A device for conducting an electrochemical reaction in a sliding meniscus and a method for conducting an electrochemical reaction in a sliding meniscus

Abstract

A device and method for conducting an electrochemical reaction in a sliding meniscus are disclosed. The device comprises a guiding system with first and second immovable, tangential, and parallel tubes made of non-electrically conductive material, which facilitate the formation of a meniscus on a substrate. A material for maintaining ionic potential is confined by the lower parts of the tubes and an adjacent membrane, which allows ion exchange. A substrate serving as a working electrode, a rod as a reference electrode, and an electrically conductive strip as a counter-electrode are connected to a potentiostat. The rod is immersed in the material maintaining ionic potential, and the conductive strip contacts the meniscus-forming solution. The method involves providing a solution to form the meniscus between the substrate and guiding system, moving the guiding system relative to the substrate to move the meniscus, and generating an electric current via the potentiostat to induce an electrochemical reaction in the meniscus. The invention allows for precise control of electrochemical reactions in a moving meniscus, enhancing reaction efficiency and stability.

Description

[0001] A DEVICE FOR CONDUCTING AN ELECTROCHEMICAL REACTION IN A SLIDING MENISCUS AND A METHOD FOR CONDUCTING AN ELECTROCHEMICAL REACTION IN A SLIDING MENISCUS

[0002] TECHNICAL FIELD

[0003] The present invention relates to the field of electrochemical deposition, specifically to a device and method for conducting an electrochemical reaction in a sliding meniscus, particularly using the three-electrode method, to achieve a homogeneous layer over a substrate.

[0004] The device and method are particularly useful for obtaining structures (of both inorganic and organic materials) of controlled shape, thickness, and / or width on various types of conductive substrates. For example, they find application in the production of substrates with conductive pathways, large-area devices for “plastic” electronics and solar cells, anti-reflection surfaces, catalytic surfaces, superhydrophobic coatings, protein microarrays, and cell culture substrates.

[0005] BACKGROUND

[0006] The field of electrochemical deposition has seen significant advancements over the years, particularly in the context of developing devices and methods for creating uniform coatings on various substrates.

[0007] Electrochemical deposition is a process that involves the reduction of metal ions from a solution onto a conductive substrate, forming a coherent metal coating. This process is widely used in industries such as electronics, energy, and materials science for applications ranging from the fabrication of microelectronic components to the development of corrosion-resistant coatings.

[0008] Despite its widespread use, traditional electrochemical deposition techniques face several challenges that limit their effectiveness and efficiency. One of the primary issues is the difficulty in achieving uniform deposition across large substrate areas. This is often due to variations in the electric field and ion concentration across the substrate surface, which can lead to non-uniform layer thickness and inconsistent material properties. Such inconsistencies are particularly problematic in applications requiring precise control over the deposited layer's thickness and composition, such as in the production of microelectronic devices and thin-film solar cells. WO2019179794A1 discloses a device comprising a platform for a substrate, a guiding element movable relative to the platform, for spreading the liquid on the substrate into a meniscus, and an activation system for inducing an electrochemical reaction in the liquid in the meniscus, coupled to the guiding element. The guiding element is a single solid, which can be a cylinder or a rotationally asymmetric solid. The device comprises two electrodes: the first electrode is a conductive layer on the substrate, and the second electrode is the guiding element of the meniscus. This solution has limitations since the deposition potential significantly changes with the distance from the grounding electrode connected at one end of the substrate, leading to difficulties in obtaining uniform reaction parameters during the process.

[0009] SUMMARY OF THE INVENTION

[0010] The existing electrochemical deposition systems are hindered by challenges related to uniformity, stability, and control. There is a clear need for innovative solutions that can enhance the precision and reliability of electrochemical deposition processes, particularly in the context of sliding meniscus techniques. Such advancements would have significant implications for a wide range of applications, from electronics manufacturing to renewable energy technologies.

[0011] Therefore, there is a need to enhance existing solutions for conducting electrochemical reactions within a sliding meniscus to ensure increased stability and reliability of the process.

[0012] In one aspect, the invention relates to a device for conducting an electrochemical reaction in a sliding meniscus. The device comprises a guiding system for sliding a solution forming the meniscus on a substrate. The guiding system comprises a first tube and a second tube having congruent side surfaces, wherein the tubes are immovable, tangential and parallel to each other, and wherein the tubes are made of an electrically non-conductive material. A membrane extends between the lower parts of the side surfaces of the tubes. The volume between the lower parts of the congruent side surfaces of the tubes and the membrane is filled with a material for maintaining ionic potential. A rod is arranged between the tubes and immersed in the material for maintaining ionic potential. The membrane is made of a material that allows ion exchange between the solution forming the meniscus and the rod. An electrically conductive strip arranged on the side surface of the second tube between the membrane and the substrate so that the strip is in contact with the solution forming the meniscus while the meniscus is formed. The device further comprises a potentiostat connected with the substrate, the rod and the strip, wherein the substrate is connected to the potentiostat as a working electrode, the rod is connected to the potentiostat as a reference electrode and the strip is connected to the potentiostat as a counter-electrode. This configuration provides a stable and efficient setup for conducting electrochemical reactions with precise control over the ionic environment and electrode potentials.

[0013] Preferably, the rod is made of silver, and the material for maintaining ionic potential is a chlorine solution. These materials enhance the stability and reliability of the reference electrode, ensuring accurate potential stabilization.

[0014] Preferably, the first tube contains a chamber arranged inside the first tube and has at least one opening for supplying the solution forming the meniscus from the chamber to the meniscus. Preferably, the first tube comprises an aperture, arranged in an upper surface or in a side surface of the first tube, for supplying the solution forming the meniscus to the chamber.

[0015] This facilitates a consistent and controlled supply of the solution, contributing to the uniformity of the meniscus formation.

[0016] In another aspect, the invention relates to a method for conducting an electrochemical reaction in a sliding meniscus by means of the device as described above. The method comprises: forming meniscus by providing a solution forming the meniscus in which the electrochemical reaction is to be carried out, between the substrate and the guiding system; moving the guiding system relative to the substrate causing movement of the meniscus on the substrate; during movement of the meniscus, generating an electric current flow by means of the potentiostat, between the substrate arranged as the working electrode and the conductive strip arranged as the counterelectrode, causing an electrochemical reaction in the meniscus, while stabilizing the voltage between the working electrode and the reference electrode by setting an appropriate potential on the strip arranged as the counter-electrode. This method ensures precise control over the electrochemical reaction process, enhancing the quality and consistency of the results.

[0017] The present invention addresses the limitations of current electrochemical deposition devices and methods by integrating the guiding system with three electrodes to ensure precise control over the deposition process using a sliding meniscus, providing the formation of a homogeneous layer over a large area. The term ‘meniscus’ is understood herein as a volume of a solution forming a meniscus between the surface of a substrate and components of the guiding system. The meniscus volume can be adjusted by controlling the distance between the substrate and the guiding system. Proper management of the meniscus ensures uniform deposition.

[0018] The guiding system directs the solution forming the meniscus to the substrate and maintains the meniscus during the deposition process. The guiding system comprises two tubes, a first tube and a second tube, immovable relative to each other to ensure the solution is evenly distributed. The guiding system can be adjusted in height and tilt to maintain a consistent distance from the substrate for uniform coating.

[0019] The first tube of the guiding system is responsible for supplying the solution forming the meniscus onto the substrate (so that the solution forms the meniscus). The first tube comprises a chamber arranged in the first tube, serving as a reservoir holding and supplying the solution forming the meniscus. The capacity and design of the chamber can be adjusted to ensure a consistent supply of the solution throughout the deposition process. The interior of the chamber is connected with the exterior by hole(s) so that, through the hole(s), the solution forming the meniscus can be dispensed. The first tube can be provided with a single hole or a series of holes along the length of the first tube, depending on the desired pattern of solution distribution, to control the flow rate of the solution and ensure even coverage of the substrate.

[0020] The second tube of the guiding system works in tandem with the first tube to maintain the meniscus. The first tube and the second tube can be made of electrically non-conductive materials, like glass or plastic, to prevent interference with the electrochemical process.

[0021] The material maintaining ionic potential ensures stable electrochemical conditions by maintaining a consistent ionic potential. It can be made of various substances, such as a chlorine solution or a specialized paste, depending on the specific requirements of the deposition process.

[0022] The membrane is arranged between the material maintaining ionic potential surrounding the reference electrode and the meniscus. The membrane holds the material maintaining ionic potential while allowing ion exchange between the meniscus and the reference electrode. The membrane is typically made of a porous material that permits the passage of ions while preventing the solution from leaking, such as frit. The properties of the membrane can be selected based on the specific requirements of the deposition process.

[0023] The device is provided with three electrodes connected to a potentiostat, an electronic device that controls the voltages and currents in the electrochemical deposition system. It ensures that the appropriate voltages are set between the working electrode, the reference electrode, and the counter-electrode. The potentiostat can be programmed to maintain specific voltages and monitor the electrochemical conditions throughout the deposition process.

[0024] The substrate is connected as a working electrode. It is typically made of an electrically conductive material, such as ITO. The material and surface properties of the substrate can be selected based on the specific requirements of the deposition process.

[0025] The counter-electrode has the form of a strip located on the surface of the second tube, such that it contacts with the solution while forming the meniscus. The counterelectrode provides a stable potential for the electrochemical deposition process. It is typically made of a conductive material like platinum and is designed to deliver a charge to the solution forming the meniscus.

[0026] The reference electrode has a form of a rod arranged between the first tube and the second tube. The rod is immersed in a material for maintaining an ionic potential, ensuring stable electrochemical conditions during the deposition process. The rod is typically made of a conductive material like silver, optionally coated with a specific material to enhance its conductivity and stability.

[0027] The device is provided with three platforms to ensure proper settings during the deposition process. The first platform is used to correct the inclination of the substrate, ensuring that the guiding system moves at a constant height throughout its length. The first platform can be adjusted in multiple planes to achieve the desired level of alignment, providing uniformity of the deposited layer.

[0028] The second platform adjusts the tilt of the guiding system so that it is parallel to the ground surface. The second platform ensures that the guiding system remains level, which is important for maintaining a consistent meniscus and achieving uniform deposition.

[0029] The micrometer screw allows for precise height adjustments of the guiding system relative to the substrate by setting the desired distance between the guiding system and the substrate, affecting the thickness and uniformity of the deposited layer. The micrometer screw can be calibrated to provide adjustments in the micrometer range, ensuring high precision.

[0030] The third platform serves as the base for the entire device. It is equipped with three leveling screws that enable fine adjustments to ensure the device is horizontal. It works in conjunction with the first and second platforms to achieve optimal alignment.

[0031] Linear stage is a mechanism that allows the substrate to be moved relative to the stationary guiding system, where control of the speed and acceleration of the substrate affects the uniformity of the deposited layer. Linear stage can be implemented using a motorized stage or a manual sliding mechanism, depending on the precision required. This component works in conjunction with the guiding system to ensure that the solution forms a continuous meniscus between the substrate and the guiding system.

[0032] The handle serves as the mounting point for the guiding system, providing a stable and ergonomic way to manipulate the device. It allows for easy adjustments and ensures that the guiding system remains securely attached to the rest of the apparatus. The handle can be designed with various ergonomic features, such as a contoured grip or adjustable positioning, to enhance user comfort and control. Its primary function is to facilitate the precise alignment of the guiding system with the substrate.

[0033] The slide holder secures the linear displacement mechanism and ensures smooth and precise movement of the substrate. The slide holder can be equipped with bearings or other low-friction elements to enhance its performance. It works in conjunction with the linear displacement mechanism to provide controlled movement of the substrate.

[0034] BRIEF DESCRIPTION OF THE DRAWINGS

[0035] These and other objects of the invention presented herein are accomplished by providing a device and method for conducting an electrochemical reaction in a sliding meniscus. Further details and features of the present invention, its nature, and various advantages will become more apparent from the following detailed description of the preferred embodiments shown in a drawing, in which:

[0036] Fig. 1 schematically shows an example of the device to be used in the method according to the invention;

[0037] Fig. 2 shows an exemplary embodiment of a guiding system. DETAILED DESCRIPTION

[0038] The method according to the invention can be carried out by the device shown in a detailed embodiment in Fig. 1. The device facilitates the movement of a solution by means of a guiding system 3 (shown in detail in Fig. 2) positioned near a substrate 22 to be moved. A small amount of the solution is supplied between the substrate 22 and the guiding system 3 so that the solution forms a meniscus.

[0039] The device comprises a linear stage 1 which allows the substrate to be moved relative to the stationary guiding system 3, resulting in the displacement of the solution relative to the substrate. Linear stage 1 enables the selection of an appropriate speed and acceleration. Handle 2 allows for mounting the guiding system 3 that directs the solution.

[0040] To obtain a homogeneous layer over a large area, it is important to properly position the guiding system 3 relative to the surface of the substrate 22 and to level the entire system. Various elements ensure proper alignment of the device components. The micrometer screw 9 allows the guiding system 3 to be set at the correct height above the substrate with an accuracy of a few micrometers. A first platform 8 corrects the inclination of the substrate 22, ensuring movement of the guiding system 3 at a constant height throughout the entire length. A second platform 10 adjusts the tilt of the guiding system 3 so that it is parallel to the ground surface. The entire device is placed on a third platform 11 with three screws, allowing the device to be leveled.

[0041] The substrate 22, being electrically conductive, is introduced into the device; the substrate 22 is placed on a platform 8 mounted on a linear stage 1 . With the platform 11 on three leveling legs, the entire device can be leveled. Additional leveling is provided by the platform 8, equipped with a tilt adjustment system in at least one plane, preferably in three planes. Similarly, a platform 10 of the guiding system 3 is equipped with a tilt adjustment system in at least two planes (preferably in three planes). A slide holder 5, with a rod 4 and guiding system 3 containing two electrodes: a reference electrode 33 and a counter-electrode 38, is rigidly attached to the platform 10.

[0042] In alternative embodiments, the guiding system 3 may be a sliding element, and a stationary base may replace the linear stage 1. In other embodiments, various mechanisms for moving the substrate, such as a roller system for rigid substrates or systems for stretching flexible substrates, may also be used. In another embodiment, both the guiding system 3 and the substrate can be movable simultaneously, either on the linear slide or another sliding mechanism. In the embodiment presented herein, the goal is to position the substrate horizontally using the aforementioned adjusting elements. However, alternative embodiments may position the substrate at an angle or vertically.

[0043] The invention utilizes a guiding system 3 comprising two immovable tubes 31 , 32, tangent and parallel to each other, with a rod 33 mounted between the tubes 31 , 32, as shown in Fig. 2. The tubes 31 , 32 are made of electrically non-conductive material, such as plastic, glass, or another. A chamber containing material 34 for maintaining ionic potential is located between the lower portions of congruent side surfaces of the tubes 31 , 32. The material 34 is retained by a lower membrane 35 (frit).

[0044] The rod 33, serving as a reference electrode, is immersed in the material 34 for maintaining ionic potential. For example, rod 33 can be made of silver and immersed in a chlorine solution, or it can be made of another metal and immersed in a suitable substance that maintains the ionic potential. The membrane 35 holds the material 34 in the form of a solution surrounding the rod 33 (serving as the reference electrode) in place, allowing ion exchange between the meniscus and the reference electrode 33.

[0045] The first tube 31 has at least one hole 36 (or a series of holes along its length) supplying a solution forming the meniscus 21 from a chamber 37, inside the first tube

[0046] 31 , to the meniscus 21 . This allows the solution forming the meniscus 21 to be dispensed or exchanged into an area of the meniscus 21 for large area coverage. The first tube 31 can be closed on both sides and have an opening, at its top or side surface (not visible in the figure), for supplying solution forming the meniscus 21 to chamber 37.

[0047] On the surface of the second tube 32, between the membrane 35 and the lower portion of the second tube 32, there is provided an electrically conductive strip 38 serving as a counter-electrode made, for example, of platinum. The strip 38 is immersed in the solution forming the meniscus 21 . The greater the length of the strip 38, the better the ability to deliver a charge; optimally, this strip should be of the same length as the tube

[0048] 32.

[0049] During operation of the device, a solution forming the meniscus 21 is moved between the electrically conductive substrate 22 and the guiding system 3, where the reaction is to be carried out. The substrate 22 serves as the working electrode. The working electrode 22, reference electrode 33, and counter-electrode 38 are connected to a potentiostat 41 , which controls the voltages and currents in the system during the reaction. The method is conducted as follows. After the system is leveled, the solution forming the meniscus 21 , where the electrochemical reaction is to be carried out, is inserted between the substrate 22 and the guiding system 3. Then, by causing displacement between the guiding system 3 and the substrate 22, the solution forming the meniscus 21 on the substrate 22 is moved. While the solution is being moved, appropriate voltages are set between the working electrode 22, the reference electrode 33, and the counter-electrode 38 by means of the potentiostat 41. Specifically, the voltage between the working electrode 22 and the reference electrode 33 is stabilized by setting an appropriate potential on the counter-electrode 38 according to the type of reaction to be induced on the surface of the counter-electrode 38. The values of the potential of the counter-electrode 38 for different materials and types of reactions are known to specialists in the field. In this way, electrochemical reactions are induced in the meniscus 21 between the guiding system 3 and the substrate 22.

[0050] Dispensing the solution forming the meniscus 21 from the chamber 37, a constant supply of the solution to the meniscus 21 is ensured, particularly so that there is a constant volume of the solution in the meniscus 21 throughout the process, allowing the meniscus 21 to be stretched over large areas.

[0051] Detailed implementation example:

[0052] Tubes 31 , 32 with an outer diameter of 6 mm and a wall thickness of 1 mm made of Plexiglas® were used. A silver wire with a diameter of 1 mm was used as a reference electrode 33, and DuPont 5874 paste containing silver (Ag) and silver chloride (AgCI) was used as a material 34 for maintaining ionic potential. A layer of DuPont 5018 paste enriched with chlorine ions (Cl) was used as the membrane 35. A platinum strip 5 mm wide and 0.5 mm thick was used as the counter-electrode.

[0053] A solution containing zinc ions (0.1 M aqueous solution of Zn(NO3)2 6H2O) was used as the solution forming the meniscus 21 . T2006B1 -Ell type potentiostat from Ossila served as the potentiostat 41 . ITO-coated slides were used as the substrate 22. The expected reaction was the deposition of zinc oxide on ITO.

[0054] While conducting the reaction using potentiostat 41 , a potential was set between the working electrode 22 and the reference electrode 33 in the range of -0.8 V to -1 .6 V. It was found that at a potential of -0.75 V, zinc oxide deposited in the form of flakes was obtained, and at a potential of -1 .2 V, zinc oxide in the form of densely packed grains was obtained.

Claims

CLAIMS:

1. A device for conducting an electrochemical reaction in a sliding meniscus (21 ), the device comprising:- a guiding system (3) for sliding a solution forming the meniscus (21 ) on a substrate (22), the guiding system (3) comprising:- a first tube and a second tube (31 , 32) having congruent side surfaces, wherein the tubes (31 , 32) are immovable, tangential and parallel to each other, and wherein the tubes (31 , 32) are made of an electrically non- conductive material;- a membrane (35) extending between the lower parts of the side surfaces of the tubes (31 , 32);- wherein the volume between the lower parts of the congruent side surfaces of the tubes (31 , 32) and the membrane (35) is filled with a material (34) for maintaining ionic potential;- a rod (33) arranged between the tubes (31 , 32) and immersed in the material (34) for maintaining ionic potential;- wherein the membrane (35) is made of a material that allows an ion exchange between the solution forming the meniscus (21 ) and the rod (33); and- an electrically conductive strip (38) arranged on the side surface of the second tube (32) between the membrane (35) and the substrate (22) so that the strip (38) is in contact with the solution forming the meniscus (21 ) while the meniscus (21 ) is formed;- a potentiostat (41 ) connected with the substrate (22), the rod (33) and the strip (38), wherein:- the substrate (22) is connected to the potentiostat (41 ) as a working electrode;- the rod (33) is connected to the potentiostat (41 ) as a reference electrode; and- the strip (38) is connected to the potentiostat (41 ) as a counter-electrode.

2. The device according to claim 1 , wherein the rod (33) is made of silver, and the material (34) for maintaining ionic potential is a chlorine solution.

3. The device according to any one of the preceding claims, wherein the first tube (31 ) contains a chamber (37) arranged inside the first tube (31 ) and has at least oneopening (36) for supplying the solution forming the meniscus (21 ) from the chamber (37) to the meniscus (21 ).

4. The device according to claim 3, wherein the first tube (31 ) comprises an aperture, arranged in an upper surface or in a side surface of the first tube (31 ), for supplying the solution forming the meniscus (21 ) to the chamber (37).

5. A method for conducting an electrochemical reaction in a sliding meniscus by means of the device according to any of claims 1 to 4, the method comprising: forming the meniscus (21 ) by providing the solution forming the meniscus in which the electrochemical reaction is to be carried out, between the substrate (22) and the guiding system (3); moving the guiding system (3) relative to the substrate (22), thereby causing movement of the meniscus (21 ) on the substrate (22); and during the movement of the meniscus (21 ), generating an electric current by means of the potentiostat (41 ), between the substrate (22) arranged as the working electrode and the conductive strip (38) arranged as the counterelectrode, causing an electrochemical reaction in the meniscus (21 ), while stabilizing the voltage between the working electrode and the reference electrode by controlling the voltage potential on the strip (38) arranged as the counterelectrode.

Images