CN206370444U - Organic electroluminescent device - Google Patents

Abstract

The utility model relates to an organic electroluminescent device, which comprises a hole injection layer (6), a hole transport layer (5), and a light emitting layer ( 4), electron transport layer (3), electron injection layer (2) and cathode layer (1); Wherein, described light-emitting layer (4) is perovskite quantum dot layer, and the thickness of described light-emitting layer (4) is 15-20nm. The organic electroluminescent device adopts the perovskite quantum dot layer as the light-emitting layer, and its thickness is strictly controlled. Through the selection of materials and thicknesses of other layers, the brightness of the organic electroluminescent device provided by the utility model can reach 32090cd/m ² , the turn-on voltage is as low as 1.5V.

Description

An organic electroluminescent device

technical field

The utility model relates to the field of optoelectronics, in particular to an optoelectronic device, in particular to an organic electroluminescent device.

Background technique

At present, the electroluminescent device is a kind of self-luminous device, which belongs to injection light emission. Under the action of forward bias, the anode injects holes into the charge transport layer, and moves to the interface of the transport layer under the action of the electric field, while the cathode The injected electrons also move from the electron transport layer to the interface. Due to the effect of the potential barrier, the electrons are not easy to enter the charge transport layer, but accumulate on the side of the light-emitting layer near the interface. The electrons injected from the cathode and the holes injected from the anode are in the light-emitting layer. Meet, recombine, release energy, transfer energy to the molecules of the luminescent substance, and make it transition from the ground state to the excited state. Because the excited state is very unstable, the excited molecules emit light from the excited state back to the ground state, and radiative transition produces luminescence. .

Due to the advantages of stable structure, long service life and strong stability, electroluminescent devices prepared by using inorganic compounds have been widely used. However, inorganic electroluminescent devices are highly successful in fabrication, difficult to process, and low in efficiency. In order to meet the needs of information display equipment, organic electroluminescent devices have a wide range of materials to choose from, and have the characteristics of low voltage drive, high brightness, wide viewing angle, and fast response speed. They have good application prospects in display lighting and other aspects, and have been rapidly developed in recent years. The development of organic electroluminescent devices has become one of the current research hotspots.

CN 103904178 A discloses a quantum dot light emitting device. The quantum dot light-emitting device includes an anode, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer and a cathode arranged adjacently in sequence. The quantum dot light-emitting device also includes an electron blocking layer, which is arranged in the electron transport layer or on the between the light-emitting layer and the electron-transporting layer. On the one hand, the electronic blocking layer ensures the balanced injection of carriers, and on the other hand, it isolates the spontaneous transfer of charges between the electron transport layer and the quantum dot light-emitting layer, thereby ensuring the electrical neutrality of the quantum dots. The quantum dot light-emitting device adopts commonly used quantum dots such as CdSe and CdS, which has low quantum efficiency and uncontrollable luminous properties.

CN 105720204 A discloses an inorganic perovskite quantum dot light-emitting diode with various inverted structures, including an ITO glass substrate, a ZnO electron transport layer deposited on the surface of the ITO glass, an inorganic perovskite _CsPbX3 quantum dot light-emitting layer, 4,4 ',4"-tris(carbazol-9-yl)triphenylamine hole transport layer, hole injection layer and anode electrode material. It is prepared by the following steps: first, ZnO is deposited on clean ITO glass by magnetron sputtering Electron transport layer, get the dispersion liquid of CsPbX3 quantum dots and spin-coat on the device surface afterwards, then thermal evaporation deposits TCTA hole transport layer, then thermal evaporation deposits hole injection layer, and finally deposits anode electrode material. The light emitting layer of the light emitting diode Using CsPbX ₃ , the light-emitting properties of the light-emitting layer can be adjusted by X being a combination of any two of Cl, Br, and I. However, the simple doping of the two compounds cannot have a great impact on the light-emitting layer, and cannot fundamentally change the light-emitting layer. Luminescent property, and it is easy to cause the problem of uneven luminescence, and at the same time, the external quantum efficiency is low.

Therefore, it is very important to study a new organic electroluminescent device in view of the problems of low brightness and high turn-on voltage of quantum dots such as CdSe and CdS used in the light-emitting layer of the organic electroluminescent device in the prior art.

Utility model content

In view of the problems existing in the prior art, one of the purposes of the present utility model is to provide an organic electroluminescent device and a preparation method thereof. The organic electroluminescent device has a large luminous brightness, a small turn-on voltage, and controllable luminous properties. The preparation method has simple process and can be used in industrialized production.

For this purpose, the utility model adopts the following technical solutions:

An organic electroluminescent device, said organic electroluminescent device comprising a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer and a cathode layer sequentially connected from the anode layer side;

Wherein, the light-emitting layer is a perovskite quantum dot layer, and the thickness of the light-emitting layer is 15-20 nm.

The thickness of the light-emitting layer can be 15nm, 16nm, 17nm, 18nm, 19nm or 20nm, etc., but is not limited to the listed values, and other unlisted values included in this range are also applicable. Wherein the perovskite quantum dot layer is a prior art, see CN 105720204 A.

The following is the preferred technical solution of the utility model, but not as a limitation of the technical solution provided by the utility model. Through the following technical solutions, the technical purpose and beneficial effects of the utility model can be better achieved and realized.

As a preferred technical solution of the present invention, the anode layer is selected from any one or a combination of at least two of the ITO layer, the Au layer or the Cu layer, and the typical but non-limiting examples of the combination are: the ITO layer and the Au layer The combination of layers, the combination of Au layer and Cu layer, the combination of ITO layer and Cu layer, or the combination of ITO layer, Au layer and Cu layer, etc., the effect is best when the anode layer is an ITO layer.

As a preferred technical solution of the present invention, the hole injection layer is selected from any one or at least two combinations of PEDOT:PSS layer, MoO ₃ layer or TDATA layer, and the thickness of the hole injection layer is 10～ 30nm.

Wherein said combination typical but non-limiting example has the combination of PEDOT:PSS layer and MoO ₃ layer, the combination of MoO ₃ layer and TDATA layer, the combination of PEDOT:PSS layer and TDATA layer or PEDOT:PSS) layer, MoO ₃ layer And the combination of TDATA layer etc., effect is best when hole injection layer is PEDOT:PSS layer; The thickness of described hole injection layer can be 10nm, 12nm, 15nm, 18nm, 20nm, 22nm, 25nm, 28nm or 30nm etc., However, it is not limited to the numerical values listed, and other unlisted numerical values included in the numerical range are also applicable.

As a preferred technical solution of the present invention, the hole transport layer is selected from any one or a combination of at least two of TPD layer, Poly-TPD layer or NPD layer, and the thickness of the hole transport layer is 5-30nm .

Wherein said combination typical but non-limiting example has: the combination of TPD layer and Poly-TPD layer, the combination of Poly-TPD layer and NPD layer, the combination of TPD layer and NPD layer or TPD layer, Poly-TPD layer and NPD layer combination etc., the effect is best when the hole transport layer is a Poly-TPD layer; the thickness of the hole transport layer can be 5nm, 8nm, 10nm, 12nm, 15nm, 18nm, 20nm, 22nm, 25nm, 28nm or 30nm, etc., but not limited to the enumerated numerical values, and other unenumerated numerical values included in this numerical range are also applicable.

As a preferred technical solution of the present invention, the electron transport layer is selected from any one or a combination of at least two of Alq ₃ layer, PBD layer or TPBi layer, and the thickness of the electron transport layer is 30-50 nm.

Wherein said combination typical but non-limiting example has, the combination of Alq ₃ layer and PBD layer, the combination of PBD layer and TPBi layer, the combination of Alq ₃ layer and TPBi layer or the combination of Alq ₃ layer, PBD layer and TPBi layer etc. , the effect is best when the electron transport layer is a TPBi layer; the thickness of the electron transport layer can be 30nm, 32nm, 35nm, 38nm, 40nm, 42nm, 45nm, 48nm or 50nm, etc., but is not limited to the listed values , other unlisted values included in this value range are also applicable.

As a preferred technical solution of the present invention, the electron injection layer is selected from any one or a combination of at least two of LiF layer, ZnO layer or _TiO2 layer, and the thickness of the electron injection layer is 1-5 nm.

Wherein said combination typical but non-limiting example has the combination of LiF layer and ZnO layer, the combination of ZnO layer and _TiO2 , the combination of LiF layer and _TiO2 layer or LiF layer, ZnO layer and _TiO2 layer etc., described electron The effect is best when the injection layer is a LiF layer; the thickness of the electron injection layer can be 1nm, 1.5nm, 2nm, 2.5nm, 3nm, 3.5nm, 4nm, 4.5nm or 5nm, etc., but not limited to the listed values , other unlisted values included in this value range are also applicable.

As a preferred technical solution of the present invention, the cathode layer is preferably selected from one or a combination of at least two of Al layer, Mg layer or Li layer, and the thickness of the cathode layer is 100-200nm.

Wherein the typical but non-limiting examples of the combination include a combination of an Al layer and a Mg layer, a combination of a Mg layer and a Li layer, a combination of an Al layer and a Li layer, or a combination of an Al layer, a Mg layer and a Li layer, etc., the The effect is best when the cathode layer is Al; the thickness of the cathode layer can be 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm or 200nm, etc., but not limited to the listed values, the Other unrecited values included in the numerical ranges also apply.

Compared with the prior art solutions, the utility model has at least the following beneficial effects:

The organic electroluminescent device provided by the utility model adopts the perovskite quantum dot layer as the light-emitting layer, and its thickness is strictly controlled, and the organic electroluminescent device provided by the utility model is made The brightness reaches 32090cd/m ² , and the turn-on voltage is as low as 1.5V.

Description of drawings

Fig. 1 is the structural representation of the organic electroluminescent device provided by the utility model;

In the figure: 1-cathode layer, 2-electron injection layer, 3-electron transport layer, 4-light-emitting layer, 5-hole transport layer, 6-hole injection layer, 7-anode layer.

detailed description

The technical scheme of the utility model will be further described below in conjunction with the accompanying drawings and through specific embodiments.

The specific embodiment part of the utility model provides an organic electroluminescent device as shown in Figure 1, the organic electroluminescent device comprises a hole injection layer 6 connected sequentially from the anode layer 7 side, a hole transport Layer 5, light emitting layer 4, electron transport layer 3, electron injection layer 2 and cathode layer 1;

Wherein, the light-emitting layer 4 is a perovskite quantum dot layer, and the thickness of the light-emitting layer 4 is 15-20 nm.

In order to better illustrate the utility model and facilitate understanding of the technical solution of the utility model, the typical but non-limiting examples of the utility model are as follows:

Example 1

An organic electroluminescent device, the anode layer 7 is an ITO layer, the hole injection layer 6 is a 20nm thick PEDOT:PSS layer, the hole transport layer 5 is a 18nm thick Poly-TPD layer, and the light emitting layer 4 is a 18nm thick The perovskite quantum dot layer, the electron transport layer 3 is a 40nm thick TPBi layer, the electron injection layer 2 is a 3nm thick LiF layer, and the cathode layer 1 is a 150nm thick Al layer.

The luminance of the prepared OLED device was 32090cd/m ² , and the turn-on voltage was 1.8V.

Example 2

An organic electroluminescent device, the anode layer 7 is an Au layer, the hole injection layer 6 is a 10nm thick TDATA layer, the hole transport layer 5 is a 5nm thick TPD layer, and the light emitting layer 4 is a 10nm thick perovskite quantum The dot layer, the electron transport layer 3 is a PBD layer with a thickness of 30nm, the electron injection layer 2 is a ZnO layer with a thickness of 1nm, and the cathode layer is a Li layer with a thickness of 100nm.

The luminance of the prepared OLED device was 30785cd/m ² , and the turn-on voltage was 1.62V.

Example 3

An organic electroluminescent device, the anode layer 7 is a Cu layer, the hole injection layer 6 is a 30nm thick MoO ₃ layer, the hole transport layer 5 is a 30nm thick NPD layer, and the light emitting layer 4 is a 30nm thick perovskite The quantum dot layer, the electron transport layer 3 is a 50nm thick Alq ₃ layer, the electron injection layer 2 is a 5nm thick TiO ₂ layer, and the cathode layer 1 is a 200nm thick Mg layer.

The luminance of the prepared OLED device was 31057cd/m ² , and the turn-on voltage was 1.56V.

Example 4

An organic electroluminescence device, except that the anode layer 7 is a combination of Au layer and Cu layer, other conditions are the same as in Example 1.

The luminance of the prepared OLED device was 29700cd/m ² , and the turn-on voltage was 1.66V.

Example 5

An organic electroluminescent device, except that the hole injection layer 6 is a combination of PEDOT:PSS layer and TDATA layer, other conditions are the same as in Example 1.

The luminance of the prepared OLED device was 30220cd/m ² , and the turn-on voltage was 1.62V.

Example 6

An organic electroluminescent device, except that the hole transport layer 5 is a combination of a TPD layer and a Poly-TPD layer, other conditions are the same as in Example 1.

The luminance of the prepared OLED device was 31980cd/m ² , and the turn-on voltage was 1.5V.

Example 7

An organic electroluminescent device, except that the electron transport layer 3 is a combination of a PBD layer and a TPBi layer, and other conditions are the same as in Example 1.

The luminance of the prepared OLED device was 29520cd/m ² , and the turn-on voltage was 1.57V.

Example 8

An organic electroluminescence device, except that the electron injection layer 2 is a combination of a LiF layer and a ZnO layer, other conditions are the same as those in Embodiment 1.

The luminance of the prepared OLED device was 28710cd/m ² , and the turn-on voltage was 1.78V.

Example 9

An organic electroluminescent device, except that the cathode layer 1 is a combination of an Al layer and a Mg layer, and other conditions are the same as in the embodiment 1.

The luminance of the prepared OLED device was 27960cd/m ² , and the turn-on voltage was 1.74V.

As can be seen from Examples 1-9, the organic electroluminescent device provided by the utility model uses perovskite quantum dots as the light-emitting layer, and strictly controls its thickness, and makes reasonable choices and controls the other layers of the device. The thickness can make the luminous brightness reach 32090cd/m ² , and the turn-on voltage is as low as 1.5V. At the same time, organic electroluminescent devices with different luminous intensities and turn-on voltages can be obtained by selecting all layers of the organic electroluminescent device except the light-emitting layer and adjusting their thickness.

The applicant declares that the utility model illustrates the detailed structural features of the present utility model through the above-mentioned embodiments, but the utility model is not limited to the above-mentioned detailed structural features, that is, it does not mean that the utility model must rely on the above-mentioned detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the utility model, the equivalent replacement of the selected components of the utility model, the addition of auxiliary components, the selection of specific methods, etc., all fall within the scope of protection and disclosure of the utility model within.

The preferred embodiment of the utility model has been described in detail above, but the utility model is not limited to the specific details in the above embodiment, and within the scope of the technical concept of the utility model, various simple modifications can be made to the technical solution of the utility model , these simple modifications all belong to the protection scope of the present utility model.

In addition, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way if there is no contradiction. The combination method will not be explained separately.

In addition, any combination of various implementations of the present invention can also be made, as long as they do not violate the idea of the present invention, they should also be regarded as the disclosed content of the present invention.

Claims (7)

1. a kind of organic electroluminescence device, it is characterised in that the organic electroluminescence device is included from anode layer (7) side The hole injection layer (6) that is sequentially connected, hole transmission layer (5), luminescent layer (4), electron transfer layer (3), electron injecting layer (2) with And cathode layer (1)；

Wherein, the luminescent layer (4) is perovskite quantum dot layer, and the thickness of the luminescent layer (4) is 15~20nm.

2. organic electroluminescence device according to claim 1, it is characterised in that the anode layer (7) be selected from ITO layer, In Au layers or Cu layers any one or at least two combination.

3. organic electroluminescence device according to claim 1, it is characterised in that the hole injection layer (6) is selected from PEDOT:PSS layer, MoO₃Layer or TDATA layers in any one or at least two combination, the thickness of the hole injection layer (6) For 10~30nm.

4. organic electroluminescence device according to claim 1, it is characterised in that the hole transmission layer (5) is selected from TPD Any one in layer, Poly-TPD layer or NPD layers or at least two combination, the thickness of the hole transmission layer (5) is 5~ 30nm。

5. organic electroluminescence device according to claim 1, it is characterised in that the electron transfer layer (3) is selected from Alq₃ Any one in layer, PBD layers or TPBi layers or at least two combination, the thickness of the electron transfer layer (3) is 30~50nm.

6. organic electroluminescence device according to claim 1, it is characterised in that the electron injecting layer (2) is selected from LiF Layer, ZnO layer or TiO₂Any one in layer or at least two combination, the thickness of the electron injecting layer (2) is 1~5nm.

7. organic electroluminescence device according to claim 1, it is characterised in that the cathode layer (1) is selected from Al layers, Mg In layer or Li layer people any one or at least two combination, the thickness of the cathode layer (1) is 100~200nm.