Liquid metal superconducting material, flexible superconducting circuit and preparation method thereof

Abstract

The invention relates to the technical field of superconducting materials, in particular to a liquid metal superconducting material, a flexible superconducting circuit and a preparation method thereof. The liquid metal superconducting material comprises a low-melting-point metal alloy and doped particles dispersed in the low-melting-point metal alloy; the low-melting-point metal alloy comprises any one or more of gallium-indium-tin alloy, gallium-indium-tin-zinc alloy, gallium-indium-tin-zinc-bismuth alloy and bismuth-indium-tin alloy; the doped particles comprise metal particles and / or metal oxide particles. In the liquid metal superconducting material provided by the invention, the low-melting-point metal alloy and the doped particles are diversified, the component limitation is low, and the universality is high. The flexible superconducting circuit is prepared by using the transfer printing method on the basis of the liquid metal superconducting material, the process flow is simple and rapid, the time is short, the cost is low, and the micro / nano-scale flexible superconducting electronic device can be rapidly, simply and conveniently prepared.

Description

Technical Field

[0001] The present invention relates to the technical field of superconducting materials, and in particular to a liquid metal superconducting material, a flexible superconducting circuit and a preparation method thereof. Background Art

[0002] Superconductors have the characteristics of no resistance, no loss, no heat generation and high current transmission density. They have broad application prospects in constructing high-speed micro / nanoscale electronic devices, including fast-response biosensors, quantum computers and micro-nuclear magnetic resonance devices.

[0003] Superconductors were first discovered in liquid mercury (Hg), but Hg is limited by its own environmental hazards, so the research value of superconducting Hg is limited. Since then, research on superconductors has mainly focused on solid superconducting materials, such as alloy superconductors, copper-based superconductors, iron-based superconductors, etc., and there is a lack of research on other liquid metal superconductors. Moreover, the complex preparation and processing methods of traditional superconductors limit their development. In addition, the flexible application of superconducting devices, including superconducting tapes, superconducting films, and some micro-superconducting devices, has also received increasing attention in recent years. In the field of superconducting film preparation, such as sputtering, electron beam evaporation, pulsed laser deposition, and chemical vapor deposition, high vacuum equipment is required, and the film deposition process is very time-consuming. Recently, the commercial application of superconducting films made by coating processes has been widely studied, and large-area films can be easily and quickly manufactured without high vacuum equipment. However, the preparation of most superconducting film materials is based on rigid substrates, which greatly limits the flexible application of superconducting materials and devices. At the same time, high-temperature superconductors, such as phosphorus oxides and copper oxides, are extremely difficult to use in the manufacture of flexible devices due to their rigidity and poor connectivity. So far, it is still a huge challenge to develop superconductors with comprehensive properties such as high critical temperature, good flexibility and easy processing that can be used in micro / nanoelectronic devices, which is also an inevitable requirement for the development of flexible superconducting micro / nanoelectronics.

[0004] Therefore, it is of great significance to provide a new liquid metal superconducting material, a flexible superconducting circuit and a preparation method thereof. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a liquid metal superconducting material, a flexible superconducting circuit and a preparation method thereof. The liquid metal superconducting material provided by the present invention has a variety of low melting point metal alloys and doped particles, low component restrictions and high universality. The flexible superconducting circuit is prepared by transfer method based on the liquid metal superconducting material. The process is simple and fast, takes less time and has low cost, and can quickly and easily prepare micro / nanoscale flexible superconducting electronic devices.

[0006] In a first aspect, the present invention provides a liquid metal superconducting material, the liquid metal superconducting material comprising a low melting point metal alloy and doping particles dispersed in the low melting point metal alloy;

[0007] The low melting point metal alloy includes any one or more of gallium indium tin alloy, gallium indium tin zinc alloy, gallium indium tin zinc bismuth alloy and bismuth indium tin alloy;

[0008] The doping particles include metal particles and / or metal oxide particles.

[0009] The liquid metal superconducting material provided by the present invention has various types of low melting point metal alloys and doped particles, low component restrictions, high universality, and good biosafety, and can be used to conveniently and quickly prepare flexible superconducting films and flexible superconducting circuits. Specifically:

[0010] The low melting point metal alloy provided by the present invention includes gallium-based alloy and bismuth-based alloy, which are of various types and have low composition restrictions. Among them, the gallium-based alloy has room temperature fluidity, is easy to process and manufacture, and can be used to conveniently and quickly manufacture superconducting films and superconducting wires. At the same time, the gallium-based alloy has good biosafety and a critical temperature T c Above the critical point of liquid helium (4.2K), it can be quickly patterned and is suitable for micro / nano flexible superconducting electronic devices. Moreover, gallium-based alloys are non-toxic and simple to manufacture. They can not only be safely used in flexible, low-cost micro / nano electronic devices, but can also be easily used to prepare superconducting films. Bismuth-based alloys (melting point of about 60°C) also have the advantages of high biosafety, and the process of preparing target patterns or circuits is simple and quick. In addition, the introduction of doped particles can improve the adhesion of liquid metal superconducting materials, facilitating the subsequent printing and preparation of flexible superconducting circuits.

[0011] As a preferred technical solution of the present invention, the mass content of the doped particles is 0.01-50%, for example, 0.01%, 0.1%, 1%, 5%, 10%, 20%, 30%, 40%, 50%, etc.

[0012] When the content of the doped particles is within this range, the liquid metal superconducting material has better adhesion, which makes it easier to print and prepare flexible superconducting circuits.

[0013] The particle size of the doped particles provided by the present invention is nanometer-level or micrometer-level. As a preferred technical solution of the present invention, the particle size of the doped particles is 1-100000nm, such as 1nm, 10nm, 100nm, 500nm, 1000nm, 5000nm, 10000nm, 50000nm, 100000nm, etc.

[0014] As a preferred technical solution of the present invention, the metal particles include any one or more of copper powder, iron powder, lead powder, zinc powder and nickel powder.

[0015] As a preferred technical solution of the present invention, the metal oxide particles include any one or more of lead oxide particles, iron oxide particles and zinc oxide particles.

[0016] The present invention realizes the regulation of the superconducting transition temperature of the liquid metal superconducting material by adjusting the composition of the liquid metal superconducting material, the type of doping particles and the degree of mixing.

[0017] In a second aspect, the present invention provides a method for preparing the liquid metal superconducting material described in the first aspect, the preparation method comprising: mixing a low-melting-point metal alloy and doping particles, and drying to obtain the liquid metal superconducting material.

[0018] The preparation method of the liquid metal superconducting material provided by the present invention is simple to operate. It can be understood that mixing means that the liquid low-melting-point metal alloy completely wraps all the doped particles, that is, no powder or particles visible to the naked eye appear. The mixing method can be stirring.

[0019] As a preferred technical solution of the present invention, an acid or a base is added during the mixing, and the acid or the base is added in the form of a solution to help the doped particles internalize, and the solvent is removed by vacuum drying after the mixing. For example, the acid can be hydrochloric acid, and the base can be sodium hydroxide.

[0020] As a preferred technical solution of the present invention, the added amount of the acid or base is the same as the volume of the low-melting-point metal alloy.

[0021] As a preferred technical solution of the present invention, the drying method is to dry at 60-80°C in a vacuum environment for 2-4h, wherein 60-80°C can be 60°C, 65°C, 70°C, 75°C, 80°C, etc., and the 2-4h can be 2h, 2.5h, 3h, 3.5h, 4h, etc.

[0022] As a preferred technical solution of the present invention, post-treatment may be performed after drying, including but not limited to ultrasonic treatment, heat treatment, chemical treatment, etc., and the liquid metal superconducting material is obtained after post-treatment.

[0023] In a third aspect, the present invention provides the use of the liquid metal superconducting material described in the first aspect or the liquid metal superconducting material prepared by the preparation method described in the second aspect in flexible superconducting circuits and flexible superconducting films.

[0024] In a fourth aspect, the present invention provides a method for preparing a flexible superconducting circuit, the method comprising the following steps:

[0025] (1) Printing the target circuit onto the substrate material;

[0026] (2) coating a liquid metal superconducting material on a substrate material printed with a target circuit to draw a circuit, thereby obtaining a liquid metal circuit;

[0027] (3) Laminating the substrate material on which the circuit is drawn with the elastic material, and adhering the liquid metal circuit to the surface of the elastic material;

[0028] (4) Encapsulating the liquid metal circuit on the surface of the elastic material.

[0029] In step (1) of the present invention, the target circuit is printed onto a base material, and the printing method may be to use a laser printer for printing.

[0030] The present invention utilizes the characteristics of liquid metal superconducting materials having different adhesion to different substrates after oxidation, and uses a transfer method to quickly prepare liquid metal circuits. The process is simple and fast, takes less time, and has low cost. It can quickly and easily prepare micro / nanoscale flexible superconducting electronic devices; specifically:

[0031] The preparation method of the present invention utilizes the difference in adhesion between the base material and the printer toner, and between the base material and the elastic material of the liquid metal superconducting material, and uses a transfer method to quickly prepare a liquid metal circuit. In addition, no complex equipment such as high vacuum equipment is required during the preparation process, and a common laser printer can be used to prepare a flexible superconducting circuit, which has low cost and high universality. Moreover, the process flow is simple, and the entire preparation process does not have excessive requirements on environmental conditions such as temperature, humidity, air cleanliness, and static electricity, and can be completed under normal conditions. In addition, the preparation process is short in time, and the target circuit can be quickly prepared to achieve rapid preparation of superconducting flexible electronic devices, that is, the preparation method of the present invention can be directly applied to the preparation of printed flexible superconducting electronic circuits and micro / nano superconducting electronic devices.

[0032] The flexible superconducting circuit prepared by the present invention is a two-dimensional planar circuit, and can realize the preparation of interconnected multi-layer three-dimensional circuits by stacking, penetrating and the like.

[0033] As a preferred technical solution of the present invention, the base material includes thermal transfer paper.

[0034] The base material provided by the present invention can provide liquid metal superconducting material with better adhesion than printer toner, and can be separated from the liquid metal circuit under appropriate conditions without causing damage to the liquid metal circuit.

[0035] As a preferred technical solution of the present invention, the elastic material includes PDMS (polydimethylsiloxane) and / or Ecoflex material (polybutylene terephthalate-adipate).

[0036] The elastic material provided by the present invention can provide liquid metal superconducting material with adhesion better than that of the base material, and has good flexibility, stretchability and toughness, and can withstand large temperature changes without being destroyed.

[0037] As a preferred technical solution of the present invention, the packaging material used in the packaging in step (4) is a thin film flexible sealing material that is the same as or similar to the elastic material.

[0038] The present invention adjusts the composition of the liquid metal superconducting material, the type of doping particles and the degree of mixing to achieve the regulation of the superconducting transition temperature of the liquid metal superconducting material, and cools the liquid metal circuit to below the superconducting transition temperature to obtain a flexible superconducting circuit.

[0039] The transfer-based liquid metal flexible superconducting circuit preparation method provided by the present invention can be extended to printing methods such as handwriting printing and embossing, has high universality, and can be directly applied to the preparation of printed flexible superconducting electronic circuits and micro / nano superconducting electronic devices.

[0040] As a specific embodiment of the present invention, the preparation method comprises the following steps:

[0041] (1) Printing the target circuit onto the substrate material using a laser printer;

[0042] (2) Using a roller brush evenly dipped in liquid metal superconducting material, under a certain pressure, the liquid metal superconducting material is applied to the substrate material printed with the target circuit to draw the circuit. Due to the difference in adhesion between the liquid metal superconducting material and the printer toner, the liquid metal superconducting material will evenly adhere to the substrate material to obtain a liquid metal circuit;

[0043] (3) Laying the substrate material with the circuit drawn on it to the elastic material, and applying appropriate pressure. Due to the difference in adhesion between the substrate material and the elastic material, the liquid metal circuit will adhere to the surface of the elastic material, thus completing the circuit transfer.

[0044] (4) Encapsulating the liquid metal circuit on the surface of the elastic material.

[0045] The preparation process of the flexible superconducting circuit provided by the present invention is divided into four steps: design, drawing, transfer and packaging. The design step requires completing the circuit design on a computer and printing the target circuit on a base material. After the target circuit is printed on the base material, a roller brush is used to print the liquid metal superconducting material on the base material under a certain pressure. Since the liquid metal superconducting material has a difference in adhesion between the base material and the printer toner, it will adhere to the base material evenly, and the circuit drawing step is completed. The third step is the transfer step, that is, the liquid metal superconducting material on the base material is transferred to the surface of the elastic material. In this step, the base material with the liquid metal circuit drawn needs to be closely attached to the surface of the elastic material, and the liquid metal circuit is transferred from the base material to the elastic material by applying appropriate pressure using the difference in adhesion between the liquid metal superconducting material and the elastic material. Since the liquid metal superconducting material has better adhesion to the elastic material, the liquid metal will adhere evenly to the elastic material to complete the transfer of the circuit. Finally, the same or similar packaging material is added to the elastic material to complete the packaging of the liquid metal circuit.

[0046] In a fifth aspect, the present invention provides a flexible superconducting circuit prepared by the preparation method described in the fourth aspect.

[0047] The technical solution provided by the embodiment of the present invention has the following advantages compared with the prior art:

[0048] The liquid metal superconducting material provided by the present invention has various types of low melting point metal alloys and doped particles, low composition restrictions and high universality. Based on the liquid metal superconducting material, a transfer method is used to prepare a flexible superconducting circuit, which has a simple and fast process flow, takes less time and has low cost, and can quickly and easily prepare micro / nano-scale flexible superconducting electronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0051] Figure 1 This is a flow chart for preparing the flexible superconducting circuit described in Example 1 of the present invention.

[0052] Figure 2 This is a schematic diagram of a method for preparing a flexible superconducting circuit by the transfer method described in Example 1 of the present invention;

[0053] Among them, 1-base material; 2-carbon powder; 3-liquid metal circuit; 4-roller; 5-elastic material.

[0054] Figure 3 The resistance variation curve of the liquid metal circuit prepared in Example 1 of the present invention is plotted against temperature. DETAILED DESCRIPTION

[0055] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0056] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0057] Preparation Example 1

[0058] This preparation example provides a liquid metal superconducting material and a preparation method thereof, the preparation method comprising the following steps:

[0059] (1) Weigh 20 g of liquid metal alloy GaInSn and add 4 g of copper powder with a particle size of 20 μm;

[0060] (2) Place the sample in a beaker and add 1 mol / L sodium hydroxide solution equivalent to the volume of the liquid metal alloy, and stir evenly with a glass rod;

[0061] (3) After the reaction is completed, the sample is placed in a vacuum drying oven and maintained at 70° C. for 2 hours in a vacuum environment to fully evaporate the solvent to obtain the liquid metal superconducting material.

[0062] Preparation Example 2

[0063] This preparation example provides a liquid metal superconducting material and a preparation method thereof, the preparation method comprising the following steps:

[0064] (1) Weigh 20 g of liquid metal alloy GaInSn and add 20 g of nickel powder with a particle size of 48 nm;

[0065] (2) Place the sample in a beaker and add 1 mol / L sodium hydroxide solution equivalent to the volume of the liquid metal alloy, and stir evenly with a glass rod;

[0066] (3) After the reaction is completed, the sample is placed in a vacuum drying oven and maintained at 70° C. for 2 hours in a vacuum environment to fully evaporate the solvent to obtain the liquid metal superconducting material.

[0067] Preparation Example 3

[0068] This preparation example provides a liquid metal superconducting material and a preparation method thereof, the preparation method comprising the following steps:

[0069] (1) Weigh 20 g of liquid metal alloy GaInSn and add 0.2 g of zinc oxide particles with a particle size of 500 nm;

[0070] (2) Place the sample in a beaker and add 1 mol / L sodium hydroxide solution equivalent to the volume of the liquid metal alloy, and stir evenly with a glass rod;

[0071] (3) After the reaction is completed, the sample is placed in a vacuum drying oven and maintained at 70° C. for 2 hours in a vacuum environment to fully evaporate the solvent to obtain the liquid metal superconducting material.

[0072] Comparative Preparation Example 1

[0073] This comparative preparation example provides a liquid metal superconducting material and a preparation method thereof. The preparation method is the same as that of Preparation Example 1, and the difference from Preparation Example 1 is that copper powder is not added in this comparative preparation example.

[0074] Example 1

[0075] This embodiment provides a flexible superconducting circuit and a method for preparing the same. The flow chart of the preparation method is as follows: Figure 1 As shown in the figure, the method of preparing flexible superconducting circuits by transfer printing is shown in Figure 2 As shown;

[0076] The preparation method specifically comprises the following steps:

[0077] (1) Design: Complete the circuit design on the computer. The circuit part is designed to be white and the background is black. Print the target circuit on a base material using a laser printer. The base material is thermal transfer paper, such as Figure 2 As shown in (a), after printing, the sample is as follows Figure 2 (b)

[0078] (2) Drawing: Use a roller brush that is evenly dipped in the liquid metal superconducting material prepared in Preparation Example 1, and brush it over the thermal transfer paper printed with a pattern or circuit under a certain pressure. Due to the difference in adhesion between the liquid metal superconducting material and the printer toner, the liquid metal superconducting material will evenly adhere to the thermal transfer paper, and the circuit drawing is completed, such as Figure 2 (c)

[0079] (3) Transfer: The thermal transfer paper with the completed pattern or circuit is placed close to the flexible PDMS surface and appropriate pressure is applied, such as Figure 2As shown in (d), due to the difference in adhesion between the liquid metal superconducting material on the thermal transfer paper and PDMS, the liquid metal superconducting material will adhere evenly to the PDMS, that is, the circuit transfer is completed, as shown in Figure 2 (e) as shown.

[0080] in, Figure 2 (a) is the base material in the design step. Figure 2 (b) is a schematic diagram of the target circuit after printing. The black part in the figure is carbon powder, and the white area is the designed circuit structure. Figure 2 (c) is the drawing step, which is to print the liquid metal on the base material using a roller. Figure 2 (b) Compared with Figure 2 The white circuit part in (c) becomes metallic, indicating that the liquid metal superconducting material has been coated on the designed target circuit. Figure 2 (d) is a schematic diagram of the transfer step, that is, the base material with the liquid metal circuit drawn on it is closely attached to the surface of the elastic material and appropriate pressure is applied. Figure 2 (e) is a schematic diagram after the transfer step is completed, at which point the liquid metal circuit has been transferred to the surface of the elastic substrate. Figure 2 (f) is a schematic diagram after the encapsulation is completed. The same material is used on the surface of the elastic substrate to which the liquid metal circuit has been transferred to complete the encapsulation of the liquid metal circuit. 1-substrate material; 2-carbon powder; 3-liquid metal circuit; 4-roller; 5-elastic material.

[0081] After the preparation is completed, the resistance change curve of the liquid metal circuit in the temperature range of 2-300K is tested. The results are as follows Figure 3 As shown in the figure, it can be seen that the superconducting transition temperature of the sample is 6.4K.

[0082] (4) Packaging: Cover the circuit surface with a layer of PDMS to complete the packaging of the liquid metal circuit. Figure 2 (f) as shown.

[0083] Example 2-3

[0084] This embodiment provides a flexible superconducting circuit and a preparation method thereof. The preparation method is the same as that of Example 1. The difference from Example 1 is that in this embodiment, the liquid metal superconducting material is replaced by the liquid metal superconducting material obtained in Preparation Example 2 (Example 2) and Preparation Example 3 (Example 3).

[0085] The resistance change curves of the liquid metal circuits prepared in Examples 2 and 3 are similar to that in Example 1, and the superconducting transition temperatures are 6.6K (Example 2) and 6.5K (Example 3), respectively.

[0086] Comparative Example 1

[0087] This comparative example provides a flexible superconducting circuit and a preparation method thereof. The preparation method is the same as that of Example 1. The difference from Example 1 is that in this comparative example, the liquid metal superconducting material is replaced by the liquid metal superconducting material obtained in Comparative Preparation Example 1.

[0088] It can be found that the liquid metal superconducting material obtained in Comparative Preparation Example 1 has insufficient adhesion and is easily scratched and disconnected after printing.

[0089] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0090] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments described herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A liquid metal superconducting material, characterized in that: The liquid metal superconducting material comprises a low melting point metal alloy and doping particles dispersed in the low melting point metal alloy; The low melting point metal alloy includes any one or more of gallium indium tin alloy, gallium indium tin zinc alloy, gallium indium tin zinc bismuth alloy and bismuth indium tin alloy; The doping particles include metal particles and / or metal oxide particles.

2. The liquid metal superconducting material according to claim 1, characterized in that: The mass content of the doped particles is 0.01-50%.

3. The liquid metal superconducting material according to claim 1 or 2, characterized in that: The particle size of the doped particles is 1-100000 nm; And / or, the metal particles include any one or more of copper powder, iron powder, lead powder, zinc powder and nickel powder; And / or, the metal oxide particles include any one or more of lead oxide particles, iron oxide particles and zinc oxide particles.

4. The method for preparing a liquid metal superconducting material according to any one of claims 1 to 3, characterized in that: The preparation method comprises: mixing a low melting point metal alloy and doping particles, and drying to obtain the liquid metal superconducting material.

5. The preparation method according to claim 4, characterized in that: Acid or alkali is also added during the mixing, and preferably the amount of the acid or alkali added is the same as the volume of the low melting point metal alloy; And / or, the drying method is drying at 60-80° C. in a vacuum environment for 2-4 hours.

6. Use of the liquid metal superconducting material according to any one of claims 1 to 3 or the liquid metal superconducting material prepared by the preparation method according to claim 4 or 5 in flexible superconducting circuits and flexible superconducting films.

7. A method for preparing a flexible superconducting circuit, characterized in that: The preparation method comprises the following steps: (1) Printing the target circuit onto the substrate material; (2) coating a liquid metal superconducting material on a substrate material printed with a target circuit to draw a circuit, thereby obtaining a liquid metal circuit; (3) Laminating the substrate material on which the circuit is drawn with the elastic material, and adhering the liquid metal circuit to the surface of the elastic material; (4) Encapsulating the liquid metal circuit on the surface of the elastic material.

8. The preparation method according to claim 7, characterized in that: The base material includes thermal transfer paper.

9. The preparation method according to claim 7 or 8, characterized in that: The elastic material includes PDMS and / or Ecoflex material.

10. The flexible superconducting circuit prepared by the preparation method according to any one of claims 7 to 9.

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