Micro nozzle device

Abstract

To provide a micro nozzle device capable of preventing a suction nozzle from being blocked to continuously form a nanowire for a long time.SOLUTION: There is provided a micro nozzle device that forms a nanowire of metal on a substrate, and has three or more discharge capillary tubes and one or more suction capillary tube, wherein at least one of the discharge capillary tubes is for discharging a metal solution including a metal compound, at least one of the other discharge capillarity tubes is for discharging a reaction liquid which reacts with the metal compound to deposit metal, and at least one of the other discharge capillary tubes is for blocking production of solid matter with the remaining liquid of the metal solution and the remaining liquid of the reaction liquid sucked by the suction capillary tubes, or for discharging a blocking suppression liquid dissolving the solid matter.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a micronozzle device for forming nanowires of metal on a substrate. [Background technology]

[0002] A nanowire is a nanoscale metal wire with a diameter of less than a few hundred nanometers. Due to their size and shape, nanowires have unique properties not seen in larger wires. For example, a transparent conductive film using silver nanowires as wiring has high electrical conductivity and high optical transparency, and is more resistant to bending than ITO, which is widely used as wiring for transparent conductive films. For this reason, nanowires are expected to be used in flexible touch panels and as electrodes for solar cells.

[0003] On the other hand, since such nanowires are extremely thin and difficult to handle individually, it has been considered to form nanowires directly on a substrate. For example, Non-Patent Document 1 describes the formation of nanowires using a nozzle chemical pen with two discharge nozzles and one suction nozzle.

[0004] According to this method, a solution of a silver compound (Ag(NH3)2OH) is ejected from one ejection nozzle, and a solution of a reducing agent that reduces the silver compound and precipitates silver is ejected from another ejection nozzle, and the remaining liquid is sucked up by a suction nozzle, thereby forming silver nanowires directly on the substrate. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Lin HF, et al. Anal. Chem. 2019, 91, 7346-7352(2019). Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the nozzle chemical pen disclosed in Non-Patent Document 1, when the remaining liquid after forming nanowires by reacting a solution of a metal compound with a reducing agent is sucked up through a suction nozzle, the solution of the metal compound contained in the remaining liquid reacts with the reducing agent, causing metal to precipitate in the suction nozzle, which tends to clog the suction nozzle. This necessitates frequent maintenance of the suction nozzle, and there has been a problem in that it is difficult to form long, continuous nanowire wiring.

[0007] The present invention has been made in consideration of the above circumstances, and has an object to provide a micronozzle device that is capable of preventing clogging of the suction nozzle and forming nanowires continuously for a long period of time. [Means for solving the problem]

[0008] That is, in order to solve the above problems, the present invention proposes the following means. The micronozzle device of the present invention is a micronozzle device for forming nanowires made of metal on a substrate, comprising three or more discharge capillaries each having one end formed as a discharge opening, one or more suction capillaries each having one end formed as a suction opening, a discharge pump for discharging a fluid from the discharge capillaries, and a suction pump for sucking a fluid from the suction capillaries, wherein at least one of the discharge capillaries discharges a metal solution containing a metal compound, and at least one of the other discharge capillaries discharges a reaction liquid that reacts with the metal compound to precipitate a metal, and further, at least one of the other discharge capillaries discharges a clogging suppression liquid that inhibits the generation of solids due to the residual liquid of the metal solution and the residual liquid of the reaction liquid sucked into the suction capillary or dissolves the solids.

[0009] According to the present invention, by simultaneously sucking in the clogging suppression liquid from the suction opening that sucks in the metal solution and the remaining liquid of the reaction solution that form the metal nanowires, the solid metal content generated by the reaction between the metal solution and the remaining liquid of the reaction solution is quickly dissolved by the clogging suppression liquid, so it is possible to prevent the suction capillary from being clogged by the metal (solid content) generated by the reaction of the remaining liquid. Therefore, it is possible to continuously form nanowires on a substrate for a long period of time without maintaining the suction capillary.

[0010] In the present invention, a discharge capillary for discharging the pretreatment liquid in advance may be provided at a position on the substrate where the nanowires are to be formed.

[0011] In addition, in the present invention, the discharge openings of the discharge capillaries that discharge the metal solution and the reaction liquid, respectively, may be formed so as to be closer to the substrate than the discharge openings of the discharge capillaries that discharge the clogging prevention liquid.

[0012] In the present invention, the discharge opening and the suction opening may each have a diameter of 1 mm or less.

[0013] In the present invention, the discharge capillary and the suction capillary may be made of a material containing silicon.

[0014] In addition, in the present invention, the discharge capillary may be formed so that its inner diameter is larger than the opening diameter of the discharge opening upstream of the discharge opening, and the suction capillary may be formed so that its inner diameter is larger than the opening diameter of the suction opening upstream of the suction opening.

[0015] In the present invention, the nanowires may be made of silver, the metal solution may contain a silver compound, and the reaction solution may contain a reducing agent that reduces the silver compound to precipitate silver.

[0016] In the present invention, the pretreatment liquid may contain tin chloride. Effect of the Invention

[0017] According to the present invention, it is possible to provide a micronozzle device capable of preventing clogging of the suction nozzle and continuously forming nanowires for a long period of time. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is an enlarged perspective view of a main portion of a micronozzle device according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a schematic diagram showing an example of an arrangement of discharge openings and suction openings of a micronozzle device. [Diagram 3] FIG. 13 is a schematic diagram showing another example of an arrangement of discharge openings and suction openings of a micronozzle device. [Figure 4] FIG. 13 is a schematic diagram showing another example of an arrangement of discharge openings and suction openings of a micronozzle device. [Diagram 5] FIG. 13 is a schematic diagram showing another example of an arrangement of discharge openings and suction openings of a micronozzle device. [Figure 6] 1 is a graph showing the results of an example. [Figure 7] 1 is a SEM photograph showing the results of an example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, a micro nozzle device according to an embodiment of the present invention will be described with reference to the drawings. Each embodiment shown below is specifically described to better understand the gist of the invention, and does not limit the present invention unless otherwise specified. Furthermore, the drawings used in the following description may show essential parts enlarged for convenience in order to make the features of the present invention easier to understand, and the dimensional ratios of each component may not necessarily be the same as the actual ones.

[0020] (First embodiment) Fig. 1 is an enlarged perspective view of a main portion of a micronozzle device according to one embodiment of the present invention, and Fig. 2 is a schematic diagram showing the arrangement of the discharge openings and suction openings of the micronozzle device. The micronozzle device 10 of this embodiment has first to third ejection capillaries 11, 12, and 13, ejection pumps 21, 22, and 23 that supply fluid to the first to third ejection capillaries 11, 12, and 13, respectively, to eject the fluid, a suction capillary 15, and a suction pump 25 that sucks the fluid from the suction capillary 15.

[0021] The first to third discharge capillaries 11, 12, and 13 are, for example, hollow capillaries made of glass, and one end (opening end) is configured as discharge openings 11a, 12a, and 13a, respectively. The suction capillary 15 is, for example, a hollow capillary made of glass, and one end (opening end) is configured as a suction opening 15a. These first to third discharge capillaries 11, 12, 13 and suction capillary 15 are bundled together near one end.

[0022] The first to third discharge capillaries 11, 12, 13 and the suction capillary 15 can also be made of a vitreous material containing silicon, such as fused silica, other than glass.

[0023] When the micronozzle device 10 is in use, that is, when the discharge openings 11a, 12a, and 13a of the first to third discharge capillaries 11, 12, and 13 and the suction opening 15a of the suction capillary 15 are directly opposed to the substrate F on which nanowires are formed, the discharge openings 11a and 12a are formed to be closer to the substrate F than the discharge opening 13a. For example, when the micronozzle device 10 is in use, the discharge openings 11a and 12a are in contact with the substrate F, and the discharge opening 13a maintains a predetermined gap from the substrate F. It is sufficient that the suction opening 15a is also formed to maintain a predetermined gap from the substrate F.

[0024] 2, the discharge opening 11a and the discharge opening 12a are disposed adjacent to each other, and the discharge opening 13a is disposed on the opposite side of the discharge openings 11a and 12a with the suction opening 15a in between. That is, in the micronozzle device 10 of this embodiment, the discharge openings 11a, 12a and the discharge opening 13a are formed so as to surround the suction opening 15a at the center.

[0025] The discharge openings 11a, 12a, 13a of the first to third discharge capillaries 11, 12, 13 may have an opening diameter of 1 mm or less, for example, about 0.5 mm to 0.01 mm. The suction opening 15a of the suction capillary 15 may also have an opening diameter of 1 mm or less, for example, about 0.5 mm to 0.01 mm. The discharge openings 11a, 12a, 13a and the suction opening 15a may have different opening diameters.

[0026] In this embodiment, the opening diameter of each of the discharge openings 11a, 12a, 13a and the suction opening 15a is 0.32 mm. The outside diameter of the first to third discharge capillaries 11, 12, 13 and the suction capillary 15 is about 0.42 mm.

[0027] The discharge pumps 21, 22, 23 and the suction pump 25 may be selected according to the type of fluid, and may be, for example, a syringe. Note that, instead of a syringe, the discharge pumps 21, 22, 23 and the suction pump 25 may be, for example, a tube pump.

[0028] In order to form metal nanowires that will become wiring on the surface of the substrate F, the micronozzle device 10 of this embodiment discharges a metal solution from the discharge opening 11a of the first discharge capillary 11 via the discharge pump 21, discharges a reaction liquid from the discharge opening 12a of the second discharge capillary 12 via the discharge pump 22, and further discharges a clogging suppression liquid from the discharge opening 13a of the third discharge capillary 13 via the discharge pump 23. Then, the discharged metal solution, remaining reaction liquid, and clogging suppression liquid are sucked from the suction opening 15a of the suction capillary 15 via the suction pump 25.

[0029] More specifically, a metal solution in which a metal compound containing the metal constituting the nanowires is dissolved is discharged from the discharge opening 11a. Also, a reaction liquid that reacts with the above-mentioned metal compound to deposit the metal on the surface of the substrate F is discharged from the discharge opening 12a. As a result, the metal compound reacts with the reaction liquid on the substrate F (e.g., a reduction reaction), and the metal constituting the nanowires is generated.

[0030] Furthermore, from the discharge opening 13a, a clogging suppression liquid that dissolves solid matter, such as metal, generated by the reaction between the residual liquid of the metal solution discharged from the discharge opening 11a and the residual liquid of the reaction liquid discharged from the discharge opening 11a is discharged. Note that from the discharge opening 13a, a clogging suppression liquid that suppresses the reaction between the residual liquid of the metal solution discharged from the discharge opening 11a and the residual liquid of the reaction liquid discharged from the discharge opening 11a and inhibits the generation of solid matter, such as metal, can also be discharged.

[0031] With this configuration, when the remaining liquid of the ejected metal solution and the remaining liquid of the reaction liquid are sucked through the suction opening 15a, the clogging prevention liquid is also sucked in at the same time, so that the metal produced by the reaction between the remaining liquid of the metal solution and the remaining liquid of the reaction liquid is dissolved, or the reaction itself between the remaining liquid of the metal solution and the remaining liquid of the reaction liquid is suppressed.

[0032] This makes it possible to prevent metal from being generated inside the suction capillary 15 having the discharge opening 13a, which would cause the suction capillary 15 to become clogged. Therefore, it becomes possible to continuously form nanowires on the substrate F for a long period of time without requiring maintenance of the suction capillary 15.

[0033] As a specific example of the liquid discharged from each discharge opening, when forming silver nanowires, for example, an ammoniacal silver nitrate aqueous solution (Ag(NH3)2OH) is used as the metal solution containing the metal compound, a mixed aqueous solution of glucose and formaldehyde, which is a reducing agent for the silver compound, is used as the reaction liquid, and dilute nitric acid, which dissolves silver, is used as the clogging suppression liquid. Note that, for example, hydrochloric acid can be used as the clogging suppression liquid that suppresses the reaction between the remaining metal solution and the remaining reaction liquid. This lowers the pH and suppresses the reaction.

[0034] The operation of the micronozzle device 10 having the above configuration will now be described. 2, for example, when forming nanowire wiring made of silver on a substrate F using a micronozzle device 10, the end of the micronozzle device 10 is aligned with the position on the substrate F where the nanowires are to be formed. Then, an ammoniacal silver nitrate aqueous solution (metal solution) is discharged from the discharge opening 11a, a mixed aqueous solution (reaction liquid) of glucose and formaldehyde is discharged from the discharge opening 12a, and dilute nitric acid (clogging suppression liquid) is discharged from the discharge opening 13a. In addition, the remaining discharged metal solution, remaining reaction liquid, and clogging suppression liquid are sucked from the suction opening 15a.

[0035] The discharge amount of the discharge openings 11a, 12a, and 13a may be, for example, about 10 μL / h, and the suction amount of the suction opening 15a may be, for example, about 350 μL / h.

[0036] Simultaneously with the ejection and suction of each liquid, the tip of the micronozzle device 10 is moved in the direction D in which the nanowires are formed. At this time, the substrate F can also be moved relatively. The amount of movement may be, for example, about 0.1 μm / s.

[0037] The metal solution discharged from the discharge opening 11a and the reaction solution discharged from the discharge opening 12a are mixed with each other while being sucked toward the suction opening 15a, and the metal solution is reduced to produce silver (silver mirror reaction). Then, the tip of the micronozzle device 10 is moved in the direction D, so that the generated silver is elongated, and a silver nanowire W, which is a silver wire with a nano-sized diameter (for example, 100 nm or less), is formed on the substrate F.

[0038] The discharged metal solution, the reacted residual liquid and the unreacted residual liquid of the reaction liquid, and the clogging prevention liquid discharged from the discharge opening 13a are sucked through the suction opening 15a disposed in the center of these discharge openings.

[0039] During this suction process, the metal solution and the unreacted remaining liquid of the reaction solution are mixed and reacted inside the suction capillary 15 to generate silver, but the generated silver is quickly dissolved by simultaneously sucking in dilute nitric acid, which is a clogging prevention liquid. This prevents the suction capillary 15 from being clogged by the generated silver (solid content). In addition, silver that is not fixed on the substrate F and is sucked in is also dissolved by the clogging prevention liquid, preventing the suction capillary 15 from being clogged.

[0040] As described above, according to the micronozzle device 10 of this embodiment, by simultaneously sucking the clogging suppression liquid discharged from the discharge opening 13a through the suction opening 15a that sucks in the metal solution forming the metal nanowires and the remaining liquid of the reaction liquid, the metal generated by the reaction between the metal solution and the remaining liquid of the reaction liquid is quickly dissolved by the clogging suppression liquid, so it is possible to prevent the suction capillary 15 from being clogged by the metal generated by the reaction of the remaining liquid. Therefore, it is possible to continuously form nanowires on the substrate F for a long period of time without maintaining the suction capillary 15.

[0041] In the above-described embodiment, the discharge amounts of the discharge openings 11a, 12a, and 13a are the same, but the discharge amounts of the discharge openings 11a, 12a, and 13a can be made different from one another according to the composition and concentration of the metal solution, reaction liquid, and clogging suppression liquid to be discharged. Moreover, these discharge amounts and the movement amount of the tip portion of the micronozzle device 10 can be arbitrarily adjusted according to the wire diameter of the nanowire to be formed.

[0042] (Other embodiments) In the above-described first embodiment, a micronozzle device is shown that is configured with a minimum number of capillaries, i.e., three ejection capillaries and one suction capillary. However, the number of capillaries can be increased depending on the application. For example, a micro nozzle device 30 according to another embodiment shown in Fig. 3 includes four discharge capillaries 31, 32, 33, and 34, and one suction capillary 35. Of these, a metal solution is discharged from the discharge opening 31a of the first discharge capillary 31, a reaction liquid is discharged from the discharge opening 32a of the second discharge capillary 32, and a clogging suppression liquid is discharged from the discharge opening 33a of the third discharge capillary 33. Furthermore, a pretreatment liquid (catalyst) is discharged from the discharge opening 34a of the fourth discharge capillary 34. Furthermore, the discharged metal solution, remaining liquid of the reaction liquid, remaining liquid of the pretreatment liquid, and clogging suppression liquid are sucked from the suction opening 35a of the suction capillary 35.

[0043] In this embodiment, the pretreatment liquid is discharged from the discharge opening 34a of the fourth discharge capillary 34, so that the process of adsorbing a catalyst formed in advance at the nanowire formation position can be omitted, and the catalyst can be formed on the substrate at the same time as the nanowire is formed. This makes it possible to easily form the nanowire with fewer processes. For example, in the formation of silver nanowires, an aqueous solution of tin chloride (SnCl2) can be used as the pretreatment liquid (catalyst).

[0044] Also, a micro nozzle device 40 of another embodiment shown in FIG. 4 includes five discharge capillaries 41, 42, 43, 44, and 45, and one suction capillary 46. Of these, a metal solution is discharged from the discharge opening 41a of the first discharge capillary 41, a reaction liquid is discharged from the discharge opening 42a of the second discharge capillary 42, and a clogging suppression liquid is discharged from the discharge opening 43a of the third discharge capillary 43 and the discharge opening 44a of the fourth discharge capillary 44. Furthermore, a pretreatment liquid (catalyst) is discharged from the discharge opening 45a of the fifth discharge capillary 45. Also, the discharged metal solution, the remaining liquid of the reaction liquid, the remaining liquid of the pretreatment liquid, and the clogging suppression liquid are sucked from the suction opening 46a of the suction capillary 46.

[0045] In this embodiment, by ejecting the clogging prevention liquid from two capillaries, the third ejection capillary 43 and the fourth ejection capillary 44, the metal generated by the reaction between the metal solution and the residual reaction liquid can be more reliably dissolved by the clogging prevention liquid than in the first embodiment, thereby preventing clogging of the suction capillary 46.

[0046] Further, the micro nozzle device 50 of another embodiment shown in FIG. 5 includes six discharge capillaries 51, 52, 53, 54, 55, and 56, and one suction capillary 57 disposed at the center of the six discharge capillaries. Of these, the metal solution is discharged from the discharge opening 51a of the first discharge capillary 51, the reaction liquid is discharged from the discharge opening 52a of the second discharge capillary 52, and the clogging suppression liquid is discharged from the discharge opening 53a of the third discharge capillary 53 and the discharge opening 54a of the fourth discharge capillary 54. Furthermore, the pretreatment liquid (catalyst) is discharged from the discharge opening 55a of the fifth discharge capillary 55 and the discharge opening 56a of the sixth discharge capillary 56. Also, the discharged metal solution, the remaining liquid of the reaction liquid, the remaining liquid of the pretreatment liquid, and the clogging suppression liquid are sucked from the suction opening 57a of the suction capillary 57.

[0047] In this embodiment, the supply amount of the pretreatment liquid (catalyst) can be increased by discharging the pretreatment liquid (catalyst) from two capillaries, the fifth discharging capillary 55 and the sixth discharging capillary 56. Also, in this embodiment, the discharge openings 51a to 16a are arranged at equal intervals around the suction opening 57a, so that each of the discharged liquids is evenly sucked toward the center, making it easier to form nanowires without distortion.

[0048] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents described in the claims, as well as in the scope and spirit of the invention. EXAMPLES

[0049] The effect of the present invention was verified. Silver nanowires were formed on a substrate using the micronozzle device 10 of the first embodiment shown in Figures 1 and 2 (an example of the present invention: referred to as CAMCP) and a micronozzle device (a comparative example: referred to as MCP) obtained by removing the third ejection capillary 13 for ejecting the clogging prevention liquid from the micronozzle device 10 of the first embodiment. Discharge port 1: Ammoniacal silver nitrate solution 10μL / h Discharge port 2: Glucose and formaldehyde mixed aqueous solution 10μL / h Discharge port 3 (CAMCP only): Dilute nitric acid 10μL / h ·Suction opening: Residual liquid suction 350μL / h -Movement speed on substrate: 0.1μm / s The discharge opening 1 and the discharge opening 2 were each in contact with the substrate, and the gap between the discharge opening 3 and the substrate was set to 30 μm.

[0050] Under the above conditions, silver nanowires with a diameter of 1.45 μm were continuously formed on the substrate using both CAMCP and MCP, and the change in diameter due to blockage of the suction opening was observed. This change in line width is shown in Figure 6. SEM photographs of silver nanowires patterned over a long period of time using MCP are shown in Figure 7(a), and SEM photographs of silver nanowires patterned over a long period of time using CAMCP are shown in Figure 7(b).

[0051] According to the results shown in Figure 6, in the CAMCP of the present invention, the wire diameter remains almost constant until about 250 min, whereas in the MCP without the clogging suppression liquid, the wire diameter expands rapidly from about 200 min. Furthermore, in the CAMCP, the wire diameter does not expand much even after 250 min. This comparison is also clearly observed in Figure 7, where it can be seen that the change in the nanowire width over time, shown in black, expands rapidly in the MCP compared to the CAMCP. This expansion of the wire width is thought to be due to a decrease in the amount of residual liquid sucked in due to clogging of the suction opening.

[0052] From these results, it was confirmed that by using a configuration such as this embodiment in which, in addition to the metal solution and reaction liquid, a clogging prevention liquid is also ejected, it is possible to form nanowires continuously over a long period of time without clogging the suction opening. [Explanation of symbols]

[0053] 10. Micro nozzle device 11...First discharge capillary 12...Second discharge capillary tube 13…Third discharge capillary 11a, 12a, 13a...Discharge opening 15...Capillary tube for suction 21, 22, 23...Discharge pump 25…Suction pump

Claims

1. A micro nozzle device for forming nanowires made of metal on a substrate, comprising: The liquid ejection device includes three or more discharge capillaries, one end of which is a discharge opening, one or more suction capillaries, one end of which is a suction opening, a discharge pump that ejects a fluid from the discharge capillaries, and a suction pump that sucks a fluid from the suction capillary, At least one of the discharge capillaries discharges a metal solution containing a metal compound, and at least one of the other discharge capillaries discharges a reaction liquid that reacts with the metal compound to precipitate a metal, and at least one of the other discharge capillaries discharges a clogging prevention liquid that inhibits the generation of solids due to the residual liquid of the metal solution and the residual liquid of the reaction liquid sucked into the suction capillary or dissolves the solids.

2. 2. The micronozzle device according to claim 1, further comprising a discharge capillary for discharging the pretreatment liquid in advance onto a position on the substrate where the nanowires are to be formed.

3. 3. The micronozzle device according to claim 1, wherein among the ejection capillaries, the ejection openings of the ejection capillaries that eject the metal solution and the reaction liquid are formed closer to the substrate than the ejection opening of the ejection capillary that ejects the clogging suppression liquid.

4. 4. The micronozzle device according to claim 1, wherein the discharge opening and the suction opening each have a diameter of 1 mm or less.

5. 5. The micronozzle device according to claim 1, wherein the discharge capillary and the suction capillary are made of a material containing silicon.

6. 6. The micronozzle device according to claim 1, wherein the discharge capillary is formed so that an inner diameter thereof is larger than an opening diameter of the discharge opening on an upstream side of the discharge opening, and the suction capillary is formed so that an inner diameter thereof is larger than an opening diameter of the suction opening on an upstream side of the suction opening.

7. 7. The micronozzle device according to claim 1, wherein the nanowires are made of silver, the metal solution contains a silver compound, and the reaction solution contains a reducing agent that reduces the silver compound to precipitate silver.

8. 3. The micronozzle device according to claim 2, wherein the pretreatment liquid contains tin chloride.

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