Slit coating head, slit coating device and slit coating method

Abstract

The invention provides a slit coating head, a slit coating device and a slit coating method. The slit coating head comprises a first die head, a second die head and a plasma air outlet device which are connected in sequence, a gasket for guiding flow is arranged between the first die head and the second die head, a continuous cavity is formed among the first die head, the second die head and the gasket, and the continuous cavity comprises a liquid inlet channel, a liquid outlet channel, a distribution cavity, a liquid channel and a liquid outlet. The slit coating head can improve the wettability of the surface of a substrate and improve the interfacial effect of a coating liquid and a matrix under the condition of ensuring stable liquid discharge, so that a coating film with uniform thickness and good crystallinity is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of slit coating, and relates to a slit coating head, a slit coating device and a slit coating method. Background Art

[0002] Slit coating is a commonly used coating method. Under a certain pressure, the coating liquid is pressed out along the gap of the mold and transferred to the moving substrate. It represents the future development direction of wet coating with its fast coating speed, good coating uniformity, and wide coating window. However, in actual applications, due to various factors, the problem of uneven coating film thickness is very common. The uneven coating film thickness will affect the coating quality, reduce coating efficiency, and even cause product quality problems.

[0003] CN114192342A discloses a high uniformity coating head device for a slit coating device and a method of using the same. The device is a first coating head device without a feed pump system or a second coating head device with a feed pump system. The coating head device can be used for a slit coating device without a feed pump system or for a conventional slit coating device with a feed pump system.

[0004] CN105170406A discloses a slit coating unit, a coating head and a coating device. The slit coating unit includes a shell, in which a feed channel, a discharge channel, a pressure-dividing channel and a slit nozzle are arranged, and the width of the feed channel decreases step by step along the direction toward the slit nozzle. The coating head includes a plurality of slit coating units as described above arranged side by side. The coating device includes the slit coating unit or coating head as described above.

[0005] When the coating device described in the above scheme is used for large-area film formation, the film quality is not high, the uniformity, thickness and flatness are difficult to control, and defects such as holes are prone to occur, which in turn affects the performance of the obtained coated film. Summary of the invention

[0006] The object of the present invention is to provide a slit coating head, a slit coating device and a slit coating method. The slit coating head of the present invention can improve the wettability of the substrate surface and improve the interface effect between the coating liquid and the substrate while ensuring stable liquid discharge, thereby obtaining a coating film with uniform thickness and good crystallinity.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a slit coating coating head, the slit coating coating head comprising a first die head, a second die head and a plasma air outlet device connected in sequence;

[0009] A gasket for guiding flow is arranged between the first die head and the second die head, and a continuous cavity is formed between the first die head, the second die head and the gasket, and the continuous cavity includes a liquid inlet channel, a liquid outlet channel, a distribution cavity, a liquid channel and a liquid outlet.

[0010] The continuous cavity described in the present invention includes a liquid inlet channel, a liquid outlet channel, a distribution cavity, a liquid channel and a liquid outlet, wherein the purpose of setting the liquid outlet channel is to confirm that all gases in the continuous cavity are discharged. When liquid is injected from the liquid inlet channel, the gas inside the continuous cavity will be discharged accordingly until the liquid outlet channel discharges the liquid, indicating that the gas inside the continuous cavity has been completely discharged.

[0011] The slit coating head of the present invention can improve the uniformity of the liquid discharge of the slit coating, so that the thickness uniformity of the prepared coating film is good. The present invention adds a plasma air outlet device to the slit coating head, and oxygen plasma treatment can improve the hydrophilicity of the material surface and enhance the interface interaction, improve the surface wettability, so that the liquid forms a uniform thin layer on the surface, so that the thickness uniformity and crystallinity of the prepared coating film are good.

[0012] Preferably, through holes are arranged on the second die head, the plasma air outlet device and the gasket, and screw holes are arranged on the first die head.

[0013] The slit coating coating head also includes a bolt, which passes through the through holes of the gasket, the second die head and the plasma air outlet device, and is fixedly connected to the screw hole on the first die head.

[0014] Preferably, the cross-section of the distribution chamber is in the shape of an arc.

[0015] Preferably, the liquid inlet channel, the liquid outlet channel and the liquid channel are respectively connected to the distribution chamber.

[0016] Preferably, the liquid inlet channel and the liquid outlet channel are arranged on one side of the distribution chamber, and the liquid channel and the liquid outlet are arranged on the other side of the distribution chamber.

[0017] Preferably, the second die head is provided with a plasma gas inlet and a plasma gas channel connected to each other.

[0018] Preferably, a guide groove is provided between the plasma air outlet device and the second die head.

[0019] Preferably, the guide groove is connected to the plasma gas channel on the second die head.

[0020] Preferably, a plasma gas outlet is provided at an outlet of the guide groove on a side away from the plasma gas channel.

[0021] In a second aspect, the present invention provides a slit coating device, the slit coating device comprising the slit coating coating head as described in the first aspect;

[0022] The slit coating device further comprises a plasma generating device.

[0023] Preferably, the plasma generating device is connected to the plasma gas inlet of the slot coating coating head.

[0024] Preferably, the plasma generating device comprises an oxygen plasma treatment machine.

[0025] In a third aspect, the present invention provides a slit coating method, wherein the slit coating method is performed using the slit coating device as described in the second aspect, and the slit coating method comprises the following steps:

[0026] Close the liquid outlet of the slit coating head, and inject the liquid to be coated from the liquid inlet channel until the liquid to be coated flows out of the liquid outlet channel;

[0027] A plasma generator is used to generate oxygen plasma, which is continuously blown to the surface of the substrate through a plasma air outlet device. At the same time, the liquid outlet is opened, and the liquid to be coated is continuously injected from the liquid inlet channel and coated on the surface of the substrate through the liquid outlet from the first die head to the plasma air outlet device to form a coating film.

[0028] The slit coating method of the present invention can discharge liquid evenly and stably, and improve the uniformity of the obtained coating film. Oxygen plasma can improve the hydrophilicity of the material surface and enhance the interface interaction, improve the surface wettability, and make the liquid form a uniform thin layer on the surface, further improve the uniformity and crystallinity of the coating film, and thus improve the product performance.

[0029] Preferably, in the process of generating oxygen plasma, the flow rate of the oxygen source is 200 mL / min to 1000 mL / min, for example, 200 mL / min, 250 mL / min, 300 mL / min, 500 mL / min, 600 mL / min, 800 mL / min or 1000 mL / min, etc., not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] In the process of generating oxygen plasma according to the present invention, the flow rate of oxygen plasma is controlled by controlling the flow rate of oxygen source. The greater the flow rate of gas source, the greater the flow rate of oxygen plasma.

[0031] Preferably, in the process of generating oxygen plasma, the power of the plasma generating device is 800W to 1000W, for example, 800W, 850W, 900W, 950W or 1000W, etc., not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, in the process of generating oxygen plasma, the frequency of the plasma generating device is 15kHz to 25kHz, for example, 15kHz, 18kHz, 20kHz, 22kHz or 25kHz, etc., not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] Preferably, during the coating process, the flow rate of the liquid to be coated is 100 μL / s to 200 μL / s, for example, 10 μL / s, 12 μL / s, 15 μL / s, 18 μL / s or 20 μL / s.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The slit coating head of the present invention can improve the wettability of the substrate surface and the interface effect between the coating liquid and the substrate while ensuring stable liquid discharge, thereby obtaining a uniform and well-crystalline coating film.

[0036] (2) The performance of the perovskite light absorbing layer prepared by the coating die head of the present invention is significantly improved compared with the perovskite light absorbing layer prepared by the conventional die head. The maximum power P of the battery made of the perovskite light absorbing layer is max It can reach 14.58W, the short-circuit current Isc can reach 0.438A, the open-circuit voltage Voc can reach 47.59V, the fill factor FF can reach 70.74%, and the conversion efficiency Eff can reach 14.48%. Compared with the perovskite light-absorbing layer made by the conventional coating die head, the performance of the battery is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the structure of the slit coating head provided in an embodiment of the present invention, wherein 1 is a first die head, 2 is a gasket, 3 is a second die head, 4 is a plasma air outlet device, 5 is a guide groove, 6 is a through hole, 6-1 is a screw hole, and 7 is a bolt.

[0038] Figure 2 It is a cross-sectional schematic diagram of a slit coating head provided in an embodiment of the present invention, wherein 1 is a first die head, 3 is a second die head, 4 is a plasma air outlet device, 5 is a guide groove, 8 is a liquid inlet channel, 9 is a liquid outlet channel, 10 is a distribution chamber, 11 is a liquid channel, 12 is a liquid outlet, 13 is a plasma gas inlet, 14 is a plasma gas channel, and 15 is a plasma gas outlet.

[0039] Figure 3 This is a schematic diagram of the structure of the slit coating coating head described in Example 1, 1 is the first die head, 2 is the gasket, 3 is the second die head, 6 is the through hole, 6-1 is the screw hole, and 7 is the bolt.

[0040] Figure 4 It is a schematic diagram of the water contact angle during the slit coating process described in Application Example 1.

[0041] Figure 5 It is a schematic diagram of the water contact angle during the slit coating process described in Comparative Application Example 1.

[0042] Figure 6 This is the thickness distribution diagram of the coating film obtained in Application Example 1.

[0043] Figure 7 This is a thickness distribution diagram of the coating film obtained by comparative application example 1. DETAILED DESCRIPTION

[0044] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0045] The perovskite precursor solution used in the application example of the present invention is prepared by the following method:

[0046] N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) were added to a clean solution bottle in a volume ratio of 4:6, and then PbI2 and CH3NH3I were added to make a solution. The concentrations of lead iodide (PbI2) and methylamine iodine (CH3NH3I) in the solution were both 1 mol / L. The bottle mouth of the solution was then sealed and placed on a constant temperature heated stirrer at 50°C and stirred for 2 hours to obtain a perovskite solution. Lead iodide (PbI2) and methylamine iodine (CH3NH3I) were purchased from Xi'an Yuri Solar Energy Company, with a purity of 99.999% for PbI2 and 99.9% for methylamine iodine.

[0047] Example 1

[0048] This embodiment provides a slit coating head, and the structural schematic diagram of the slit coating head is as follows Figure 1 As shown, the cross-sectional schematic diagram of the slit coating coating head is as shown Figure 2 As shown, the slit coating coating head comprises:

[0049] A first die head 1, a second die head 3 and a plasma air outlet device 4, a gasket 2 for guiding flow is arranged between the first die head 1 and the second die head 3, a continuous cavity is formed between the first die head 1, the second die head 3 and the gasket 2, and the continuous cavity includes a liquid inlet channel 8, a liquid outlet channel 9, a distribution cavity 10, a liquid channel 11 and a liquid outlet 12;

[0050] The second die head 3, the plasma air outlet device 4 and the gasket 2 are all provided with a through hole 6, the first die head 1 is provided with a screw hole 6-1, the through hole 6 is penetrated by a bolt 7, and the bolt 7 is fixedly connected to the screw hole 6-1 on the first die head 1;

[0051] The cross-sectional view of the distribution chamber 10 is arc-shaped, and the liquid inlet channel 8, the liquid outlet channel 9 and the liquid channel 11 are respectively connected to the distribution chamber 10. The liquid inlet channel 8 and the liquid outlet channel 9 are arranged on one side of the distribution chamber 10, and the liquid channel 11 and the liquid outlet 12 are arranged on the other side of the distribution chamber 10.

[0052] The second die head 3 is provided with a plasma gas inlet 13 and a plasma gas channel 14 which are connected to each other;

[0053] A guide groove 5 is provided between the plasma air outlet device 4 and the second die head 3 . The guide groove 5 is connected to the plasma gas channel 14 on the second die head 3 . A plasma gas outlet 15 is provided at the end of the guide groove 5 .

[0054] Comparative Example 1

[0055] The difference between this comparative example and Example 1 is that the plasma air outlet device and the structure related to the plasma air outlet device are not provided, and the other structures are exactly the same as those in Example 1. The structural schematic diagram of the slit coating coating head of this comparative example is shown as follows: Figure 3 As shown, the slit coating coating head comprises:

[0056] A first die head 1 and a second die head 3, a gasket 2 for guiding flow is arranged between the first die head 1 and the second die head 3, a through hole 6 is arranged on the second die head 3 and the gasket 2, a screw hole 6-1 is arranged on the first die head 1, a bolt 7 is passed through the through hole 6, and the bolt 7 is fixedly connected to the screw hole on the first die head 1.

[0057] Application Example 1

[0058] This application example provides a slit coating method, wherein the slit coating method uses a slit coating device including the slit coating head as described in Example 1, and the slit coating device also includes an oxygen plasma treatment machine connected to the plasma gas inlet of the slit coating head;

[0059] The slit coating method comprises the following steps:

[0060] Close the liquid outlet of the slit coating head (use high-temperature tape to seal the liquid outlet), inject the liquid to be coated (here, the perovskite precursor solution) from the liquid inlet channel until the liquid to be coated flows out of the liquid outlet channel;

[0061] 400 mL / min of oxygen is introduced into the oxygen plasma treatment machine, and oxygen plasma is generated at a power of 900 W and a frequency of 20 kHz. The generated oxygen plasma is continuously blown to the surface of the substrate through the plasma air outlet device, and at the same time, the liquid outlet is opened, and the liquid to be coated is continuously injected from the liquid inlet channel and is coated on the surface of the substrate through the liquid outlet from the first die head to the plasma air outlet device to form a coating film;

[0062] Wherein, the flow rate of the liquid to be coated is 140 μL / s.

[0063] During the slit coating process, the schematic diagram of the water contact angle is as follows: Figure 4 shown.

[0064] The thickness distribution diagram of the coating film is shown in Figure 2. Figure 6 As shown, the uniformity of the coating film was tested, U% = (maximum value - minimum value) / (maximum value + minimum value) × 100% = (378-353) / (378+353) × 100% = 3.4%.

[0065] Comparative application example 1

[0066] This comparative application example provides a slit coating method, wherein the slit coating method uses a slit coating device including the slit coating head as described in Application Example 1, and the slit coating method comprises the following steps:

[0067] The liquid outlet is sealed with a high-temperature tape, and the liquid to be coated (here, the perovskite precursor solution) is injected from the liquid inlet channel until the liquid to be coated flows out of the liquid outlet channel;

[0068] Open the liquid outlet, continuously inject the liquid to be coated from the liquid inlet channel and coat it on the surface of the substrate through the liquid outlet to form a coating film;

[0069] Wherein, the flow rate of the liquid to be coated is 140 μL / s.

[0070] During the slit coating process, the schematic diagram of the water contact angle is as follows: Figure 5 shown.

[0071] The thickness distribution diagram of the coating film is shown in Figure 2. Figure 7As shown, the uniformity of the coating film was tested, U% = (maximum value - minimum value) / (maximum value + minimum value) × 100% = (399-353) / (399+353) × 100% = 6.1%.

[0072] Depend on Figure 4-Figure 5 By comparison, it can be seen that the water contact angle of Application Example 1 is 4.3°, and the water contact angle of the comparative application example is 11.2°, indicating that oxygen plasma treatment can improve the hydrophilicity of the material surface and enhance the interface interaction, thereby improving the surface wettability.

[0073] The coating film obtained in the embodiment and the comparative example is used as the perovskite light absorbing layer to make a perovskite solar cell. The specific structure of the perovskite solar cell is: glass / FTO / NiO x / Perovskite light absorbing layer / SnO x / Cu), and the test results are shown in Table 1.

[0074] Table 1

[0075] <![CDATA[P max (In)]]> Isc(A) Voc(V) FF(%) Eff(%) Application Example 1 14.58 0.438 47.059 70.74％ 14.48 Comparative application example 1 13.34 0.427 47.791 65.34％ 13.24

[0076] It can be seen from Table 1 that the performance of the perovskite light absorbing layer prepared by the coating die head of the present invention is significantly improved compared with the perovskite light absorbing layer prepared by the conventional die head. The maximum power P of the battery made of the perovskite light absorbing layer is max It can reach 14.58W, the short-circuit current Isc can reach 0.438A, the open-circuit voltage Voc can reach 47.59V, the fill factor FF can reach 70.74%, and the conversion efficiency Eff can reach 14.48%. Compared with the perovskite light-absorbing layer made by the conventional coating die head, the performance of the battery is significantly improved.

[0077] From the comparison between Application Example 1 and Comparative Application Example 1, it can be seen that the present invention adds a plasma air outlet device to the slit coating head, and oxygen plasma treatment can improve the hydrophilicity of the material surface and enhance the interface interaction, improve the surface wettability, and make the liquid form a uniform thin layer on the surface, so that the obtained coating film has good thickness uniformity and crystallinity.

[0078] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A slit coating coating head, characterized in that, The slit coating coating head comprises a first die head, a second die head and a plasma air outlet device which are connected in sequence; A gasket for guiding flow is arranged between the first die head and the second die head, and a continuous cavity is formed between the first die head, the second die head and the gasket, and the continuous cavity includes a liquid inlet channel, a liquid outlet channel, a distribution cavity, a liquid channel and a liquid outlet.

2. The slit coating coating head according to claim 1, characterized in that The second die head, the plasma air outlet device and the gasket are all provided with through holes, and the first die head is provided with screw holes; The slit coating coating head also includes a bolt, which passes through the through holes of the gasket, the second die head and the plasma air outlet device, and is fixedly connected to the screw hole on the first die head.

3. The slit coating coating head according to claim 1 or 2, characterized in that: The cross-sectional view of the distribution chamber is in the shape of an arc; Preferably, the liquid inlet channel, the liquid outlet channel and the liquid channel are connected to the distribution chamber respectively; Preferably, the liquid inlet channel and the liquid outlet channel are arranged on one side of the distribution chamber, and the liquid channel and the liquid outlet are arranged on the other side of the distribution chamber.

4. The slit coating coating head according to any one of claims 1 to 3, characterized in that: The second die head is provided with a plasma gas inlet and a plasma gas channel connected to each other.

5. The slit coating coating head according to any one of claims 1 to 4, characterized in that: A guide groove is provided between the plasma air outlet device and the second die head; Preferably, the guide groove is connected to the plasma gas channel on the second die head; Preferably, a plasma gas outlet is provided at an outlet of the guide groove on a side away from the plasma gas channel.

6. A slit coating device, characterized in that: The slit coating device comprises a slit coating coating head as described in any one of claims 1 to 5; The slit coating device further comprises a plasma generating device.

7. The slit coating device according to claim 6, characterized in that: The plasma generating device is connected to the plasma gas inlet of the slot coating coating head; Preferably, the plasma generating device comprises an oxygen plasma treatment machine.

8. A slit coating method, characterized in that: The slit coating method is performed using the slit coating device as claimed in claim 6 or 7, and the slit coating method comprises the following steps: Close the liquid outlet of the slit coating head, and inject the liquid to be coated from the liquid inlet channel until the liquid to be coated flows out of the liquid outlet channel; A plasma generator is used to generate oxygen plasma, which is continuously blown to the surface of the substrate through a plasma air outlet device. At the same time, the liquid outlet is opened, and the liquid to be coated is continuously injected from the liquid inlet channel and coated on the surface of the substrate through the liquid outlet from the first die head to the plasma air outlet device to form a coating film.

9. The slit coating method according to claim 8, wherein: In the process of generating oxygen plasma, the flow rate of the oxygen source is 200 mL / min to 1000 mL / min; Preferably, in the process of generating oxygen plasma, the power of the plasma generating device is 800W to 1000W; Preferably, during the process of generating oxygen plasma, the frequency of the plasma generating device is 15 kHz to 25 kHz.

10. The slit coating method according to claim 8 or 9, characterized in that: During the coating process, the flow rate of the liquid to be coated is 100 μL / s to 200 μL / s.

Images