OLED packaging structure and preparation method and application thereof

Abstract

The invention relates to the technical field of silicon-based OLED packaging structures, in particular to an OLED packaging structure and a preparation method and application thereof. The invention provides an OLED packaging structure. The OLED packaging structure comprises a graphene layer, an inorganic barrier layer and a polymer layer which are sequentially stacked. The OLED packaging structure can improve the light emitting efficiency of the device, and also has the advantages of low cost and stable structure.

Description

Technical Field

[0001] The present invention relates to the technical field of silicon-based OLED packaging structures, and particularly to an OLED packaging structure, a preparation method thereof, and an application thereof. Background Art

[0002] With the rapid development of display technology, OLED has been widely used in the display field due to its self-luminous, bright color, and wide viewing angle characteristics. However, OLED devices are extremely sensitive to moisture and oxygen. Once the packaging effect is poor, it may lead to a decline in device performance or even failure. Traditional packaging methods, such as glass cover plate packaging and thin film packaging, although they can provide certain protection, have problems such as high cost, complex manufacturing process, and poor flexibility. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide an OLED packaging structure, a preparation method thereof, and an application thereof. The OLED packaging structure can improve the light extraction efficiency of the device while having the advantages of low cost and stable structure.

[0004] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0005] The present invention provides an OLED packaging structure, including a graphene layer, an inorganic barrier layer, and a polymer layer stacked in sequence.

[0006] Preferably, the material of the inorganic barrier layer is one or more of aluminum oxide, silicon oxide, silicon nitride, and aluminum oxynitride.

[0007] Preferably, the thickness of the inorganic barrier layer is 50 - 500 nm.

[0008] Preferably, the thickness of the graphene layer is 1 - 10 nm.

[0009] Preferably, the material of the polymer layer is one or more of polyvinyl alcohol, polyimide, polycarbonate, epoxy resin, and polyethylene terephthalate.

[0010] Preferably, the thickness of the polymer layer is 1 - 10 μm.

[0011] The present invention also provides a preparation method of the OLED packaging structure according to the above technical solution, including the following steps:

[0012] Prepare a graphene layer, an inorganic barrier layer, and a polymer layer on the surface of the OLED device in sequence to obtain the OLED packaging structure.

[0013] Preferably, the preparation method of the graphene layer is chemical vapor deposition;

[0014] The working gas used in the chemical vapor deposition is a carbon-containing gas and hydrogen, the temperature is 800 - 1000 °C, the flow rate of the carbon-containing gas is 50 - 500 mL / min, the flow rate of hydrogen is 100 - 1000 mL / min, and the deposition time is 10 - 50 min.

[0015] Preferably, the preparation method of the inorganic barrier layer is atomic layer deposition;

[0016] The preparation method of the polymer layer is coating.

[0017] The present invention also provides an application of the OLED encapsulation structure described in the above technical solution or the OLED encapsulation structure prepared by the preparation method described in the above technical solution in the field of encapsulation of silicon-based OLED devices.

[0018] The present invention provides an OLED encapsulation structure, including a graphene layer, an inorganic barrier layer, and a polymer layer stacked in sequence. The graphene layer in the present invention provides excellent strong water and oxygen barrier performance and high light transmittance ability for the OLED encapsulation structure, improves the light extraction efficiency of the OLED encapsulation structure, and improves the optical performance of the OLED encapsulation structure; under the combined action of the graphene layer and the inorganic barrier layer, the water and oxygen barrier effect of the encapsulation structure is significantly improved, and the service life of the OLED device is extended; the addition of the polymer layer provides good flexibility and buffering effect for the encapsulation structure, and enhances the stability and reliability of the overall structure.

[0019] The present invention also provides a preparation method of the OLED encapsulation structure described in the above technical solution, including the following steps: sequentially preparing a graphene layer, an inorganic barrier layer, and a polymer layer on the surface of the OLED device to obtain the OLED encapsulation structure. The preparation method in the present invention simplifies the manufacturing process steps of the encapsulation structure and reduces the cost. Description of the Drawings

[0020] Figure 1 is a schematic structural diagram of the OLED encapsulation structure described in the present invention, where 1 is the OLED device, 2 is the graphene layer, 3 is the inorganic barrier layer, and 4 is the polymer layer;

[0021] Figure 2 is a schematic structural diagram of the OLED encapsulation structure described in Comparative Example 1, where 1 is the OLED device, 5 is the first ATO transparent conductive thin film layer, 6 is the silicon nitride layer, and 7 is the second ATO transparent conductive thin film layer. Detailed Embodiments

[0022] The present invention provides an OLED encapsulation structure, including a graphene layer, an inorganic barrier layer, and a polymer layer stacked in sequence.

[0023] In the present invention, the thickness of the graphene layer is preferably 1 to 10 nm, more preferably 3 nm.

[0024] In the present invention, the graphene layer provides excellent water and oxygen barrier properties and high light transmittance, thereby improving the light extraction efficiency of the OLED device and enhancing the optical performance of the OLED device.

[0025] In the present invention, the material of the inorganic barrier layer is preferably one or more of aluminum oxide, silicon oxide, silicon nitride, and aluminum oxynitride, more preferably aluminum oxide. In the present invention, the thickness of the inorganic barrier layer is preferably 50 to 500 nm, more preferably 100 to 300 nm, and most preferably 100 nm.

[0026] In the present invention, the inorganic barrier layer can further enhance the water and oxygen barrier effect of the OLED encapsulation structure.

[0027] In the present invention, the material of the polymer layer is preferably one or more of polyvinyl alcohol, polyimide, polycarbonate, epoxy resin, and polyethylene terephthalate, more preferably polyvinyl alcohol or polyimide. In the present invention, the thickness of the polymer layer is preferably 1 to 10 μm, more preferably 5 μm.

[0028] In the present invention, the polymer layer can provide a buffering effect and improve the flexibility of the OLED encapsulation structure.

[0029] The present invention also provides a method for preparing the OLED encapsulation structure according to the above technical solution, comprising the following steps:

[0030] A graphene layer, an inorganic barrier layer, and a polymer layer are sequentially prepared on the surface of the OLED device to obtain the OLED encapsulation structure.

[0031] In the present invention, unless otherwise specified, all preparation raw materials are commercially available products well-known to those skilled in the art.

[0032] In the present invention, the OLED device is preferably a silicon-based OLED device. The present invention does not have any special limitation on the structure of the silicon-based OLED device, and a structure well-known to those skilled in the art can be adopted.

[0033] In the present invention, the preparation method of the graphene layer is preferably chemical vapor deposition (CVD). The working gas used in the chemical vapor deposition is preferably a carbon-containing gas and hydrogen. The carbon-containing gas is preferably methane and / or ethylene, more preferably methane. In the present invention, the flow rate of the carbon-containing gas is preferably 50-500 mL / min, more preferably 50-100 mL / min, and most preferably 50 mL / min; the flow rate of hydrogen is preferably 100-1000 mL / min, more preferably 200-500 mL / min, and most preferably 200 mL / min. The temperature of the chemical vapor deposition is preferably 800-1000 °C, more preferably 900 °C; the time of the chemical vapor deposition is preferably 10-50 min, more preferably 30 min.

[0034] In the present invention, controlling the conditions of the above chemical vapor deposition within the above ranges can be more conducive to obtaining a continuous, uniform and less defective graphene layer.

[0035] In the present invention, the preparation method of the inorganic barrier layer is preferably atomic layer deposition. The present invention has no special limitation on the process of the atomic layer deposition (ALD), and a process well-known to those skilled in the art can be adopted as long as it can form a continuous and uniform inorganic barrier layer. When the inorganic barrier layer is an alumina layer, the preparation process of the alumina layer is preferably as follows: The OLED with the grown graphene layer is placed in the ALD reaction chamber, and an aluminum source and an oxygen source are alternately introduced, and a dense, continuous and uniform alumina thin film is prepared by controlling the deposition parameters. In the present invention, the aluminum source is preferably trimethylaluminum; the oxygen source is preferably water vapor or oxygen. In the present invention, the deposition parameters include: the deposition temperature is preferably 100-500 °C, more preferably 200 °C; the pulse frequency is preferably 0.1-1 Hz, more preferably 0.5 Hz; the pulse time is preferably 100-200 s, more preferably 120 s; the flow rate of the aluminum source is preferably 10-50 mL / min, more preferably 20 mL / min, and the flow rate of the oxygen source is preferably 50-200 mL / min, more preferably 100 mL / min.

[0036] In the present invention, the preparation method of the polymer layer is preferably coating; the coating method is preferably spin coating or printing. The present invention has no special limitation on the coating process, and a process well-known to those skilled in the art can be adopted; after the coating is completed, the present invention also preferably includes drying and curing in sequence; the present invention has no special limitation on the drying and curing processes, and a process well-known to those skilled in the art can be adopted.

[0037] The present invention also provides an application of the OLED encapsulation structure described in the above technical solution or the OLED encapsulation structure prepared by the preparation method described in the above technical solution in the field of encapsulation of silicon-based OLED devices. The present invention has no special limitation on the method of the application, and the method well-known to those skilled in the art can be adopted.

[0038] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0039] Example 1

[0040] As Figure 1 shown, the silicon-based OLED encapsulation structure includes a graphene layer (with a thickness of 3 nm), an inorganic barrier layer (made of alumina with a thickness of 100 nm), and a polymer layer (with a thickness of 5 μm and made of polyvinyl alcohol) sequentially arranged on the surface of the silicon-based OLED device;

[0041] Preparation method of the silicon-based OLED encapsulation structure:

[0042] Provide a silicon-based OLED device, including an anode (made of ITO with a thickness of 100 nm), a hole injection layer (made of PEDOT:PSS with a thickness of 30 nm), a hole transport layer (made of NPD with a thickness of 50), a light-emitting layer (made of PPV with a thickness of 70 nm), an electron transport layer (made of TPBi with a thickness of 40 nm), an electron injection layer (made of LiF with a thickness of 1 nm), and a cathode (made of Al with a thickness of 200 nm) sequentially formed on a silicon substrate;

[0043] Grow a graphene layer on the surface of the silicon-based OLED device by chemical vapor deposition technology: Place the silicon-based OLED in a chemical vapor deposition reaction chamber, heat it to 900 °C, and then introduce methane and hydrogen as reaction gases (where the flow rate of methane is 50 mL / min and the flow rate of hydrogen is 200 mL / min) for chemical vapor deposition for 30 min to obtain the graphene layer;

[0044] Grow an inorganic barrier layer on the surface of the graphene layer by atomic layer deposition technology: Place the silicon-based OLED device with the grown graphene layer in an ALD reaction chamber, and alternately introduce trimethylaluminum and oxygen (the flow rate of trimethylaluminum is 20 mL / min and the flow rate of oxygen is 100 mL / min) for atomic layer deposition (the deposition temperature is 200 °C, the pulse frequency is 0.5 Hz, and the time is 120 s) to obtain an aluminum oxide layer;

[0045] A polymer layer is grown on the surface of the aluminum oxide layer by spin coating technology: after uniformly spin coating a polymer solution with a concentration of 10% (the polymer is polyvinyl alcohol and the solvent is deionized water) on the surface of the aluminum oxide layer, it is dried at 60 °C for 1 hour, and then cured at 120 °C for 2 hours to obtain a polymer layer, and finally a silicon-based OLED encapsulation structure is obtained;

[0046] The silicon-based OLED encapsulation structure is subjected to electrical performance testing, optical performance testing, and barrier performance testing. The electrical performance testing is to use a source measurement unit (SMU) or a similar electrical performance testing device to measure the current-voltage (I-V) characteristics of the encapsulation structure. Within a specific voltage range, the change in current is recorded, and electrical parameters such as resistance and capacitance are calculated; the optical performance testing is to use a spectrometer or a photometer to measure optical parameters such as the transmittance, reflectance, and chromaticity of the encapsulation structure. Within the visible light range, the spectral transmittance curve is recorded, and the average transmittance is calculated; the barrier performance testing is to use a water vapor transmission rate tester or an oxygen transmission rate tester to measure the water vapor transmission rate (WVTR) and oxygen transmission rate (OTR) of the encapsulation structure. Under specific temperature and humidity conditions, the transmittance data is recorded. The test results are as follows: the silicon-based OLED encapsulation structure exhibits low resistance, high capacitance stability, and good conductivity; the silicon-based OLED encapsulation structure of the example has a high transmittance (>90%), a low reflectance (<5%), and the chromaticity coordinates meet the design requirements; the silicon-based OLED encapsulation structure of the example exhibits an extremely low water vapor transmission rate (<1×10 -5 cc / m 2 ·day), indicating that it has good barrier performance.

[0047] Comparative Example 1

[0048] As Figure 2 shown, the silicon-based OLED encapsulation structure includes a first ATO transparent conductive thin film layer (with a thickness of 40 nm), a silicon nitride layer (with a thickness of 600 nm), and a second ATO transparent conductive thin film layer (with a thickness of 40 nm) sequentially arranged on the surface of the silicon-based OLED device (the structure refers to Example 1).

[0049] The silicon-based OLED encapsulation structure is subjected to electrical performance testing, optical performance testing, and barrier performance testing, and the testing method is the same as that of Example 1. The test results are as follows: the silicon-based OLED encapsulation structure of Comparative Example 1 has a higher resistance, slightly worse capacitance stability, and lower conductivity than Example 1; the silicon-based OLED encapsulation structure of Comparative Example 1 has a slightly lower transmittance (about 85%), a slightly higher reflectance (about 7%), and the chromaticity coordinates deviate from the design requirements; the water vapor transmission rate and oxygen transmission rate of the silicon-based OLED encapsulation structure of Comparative Example 1 are both higher than those of the example, and the barrier performance is poor.

[0050] Comparative Example 2

[0051] Referring to Example 1, the difference is that the graphene layer is not included, and a silicon-based OLED encapsulation structure is obtained;

[0052] The silicon-based OLED encapsulation structure is subjected to electrical property tests, optical property tests, and barrier property tests. The test methods are the same as those in Example 1; the test results are as follows: the resistance of the silicon-based OLED encapsulation structure in Comparative Example 2 increases significantly, and the conductivity decreases significantly; the transmittance of the silicon-based OLED encapsulation structure in Comparative Example 2 decreases slightly, and the reflectance increases; the barrier property of the silicon-based OLED encapsulation structure in Comparative Example 2 decreases slightly, but not as significantly as in Example 1.

[0053] Comparative Example 3

[0054] Referring to Example 1, the difference is that the aluminum oxide layer is not included, and a silicon-based OLED encapsulation structure is obtained;

[0055] The silicon-based OLED encapsulation structure is subjected to electrical property tests, optical property tests, and barrier property tests. The test methods are the same as those in Example 1; the test results are as follows: the electrical properties of the silicon-based OLED encapsulation structure in Comparative Example 3 change little, but the conductivity stability decreases; the transmittance of the silicon-based OLED encapsulation structure in Comparative Example 3 is not affected much, but the chromaticity coordinates deviate from the design requirements; the barrier property of the silicon-based OLED encapsulation structure in Comparative Example 3 decreases significantly, and both the water vapor transmission rate and the oxygen transmission rate increase.

[0056] Comparative Example 4

[0057] Referring to Example 1, the difference is that the polymer layer is not included, and a silicon-based OLED encapsulation structure is obtained;

[0058] The silicon-based OLED encapsulation structure is subjected to electrical property tests, optical property tests, and barrier property tests. The test methods are the same as those in Example 1; the test results are as follows: the electrical properties of the silicon-based OLED encapsulation structure in Comparative Example 4 change little, but the mechanical stability and flexibility decrease; the transmittance of the silicon-based OLED encapsulation structure in Comparative Example 4 decreases slightly, and the reflectance increases; the barrier property of the silicon-based OLED encapsulation structure in Comparative Example 4 decreases, especially the water vapor transmission rate increases significantly.

[0059] The above is only the preferred embodiment of the present invention and does not impose any form of limitation on the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An OLED packaging structure, characterized in that: It includes a graphene layer, an inorganic barrier layer and a polymer layer which are stacked in sequence.

2. The OLED encapsulation structure according to claim 1, characterized in that: The material of the inorganic barrier layer is one or more of aluminum oxide, silicon oxide, silicon nitride and aluminum oxynitride.

3. The OLED encapsulation structure according to claim 1 or 2, characterized in that: The thickness of the inorganic barrier layer is 50-500 nm.

4. The OLED encapsulation structure according to claim 1, characterized in that: The thickness of the graphene layer is 1-10 nm.

5. The OLED encapsulation structure according to claim 1, characterized in that: The material of the polymer layer is one or more of polyvinyl alcohol, polyimide, polycarbonate, epoxy resin and polyethylene terephthalate.

6. The OLED encapsulation structure according to claim 1 or 5, characterized in that: The thickness of the polymer layer is 1-10 μm.

7. The method for preparing the OLED encapsulation structure according to any one of claims 1 to 6, characterized in that: The following steps are involved: A graphene layer, an inorganic barrier layer and a polymer layer are sequentially prepared on the surface of the OLED device to obtain an OLED encapsulation structure.

8. The preparation method according to claim 7, characterized in that: The graphene layer is prepared by chemical vapor deposition; The working gases used in the chemical vapor deposition are carbon-containing gas and hydrogen, the temperature is 800-1000° C., the flow rate of the carbon-containing gas is 50-500 mL / min, the flow rate of the hydrogen is 100-1000 mL / min, and the deposition time is 10-50 min.

9. The preparation method according to claim 7, characterized in that: The inorganic barrier layer is prepared by atomic layer deposition; The polymer layer is prepared by coating.

10. Use of the OLED encapsulation structure according to any one of claims 1 to 6 or the OLED encapsulation structure prepared by the preparation method according to any one of claims 7 to 9 in the field of encapsulation of silicon-based OLED devices.

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