A preparation method of tellurium nanowires, tellurium nanowire ink and application

Abstract

The application relates to the technical field of nanomaterial preparation, and discloses a preparation method of tellurium nanowires, tellurium nanowire ink and application. The preparation method of the tellurium nanowires comprises the following steps: dissolving L-ascorbic acid in deionized water to obtain an L-ascorbic acid solution; dissolving hyperbranched polymer containing a functional group in deionized water to obtain a hyperbranched polymer solution; adding the hyperbranched polymer solution into the L-ascorbic acid solution, uniformly stirring, and obtaining a precursor solution; adding a tellurium source into the precursor solution for reaction, collecting a solid-phase product; and washing and drying the solid-phase product to obtain the tellurium nanowires. The preparation method of the tellurium nanowires is simple in process, green and environment-friendly, safe in operation process, and suitable for large-scale production; the tellurium nanowires in the tellurium nanowire ink are good in dispersity and high in solid content; high-precision printing on different substrates can be realized through a silk screen printing process; and the obtained composite thin film has excellent thermoelectric response performance and a high Seebeck coefficient.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nanomaterial preparation, and particularly relates to a preparation method of tellurium nanowires, tellurium nanowire ink and application. BACKGROUND

[0002] As a narrow-bandgap semiconductor, tellurium has excellent thermoelectric response characteristics and has wide application prospects in the fields of electronic industry, new energy technology, flexible wearable devices and the like. Tellurium-based thermoelectric materials have excellent quantum confinement effect, super strong phonon scattering properties, great specific surface area and excellent energy density, so that they become an ideal thermoelectric material.

[0003] At present, tellurium nanowires are widely studied as commonly used tellurium-based thermoelectric materials. For example, patent CN 100509619C discloses a synthesis method of tellurium nanowires, which obtains tellurium nanowires by sealing a polyvinylpyrrolidone and sodium tellurite aqueous solution, hydrazine hydrate and ammonia water in a reaction container for reaction. Literature (Energy, 2017, 125:519-525) reports an in-situ synthesis method of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) functionalized tellurium nanorods, which combines tellurium nanorods with PEDOT:PSS by a vacuum-assisted filtration method to form a PEDOT:PSS / PF-Te composite film, so that the Seebeck coefficient is increased from 15.6 muV / K to 51.6 muV / K. However, the above method is complex, usually needs to add a large amount of organic polymer (such as polyvinylpyrrolidone), uses a large amount of organic solvent in the synthesis process, and the synthesized product needs to be treated (such as acetone washing) to remove the residual organic polymer on the tellurium nanowires, and the use of organic solvent, acetone and waste liquid treatment increases the production cost and the risk of environmental pollution; and the above synthesis method usually uses a dangerous reducing agent (such as hydrazine hydrate which has strong corrosiveness and toxicity), which increases the danger of production operation. In addition, the tellurium nanowires prepared by the existing method have low dispersion concentration and poor dispersibility, and it is difficult to realize high-precision printing on different substrates, and there are still challenges in constructing thermoelectric devices with high resolution and high thermoelectric performance.

[0004] Therefore, it is urgent to develop a new preparation method of tellurium nanowires. SUMMARY

[0005] The present application provides a preparation method of tellurium nanowires, tellurium nanowire ink and application, and aims to solve the technical problems of complex preparation process, serious environmental pollution and low production safety of tellurium nanowires in the prior art, and the technical problems of low solid content, poor dispersibility and low printing resolution of the existing tellurium nanowire ink, and the technical problems of poor thermoelectric response and low Seebeck coefficient of the composite film prepared by the existing tellurium nanowire ink.

[0006] In order to achieve the above object, the following technical scheme is adopted.

[0007] The first aspect of the present application provides a preparation method of tellurium nanowires, comprising:

[0008] S1, dissolving L-ascorbic acid in deionized water to obtain an L-ascorbic acid solution;

[0009] dissolving the hyperbranched polymer containing functional groups in deionized water to obtain a hyperbranched polymer solution;

[0010] S2, adding the hyperbranched polymer solution to the L-ascorbic acid solution and stirring uniformly to obtain a precursor solution;

[0011] S3, adding a tellurium source to the precursor solution for reaction, and collecting a solid-phase product; the solid-phase product is washed and dried to obtain tellurium nanowires.

[0012] Preferably, the functional groups of the hyperbranched polymer containing functional groups include any one of carboxyl, sulfonic acid group, hydroxyl, mercapto, carbonyl, primary amine, secondary amine and tertiary amine.

[0013] Further preferably, the hyperbranched polymer containing functional groups is an amino-terminated hyperbranched polymer, and the chemical structure is shown in formula (1)-(3):

[0014]

[0015]

[0016] Preferably, the tellurium source is sodium tellurite or tellurium dioxide.

[0017] The molar ratio of the tellurium source, the hyperbranched polymer containing functional groups and L-ascorbic acid is 1:(0.1-2):(1-30).

[0018] Preferably, the reaction temperature in S3 is 25-100℃.

[0019] and / or,

[0020] In S3, the washing includes filtration or centrifugation.

[0021] and / or,

[0022] In S3, the drying includes freeze-drying or drying.

[0023] The second aspect of the present application provides the tellurium nanowires prepared by the above preparation method.

[0024] The third aspect of the present application provides a tellurium nanowire ink prepared by the following method:

[0025] The tellurium nanowires are dispersed in a solvent to obtain the tellurium nanowire ink.

[0026] Preferably, the solvent comprises one or more than two of water, methanol, ethanol, n-propanol, isopropanol, n-butanol, ethyl acetate, butyl acetate, isopropyl acetate, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone or dimethyl sulfoxide.

[0027] Preferably, the content of the tellurium nanowires in the tellurium nanowire ink is 0.01-25wt%.

[0028] In a fourth aspect, the present application provides the above tellurium nanowire ink for use in the field of thermoelectric materials, flexible electronics and wearable devices.

[0029] Compared with the prior art, the present application has the following advantages:

[0030] In the present application, the tellurium nanowires are prepared by reducing a tellurium source with a reducing agent under the action of a hyperbranched polymer, which acts as a surface stabilizer, a growth modifier and a dispersant, thereby affecting the growth morphology of the tellurium nanowires and regulating the morphology and size of the tellurium nanowires. The preparation method of the tellurium nanowires of the present application is simple, does not use organic solvents and dangerous reducing agents, is safe in operation, is green and environmentally friendly in production, and is suitable for large-scale production.

[0031] The tellurium nanowire ink of the present application uses a hyperbranched polymer as a dispersant, a surface stabilizer and a rheological modifier without other additives. The hyperbranched polymer adsorbs on the surface of the tellurium nanowires through functional groups (anchoring groups) and induces spatial stability through the interaction of solvated chains with solvents, so that the tellurium nanowires are uniformly dispersed in the solvent; the hyperbranched polymer molecular chain regulates the viscosity and rheological properties of the tellurium nanowire ink through the disentangling effect, so that the tellurium nanowire ink of the present application still has excellent dispersibility and high stability at high solid content, and can be printed on different substrates through a screen printing process with high precision.

[0032] The content of the tellurium nanowires in the tellurium nanowire ink of the present application can reach 200mg / mL, which has high printing resolution and wide applicability; it can be printed into a film on different substrates through a screen printing technology, and the printed thin film has excellent thermoelectric response performance, and the Seebeck coefficient thereof can reach 427.07μV / K. BRIEF DESCRIPTION OF DRAWINGS

[0033] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 SEM image of the tellurium nanowires prepared in Example 1;

[0035] Figure 2 XRD pattern of tellurium nanowires prepared in Example 1;

[0036] Figure 3 A photograph of the tellurium nanowire / deionized water ink with a concentration of 200 mg / mL prepared in Example 5;

[0037] Figure 4 The image shows a flexible tellurium nanowire electrode prepared by screen printing using tellurium nanowire / deionized water ink and paper substrate with a concentration of 200 mg / mL, as shown in Example 5.

[0038] Figure 5 A photograph of the tellurium nanowire / isopropanol ink with a concentration of 200 mg / mL prepared in Example 6;

[0039] Figure 6 The Seebeck coefficient test results are shown for the thin film prepared by screen printing using the 200 mg / mL tellurium nanowire / deionized water ink prepared in Example 5. Detailed Implementation

[0040] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0041] In the following description of this embodiment, the terms "including", "comprising", "having", and "containing" are all open-ended terms, meaning that they include but are not limited to.

[0042] In the following description of this embodiment, the term "and / or" is used to describe the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, B existing alone, and A and B existing simultaneously. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0043] In the following description of the present embodiments, the term "at least one" means one or more and the term "multiple" means two or more. The phrase "at least one of the following (one or more)" or similar expressions refers to any combination of the items, including single (one) or multiple items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can mean a, b, c, a-b (i.e., a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

[0044] The terminology used in the present embodiments is for the purpose of describing particular embodiments only and is not intended to be limiting of the present embodiments. As used in the description of the present embodiments and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0045] Those skilled in the art understand that in the following description of the present embodiments, the order of the serial numbers does not mean the order of execution, and some or all steps can be executed in parallel or in sequence, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the present embodiments.

[0046] Those skilled in the art understand that the numerical ranges in the present embodiments should be understood as each intermediate value between the upper limit and the lower limit of the range. Each smaller range between any stated value or stated range of intermediate values and any other stated value or intermediate value within the stated range is also included in the present application. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0047] Unless otherwise defined, technical / scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of conflict between the content of this specification and any incorporated document, the content of this specification prevails.

[0048] In a first aspect, the present application provides a preparation method of tellurium nanowires, comprising:

[0049] S1, dissolving L-ascorbic acid in deionized water to obtain an L-ascorbic acid solution;

[0050] The hyperbranched polymer containing a functional group is dissolved in deionized water to obtain a hyperbranched polymer solution;

[0051] In the present application, the functional groups of the hyperbranched polymer are polar functional groups, such as any one of carboxyl, sulfonic acid group, hydroxyl, mercapto, carbonyl, primary amine, secondary amine, tertiary amine and the like, preferably primary amine.

[0052] As a preferred solution, the present application preferably uses hyperbranched polymer with terminal amino group. The hyperbranched polymer with terminal amino group includes any one of the following chemical structures:

[0053]

[0054] S2, the hyperbranched polymer solution is added to the L-ascorbic acid solution, stirred uniformly to obtain a precursor solution;

[0055] S3, the tellurium source is added to the precursor solution, and the reaction is carried out at a temperature of 25-100℃ for 4-36h. After the reaction is completed, the solid product is collected. The solid product is washed and dried to obtain tellurium nanowires.

[0056] In the present application, the tellurium source is sodium tellurite or tellurium dioxide. In the present application, L-ascorbic acid and sodium tellurite or tellurium dioxide undergo a reduction reaction, and the hyperbranched polymer acts as a surface stabilizer, a growth modifier and a dispersant, thereby affecting the growth morphology of the tellurium nanowires and regulating the morphology and size of the tellurium nanowires. In the present application, the molar ratio of the tellurium source, the hyperbranched polymer with functional groups and L-ascorbic acid is preferably 1:(0.1-2):(1-30).

[0057] In the present application, deionized water and ethanol are preferably used as the washing solvent, and the purity of the tellurium nanowires is improved by filtration or centrifugal washing. After washing, the tellurium nanowires are obtained by drying or freeze-drying.

[0058] The preparation method of the tellurium nanowires of the present application has a simple process, does not use organic solvents and dangerous reducing agents, is safe in operation, is green and environmentally friendly in production, and is suitable for large-scale production. The tellurium nanowires prepared by the present application have excellent thermoelectric response performance and can be used to prepare tellurium nanowire ink.

[0059] The present application also provides a tellurium nanowire ink, which is prepared by the following method:

[0060] The tellurium nanowires prepared by the present application are dispersed in a solvent and mixed uniformly to obtain the tellurium nanowire ink.

[0061] In the present application, the solvent includes one or a mixture of two or more of water, methanol, ethanol, n-propanol, isopropanol, n-butanol, ethyl acetate, butyl acetate, isopropyl acetate, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone or dimethyl sulfoxide.

[0062] The tellurium nanowire ink prepared in the application is prepared by using a hyperbranched polymer as a dispersant, a surface stabilizer and a rheological modifier without other additives. The tellurium nanowire ink prepared in the application has a tellurium nanowire content of 0.01-25wt%, and a viscosity of 0.01-10000Pa·s; wherein the diameter of the tellurium nanowire is 10-100nm, and the length is 0.5-2.5μm.

[0063] The tellurium nanowire ink prepared in the application is prepared by using a hyperbranched polymer as a dispersant, a surface stabilizer and a rheological modifier without other additives. The tellurium nanowire ink prepared in the application has a tellurium nanowire content of 0.01-25wt%, and a viscosity of 0.01-10000Pa·s; wherein the diameter of the tellurium nanowire is 10-100nm, and the length is 0.5-2.5μm.

[0064] The tellurium nanowire ink prepared in the application is prepared by using a hyperbranched polymer as a dispersant, a surface stabilizer and a rheological modifier without other additives. The tellurium nanowire ink prepared in the application has a tellurium nanowire content of 0.01-25wt%, and a viscosity of 0.01-10000Pa·s; wherein the diameter of the tellurium nanowire is 10-100nm, and the length is 0.5-2.5μm.

[0065] The application is further described below through examples.

[0066] In the examples of the application, the terminal amino hyperbranched polymer is prepared by the method disclosed in the literature ACS Sustain. Chem. Eng. 5, 10258-10265 (2017). The names of the three terminal amino hyperbranched polymers are HPA-4, HPA-8 and HPA-16, and their chemical structures are as shown below:

[0067] HPA-4:

[0068]

[0069] HPA-8:

[0070]

[0071] HPA-16:

[0072]

[0073] Example 1

[0074] The embodiment provides a preparation method of a tellurium nanowire, comprising:

[0075] S1, 4g of L-ascorbic acid was weighed into a round-bottom flask, added into 100 mL of deionized water, and magnetically stirred for 0.5h to obtain an L-ascorbic acid solution;

[0076] 0.55g of amino-terminated hyperbranched polymer (HPA-8) was weighed and dissolved in 60 mL of deionized water to obtain an HPA-8 solution;

[0077] S2, the HPA-8 solution was added to the L-ascorbic acid solution, and magnetically stirred for 10 min to mix uniformly to obtain a precursor solution;

[0078] S3, 0.208g of sodium tellurite was added to the precursor solution, heated to 90℃ for 24h, and cooled to room temperature after the reaction to obtain a tellurium nanowire stock solution;

[0079] The tellurium nanowire stock solution was washed with water and ethanol three times to remove impurities, and the solid-phase product was collected by centrifugation; the solid-phase product was freeze-dried to obtain tellurium nanowires.

[0080] Example 2

[0081] The embodiment provides a preparation method of tellurium nanowires, comprising:

[0082] S1, the difference from example 1 is that the mass of the amino-terminated hyperbranched polymer (HPA-8) is 0.287g, and the rest is the same as example 1;

[0083] S2, the same as example 1;

[0084] S3, the difference from example 1 is that the reaction time is 20h, and the rest is the same as example 1.

[0085] Example 3

[0086] The embodiment provides a preparation method of tellurium nanowires, comprising:

[0087] S1, the difference from example 1 is that the mass of the amino-terminated hyperbranched polymer (HPA-8) is 1.102g, and the rest is the same as example 1;

[0088] S2, the same as example 1;

[0089] S3, the difference from example 1 is that the heating reaction time is 20h, and the rest is the same as example 1.

[0090] Example 4

[0091] The embodiment provides a preparation method of tellurium nanowires, comprising:

[0092] S1, weigh 4 g of L-ascorbic acid into a round-bottom flask, add 100 mL of deionized water, and magnetically stir for 0.5 h to obtain an L-ascorbic acid solution;

[0093] Weigh 0.411 g of amino-terminated hyperbranched polymer (HPA-4) into 60 mL of deionized water to prepare an HPA-4 solution;

[0094] S2, add the HPA-4 solution to the L-ascorbic acid solution, and magnetically stir for 10 min to mix uniformly to obtain a precursor solution;

[0095] S3, add 0.208 g of sodium tellurite to the precursor solution, heat to 90°C, and react for 20 h. After the reaction is completed, cool to room temperature to obtain a tellurium nanowire stock solution. Wash the tellurium nanowire stock solution with water and ethanol three times in sequence to remove impurities, and centrifuge to collect the solid-phase product. Freeze-dry the solid-phase product to obtain tellurium nanowires.

[0096] Example 5

[0097] The embodiment provides a preparation method of a tellurium nanowire ink, comprising:

[0098] Take 200 mg of the tellurium nanowires prepared in Example 1, disperse in 1 mL of deionized water, and stir uniformly to obtain a tellurium nanowire / deionized water ink with a concentration of 200 mg / mL, and a tellurium nanowire content of 16.7 wt%.

[0099] Example 6

[0100] The embodiment provides a preparation method of a tellurium nanowire ink, comprising:

[0101] Take 200 mg of the tellurium nanowires prepared in Example 1, disperse in 1 mL of isopropanol, and stir uniformly to obtain a tellurium nanowire / isopropanol ink with a concentration of 200 mg / mL, and a tellurium nanowire content of 20.3 wt%.

[0102] Example 7

[0103] The embodiment provides a preparation method of a tellurium nanowire ink, comprising:

[0104] Take 200 mg of the tellurium nanowires prepared in Example 2, disperse in 1 mL of deionized water, and stir uniformly to obtain a tellurium nanowire / deionized water ink with a concentration of 200 mg / mL, and a tellurium nanowire content of 16.7 wt%.

[0105] Example 8

[0106] The embodiment provides a preparation method of a tellurium nanowire ink, comprising:

[0107] Take the tellurium nanowire 200 mg prepared in Example 3, disperse in 1 mL deionized water, stir evenly, to obtain a concentration of 200 mg / mL of tellurium nanowire / deionized water ink, and the tellurium nanowire content is 16.7wt%.

[0108] Example 9

[0109] The present embodiment provides a preparation method of a tellurium nanowire ink, comprising:

[0110] Take the tellurium nanowire 200 mg prepared in Example 4, disperse in 1 mL deionized water, stir evenly, to obtain a concentration of 200 mg / mL of tellurium nanowire / deionized water ink, and the tellurium nanowire content is 16.7wt%.

[0111] The tellurium nanowire prepared in Example 1 is subjected to SEM test, and the SEM graph is as shown in Figure 1 From Figure 1 it can be known that the diameter of the tellurium nanowire is 10-100 nm, and the length is 0.5-2.5 μm.

[0112] The tellurium nanowire prepared in Example 1 is subjected to X-ray diffraction test, and the XRD graph is as shown in Figure 2 From Figure 2 it can be known that the graph is consistent with the diffraction graph of tellurium (PDF #36-1452), proving that the prepared material is a tellurium nanowire.

[0113] The concentration of 200 mg / mL of tellurium nanowire / deionized water ink prepared in Example 5 is as shown in Figure 3 From Figure 3 it can be known that the tellurium nanowire is uniformly dispersed in deionized water, the color of the ink is uniform black, and the stable dispersion of the tellurium nanowire in deionized water is realized.

[0114] The concentration of 200 mg / mL of tellurium nanowire / deionized water ink prepared in Example 5 is printed on a paper substrate by a screen printing process, dried at 60°C for 5 min, to obtain a flexible tellurium nanowire electrode, as shown in Figure 4 The line width is 30, 50, 100, 150, 200, and 250 μm.

[0115] The concentration of 200 mg / mL of tellurium nanowire / isopropanol ink prepared in Example 6 is as shown in Figure 5 From Figure 5 it can be known that the tellurium nanowire is uniformly dispersed in isopropanol, the color of the ink is uniform black, and the stable dispersion of high-concentration tellurium nanowire in isopropanol is realized.

[0116] The tellurium nanowire ink prepared in Example 5 is subjected to thermoelectric test after being printed into a film and dried by a screen printing process, and the test results are as shown inFigure 6 The Te nanowire inks prepared in Examples 7-9 were printed into films by a screen printing process, and the films were dried and then subjected to thermoelectric testing, and the results of Seebeck coefficient testing are shown in Table 1. From Table 1 and Figure 6 It can be seen that the films printed by the screen printing process from the Te nanowire inks prepared in Example 5, Examples 7-9 have Seebeck coefficients of 413.32 μV / K, 404.42 μV / K, 427.07 μV / K and 417.72 μV / K, respectively.

[0117] Table 1 Seebeck coefficient test values for Te nanowire films

[0118]

[0119] The above shows that the Te nanowire inks prepared in the present application have excellent dispersibility and high stability at high solid content, and can be printed on different substrates with high precision by a screen printing process; the films prepared by printing have high Seebeck coefficients.

[0120] Although the present application has been described in detail in the foregoing description with general principles and specific embodiments thereof, it should be further appreciated that modifications and improvements can be made to the application, which will be apparent to those skilled in the art. Therefore, such modifications and improvements are intended to be included within the scope of the present application.

Claims

1. A method for producing a tellurium nanowire, characterized by, The preparation method comprises the following steps: S1, dissolving L-ascorbic acid in deionized water to obtain an L-ascorbic acid solution; dissolving the hyperbranched polymer containing functional groups in deionized water to obtain a hyperbranched polymer solution; The hyperbranched polymer containing functional groups is an amino-terminated hyperbranched polymer, and its chemical structure is shown in formula (1)-(3): (1) (2) (3)； S2, adding the hyperbranched polymer solution into the L-ascorbic acid solution and stirring uniformly to obtain a precursor solution; S3, adding a tellurium source into the precursor solution to perform a reaction, and collecting a solid-phase product; The solid-phase product is washed and dried to obtain tellurium nanowires.

2. The production method according to claim 1, characterized by, The tellurium source is sodium tellurite or tellurium dioxide; The molar ratio of the tellurium source, the hyperbranched polymer containing functional groups, and L-ascorbic acid is 1:(0.1-2):(1-30).

3. The preparation method according to claim 1, characterized in that, S3 in the reaction temperature is 25~100 o C; And / or, In S3, the washing comprises filtering or centrifuging; And / or, In S3, the drying comprises freeze-drying or oven-drying.

4. The tellurium nanowires prepared by the preparation method in any one of claims 1-3.

5. A tellurium nanowire ink, characterized by, The preparation method comprises the following steps: The tellurium nanowires in claim 4 are dispersed in a solvent and mixed uniformly to obtain the tellurium nanowires.

6. The tellurium nanowire ink of claim 5, wherein, The solvent comprises one or more than two mixtures of water, methanol, ethanol, n-propanol, isopropanol, n-butanol, ethyl acetate, butyl acetate, isopropyl acetate, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, or dimethyl sulfoxide.

7. The tellurium nanowire ink of claim 5, wherein the tellurium nanowire ink has a viscosity of 1 to 1000 centipoise at 25°C. In the tellurium nanowire ink, the content of the tellurium nanowires is 0.01-25wt%.

8. The application of the tellurium nanowire ink in claim 5 in the field of thermoelectric materials, flexible electronics, and wearable devices.

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