CN109216512B - QLED device, preparation method thereof and high-voltage processing device - Google Patents

Abstract

The invention discloses a QLED device, a preparation method thereof, and a high-pressure processing device, wherein the preparation method includes the step of performing high-pressure processing on the functional transmission layer in an inert environment after the functional transmission layer is deposited on the device. In the present invention, by performing high pressure treatment on the functional transmission layer, the materials of each functional layer in the QLED device are combined more densely, the functional transmission layer and the quantum dot light-emitting layer are combined more closely, the defects between the interfaces are reduced, and the non-toxicity is reduced. Radiation recombination further improves the injection efficiency of carriers and the efficiency of recombination luminescence.

Description

A kind of QLED device and preparation method thereof, high voltage processing device

technical field

The invention relates to the technical field of quantum dots, in particular to a QLED device, a preparation method thereof, and a high-voltage processing device.

Background technique

Semiconductor quantum dots (QDs) have the characteristics of high fluorescence quantum efficiency, tunable emission in the visible light band, and wide color gamut coverage. Light-emitting diodes using quantum dots as light-emitting materials are called quantum dot light-emitting diodes (QLEDs), which have the advantages of color saturation, higher energy efficiency, better color temperature, and long life. and the mainstream technology of flat panel display.

In order to improve the efficiency and performance of QLED devices, most researchers mainly study the quantum dot light-emitting layer materials, and only a few researchers study the functional transport layer of QLED devices. It is limited to modify the functional transport layer materials of QLED devices by chemical methods to improve the efficiency of the device.

However, in the process of device fabrication, there are few reports on the use of physical methods to modify the functional transport layer of QLED devices to improve the device film quality and carrier transport efficiency.

Therefore, the existing technology still needs to be improved and developed.

SUMMARY OF THE INVENTION

In view of the above-mentioned deficiencies of the prior art, the purpose of the present invention is to provide a QLED device, a preparation method thereof, and a high-voltage processing device, and by physically modifying the functional transmission layer during the preparation of the device, aiming to realize the thin film of the QLED device through a physical method Mass and carrier transport efficiency improvements.

The technical scheme of the present invention is as follows:

A preparation method of a QLED device, which includes the step of performing high pressure treatment on the functional transport layer in an inert environment after the functional transport layer is deposited on the device.

Further, in the preparation method of the QLED device, the functional transport layer is a hole transport layer and/or an electron transport layer.

Further, in the preparation method of the QLED device, the pressure of the high-pressure treatment on the functional transmission layer is 0.1-10MPa, and the time is 5-120min.

In one of the embodiments, the method for preparing a QLED device, wherein the high-pressure treatment process includes: S10. After the functional transmission layer is deposited on the device, the device is fixed in a sealed high-pressure treatment device. In the container, the high-pressure processing device also includes an air inlet valve and an air outlet valve, and by opening the air inlet valve and the air outlet valve, the inert gas is introduced into the airtight container and the air in the airtight container is removed; S20, close the air outlet valve, and continue to open the airtight container. Inert gas is injected until the pressure in the airtight container reaches a predetermined pressure, and high-pressure treatment is carried out for a predetermined time. Further, after the step S20 is completed, it also includes step S30, opening the air outlet valve, and adjusting the pressure of the air outlet valve and the air inlet valve, so that the airtight container forms a flowing inert gas, and removes the inert gas adsorbed on the surface of the device. The inert gas is one of nitrogen, helium, neon or argon.

Further, the preparation method of the QLED device further includes the step of performing annealing treatment after the functional transmission layer is subjected to high pressure treatment.

Further, in the preparation method of the QLED device, after the functional transmission layer is subjected to high pressure treatment, the annealing temperature of the annealing treatment is 50-200° C., and the time is 10-30 min.

The present invention also provides a QLED device prepared by any one of the methods of the present invention.

Further, the present invention also provides a high-pressure processing device for a QLED device, which includes an airtight container, a bracket for fixing the QLED device is arranged in the airtight container, one end of the airtight container is connected with an air inlet pipe, and the other end of the airtight container is connected. One end is connected with an outlet pipe, the inlet pipe is provided with an inlet valve and a first pressure gauge, the outlet pipe is connected with an outlet valve and a second pressure gauge, and the other end of the inlet pipe is connected with an inert gas bottle.

Beneficial effects: the present invention makes the material of each functional transmission layer in the QLED device more densely combined by performing high-voltage treatment on the functional transmission layer of the QLED device, and the combination between the various functional transmission layers is tighter, which reduces the defects between the interfaces and reduces the Non-radiative recombination is achieved, which further improves the injection efficiency of carriers and the efficiency of recombination luminescence, thereby improving the overall efficiency of the QLED device.

Description of drawings

Fig. 1 is the flow chart of the preferred embodiment of the high pressure treatment process of the present invention;

2 is a schematic structural diagram of a preferred embodiment of a high-voltage processing device for a QLED device according to the present invention;

3 is a schematic structural diagram of a preferred embodiment of a positive-type QLED device in Embodiment 1 of the present invention;

FIG. 4 is a schematic structural diagram of a preferred embodiment of an inversion QLED device in Embodiment 2 of the present invention.

Detailed ways

The present invention provides a QLED device, a preparation method thereof, and a high-voltage treatment device. In order to make the purpose, technical solution and effect of the present invention clearer and clearer, the present invention is further described below in detail. 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 the prior art, in the process of preparing a QLED device, the materials of the functional transport layers are not densely bonded, and there are usually interface defects between the functional transport layers, which easily leads to a decrease in the transport efficiency of carriers. For this reason, the present invention mainly performs high-voltage treatment on the functional transmission layer of the QLED device, and through further high-voltage action on the functional transmission layer, the compactness of the bonding between adjacent film layers can be significantly improved, and the interface between the interfaces can be reduced. defects, thereby improving the carrier transport efficiency and the efficiency of recombination luminescence. The functional transport layer of the present invention includes an electron injection layer, an electron transport layer, a hole injection layer and a hole transport layer, preferably an electron transport layer and/or a hole transport layer adjacent to the quantum dot light-emitting layer.

The material of the electron transport layer of the present invention is not limited, and can be the common n-type ZnO and TiO2 with electron transport properties, or metals such as Ca and Ba with low work function, and can also be ZrO2, CsF, LiF, CsCO3 and Alq3 and other compound materials or other electron transport materials.

The hole transport layer material of the present invention can be PEDOT:PSS, nickel oxide, molybdenum oxide, vanadium oxide, copper oxide, copper sulfide, copper thiocyanide, copper iodide, etc. and other hole transport materials.

After the functional transport layer is deposited on the device, the device is placed in an airtight container under an inert environment for the autoclaving step. In order to ensure the pressing effect and form a dense film, the pressure of the high-pressure treatment should be greater than 1MPa, and the time should be 5-120min. It has been verified by the inventor for many times that, preferably, the pressure of the high-pressure treatment is greater than 4MPa. More preferably, it is greater than 6MPa. Since the larger pressure has higher requirements on the equipment and is likely to cause damage to the device, the pressure of the high-pressure treatment should be less than 10MPa.

Still further, in a specific embodiment, as shown in FIG. 1 , the process of the high-pressure treatment of the present invention specifically includes the steps:

S10. After the functional transmission layer is deposited on the device, fix the device in a closed container of a high-pressure processing device. The high-pressure processing device further includes an air inlet valve and an air outlet valve. By opening the air inlet valve and the air outlet valve, the The inert gas is introduced into the airtight container and the air in the airtight container is removed;

S20, close the gas outlet valve, continue to introduce inert gas until the pressure in the airtight container reaches a predetermined pressure, and perform high-pressure treatment for a predetermined time.

Further, after the step of S20 is completed, step S30 may be further performed to open the air outlet valve, and control the pressure of the air inlet valve and the air outlet valve, so that a flowing inert gas is formed in the airtight container, and the inert gas adsorbed on the surface of the device is removed.

In the present invention, the high-pressure treatment of the functional transmission layer is all realized in an inert environment, and the inert gas can be nitrogen, helium, neon, or argon, or the like.

Furthermore, the present invention also provides a high-pressure processing device for a QLED device. As shown in FIG. 2 , the high-pressure processing device includes an airtight container 10 , and a bracket for fixing the device to be processed is arranged in the airtight container 10 . 20. One end of the airtight container 10 is connected with an air inlet pipe 30, and the other end is connected with an air outlet pipe 40. The air inlet pipe 30 is provided with an air inlet valve 31 and a first pressure gauge 32, and the air outlet pipe 40 is provided with There is an outlet valve 41 and a second pressure gauge 42 ; the other end of the inlet pipe 30 is connected to an inert gas cylinder 50 .

Specifically, in the step S10, before the high-pressure treatment, the device is first fixed in the bracket 20 of the airtight container 10, and then the air inlet valve 31 and the air outlet valve 41 are opened at the same time, and an inert gas is introduced into the airtight container 10. Therefore, the oxygen in the air can be prevented from interacting with various functional transport layers in the device under high pressure, thereby affecting the performance of the device.

In the step S20, after the air in the airtight container 10 is completely removed, the air outlet valve 41 is closed, and the inert gas is continuously introduced until the airtight container reaches a predetermined pressure value of 1-10MPa, and the high pressure treatment is continued for 5-120min.

In the step S30, the air outlet valve 41 is opened, and the pressure of the air inlet valve 31 and the air outlet valve 41 is controlled to form a flowing inert gas in the airtight container 10, and try to avoid the adsorption of inert gas on the surface of the device. This is because inert gas will be adsorbed on the surface of the device after high-pressure treatment, which may easily lead to weak bonding between adjacent layers in the device and affect the transport rate of carriers. By controlling the pressure between the air inlet valve and the air outlet valve, the pressure of the air inlet valve is greater than the pressure of the air outlet valve, so as to form an inert gas flow, so as to remove the inert gas adsorbed on the surface of the device.

Furthermore, the present invention also includes the step of performing annealing treatment after the high-pressure treatment of the functional transport layer. After the high-pressure treatment of the functional transport layer, a quantum dot light-emitting layer or another functional transport layer needs to be deposited on its surface. The solute component in the layer material will not be washed away by the solvent component in the quantum dot light-emitting layer or another functional transport layer, and the functional transport layer needs to be annealed in advance, and the annealing temperature of the functional transport layer is 50- 200°C, preferably 120°C-180°C, for 10-30min.

A kind of preparation method of improving QLED device of the present invention is further explained below by specific embodiment:

Example 1 Preparation of positive QLED device

As shown in FIG. 3 , the positive QLED device includes, from bottom to top, a substrate 100 , a bottom electrode 200 , a hole injection layer 300 , a hole transport layer 400 , a quantum dot light-emitting layer 500 , an electron transport layer 600 and a top electrode. 700, and the specific preparation process is as follows:

1) First, place the glass substrate 100 in ultrapure water, acetone water and isopropanol successively for ultrasonic cleaning. The cleaning time for each step is 15 minutes. After the ultrasonication is completed, the glass substrate is blown dry with a nitrogen gun. drying in an oven to obtain the cleaned glass substrate 100 for subsequent use;

2) On the cleaned glass substrate, a layer of patterned ITO electrode, that is, the bottom electrode 200, is deposited by sputtering on the mask plate, and the thickness of the ITO electrode is 50 nm;

3), deposit a layer of hole injection layer 300 on the bottom electrode 200, the material of the hole injection layer 300 is PEDOT:PSS, after the deposition is completed, perform 150 ℃ annealing treatment for 15min;

4), deposit a layer of hole transport layer 400 on the hole injection layer 300, the material of the hole transport layer 400 is TFB, and then put it into a closed container as shown in Figure 2 for high pressure treatment, the pressure of the high pressure treatment It is 5MPa, and the high pressure treatment time is 30min. After the high pressure treatment is completed, annealing treatment is carried out. The annealing temperature is 150℃ and the time is 15min;

5) A layer of quantum dot light-emitting layer 500 is deposited on the hole transport layer 400, and the material of the quantum dot light-emitting layer 500 is red light quantum dot material; after the deposition is completed, the quantum dot light-emitting layer is annealed, and the annealing temperature is 60 ℃, the time is 10min.

6) A layer of electron transport layer 600 is deposited on the quantum dot light-emitting layer 500, and the material of the electron transport layer 600 is n-type ZnO. Treatment, the pressure of high-pressure treatment is 7MPa, and the time is 2h. After the high-pressure treatment is completed, continue the annealing treatment, the annealing temperature is 150 °C, and the time is 15min;

7), place the device on which each functional layer has been deposited in an evaporation chamber and thermally evaporate a layer of 100nm top electrode 700 through a mask plate, and the top electrode material is Ag;

8) After the evaporation of the device is completed, package the device, which can be packaged by a common machine or by a simpler manual package to obtain the positive QLED device of this embodiment.

Example 2 Preparation of Inversion QLED Device

As shown in FIG. 4 , the inversion QLED device sequentially includes a substrate 100 , a bottom electrode 200 , an electron transport layer 600 , a quantum dot light-emitting layer 500 , a hole transport layer 400 and a top electrode 700 from bottom to top. The specific preparation process is as follows shown:

1) First, place the mica sheet substrate 100 in ultrapure water, acetone water and isopropanol successively for ultrasonic cleaning. The cleaning time for each step is 15 minutes. After the ultrasound is completed, the mica sheet substrate is blown dry with a nitrogen gun. , placed in an oven for drying to obtain a cleaned mica sheet substrate 100 for subsequent use;

2) On the cleaned mica sheet substrate, a layer of patterned ITO electrode, namely the bottom electrode 200, is deposited thereon by sputtering through a mask, and the thickness of the ITO electrode is 70 nm;

3) A layer of electron transport layer 600 is deposited on the substrate containing the bottom electrode, and the material of the electron transport layer 600 is Alq3; after the deposition of the layer is completed, the device is then placed in a closed container as shown in Figure 2 for High-pressure treatment, the pressure of high-pressure treatment is 6MPa, the time of high-pressure treatment is 2h, after the high-pressure treatment is completed, annealing treatment is performed, the annealing temperature is 80 ℃, and the time is 15min;

4), deposit a layer of quantum dot light-emitting layer 500 on the electron transport layer 600, and the material of the quantum dot light-emitting layer is a blue light quantum dot material; after the deposition is completed, anneal the quantum dot light-emitting layer, and the annealing temperature is 80 ℃ , the time is 20min.

5) A layer of hole transport layer 400 is deposited on the quantum dot light-emitting layer 500. The material of the hole transport layer 400 is Poly-TPD, and the device is placed in a closed container as shown in Figure 2 for high pressure treatment. The pressure is 10MPa, the treatment time is 1.5h, and then the annealing treatment is carried out, the annealing temperature is 120℃, and the time is 5min;

6) Place the device on which each functional layer has been deposited in an evaporation chamber, and thermally evaporate a layer of 80 nm top electrode 700 through a mask, and the top electrode material is Al.

7) After the evaporation of the device is completed, it is packaged, and the inverse QLED device of this embodiment can be obtained by using a common machine packaging or a simple manual packaging.

To sum up, the present invention provides a method for preparing a QLED device. The quantum dot light-emitting layer prepared from nanomaterials is subjected to high pressure treatment to form a dense thin film, and the nanomaterials produce certain crystallization under the action of high pressure. In addition, the present invention also performs high-pressure treatment on the functional transport layer of the QLED device, so that the functional transport layer in the QLED device and the quantum dot light-emitting layer are more closely combined. The tightness reduces the defects between the interfaces, reduces the non-radiative recombination, and further improves the carrier injection efficiency and the recombination luminescence efficiency, thereby improving the overall efficiency of the QLED device.

It should be understood that the application of the present invention is not limited to the above examples. For those of ordinary skill in the art, improvements or transformations can be made according to the above descriptions, and all these improvements and transformations should belong to the protection scope of the appended claims of the present invention.

Claims (9)

1. A preparation method of a QLED device, characterized in that, after the functional transport layer is deposited on the device, in an inert environment, the functional transport layer is subjected to a step of high pressure treatment of 1-10 Mpa. 2 . The method for preparing a QLED device according to claim 1 , wherein the functional transport layer is a hole transport layer and/or an electron transport layer. 3 . 3. The method for preparing a QLED device according to any one of claims 1-2, wherein the time of the high-pressure treatment is 5-120 min. 4. The preparation method of the QLED device according to any one of claims 1-2, wherein the process of the high-pressure treatment comprises the following steps: (1) After the functional transmission layer is deposited on the device, the device is fixed in a closed container of a high-pressure processing device, and the high-pressure processing device also includes an air inlet valve and an air outlet valve, and by opening the air inlet valve and the air outlet valve, Pass the inert gas into the airtight container and remove the air in the airtight container; (2) Close the gas outlet valve, continue to introduce inert gas until the pressure in the airtight container reaches the predetermined pressure, and perform high-pressure treatment for a predetermined time. 5. The preparation method of QLED device according to claim 4, is characterized in that, after described step (2) is completed, open air outlet valve, and adjust air outlet valve and air inlet valve pressure, make airtight container form flowing inert gas , remove the inert gas adsorbed on the surface of the device. 6 . The method for preparing a QLED device according to claim 4 , wherein the inert gas is one of nitrogen, helium, neon, or argon. 7 . 7 . The method for preparing a QLED device according to claim 1 , further comprising the step of performing annealing treatment on the functional transport layer after being subjected to high pressure treatment. 8 . 8 . The method for preparing a QLED device according to claim 7 , wherein after the functional transmission layer is subjected to high pressure treatment, the annealing temperature of the annealing treatment is 50-200° C., and the time is 10-30 min. 9 . 9. A QLED device, characterized in that, it is prepared by the preparation method of any one of claims 1-8.

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