CN105932178A - Preparation method for organic electroluminescent device - Google Patents

Abstract

The invention discloses a preparation method of an organic electroluminescence device, which comprises: forming a common layer on a base substrate; forming a green photon hole injection layer on the common layer corresponding to the green light area; A red photon hole injection layer is formed on the layer, and an electric field or a magnetic field is applied during the process of forming the green photon hole injection layer and the red photon hole injection layer. The technical solution provided by the present invention changes the hole injection characteristics of the hole injection layer by applying an electric field or a magnetic field during the formation process of the hole injection layer of the green light device and the red light device, thereby improving the green light device and the red light device. The performance of the device makes the exciton recombination center of the green light device and the red light device located in the center of the light-emitting layer, which improves the efficiency and life of the organic electroluminescent device. In addition, the technical solution provided by the invention makes the performance of the light-emitting device reach the best state under a given material system, improves the utilization rate of the material, and reduces the cost.

Description

Preparation method of organic electroluminescence device

technical field

The invention relates to the field of display technology, in particular to a method for preparing an organic electroluminescent device.

Background technique

Organic light-emitting diodes (Organic Light-Emitting Diode, OLED) have the advantages of self-luminescence, low power consumption, flexible fabrication, and high contrast. Due to the different wavelengths of red light, green light and blue light, the corresponding optical film thicknesses of the red light devices, green light devices and blue light devices of the existing organic electroluminescent devices are different, so the red light devices, green light devices and blue light devices The corresponding physical film thickness is also different, the film thickness of the red light device is the largest, and the film thickness of the blue light device is the smallest. In the prior art, the film thickness can be adjusted by adjusting the thickness of the hole injection layer. The optimal film thickness of an organic electroluminescent device is determined by the red, green and blue light-emitting materials, and in order to reduce costs, the existing red, green and blue devices use the same material for the hole injection layer. The efficiency and lifetime of an organic electroluminescent device are related to the position of the exciton recombination center. Among the existing organic electroluminescent devices, the exciton recombination center of the green light device and the red light device is located at the side of the light-emitting layer that is biased towards the electron injection layer. On the other hand, the efficiency and lifetime of the organic electroluminescent device are reduced.

Contents of the invention

In order to solve the above problems, the present invention provides a method for preparing an organic electroluminescent device, which is used to solve the problem that in the existing organic electroluminescent devices, the exciton recombination center of the green light device and the red light device is located in the light-emitting layer and deflects electrons. On the one hand, it reduces the efficiency and lifetime of organic electroluminescent devices.

For this reason, the invention provides a kind of preparation method of organic electroluminescent device, comprising:

forming a common layer on the base substrate;

A green photon hole injection layer is formed on the common layer corresponding to the green light area, a red photon hole injection layer is formed on the common layer corresponding to the red light area, and the green photon hole injection layer and the red photon hole injection layer are formed. An electric or magnetic field is applied during the process of photon hole injection into the layer.

Optionally, the electric field direction of the electric field is parallel to the base substrate.

Optionally, the electric field intensity range of the electric field includes 500V/m to 1000V/m.

Optionally, the electric field intensity range of the electric field includes 600V/m to 800V/m.

Optionally, the electric field strength of the electric field is 700V/m.

Optionally, the magnetic field direction of the magnetic field is parallel to the base substrate.

Optionally, the magnetic field strength of the magnetic field ranges from 500A/m to 1000A/m.

Optionally, the magnetic field strength of the magnetic field ranges from 600A/m to 800A/m.

Optionally, the magnetic field strength of the magnetic field is 700A/m.

Optionally, the common layer has a thickness ranging from 40 nm to 80 nm, the green photon hole injection layer has a thickness ranging from 20 nm to 50 nm, and the red photon hole injection layer has a thickness ranging from 60 nm to 100 nm.

Optionally, the common layer has a thickness of 60 nm, the green photon hole injection layer has a thickness of 35 nm, and the red photon hole injection layer has a thickness of 80 nm.

Optionally, the evaporation rate for forming the common layer is 1A/s, the evaporation rate for forming the green photon hole injection layer is 0.5A/s, and the evaporation rate for forming the red photon hole injection layer is 1A/s.

The present invention has following beneficial effect:

The preparation method of the organic electroluminescent device provided by the present invention comprises: forming a common layer on the base substrate; forming a green photon hole injection layer on the common layer corresponding to the green light region; A red photon hole injection layer is formed on the green photon hole injection layer, and an electric field or a magnetic field is applied during the process of forming the green photon hole injection layer and the red photon hole injection layer. The technical solution provided by the present invention changes the hole injection characteristics of the hole injection layer by applying an electric field or a magnetic field during the formation process of the hole injection layer of the green light device and the red light device, thereby improving the green light device and the red light device. The performance of the device makes the exciton recombination center of the green light device and the red light device located in the center of the light-emitting layer, which improves the efficiency and life of the organic electroluminescent device. In addition, the technical solution provided by the present invention does not increase the process, and can achieve the best performance of red light devices, green light devices and blue light devices under a given material system, so that the same hole injection can be used. The layer material forms an organic electroluminescent device, which improves the utilization rate of the material and reduces the cost.

Description of drawings

FIG. 1 is a flow chart of a method for preparing an organic electroluminescent device provided in Embodiment 1 of the present invention;

2 is a schematic diagram of forming a green photon hole injection layer and a red photon hole injection layer in Embodiment 1;

FIG. 3 is a schematic diagram of the organic electroluminescent device provided in Embodiment 1.

detailed description

In order for those skilled in the art to better understand the technical solution of the present invention, the method for preparing the organic electroluminescent device provided by the present invention will be described in detail below with reference to the accompanying drawings.

Embodiment one

FIG. 1 is a flow chart of a method for preparing an organic electroluminescent device provided in Embodiment 1 of the present invention. As shown in Figure 1, the preparation method of the organic electroluminescence device comprises:

Step 1001, forming a common layer on a base substrate.

FIG. 2 is a schematic diagram of forming a green photon hole injection layer and a red photon hole injection layer in Embodiment 1. FIG. As shown in FIG. 2 , an anode 200 is formed on the base substrate 100 , a buffer layer 300 is formed on the anode 200 , and a common layer 400 is formed on the buffer layer 300 . It should be explained that the substrate is indeed inverted in the actual process, and FIG. 2 is also obtained according to the actual process. However, in this embodiment, the description of the process is based on the normal placement of the substrate. For the blue light region, the common layer 400 is the blue light hole injection layer. At this time, the exciton recombination center of the blue light device is located at the center of the light-emitting layer near the hole side, and the device has the best efficiency and lifetime.

Step 1002, forming a green photon hole injection layer on the common layer corresponding to the green light area, forming a red photon hole injection layer on the common layer corresponding to the red light area, and forming the green photon hole injection layer and An electric field or a magnetic field is applied during the process of injecting the red photon holes into the layer.

In this embodiment, applying a magnetic field and an electric field have the same effect, so the following descriptions all use the electric field as an example. Applying an electric field parallel to the base substrate 100 , optionally, the electric field strength range of the electric field includes 500V/m to 1000V/m. Preferably, the electric field strength of the electric field ranges from 600V/m to 800V/m. More preferably, the electric field strength of the electric field is 700V/m. A green photon hole injection layer 401 is formed on the common layer 400 corresponding to the green light region, and a red photon hole injection layer 402 is formed on the common layer 400 corresponding to the red light region. Therefore, the green hole injection layer provided in this embodiment is composed of the green hole injection layer 401 and the common layer 400 , and the red hole injection layer is composed of the red hole injection layer 402 and the common layer 400 .

The hole injection layer is formed by evaporating organic materials from an evaporation source to the common layer 400 , and this process can be regarded as the result of accumulation of molecular-thick ultra-thin films layer by layer. During this process, the morphology of organic materials is easily affected by electric or magnetic fields, thereby changing the electrical properties of the hole injection layer—mobility and energy levels. In this way, the concentration and mobility of carriers (electrons and holes) in red and green devices can be adjusted, thereby improving the performance of organic light-emitting devices, so that the exciton recombination centers of green and red devices are located in the light-emitting layer center, improving the efficiency and lifetime of organic electroluminescent devices. In addition, the technical solution provided by this embodiment does not increase the process, and can achieve the best performance of red light devices, green light devices and blue light devices under a given material system, so that the same hole can be used The injection layer material forms an organic electroluminescent device, which improves the utilization rate of the material and reduces the cost.

Table 1

Table 1 is a comparison of the performance of the organic light-emitting device before and after the electric field is applied. As shown in Table 1, when there is no electric field during the formation process, the luminous efficiency of the green light device is 80cd/A, and the time for the luminous lifetime to change from 100% to 97% is 40h. When there is an electric field during the forming process, the luminous efficiency of the green light device is 87cd/A, and the time for the luminous lifetime to change from 100% to 97% is 56h. When there is no electric field action during the formation process, the luminous efficiency of the red light device is 27cd/A, and the time for the luminous lifetime to change from 100% to 97% is 102h. When there is an electric field during the forming process, the luminous efficiency of the green light device is 32cd/A, and the time for the luminous lifetime to change from 100% to 97% is 150h. It can be seen that the efficiency and lifetime of the green light device and the red light device are greatly improved after the electric field is applied.

In this embodiment, the evaporation rate for forming the common layer 400 is 1A/s, the evaporation rate for forming the green photon hole injection layer is 0.5A/s, and the evaporation rate for forming the red photon hole injection layer is 1A/s . Optionally, the common layer has a thickness ranging from 40 nm to 80 nm, the green photon hole injection layer has a thickness ranging from 20 nm to 50 nm, and the red photon hole injection layer has a thickness ranging from 60 nm to 100 nm. Preferably, the common layer has a thickness of 60 nm, the green photon hole injection layer has a thickness of 35 nm, and the red photon hole injection layer has a thickness of 80 nm.

FIG. 3 is a schematic diagram of the organic electroluminescent device provided in Embodiment 1. As shown in FIG. 3 , a hole transport layer 500 is formed on the hole injection layer, and a light emitting layer is formed on the hole transport layer 500. The light emitting layer includes a blue light emitting layer 601, a green light emitting layer 602 and a red light emitting layer. layer 603 , an electron transport layer 700 is formed on the light emitting layer, an electron injection layer 800 is formed on the electron transport layer 700 , and a cathode 900 is formed on the electron injection layer 800 . The organic electroluminescent device provided in this embodiment includes an anode, a cathode, and a functional layer arranged between the anode and the cathode. When a voltage is applied between the anode and the cathode, driven by the external voltage, the holes injected from the anode and the electrons injected from the cathode recombine into the recombination region of the functional layer to form excitons. The sub-radiative transitions emit photons to form electroluminescence. In the technical solution provided by this embodiment, during the formation of the hole injection layer of the green light device and the red light device, the hole injection characteristics of the hole injection layer are changed by applying an electric field or a magnetic field, so that the green light device and the red light device The exciton recombination center of the organic electroluminescent device is located in the center of the light-emitting layer, and the exciton recombination center of the blue light device is located in the center of the light-emitting layer near the hole side, thereby improving the efficiency and life of the organic electroluminescent device.

The preparation method of the organic electroluminescent device provided in this embodiment includes: forming a common layer on the base substrate; forming a green photon hole injection layer on the common layer corresponding to the green light region; A red photon hole injection layer is formed on it, and an electric field or a magnetic field is applied during the process of forming the green photon hole injection layer and the red photon hole injection layer. In the technical solution provided by this embodiment, during the formation of the hole injection layer of the green light device and the red light device, the hole injection characteristics of the hole injection layer are changed by applying an electric field or a magnetic field, thereby improving the green light device and the red light device. The performance of the optical device makes the exciton recombination center of the green light device and the red light device located in the center of the light-emitting layer, which improves the efficiency and life of the organic electroluminescent device. In addition, the technical solution provided by this embodiment does not increase the process, and can achieve the best performance of red light devices, green light devices and blue light devices under a given material system, so that the same hole can be used The injection layer material forms an organic electroluminescent device, which improves the utilization rate of the material and reduces the cost.

It can be understood that, the above embodiments are only exemplary embodiments adopted for illustrating the principle of the present invention, but the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims (12)

1. the preparation method of an organic electroluminescence device, it is characterised in that including:

Underlay substrate is formed shared layer；

The sub-hole injection layer of green glow is formed, at ruddiness on the shared layer that green wavelength is corresponding Form the sub-hole injection layer of ruddiness on the shared layer that region is corresponding, form described green glow Electric field or magnetic field is applied among the process of hole injection layer and the sub-hole injection layer of described ruddiness.

The preparation method of organic electroluminescence device the most according to claim 1, it is special Levying and be, the direction of an electric field of described electric field is parallel to described underlay substrate.

The preparation method of organic electroluminescence device the most according to claim 1, it is special Levying and be, the electric-field intensity scope of described electric field includes 500V/m to 1000V/m.

The preparation method of organic electroluminescence device the most according to claim 3, it is special Levying and be, the electric-field intensity scope of described electric field includes 600V/m to 800V/m.

The preparation method of organic electroluminescence device the most according to claim 4, it is special Levying and be, the electric-field intensity of described electric field is 700V/m.

The preparation method of organic electroluminescence device the most according to claim 1, it is special Levying and be, the magnetic direction in described magnetic field is parallel to described underlay substrate.

The preparation method of organic electroluminescence device the most according to claim 1, it is special Levying and be, the magnetic field intensity scope in described magnetic field includes 500A/m to 1000A/m.

The preparation method of organic electroluminescence device the most according to claim 7, it is special Levying and be, the magnetic field intensity scope in described magnetic field includes 600A/m to 800A/m.

The preparation method of organic electroluminescence device the most according to claim 8, it is special Levying and be, the magnetic field intensity in described magnetic field is 700A/m.

The preparation method of organic electroluminescence device the most according to claim 1, its Being characterised by, the thickness range of described shared layer includes 40nm to 80nm, described green glow The thickness range of hole injection layer includes 20nm to 50nm, the sub-hole injection layer of described ruddiness Thickness range include 60nm to 100nm.

The preparation method of 11. organic electroluminescence devices according to claim 10, its Being characterised by, the thickness of described shared layer is 60nm, the thickness of the sub-hole injection layer of described green glow Degree is 35nm, and the thickness of the sub-hole injection layer of described ruddiness is 80nm.

The preparation method of 12. organic electroluminescence devices according to claim 1, its Being characterised by, the evaporation rate forming shared layer is 1A/s, forms the sub-hole injection layer of green glow Evaporation rate be 0.5A/s, the evaporation rate forming the sub-hole injection layer of ruddiness is 1A/s.