CN209912898U - Quantum Dot Light Emitting Diode - Google Patents

Abstract

The embodiment of the utility model discloses quantum dot emitting diode, include: a substrate; an anode formed on the substrate; a hole transport layer formed on the anode; the multiple quantum well layer is formed on the hole transport layer and comprises at least two barrier layers and a light emitting layer with one layer less than the barrier layers, the barrier layers and the light emitting layer are arranged in a laminated mode at intervals, and the hole transport layer is close to the barrier layers; an electron transport layer formed in the multiple quantum well layer, adjacent to the barrier layer in the multiple quantum well layer; and a cathode formed on the electron transport layer. The embodiment of the utility model provides a technical scheme is through the barrier layer with the better restriction of carrier compound luminescence in the luminescent layer to quantum dot emitting diode's luminous efficacy has been improved.

Description

Quantum Dot Light Emitting Diode

technical field

The embodiments of the present utility model relate to the technical field of semiconductors, and in particular, to a quantum dot light-emitting diode.

Background technique

Quantum dots are a new type of luminescent material with the advantages of tunable spectrum, low cost and large area preparation.

For quantum dot light-emitting diodes, it is necessary to confine the carriers (holes, electrons) in the light-emitting layer for recombination. Although the current device structure can be restricted to a certain extent, the carriers still pass through. Therefore, in the current quantum dot light-emitting diodes, the carriers cannot be well confined in the light-emitting layer, and there is a technical problem that the light-emitting efficiency of the device is not very high.

Utility model content

In view of this, the embodiment of the present invention provides a quantum dot light-emitting diode to solve the problem that in the current quantum dot light-emitting diode in the prior art, the carriers cannot be well confined in the light-emitting layer, and there is a luminescence of the device. Efficiency is not a very technical issue.

The embodiment of the present utility model provides a quantum dot light-emitting diode, comprising:

base;

an anode formed on the substrate;

a hole transport layer formed on the anode;

a multiple quantum well layer formed on the hole transport layer, the multiple quantum well layer including at least two barrier layers and a light-emitting layer one less than the number of the barrier layers, the barrier layer and the light-emitting layer is stacked and arranged at intervals, and the hole transport layer is adjacent to the barrier layer; the electron transport layer formed in the multiple quantum well layer is adjacent to the potential barrier layer in the multiple quantum well layer;

A cathode formed on the electron transport layer.

Optionally, the barrier layer is a first forbidden quantum dot layer, the light emitting layer is a second forbidden quantum dot layer, and the forbidden band width of the first forbidden quantum dot layer is larger than that of the second forbidden quantum dot layer. The forbidden band width of the layer with quantum dots.

Optionally, it also includes a thin film encapsulation layer formed on the cathode.

Optionally, the hole transport layer is a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate hole transport layer.

Optionally, the electron transport layer includes any one of a zinc oxide electron transport layer, a titanium oxide electron transport layer and a zirconia electron transport layer.

Optionally, the first band gap quantum dot layer and the second band gap quantum dot layer include any one of a lead sulfide quantum dot layer, a lead selenide quantum dot layer, or a lead telluride quantum dot layer.

The embodiment of the present utility model provides a quantum dot light emitting diode, the quantum dot light emitting diode includes a multiple quantum well layer composed of a barrier layer and a light emitting layer, and the barrier layer better confines the carriers in the light emitting layer to recombine It emits light, thereby improving the luminous efficiency of quantum dot light-emitting diodes, and solving the problem that in the current near-infrared quantum dot light-emitting diodes in the prior art, the carriers cannot be well confined in the light-emitting layer, and the luminous efficiency of the existing devices is not very high. high technical issues.

Description of drawings

1 is a schematic structural diagram of a quantum dot light-emitting diode according to Embodiment 1 of the present invention;

2 is a schematic structural diagram of another quantum dot light-emitting diode according to Embodiment 1 of the present invention;

FIG. 3 is a flow chart of a method for preparing a light-emitting diode with quantum dots according to the second embodiment of the present invention.

Detailed ways

The present utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for the convenience of description, the drawings only show some but not all structures related to the present invention.

Example 1

An embodiment of the present invention provides a schematic structural diagram of a quantum dot light-emitting diode. As shown in FIG. 1 , the quantum dot light-emitting diode includes: a substrate 1 ; an anode 2 formed on the substrate 1 ; holes formed on the anode 2 Transport layer 3; a multi-quantum well layer 4 formed on the hole transport layer 3, the multi-quantum well layer 4 includes at least two barrier layers 41 and a light-emitting layer 42 that is one layer less than the number of barrier layers 41, and the potential The barrier layer 41 and the light-emitting layer 42 are stacked and arranged at intervals, and the hole transport layer 3 is adjacent to the barrier layer 41; the electron transport layer 5 formed in the multiple quantum well layer 4 is adjacent to the potential barrier layer 41 in the multiple quantum well layer 4; Cathode 6 on electron transport layer 5 .

It should be noted that, in the schematic structural diagram of the quantum dot light emitting diode shown in FIG. 1 , three barrier layers 41 and two light emitting layers 42 are exemplarily shown, wherein the hole transport layer 3 is adjacent to the barrier layer 41 . . The specific number of layers of the barrier layer 41 and the light-emitting layer 42 is not limited in the embodiment of the present invention.

In this embodiment, the anode can be exemplarily selected from indium tin oxide (Indium Tin Oxides, ITO) conductive glass with good transmittance. Cathodes can employ higher work function metals such as silver and aluminum.

In this embodiment, the light-emitting mechanism of the quantum dot light-emitting diode is as follows:

A positive voltage is applied to the anode of the quantum dot light-emitting diode, and a negative voltage is applied to the cathode. Under the action of the applied electric field, the carriers are injected from the anode 2 and the cathode 6, pass through the hole transport layer 3 and the electron transport layer 5, and reach the multiple quantum well layer. The light-emitting layer 42 of 4 emits compound light. Among them, the function of the barrier layer 41 is to confine the carriers in the light-emitting layer 42 to recombine light emission.

The embodiment of the present utility model provides a quantum dot light-emitting diode, the quantum dot light-emitting diode comprises a multi-quantum well layer composed of a barrier layer and a light-emitting layer, and the barrier layer better confines the carriers in the light-emitting layer to recombine It emits light, thereby improving the luminous efficiency of the quantum dot light-emitting diode, and solving the problem that in the current quantum dot light-emitting diode in the prior art, the carriers cannot be well confined in the light-emitting layer, and the luminous efficiency of the existing device is not very high. technical problem.

Optionally, on the basis of the above technical solution, the barrier layer 41 is the first forbidden quantum dot layer, the light emitting layer 42 is the second forbidden quantum dot layer, and the forbidden band width of the first forbidden quantum dot layer is greater than that of the first forbidden quantum dot layer. The forbidden band width of the two-bandgap quantum dot layer. The forbidden band width of the barrier layer is larger than the forbidden band width of the light emitting layer, and the carriers injected from the anode 2 and the cathode 6 are confined to the light emitting layer 42 to recombine light.

Optionally, on the basis of the above technical solution, referring to FIG. 2 , the quantum dot light-emitting diode provided by the embodiment of the present invention further includes a thin film encapsulation layer 7 formed on the cathode 6 . The function of the thin film encapsulation layer 7 is to prevent the invasion of external water and oxygen, which affects the light-emitting performance of the quantum dot light-emitting diode. Floor.

In this embodiment, the light-emitting mechanism of the quantum dot light-emitting diode is as follows: the carriers are injected from the anode and the cathode, pass through the hole transport layer and the electron transport layer, and reach the light-emitting layer in the multi-quantum well layer for composite light emission. The function of the barrier layer 41 is to confine the carriers in the light-emitting layer 42 to recombine light emission.

Quantum dots are zero-dimensional semiconductor nanoparticles with nano-effects such as quantum confinement effect, quantum size effect and quantum surface effect. The particle size of quantum dots is smaller than the exciton Bohr radius of their corresponding bulk materials, and the quasi-continuous energy band splitting into discrete energy levels occurs due to the quantum confinement effect. The smaller the nanoparticle size, the larger the energy level splitting, the wider the forbidden band width, and the blue-shift of the emission spectrum of quantum dots with the decrease of particle size, so the emission wavelength can be adjusted by adjusting the size of quantum dots. The size of the quantum dots can be controlled by adjusting the synthesis temperature and synthesis time in the process of preparing the quantum dots.

Optionally, based on the above technical solution, the hole transport layer 3 is a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate hole transport layer. Among them, the poly(3,4-ethylenedioxythiophene)-polystyrenesulfonate (Poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate), PEDOT/PSS) hole transport layer plays the role of transporting holes .

Optionally, based on the above technical solution, the electron transport layer 5 includes any one of a zinc oxide electron transport layer, a titanium oxide electron transport layer and a zirconium oxide electron transport layer, which plays the role of transporting electrons.

Optionally, on the basis of the above technical solution, the first band gap quantum dot layer and the second band gap quantum dot layer include any one of a lead sulfide quantum dot layer, a lead selenide quantum dot layer, or a lead telluride quantum dot layer. One by one. The emission wavelength of any one of the lead sulfide quantum dot layer, the lead selenide quantum dot layer, or the lead telluride quantum dot layer is in the infrared band.

Embodiment 2

On the basis of the above-mentioned embodiments, the embodiment of the present invention provides a preparation method of a quantum dot light-emitting diode. The quantum dot light-emitting diode shown in FIG. 1 is used as an example for description. For the preparation method of the quantum dot light-emitting diode, see FIG. , including the following steps:

Step 110, providing a substrate.

Referring to Figure 1, a substrate 1 is provided.

Step 120, forming an anode on the substrate.

Referring to FIG. 1 , an anode 2 is formed on a substrate 1 .

Step 130, forming a hole transport layer on the anode.

In FIG. 1 , a hole transport layer 3 is formed on the anode 2 .

Step 140, forming a multi-quantum well layer on the hole transport layer, the multi-quantum well layer includes at least two barrier layers and a light-emitting layer that is one layer less than the number of barrier layers, and the barrier layers and the light-emitting layer are stacked at intervals , the hole transport layer is immediately adjacent to the barrier layer.

Referring to FIG. 1 , a multi-quantum well layer 4 is formed on the hole transport layer 3, and the multi-quantum well layer 4 includes at least two barrier layers 41 and a light-emitting layer 42 that is one layer less than the number of the barrier layers 41. The layer 41 and the light emitting layer 42 are stacked at intervals, and the hole transport layer 3 is adjacent to the barrier layer 41 .

Step 150 , forming an electron transport layer on the multiple quantum well layer, which is adjacent to the barrier layer in the multiple quantum well layer.

Referring to FIG. 1 , the electron transport layer 5 is formed on the multiple quantum well layer 4 next to the barrier layer 41 in the multiple quantum well layer 4 .

Step 160, forming a cathode on the electron transport layer.

Referring to FIG. 1 , the cathode 6 is formed on the electron transport layer 5 .

The embodiment of the present invention provides a preparation method of a quantum dot light-emitting diode. By forming a multi-quantum well layer composed of a barrier layer and a light-emitting layer in the quantum dot light-emitting diode, the barrier layer can better confine the carriers to Compound light emission in the light-emitting layer, thereby improving the light-emitting efficiency of the quantum dot light-emitting diode, solving the problem that in the current quantum dot light-emitting diode in the prior art, the carriers cannot be well confined in the light-emitting layer, and the light-emitting efficiency of the device exists. Not a very technical problem.

Optionally, on the basis of the above technical solution, forming the multiple quantum well layer 4 on the hole transport layer 3 in step 140 specifically includes: using a solution spin coating method on the hole transport layer 3, and cross-spin coating the barrier layer 41. and the light-emitting layer 42 .

Optionally, on the basis of the above technical solution, taking the quantum dot light emitting diode shown in FIG. 2 as an example for illustration, after step 160 , it also includes forming a thin film encapsulation layer 7 on the cathode 6 .

Optionally, on the basis of the above technical solution, forming a cathode on the electron transport layer in step 160 specifically includes: forming a cathode on the electron transport layer through an evaporation process.

Note that the above are only preferred embodiments of the present invention and applied technical principles. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations and substitutions can be made to those skilled in the art without departing from the protection of the present invention scope. Therefore, although the present utility model has been described in detail through the above embodiments, the present utility model is not limited to the above embodiments, and can also include more other equivalent embodiments without departing from the concept of the present utility model. Rather, the scope of the present invention is determined by the scope of the appended claims.

Claims (6)

1. A quantum dot light emitting diode, comprising:

a substrate;

an anode formed on the substrate;

a hole transport layer formed on the anode;

a multiple quantum well layer formed on the hole transport layer, wherein the multiple quantum well layer comprises at least two barrier layers and a light-emitting layer with one layer less than the barrier layers, the barrier layers and the light-emitting layer are arranged in a spaced and laminated mode, and the hole transport layer is adjacent to the barrier layers;

an electron transport layer formed on the MQW layer, immediately adjacent to the barrier layer in the MQW layer;

a cathode formed on the electron transport layer.

2. The quantum dot light-emitting diode of claim 1,

the barrier layer is a first forbidden band quantum dot layer, the light-emitting layer is a second forbidden band quantum dot layer, and the forbidden band width of the first forbidden band quantum dot layer is larger than that of the second forbidden band quantum dot layer.

3. The quantum dot light-emitting diode of claim 1,

and a thin film encapsulation layer formed on the cathode.

4. The quantum dot light-emitting diode of claim 1,

the hole transport layer is a poly (3, 4-ethylenedioxythiophene) polystyrene sulfonate hole transport layer.

5. The quantum dot light-emitting diode of claim 1,

the electron transport layer comprises any one of a zinc oxide electron transport layer, a titanium oxide electron transport layer and a zirconium oxide electron transport layer.

6. The QD LED of claim 2,

the first forbidden quantum dot layer and the second forbidden quantum dot layer include any one of a lead sulfide quantum dot layer, a lead selenide quantum dot layer, or a lead telluride quantum dot layer.

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