to each other on the second end 3212 of the green light emitting layer 321 away from the surface of the hole transport layer 330, and the green light emitting region 326b A first end 3211 is disposed on a surface of the green light emitting layer 321 away from the hole transport layer 330. Correspondingly, the red light emitting layer 324 and the blue light emitting layer 325 are located on the right side of the green light emitting layer 321, and the green light emitting area 326a is disposed on the right side of the green light emitting layer 321. When viewed from directly above the quantum dot electroluminescent device 1, the arrangement of the luminescent colors is green, red, and blue.

Referring to FIG. 4, in the fourth embodiment provided by the present invention, the functional layer 30 further includes a hole blocking layer 340 disposed in the middle of the light emitting layer 320 and the electron transport layer 310. And The surface of the red light emitting layer 324 and the blue light emitting layer 325 away from the green light emitting layer 321 and the surface of the green light emitting layer 321 away from the hole transport layer 330 are disposed. The hole blocking layer 340 serves to block the role of hole transport to balance the hole and electron transport and improve the light-emitting effect of the quantum dot electroluminescent device.

In a further embodiment, the HOMO level of the hole blocking layer 340 is lower than the third predetermined energy level of the blue light emitting layer 325, and the LUMO level of the hole blocking layer 340 is 2.8-3.0 eV. . The HOMO level refers to the Highest Occupied Molecular Orbital (HOMO) level. The third predetermined energy level refers to a lowest energy level at which the hole blocking layer 340 can block holes passing through the hole blocking layer 340 and lower than the HOMO level of the blue light emitting layer 325. Preferably, the third preset energy level is 0.3-0.5 eV.

In a further embodiment, the HOMO level of the red light emitting layer is 5.2-5.4 eV, and the LOMO level of the red light emitting layer is 2.9-3.1 eV. The blue light emitting layer has a HOMO level of 5.6-6.0 eV, and the blue light emitting layer has a LOMO level of 2.6-3.0 eV. The HOMO level of the first electron blocking layer is between the energy levels of the hole transport layer and the red light emitting layer, and the LUMO level of the first electron blocking layer is 2.1-2.3 eV. The HOMO level of the second electron blocking layer is between the energy levels of the hole transport layer and the blue light emitting layer, and the LUMO level of the second electron blocking layer is 2.1-2.3 eV.

In a further embodiment, the functional layer 30 further includes a hole injection layer 350 disposed between the substrate 10 and the hole transport layer 330. The hole injection layer 350 functions to efficiently inject holes and pass the energy gap between the two layers of the anode layer 20 and the hole transport layer 330 to migrate holes from the anode layer 20 to the hole transport layer 330. The transport rate of hole carriers and electron carriers is balanced. The luminescent display performance of the quantum dot electroluminescent device 1 is improved.

In a further embodiment, the functional layer 30 further includes an electron injection layer 360 disposed between the electron transport layer 310 and the cathode layer 40. The function of the electron injection layer 360 is to effectively inject and reduce the barrier between the two layers of the cathode layer 40 and the electron transport layer 310, and to remove electrons from the cathode. The pole layer 40 migrates to the electron transport layer 310, balancing the transport rates of electron carriers and hole carriers. The luminescent display performance of the quantum dot electroluminescent device 1 is improved.

Referring to FIG. 5, in a fifth embodiment provided by the present invention, a method for preparing a quantum dot electroluminescent device is provided, and the preparation method includes steps S10 and S20. The specific scheme will be described in detail below.

In step S10, a substrate 10 is provided.

In step S20, the anode layer 20, the functional layer 30, and the cathode layer 40 are sequentially formed on the surface of the substrate 10.

Referring to FIG. 6, the forming method of the functional layer 30 includes steps S200, S300, S400, and S500. The specific schemes of the steps S200, S300, S400 and S500 are described in detail below.

Step S200, an electron transport layer 310, a light emitting layer 320, and a hole transport layer 330 are sequentially formed on a side of the anode layer 20 away from the substrate 10, and the light emitting layer 320 is formed between the electron transport layer 310 and the hole transport layer 330. .

Referring to FIG. 7, the method for forming the light emitting layer 320 includes steps S210, S220, S230, and S240. The specific scheme of the step S210 is described in detail below.

In step S210, a green light emitting layer 321 is formed on the surface of the hole transport layer 330 away from the anode layer 20, and the green light emitting layer 321 is a quantum dot light emitting layer. In a further embodiment, the material of the green light-emitting layer 321 may also be used by mixing a hole-transporting host material and a green light quantum dot. In a further embodiment, the forming method is formed on the surface of the hole transport layer 330 by coating. Since quantum dot materials cannot be evaporated at present, they can only be patterned by inkjet printing technology to produce RGB pixels. However, inkjet printing technology has many shortcomings, such as coffee rings and satellite dots, resulting in poor film formation. The presence of the coffee ring effect results in uneven illumination of the device, a decrease in lifetime, and the presence of satellite dots causes color mixing of the screen. Therefore, in the embodiment of the present invention, the formation of the quantum dot luminescent layer by the coating method can avoid the above-mentioned adverse effects such as the coffee ring effect and the satellite point. A uniform green quantum dot film is obtained to make the quantum dot electroluminescent device 1 have better luminescence performance.

Step S220, forming a first electron blocking layer 322 and a second electron blocking layer 323 on a surface of the green light emitting layer 321 away from the hole transport layer 330. In a further embodiment, the first electron blocking layer 322 and the second electron blocking layer 323 are formed by using a patterned mask technique.

Step S230, forming a red light emitting layer 324 on a surface of the first electron blocking layer 322 away from the green light emitting layer 321 . In a further embodiment, the method of forming the red light emitting layer 324 is formed using a patterned mask technique. Preferably, the red light emitting material of the red light emitting layer 324 adopts a deep red organic light emitting material, and a wide color gamut of red light can be realized.

Step S240, forming a blue light emitting layer 325 on a surface of the second electron blocking layer 323 away from the green light emitting layer 321 . In a further embodiment, the method of forming the blue light emitting layer 325 is formed using a patterned mask technique. Preferably, the blue light emitting material of the blue light emitting layer 325 adopts a deep blue organic light emitting material, and can realize a wide color gamut of blue light.

The above steps S220, S230 and S240 are formed using a four-pattern patterned mask technique. Save process costs and increase yield. At present, it is difficult to realize a wide color gamut by using a green organic light-emitting material. According to the embodiment of the present invention, a dark red organic light-emitting material, a deep blue organic light-emitting material and green quantum dots are used to form three colors of the light-emitting device, and the BT2020 color gamut can be realized. The super wide gamut is displayed.

In step S300, a hole blocking layer 340 is formed on a surface of the light emitting layer 320 away from the hole transport layer 330. In a further embodiment, the method for forming the hole blocking layer 340 is formed by a photomask technique, where the mask technology is different from the four patterned mask techniques in the light emitting layer 320, and the mask is used. The pattern has a different shape. It will be appreciated that the reticle technique herein creates a larger pattern for the entire quantum dot electroluminescent device. The four-patterned reticle technique in the luminescent layer 320 is a pattern formed for the size of the red and blue sub-pixels.

In step S400, a hole injection layer 350 is formed on the surface of the anode layer 20 away from the substrate. In a further embodiment, the method of forming the hole injection layer 350 is formed using a photomask technique. Here, the pattern of the reticle technique is the same as step S300.

In step S500, an electron injection layer 360 is formed on the surface of the electron transport layer 310 away from the light emitting layer 320. In a further embodiment, the method of forming the electron injection layer 360 is formed using a photomask technique. Here, the pattern of the reticle technique is the same as step S300.

Referring to FIG. 8, the present invention further provides a display device 2 comprising the quantum dot electroluminescent device 1 of any of the above embodiments. The display device 2 may include, but is not limited to, a portable device such as a smartphone, an Internet device (MID), an e-book, a Play Station Portable (PSP), or a Personal Digital Assistant (PDA). The electronic device can also be a display or the like.

The above-mentioned embodiments are merely illustrative of several embodiments of the present invention, and the description thereof is more specific and detailed, but is not to be construed as limiting the scope of the invention. It should be noted that a number of variations and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of the invention should be determined by the appended claims.

Claims (16)

A quantum dot electroluminescent device, characterized in that the quantum dot electroluminescent device comprises a substrate, an anode layer, a functional layer and a cathode layer which are sequentially stacked, the functional layer comprising an electron transport layer, a light emitting layer and a cavity a transport layer, the electron transport layer is disposed on a side of the cathode layer adjacent to the substrate, the light emitting layer is disposed between the electron transport layer and the hole transport layer, and the hole transport layer is disposed at the anode a layer away from a side of the substrate; The light emitting layer includes a green light emitting layer, a first electron blocking layer, a second electron blocking layer, a red light emitting layer, and a blue light emitting layer; the green light emitting layer is disposed on a surface of the hole transport layer away from the anode layer The first electron blocking layer and the second electron blocking layer are disposed on a surface of the green light emitting layer away from the hole transport layer, and the first electron blocking layer and the second electron blocking layer are not completely covered a green light emitting layer, wherein the green light emitting layer is a quantum dot light emitting layer; the red light emitting layer is disposed on a surface of the first electron blocking layer away from the green light emitting layer, wherein the blue light emitting layer is disposed at The second electron blocking layer is away from the surface of the green light emitting layer. The quantum dot electroluminescent device of claim 1 , wherein the LUMO level of the first electron blocking layer is higher than the LUMO level of the red light emitting layer by at least a first predetermined energy level, The LUMO energy level of the second electron blocking layer is higher than the LUMO energy level of the blue light emitting layer by at least a second predetermined energy level. A quantum dot electroluminescent device according to claim 1, wherein said green light-emitting layer further comprises a hole transport type body. The quantum dot electroluminescent device according to claim 1, wherein a region of the green light-emitting layer that is not covered by the first electron blocking layer and the second electron blocking layer is a green light-emitting region, the green The area of the light emitting region is smaller than the area of the red light emitting layer and smaller than the area of the blue light emitting layer. The area of the red light emitting layer is smaller than the area of the blue light emitting layer, so that the difference between the light emitting brightness of the green light emitting area, the red light emitting layer and the blue light emitting layer is within a preset range. . The quantum dot electroluminescent device according to claim 1, wherein said first electron blocking layer and said second electron blocking layer are disposed on a surface of said green light emitting layer away from said hole transport layer and spaced apart from each other Settings. The quantum dot electroluminescent device according to claim 1, wherein the green light emitting layer comprises opposite first and second ends, and the first electron blocking layer and the second electron blocking layer are juxtaposed Adjacently disposed at a first end of the green light emitting layer on a surface away from the hole transport layer, the green light emitting region being disposed at a second end of the green light emitting layer on a surface away from the hole transport layer . The quantum dot electroluminescent device according to claim 1, wherein the green light emitting layer comprises opposite first and second ends, and the first electron blocking layer and the second electron blocking layer are juxtaposed Adjacently disposed at a second end of the green light emitting layer on a surface away from the hole transport layer, the green light emitting region being disposed at a first end of the green light emitting layer on a surface away from the hole transport layer . The quantum dot electroluminescent device according to claim 1, wherein said functional layer further comprises a hole blocking layer disposed in the middle of said light emitting layer and said electron transport layer, and disposed The surface of the red light emitting layer and the blue light emitting layer away from the green light emitting layer and the surface of the green light emitting layer away from the hole transport layer. The quantum dot electroluminescent device according to claim 8, wherein a HOMO level of the hole blocking layer is lower than a HOMO level of the blue light emitting layer by a third predetermined energy level, the hole blocking layer The LUMO level is 2.8-3.0 eV. The quantum dot electroluminescent device according to claim 9, wherein the red light emitting layer has a HOMO level of 5.2-5.4 eV, and the red light emitting layer has a LOMO level of 2.9-3.1 eV; The blue light emitting layer has a HOMO energy level of 5.6-6.0 eV, and the blue light emitting layer has a LOMO energy level of 2.6-3.0 eV; The HOMO level of the first electron blocking layer is between the energy levels of the hole transport layer and the red light emitting layer, and the LUMO level of the first electron blocking layer is 2.1-2.3 eV; The HOMO level of the electron blocking layer is between the energy levels of the hole transport layer and the blue light emitting layer, and the LUMO level of the second electron blocking layer is 2.1-2.3 eV. A quantum dot electroluminescent device according to claim 1, wherein said functional layer further comprises a hole injecting layer disposed between the substrate and the hole transporting layer. A quantum dot electroluminescent device according to claim 1, wherein said functional layer further comprises an electron injecting layer disposed between the electron transporting layer and the cathode layer. A method for preparing a quantum dot electroluminescent device, characterized in that the preparation method comprises: Providing a substrate; Forming an anode layer, a functional layer and a cathode layer on the surface of the substrate; The method for forming the functional layer includes sequentially forming an electron transport layer, a light emitting layer, and a hole transport layer on a side of the anode layer away from the substrate, the light emitting layer being formed between the electron transport layer and the hole transport layer; The method for forming the light emitting layer includes: Forming a green light emitting layer on the surface of the hole transport layer away from the anode layer, the green light emitting layer being a quantum dot light emitting layer; Forming a first electron blocking layer and a second electron blocking layer on a surface of the green light emitting layer away from the hole transport layer; Forming a red light emitting layer on a surface of the first electron blocking layer away from the green light emitting layer; A blue light emitting layer is formed on a surface of the second electron blocking layer away from the green light emitting layer. The method of producing a quantum dot electroluminescent device according to claim 13, wherein the green light-emitting layer is formed on a surface of the hole transport layer by a coating method. The method of fabricating a quantum dot electroluminescent device according to claim 13, wherein the first electron blocking layer, the second electron blocking layer, the red light emitting layer and the blue light emitting layer are formed by using a patterned mask technology. . A display device comprising the quantum dot electroluminescent device of any one of claims 1-12.

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