A flexible inorganic-organic composite water vapor and oxygen barrier film and a low-temperature preparation method thereof

Abstract

The application provides a flexible inorganic-organic composite water vapor and oxygen barrier film and a low-temperature preparation method thereof. The barrier film comprises a substrate layer, and an Al2O3 inorganic barrier layer and a PU organic barrier layer which are alternately deposited on the upper surface or upper and lower surfaces of the substrate layer, so that the preparation of the flexible inorganic-organic composite water vapor and oxygen barrier film with different thickness ranges is completed. The low-temperature preparation method is to use an atomic layer deposition technology to deposit the flexible inorganic-organic composite water vapor and oxygen barrier film on the surface of the substrate layer. The water vapor and oxygen barrier film prepared by the application has high water vapor and oxygen barrier properties, chemical stability and thermal stability, and has the characteristics of low reaction temperature, small damage to the substrate layer, high automation degree, good repeatability, controllable and accurate film thickness in the deposition process, good integrity of the film layer, uniform thickness, strong adhesion between the barrier film and the substrate layer and the like, and can be used in the fields of waterproofing, packaging and sealing of various devices.

Description

Technical Field

[0001] This invention belongs to the field of device waterproofing, encapsulation and sealing technology, specifically relating to a flexible inorganic-organic composite water vapor and oxygen barrier film and its low-temperature preparation method. Background Technology

[0002] Flexible electronics involves fabricating organic / inorganic materials and electronic display devices on a flexible / ductile substrate, enabling the entire device to flex and bend, thus adapting to different environments and meeting deformation requirements. Due to its unique flexibility / ductility, high efficiency, and low-cost manufacturing processes, flexible electronics have broad application prospects in information, energy, medical, and defense fields. The most extensively researched areas are organic light-emitting diodes (OLEDs) and organic thin-film solar cells (OPVs).

[0003] OLED-based flat panel displays boast rich colors, high brightness, low-current energy saving, and relatively simple fabrication processes. However, moisture and oxygen significantly impact the lifespan and efficiency of OLEDs. This is fundamentally due to the reaction of the relatively reactive cathode material with moisture and oxygen, as well as the chemical reactions between moisture and the hole output layer and electron transport layer, leading to a substantial reduction in lifespan. Furthermore, the introduction of quantum dot film technology further enhances the color gamut and provides higher color display capabilities; however, moisture and oxygen in the environment also significantly reduce the lifespan of quantum dot films. OPVs have garnered widespread attention due to their low cost, lightweight, good stretching and deformation properties, and ability to be deposited over large areas, making them a potential replacement for silicon-based solar cells. However, the organic polymers in OPVs are also affected by moisture and oxygen in the environment, resulting in a significant reduction in their lifespan and stability. Therefore, moisture and oxygen barrier properties are crucial for the encapsulation and sealing of various devices, directly affecting their lifespan and stability.

[0004] Traditional water vapor and oxygen barrier films mostly employ dense, chemically inert inorganic oxides and nitrides, such as aluminum oxide (Al₂O₃), titanium dioxide (TiO₂), silicon dioxide (SiO₂), and silicon nitride (Si₃N₄). Because inorganic oxide and nitride barrier films lack flexibility and stretchability, any bending or flexing during the use of flexible electronics will cause the inorganic water vapor and oxygen barrier layer to crack, significantly reducing its barrier performance. Currently, many research groups are conducting research on flexible water vapor and oxygen barrier films, including flexible barrier films made of polypropylene, polyvinyl alcohol, p-xylene, and polymethyl methacrylate. Although these organic barrier films can maintain a relatively constant water vapor and oxygen permeability under bending and flexing conditions, their low density and poor environmental stability limit their widespread application.

[0005] Inorganic-organic laminated water vapor and oxygen barrier films not only possess the dense structure, chemical inertness, and high chemical stability of inorganic barrier films, but also exhibit flexibility and stretchability. Therefore, inorganic-organic barrier films can be used for extended periods under flexural and bending conditions while effectively maintaining low water vapor and oxygen permeability. Different film preparation technologies have different process conditions, and the temperature range of the substrate environment during film preparation determines whether the barrier layer can be prepared using that technology. The substrate used in flexible electronics has a low temperature tolerance limit, making the selection of barrier layer film preparation technology and related processes crucial. Furthermore, the density of barrier films prepared by different technologies varies significantly, greatly affecting water vapor and oxygen permeability. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] This invention proposes a flexible inorganic-organic composite water vapor and oxygen barrier film and its low-temperature preparation method, in order to solve the technical problem of how to improve the water vapor and oxygen barrier film under flexural and bending conditions, while reducing the damage to the base film caused by excessive temperature during the entire barrier layer preparation process.

[0008] (II) Technical Solution

[0009] To address the aforementioned technical problems, this invention proposes a low-temperature preparation method for a flexible inorganic-organic composite water vapor and oxygen barrier film, which includes the following steps:

[0010] Step 1: Place the substrate layer in the reaction chamber of the atomic layer deposition system and introduce inert carrier gas into the reaction chamber so that the inert carrier gas flows directly over the surface of the substrate layer.

[0011] Step 2: Heating the reaction chamber and precursor storage tank;

[0012] Step 3: Deposit an inorganic barrier layer of aluminum oxide on the surface of the substrate, including injecting trimethylaluminum reaction precursor into the reaction chamber; purging with inert carrier gas after the chemical reaction on the surface of the substrate has fully occurred; injecting water vapor reaction precursor after complete purging; purging with inert carrier gas again after the chemical reaction on the surface of the substrate has fully occurred.

[0013] Step 4: Repeat step 3 to obtain an inorganic barrier layer of aluminum oxide with a certain thickness range;

[0014] Step 5: Deposit a polyurea organic barrier layer on the substrate surface, including injecting a terephthalic acid diisocyanate reaction precursor into the reaction chamber; purging with an inert carrier gas after the chemical reaction on the substrate surface has fully occurred; injecting an ethylenediamine reaction precursor after complete purging; purging with an inert carrier gas again after the chemical reaction on the substrate surface has fully occurred.

[0015] Step 6: Repeat step 5 to obtain a polyurea organic barrier layer with a certain thickness range;

[0016] Step 7: Repeat steps 3 to 6 to obtain a flexible inorganic-organic composite water vapor and oxygen barrier film with alternating aluminum oxide inorganic barrier layer and polyurea organic barrier layer within a certain thickness range.

[0017] Furthermore, the base layer can be a flexible base layer or a rigid base layer.

[0018] Furthermore, the inert carrier gas is one of nitrogen, helium, or argon.

[0019] Further, in step 1, the substrate layer is laid flat or rolled up in the reaction chamber of the atomic layer deposition system; wherein, laying the substrate layer flat is applied to a flexible substrate layer or a rigid substrate layer, and rolling the substrate layer is applied to a flexible substrate layer.

[0020] Furthermore, in step 1, the inert carrier gas is allowed to flow directly over the upper surface or both sides of the substrate.

[0021] Furthermore, in step 2, the temperature range of the reaction chamber is 50℃~100℃, the temperature range of the phenyl diisocyanate reaction precursor in the precursor storage tank is 30℃~80℃, and the temperature range of the trimethylaluminum reaction precursor, the steam reaction precursor, and the ethylenediamine reaction precursor is 15℃~35℃.

[0022] Furthermore, in step 4, the thickness of the inorganic aluminum oxide barrier layer is 0.1 nm to 1000 nm.

[0023] Furthermore, in step 6, the thickness of the organic polyurea barrier layer is 0.1 nm to 1000 nm.

[0024] Furthermore, in step 7, the thickness of the flexible inorganic-organic composite water vapor and oxygen barrier film with alternating aluminum oxide inorganic barrier layer and polyurea organic barrier layer is 0.2 nm to 2000 nm.

[0025] In addition, the present invention also proposes a flexible inorganic-organic composite water vapor and oxygen barrier film, which is prepared by the above method.

[0026] (III) Beneficial Effects

[0027] This invention proposes a flexible inorganic-organic composite water vapor and oxygen barrier film and its low-temperature preparation method. The inorganic barrier film is alumina (Al2O3), and the organic barrier film is polyurea (PU). The flexible inorganic-organic composite water vapor and oxygen barrier film includes a substrate layer, a first Al2O3 inorganic barrier layer, a first PU organic barrier layer, a second Al2O3 inorganic barrier layer, a second PU organic barrier layer, and so on. Al2O3 inorganic barrier layers and PU organic barrier layers are repeatedly deposited on the upper surface or both sides of the substrate layer to prepare flexible inorganic-organic composite water vapor and oxygen barrier films of different thicknesses. The low-temperature preparation method uses atomic layer deposition (ALD) technology to deposit the flexible inorganic-organic composite water vapor and oxygen barrier film on the surface of the substrate layer. The water vapor and oxygen barrier film of the present invention has high water vapor and oxygen barrier properties, chemical stability and thermal stability. It has the characteristics of low reaction temperature, minimal damage to the substrate, high degree of automation, good repeatability, precise control of film thickness during deposition, good integrity of the film layer, uniform thickness, and strong adhesion between the barrier film and the substrate. It can be used in waterproofing, encapsulation and sealing of various devices.

[0028] The beneficial technical effects of this invention compared to the prior art are as follows:

[0029] 1. The process of preparing Al2O3 inorganic barrier layer and PU organic barrier layer by ALD is at a low temperature, which can be applied to various substrates without causing damage to the substrate.

[0030] 2. The Al2O3 inorganic barrier layer prepared by ALD is uniform and dense, and the nanoscale barrier layer has good water vapor and oxygen barrier effect.

[0031] 3. The PU organic barrier layer prepared by ALD has strong waterproof, anti-corrosion, wear-resistant and bending-resistant properties.

[0032] 4. The flexible inorganic-organic composite water vapor and oxygen barrier film prepared by ALD has high water vapor and oxygen barrier properties and good flexibility and bending resistance.

[0033] 5. The barrier film has strong adhesion to the substrate layer and is not prone to peeling under bending and flexing conditions.

[0034] 6. The ALD barrier film deposition process allows for precise control of film thickness, good film integrity, and uniform thickness.

[0035] 7. The preparation method of the present invention has a high degree of automation and good repeatability. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the atomic layer deposition system used in this invention.

[0037] Figure 2Quartz crystal microbalance (QCM) curves for the preparation of Al2O3 inorganic barrier films for ALD.

[0038] Figure 3 QCM curves for the preparation of PU organic barrier films for ALD.

[0039] Figure 4 This is a schematic diagram of the flexible inorganic-organic composite water vapor and oxygen barrier film of the present invention.

[0040] Figure 5 QCM curves for the preparation of PU organic barrier films by ALD on the surface of Al2O3 inorganic barrier films.

[0041] Figure 6 QCM curves for the preparation of Al2O3 inorganic barrier films by ALD on the surface of PU organic barrier films.

[0042] Figure 7 This diagram illustrates the appearance of cracks during the bending process of a thin film.

[0043] Figure 8 SEM image of the Al2O3 inorganic barrier film after bending.

[0044] Figure 9 This is a SEM image of the surface of the flexible inorganic-organic composite barrier film after bending. Detailed Implementation

[0045] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0046] Example 1

[0047] This embodiment proposes a low-temperature preparation method for a flexible inorganic-organic composite water vapor and oxygen barrier film, which specifically includes the following steps:

[0048] Step 1: Roll up the flexible polyimide (PI) substrate and place it in a position such as... Figure 1 The atomic layer deposition system shown in the diagram allows gas to flow directly across the upper surface of the substrate.

[0049] Step 2: Introduce nitrogen as a carrier gas into the atomic layer deposition (ALD) system and turn on the mechanical vacuum pump to evacuate the ALD reaction chamber, controlling the pressure at 100 Pa; use an electric heating belt to heat the reaction chamber to control the temperature at 70°C, the temperature of the phenyl diisocyanate (PDIC) precursor to control the temperature at 60°C, and the temperatures of trimethylaluminum (TMA), water (H2O) and ethylenediamine (ED) to room temperature.

[0050] Step 3: First, deposit the first aluminum oxide (Al2O3) inorganic barrier layer on the surface of the PI substrate. A total of 125 deposition cycles are performed, and each cycle includes the following four steps:

[0051] (1) Inject the first precursor TMA into the reaction chamber to allow it to undergo a saturated chemical reaction with the surface of the PI substrate and replace the hydroxyl (-OH) functional groups on the surface of the PI substrate. The specific chemical reaction formula is as follows:

[0052] ||-OH+Al(CH3)3→||-O-Al(CH3)2+CH4

[0053] "||-" indicates the surface of the PI substrate material;

[0054] (2) Purge unreacted TMA and byproducts with nitrogen gas;

[0055] (3) Water vapor is injected into the reaction chamber to react with the adsorbed TMA on the surface of the PI substrate layer, thereby replacing the surface functional groups again. The specific chemical reaction formula is as follows:

[0056] ||-O-Al(CH3)2+H2O→||-OAl-OH+CH4

[0057] (4) Purge unreacted H2O and byproducts with nitrogen gas.

[0058] Following the steps described in (1) to (4) above, the pulse sequence for the atomic layer deposition process to prepare the Al2O3 inorganic barrier layer is represented by t1-t2-t3-t4, where t1 is the injection time of the TMA precursor, t3 is the injection time of the H2O precursor, and t2 and t4 are both nitrogen purging times. In this embodiment, the pulse sequence used is 10s-20s-10s-20s. Figure 2 The figure shows the quartz crystal microbalance (QCM) curve after the Al2O3 inorganic barrier film prepared by ALD has been stabilized. The mass change of the QCM wafer surface during each cycle of ALD preparation of Al2O3 is consistent with the mass change of the group exchange reaction and carrier gas purging process corresponding to the four steps (1) to (4) above. Under the ALD preparation of Al2O3 process parameters described in this embodiment, based on the QCM wafer size and the inorganic Al2O3 density, the growth rate of the Al2O3 film prepared by ALD is approximately / cycle. Therefore, the thickness of the first Al2O3 inorganic barrier film is approximately 25nm.

[0059] Step 4: Deposit the first polyurea (PU) organic barrier layer on the surface of the first Al2O3 inorganic barrier layer, for a total of 500 cycles. Each cycle includes the following four steps:

[0060] (1) The first precursor PDIC is injected into the reaction chamber, so that it undergoes a saturated chemical reaction with the surface of the Al2O3 inorganic barrier layer and replaces the hydroxyl (-OH) functional groups on the surface of the Al2O3 inorganic barrier layer. The specific chemical reaction formula is as follows:

[0061]

[0062] "||-" indicates the surface of the Al2O3 inorganic barrier layer;

[0063] (2) Purge unreacted PDICs and byproducts with nitrogen gas;

[0064] (3) ED is injected into the reaction chamber and reacts with the PDIC adsorbed on the surface of the Al2O3 inorganic barrier layer to undergo a surface chemical reaction, thereby replacing the surface functional groups again. The specific chemical reaction formula is as follows:

[0065]

[0066] (4) Nitrogen gas is introduced to purge unreacted ED precursors and byproducts.

[0067] According to the steps described in (1) to (4) above, the pulse sequence of the ALD preparation of the PU organic barrier layer deposition process is represented by t5-t6-t7-t8, where: t5 is the injection time of the PDIC precursor, t7 is the injection time of the ED precursor, and t6 and t8 are both nitrogen purging times. In this embodiment, the pulse sequence used is 5s-10s-50s-10s. Figure 3 The figure shows the QCM curve after the PU organic barrier film prepared by ALD has stabilized. The mass change of the QCM wafer surface during each cycle of ALD preparation of PU is consistent with the mass change of the group exchange reaction and carrier gas purging process in the four steps (1) to (4) described in step four. Under the ALD preparation process parameters described in this embodiment, the growth rate of the PU film prepared by ALD is calculated to be approximately based on the QCM wafer size and the organic PU density. / cycle. Therefore, the thickness of the first layer of PU organic barrier film is approximately 25nm.

[0068] Step 5: Repeat steps 3 and 4 twice each to obtain a flexible inorganic-organic composite water vapor and oxygen barrier film with a thickness of approximately 100 nm, PI / (25nm Al2O3 / 25nm PU / 25nm Al2O3 / 25nm PU), as shown. Figure 4 The diagram shows a flexible inorganic-organic composite water vapor and oxygen barrier film.

[0069] Similarly, QCM was used to analyze the growth process of PU organic film on Al2O3 inorganic film surface and Al2O3 inorganic film on PU organic film surface, and to analyze and study its adsorption state, nucleation delay and growth rate. Figure 5 The figure shows the QCM curves for the initial stage of ALD (Al2O3) deposition of PU organic barrier films on an Al2O3 inorganic barrier film surface. Firstly, the deposition of PU organic barrier films on an Al2O3 inorganic film surface by ALD does not present the problem of difficult or impossible nucleation, thus PU film preparation can be performed relatively well on the Al2O3 inorganic film surface. Secondly, during the PU deposition process on the Al2O3 inorganic film surface, the deposition rate and trend in the first few cycles are completely different from those after stabilization. This is due to the different properties and number of surface adsorption sites. In the initial stage of PU deposition on the Al2O3 inorganic film surface using ALD, the chemisorption of PDIC or ED mainly reacts with the hydroxyl groups on the Al2O3 surface. Due to the relatively smooth surface of the Al2O3 inorganic barrier film and the large number of surface hydroxyl groups, the growth rate of the PU organic film is relatively fast in the early stage. As the number of ALD cycles increases, the surface of the Al2O3 inorganic barrier film is basically covered by the PU organic barrier film. After stabilization, the adsorption of PDIC or ED reacts with the amino groups on the PU surface. Due to the phenomenon of molecular entanglement, collapse, and bidirectional site occupancy by long-chain molecules after collapse, which reduces the number of sites, the subsequent growth process and rate tend to stabilize, and the film thickness growth rate is lower than the growth rate of the film in the initial stage of deposition on the Al2O3 surface.

[0070] Figure 6 The image shows the QCM curve of the Al2O3 inorganic barrier film deposition process on the surface of the PU organic barrier film via ALD. It also confirms that the preparation of the Al2O3 inorganic barrier film via ALD on the surface of the PU organic barrier film essentially eliminates nucleation delay and nucleation difficulties, enabling direct growth. Compared to... Figure 5 The diagram shows the growth of a PU organic film on the surface of an Al2O3 inorganic barrier film. Because the PU organic film obtained by ALD deposition has a lower density and larger pores, resulting in a larger surface area, the initial growth rate of the Al2O3 inorganic barrier film deposited on the PU organic film surface is slightly higher than the later, more stable growth rate of the Al2O3 inorganic barrier film deposited by ALD. Since Al2O3 molecules are rigid molecules with short chains, there is no entanglement of long-chain organic molecules, nor are there problems such as site preemption caused by collapse. Therefore, the growth process (pattern) is basically the same as that of the Al2O3 inorganic barrier film prepared by ALD after stabilization.

[0071] Figure 7The diagram illustrates the crack formation during the bending process of a thin film. Because inorganic thin films are rigid and have poor ductility and deformability, they exhibit significant through-cracks after bending and deflection, allowing water vapor and oxygen to easily penetrate the barrier layer and reach the substrate surface. Flexible thin films, formed by alternating layers of flexible and rigid films, not only possess the high density of inorganic films but also ensure that they do not experience through-cracks after bending and deflection, maintaining high barrier properties against water vapor and oxygen.

[0072] Figure 8 The image shows the PI / (25nm Al2O3 / 25nm PU / 25nm Al2O3 / 25nm PU) inorganic-organic flexible water-oxygen barrier layer sample after bending and flexing. No through-cracks or peeling occurred on the sample surface. Table 1 shows the water vapor transmission rate and oxygen transmission rate of the PI substrate layer and the PI / (25nm Al2O3 / 25nm PU / 25nm Al2O3 / 25nm PU) sample. The water vapor transmission rate was tested at 38℃ / 90% RH, and the oxygen transmission rate was tested at 38℃ / 1 atm oxygen partial pressure. Compared to the PI substrate layer, the water vapor and oxygen transmission rates were significantly reduced.

[0073] Table 1. Water vapor and oxygen transmission rates of the PI substrate and samples

[0074]

[0075] Example 2

[0076] This embodiment proposes a low-temperature preparation method for a flexible inorganic-organic composite water vapor and oxygen barrier film, which specifically includes the following steps:

[0077] Steps 1 and 2 of this method are the same as steps 1 and 2 of Example 1, the difference being step 3.

[0078] Step 3: First, deposit the first Al2O3 inorganic barrier layer on the surface of the PI substrate layer. A total of 50 cycles are deposited. Each cycle includes the same four steps as the four steps in Step 3 of Example 1. The pulse sequence used is 10s-20s-10s-20s. Therefore, the thickness of the first Al2O3 inorganic barrier film is about 10nm.

[0079] Step 4: Deposit the first layer of polyurea (PU) organic barrier layer on the surface of the first layer of Al2O3 inorganic barrier layer. A total of 200 cycles are deposited. Each cycle includes the same four steps as the four steps in step four of Example 1. The pulse sequence used is 5s-10s-5s-10s. Therefore, the thickness of the first layer of PU organic barrier film is about 10nm.

[0080] Step 5: Repeat steps 3 and 4 five times to obtain a flexible inorganic-organic composite water vapor and oxygen barrier film with a thickness of approximately 100 nm, PI / (10nm Al2O3 / 10nm PU) x 5. The total thickness of the PI surface flexible inorganic-organic composite water vapor and oxygen barrier film (PI / (10nm Al2O3 / 10nm PU) x 5) obtained in Example 2 is the same as the total thickness of the PI / (25nm Al2O3 / 25nm PU) x 2 sample surface barrier film obtained in Example 1, the difference being the degree of overlapping and mixing. The water vapor and oxygen permeability of the sample obtained in Example 2 is shown in Table 2, and the water vapor and oxygen permeability test conditions are the same as in Example 1. Comparing the water vapor and oxygen permeability of the sample obtained in Example 1 and the sample obtained in Example 2, it can be seen that increasing the degree of mixing of the inorganic barrier film and the organic barrier film can further reduce the overall water vapor and oxygen permeability.

[0081] Table 2. Water vapor and oxygen transmission rate of PI / (10nm Al2O3 / 10nm PU) x 5

[0082]

[0083] Comparative Example 1

[0084] Steps 1 and 2 of this method are the same as step 1 of Example 1, the difference lies in step 3.

[0085] Step 3: First, deposit the first Al2O3 inorganic barrier layer on the surface of the PI substrate layer. A total of 125 cycles are deposited. Each cycle includes the same four steps as the four steps in Step 3 of Example 1. The pulse sequence used is 10s-20s-10s-20s. Therefore, the thickness of the first Al2O3 inorganic barrier film is about 25nm.

[0086] Step 4: Repeat step 3 twice to obtain a 50nm Al2O3 inorganic barrier film deposited on the surface of the PI substrate, i.e., PI / 50nm Al2O3.

[0087] After depositing a 50nm Al2O3 inorganic barrier film on the PI substrate surface and then bending and twisting it, the low elasticity and low extensibility of the rigid inorganic film led to severe peeling and cracking of the Al2O3 inorganic barrier film on the PI substrate surface (e.g. Figure 9 (As shown).

[0088] The water vapor and oxygen transmission rates of the samples obtained in Comparative Example 1 are shown in Table 3. The water vapor and oxygen transmission rate test conditions were the same as those in Example 1.

[0089] Table 3. PI / 50nm Al2O3 Water Vapor and Oxygen Transmission Rate

[0090]

[0091] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for low-temperature preparation of a flexible inorganic-organic composite water vapor and oxygen barrier film, characterized in that, The preparation method includes the following steps: Step 1: Place the flexible polyimide substrate in the reaction chamber of the atomic layer deposition system, introduce nitrogen gas into the reaction chamber as a carrier gas, and evacuate the atomic layer deposition reaction chamber to a pressure of 100 Pa. Step 2: Heating the reaction chamber and precursor storage tank; the temperature of the reaction chamber is 70℃, the temperature of the phenyl diisocyanate reaction precursor in the precursor storage tank is 60℃, and the temperature range of the trimethylaluminum reaction precursor, the steam reaction precursor, and the ethylenediamine reaction precursor is 15℃~35℃. Step 3: First, deposit the first aluminum oxide inorganic barrier layer on the surface of the flexible polyimide substrate. Multiple deposition cycles are performed, each cycle consisting of the following four steps: (1) Inject the first precursor, trimethylaluminum, into the reaction chamber to make it react with the surface of the flexible polyimide substrate to saturate and replace the hydroxyl-OH functional groups on the surface of the flexible polyimide substrate. (2) Purge unreacted trimethylaluminum and byproducts with nitrogen gas; (3) Inject water vapor into the reaction chamber to react with the adsorbed trimethylaluminum on the surface of the flexible polyimide substrate, and replace the surface functional groups again. (4) Purge unreacted H2O and byproducts with nitrogen gas; According to the steps described in (1) to (4) above, the pulse sequence of the atomic layer deposition process for preparing the Al2O3 inorganic barrier layer is represented by t1-t2-t3-t4, where: t1 is the injection time of the trimethylaluminum precursor, t3 is the injection time of the H2O precursor, and t2 and t4 are both nitrogen purging times; t1-t2-t3-t4 is 10s-20s-10s-20s; Step 4: Deposit the first polyurea organic barrier layer on the surface of the first Al2O3 inorganic barrier layer. Multiple deposition cycles are performed, and each cycle includes the following four steps: (1) The first precursor, phenyl diisocyanate, is injected into the reaction chamber to allow it to undergo a saturated chemical reaction with the surface of the Al2O3 inorganic barrier layer and replace the hydroxyl-OH functional groups on the surface of the Al2O3 inorganic barrier layer. (2) Purge unreacted phenyl diisocyanate and byproducts with nitrogen gas; (3) Inject ethylenediamine into the reaction chamber to react with the phenyl diisocyanate adsorbed on the surface of the Al2O3 inorganic barrier layer, and replace the surface functional groups again. (4) Purge unreacted ED precursors and byproducts with nitrogen gas; According to the steps (1) to (4) in step 4, the pulse sequence of the ALD preparation of polyurea organic barrier layer deposition process is represented by t5-t6-t7-t8, where: t5 is the injection time of PDIC precursor, t7 is the injection time of ED precursor, t6 and t8 are both nitrogen purging times; t5-t6-t7-t8 is 5s-10s-5s-10s; Step 5: Repeat steps 3 and 4 to obtain a flexible inorganic-organic composite water vapor and oxygen barrier film with alternating aluminum oxide inorganic barrier layer and polyurea organic barrier layer of a certain thickness. The thickness of the single-layer aluminum oxide inorganic barrier layer is 10 nm, and the thickness of the single-layer polyurea organic barrier layer is 10 nm.

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