Ag2Se composite film and preparation method and application thereof

Abstract

The invention provides an Ag2Se composite film and a preparation method and application thereof, and belongs to the technical field of thermoelectric films. The invention provides an Ag2Se composite film. The Ag2Se composite film comprises silver selenide and graphene oxide doped in the silver selenide. According to the invention, trace doping is carried out on Ag2Se by using the characteristic of high mobility of graphene, which is beneficial for improving the mobility of carriers in Ag2Se, thereby further improving the conductivity and thermoelectric performance of Ag2Se. The preparation method provided by the invention has universality. In addition, the Ag2Se composite thermoelectric thin film provided by the invention has good thermoelectric performance and has a wide application prospect in the field of waste heat recovery and utilization.

Description

Technical Field

[0001] The invention belongs to the technical field of thermoelectric thin films, and in particular relates to an Ag2Se composite thin film and a preparation method and application thereof. Background Art

[0002] Thermoelectric materials can realize direct conversion of heat and electricity, thus recycling low-grade waste heat, and are a kind of green and environmentally friendly energy material. For thermoelectric materials, the power factor (PF = S 2 The performance of thermoelectric materials is evaluated by the power factor (σ, where S is the Seebeck coefficient and σ is the electrical conductivity). The larger the S, the larger the σ, the larger the power factor, and the better the material performance. The progress of wearable electronic devices has promoted the development of flexible thermoelectric materials. At present, flexible thermoelectric materials are mainly concentrated in conductive polymers, but their thermoelectric performance is relatively low (~5μW·cm -1 K -2 ). Therefore, it is of great significance to explore thermoelectric materials with good flexibility and excellent thermoelectric performance.

[0003] Ag2Se has high electrical conductivity and Seebeck coefficient at room temperature and is an n-type thermoelectric material with excellent performance. Therefore, further improving its thermoelectric performance is of great research value. Summary of the invention

[0004] In view of this, an object of the present invention is to provide an Ag2Se composite film and a preparation method and application thereof. The Ag2Se composite film provided by the present invention has good flexibility and has higher thermoelectric performance than a single Ag2Se film.

[0005] In order to achieve the above object, the present invention provides the following scheme:

[0006] The invention provides an Ag2Se composite film, comprising silver selenide and graphene oxide doped in the silver selenide; the mass ratio of the graphene oxide to the silver selenide is (0.0001-0.001):1.

[0007] The present invention provides a method for preparing the Ag2Se composite thin film described in the above scheme, comprising the following steps:

[0008] A selenium source, a soluble silver salt, graphene oxide and an alcohol solvent are mixed to carry out an oxidation-reduction reaction, wherein the selenium source and the soluble silver salt form silver selenide, the graphene oxide is doped into the silver selenide, and the obtained reaction liquid is filtered to obtain a silver selenide-graphene oxide filter membrane; the ratio of the mass of the graphene oxide to the theoretical mass of the silver selenide is (0.0001-0.001):1;

[0009] The silver selenide-graphene oxide filter membrane is hot-pressed to obtain the Ag2Se composite film.

[0010] Preferably, the molar ratio of Se in the selenium source to Ag in the soluble silver salt is 1:(2-4).

[0011] Preferably, the selenium source comprises selenium nanowires; and the soluble silver salt comprises silver nitrate or silver fluoride.

[0012] Preferably, the concentration of the selenium source in the alcohol solvent is 0.0002-0.002 g / mL.

[0013] Preferably, the temperature of the redox reaction is 30-100° C. and the time is 2-3 hours.

[0014] Preferably, the redox reaction is carried out under stirring; the stirring speed is 500-2000 rad / min.

[0015] Preferably, the hot pressing pressure is 0.8-1.5 MPa.

[0016] Preferably, the hot pressing temperature is 170-250° C. and the time is 30-90 min.

[0017] The present invention provides the use of the Ag2Se composite film described in the above scheme or the Ag2Se composite film prepared by the preparation method described in the above scheme in thermoelectric materials.

[0018] The present invention provides an Ag2Se composite film, silver selenide and graphene oxide doped in the silver selenide; the mass ratio of the graphene oxide to the silver selenide is (0.0001-0.001):1. In the present invention, hydrogen bonds and van der Waals forces exist between the graphene oxide and Ag2Se, and the interface bonding force between the two is good. The present invention utilizes the high mobility characteristics of graphene to micro-dope Ag2Se, which helps to improve the mobility of carriers in Ag2Se, and has higher electrical conductivity and thermoelectric performance than a single Ag2Se film.

[0019] The preparation method provided by the present invention has universal applicability. In addition, the Ag2Se composite thermoelectric film provided by the present invention has good thermoelectric performance and has broad application prospects in the field of waste heat recovery and utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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 will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0021] Figure 1is the SEM image of the Ag2Se / GO film of Example 1;

[0022] Figure 2 is the XRD pattern of the Ag2Se / GO film of Example 2;

[0023] Figure 3 This is the thermoelectric performance diagram of the Ag2Se / GO film of Example 3. DETAILED DESCRIPTION

[0024] The invention provides an Ag2Se composite film, comprising silver selenide and graphene oxide doped in the silver selenide.

[0025] In the present invention, the mass ratio of graphene oxide to silver selenide is (0.0001-0.001):1. In an embodiment of the present invention, it can be 0.0002:1, 0.0004:1, 0.0006:1, 0.0008:1 or 0.001:1.

[0026] In the present invention, hydrogen bonds and van der Waals forces exist between the graphene oxide and Ag2Se, and the interface bonding between the two is good. The present invention utilizes the high mobility characteristics of graphene to micro-dope Ag2Se, which helps to improve the mobility of carriers in Ag2Se, and has higher electrical conductivity and thermoelectric performance than a single Ag2Se film.

[0027] The present invention provides a method for preparing the Ag2Se composite thin film described in the above scheme, comprising the following steps:

[0028] A selenium source, a soluble silver salt, graphene oxide and an alcohol solvent are mixed to carry out an oxidation-reduction reaction, wherein the selenium source and the soluble silver salt form silver selenide, the graphene oxide is doped into the silver selenide, and the obtained reaction liquid is filtered to obtain a silver selenide-graphene oxide filter membrane; the ratio of the mass of the graphene oxide to the theoretical mass of the silver selenide is (0.0001-0.001):1;

[0029] The silver selenide-graphene oxide filter membrane is hot-pressed to obtain the Ag2Se composite film.

[0030] Unless otherwise specified, the materials and equipment used in the present invention are commercially available products.

[0031] The invention mixes a selenium source, a soluble silver salt, graphene oxide and an alcohol solvent to carry out an oxidation-reduction reaction, wherein the selenium source and the soluble silver salt form silver selenide, the graphene oxide is doped into the silver selenide, and the obtained reaction liquid is filtered to obtain a silver selenide-graphene oxide filter membrane.

[0032] In the present invention, the selenium source preferably includes selenium nanowires; the soluble silver salt preferably includes silver nitrate or silver fluoride; the molar ratio of Se in the selenium source to Ag in the soluble silver salt is preferably 1:(2-4), and in the embodiment of the present invention, it can be specifically 1:2, 1:3 or 1:4. In the present invention, the alcohol solvent preferably includes ethylene glycol.

[0033] In the present invention, the ratio of the mass of graphene oxide to the theoretical mass of silver selenide is (0.0001-0.001):1. In an embodiment of the present invention, it can be 0.0002:1, 0.0004:1, 0.0006:1, 0.0008:1 or 0.001:1.

[0034] In the present invention, the concentration of the selenium source in the alcohol solvent is preferably 0.0002-0.002 g / mL. In embodiments of the present invention, it can be 0.0002 g / mL, 0.0005 g / mL, 0.0008 g / mL, 0.001 g / mL, 0.0015 g / mL, 0.0018 g / mL or 0.002 g / mL.

[0035] In the present invention, the temperature of the redox reaction is preferably 30-100°C, and in the embodiment of the present invention, it can be 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C or 100°C; the time of the redox reaction is preferably 2-3h, and in the embodiment of the present invention, it can be 2h, 2.5h or 3h. In the present invention, the redox reaction is preferably carried out under stirring; the stirring speed is preferably 500-2000rad / min, and in the embodiment of the present invention, it can be 500rad / min, 600rad / min, 700rad / min, 800rad / min, 1000rad / min, 1200rad / min, 1400rad / min, 1600rad / min, 1800rad / min or 2000rad / min.

[0036] Before the suction filtration, the present invention also preferably includes washing; the washing is preferably performed by centrifugation.

[0037] In the present invention, the washing is preferably performed with ethanol for 2 to 3 times. The present invention can remove the alcohol solvent and some unreacted substances by washing.

[0038] The silver selenide-graphene oxide film obtained by suction filtration in the present invention is relatively loose.

[0039] After obtaining the silver selenide-graphene oxide filter membrane, the present invention hot presses the silver selenide-graphene oxide filter membrane to obtain the Ag2Se composite film.

[0040] In the present invention, the hot pressing pressure is preferably 0.8-1.5 MPa. In the embodiments of the present invention, it can be 0.8 MPa, 1.0 MPa, 1.2 MPa or 1.5 MPa.

[0041] In the present invention, the temperature of the hot pressing is preferably 170-250° C., and in the embodiments of the present invention, it can be 170° C., 200° C., 220° C., 240° C. or 250° C. In the present invention, the time of the hot pressing is preferably 30-90 min., and in the embodiments of the present invention, it can be 30 min., 40 min., 50 min., 60 min., 70 min., 80 min. or 90 min. The present invention obtains a densified film by hot pressing.

[0042] The preparation method provided by the present invention has universal applicability. In addition, the Ag2Se composite thermoelectric film provided by the present invention has good thermoelectric performance and has broad application prospects in the field of waste heat recovery and utilization.

[0043] The present invention provides the use of the Ag2Se composite film described in the above scheme or the Ag2Se composite film prepared by the preparation method described in the above scheme in thermoelectric materials.

[0044] In order to further illustrate the present invention, an Ag2Se composite film provided by the present invention and its preparation method and application are described in detail below in combination with the accompanying drawings and embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0045] Example 1

[0046] 0.038 g of selenium nanowires, 0.1635 g of AgNO3, 0.00007 g of graphene oxide (GO) and 50 mL of ethylene glycol were mixed and subjected to a redox reaction at 60 ° C for 2 h. After the reaction, the solid product was collected by centrifugation, washed three times with anhydrous ethanol, and filtered to obtain a silver selenide-graphene oxide filter membrane;

[0047] The above filter membrane was hot-pressed at 1 MPa and 200°C for 30 min to obtain a Ag2Se composite thin film, which was recorded as Ag2Se / GO thin film.

[0048] Example 2

[0049] The preparation steps are the same as those in Example 1, except that the amount of GO added is 0.0001 g.

[0050] Example 3

[0051] The preparation steps are the same as those in Example 1, except that the amount of GO added is 0.0001 g and the temperature of the redox reaction is 70°C.

[0052] Comparative Example 1

[0053] The steps are the same as those in Example 3, except that GO is not added to obtain an Ag2Se thin film.

[0054] Performance Testing

[0055] Figure 1 is the SEM image of the Ag2Se / GO film of Example 1. Figure 1 It can be seen that the surface of the Ag2Se / GO film of the present invention is smooth and flat, and the grain boundary is relatively large. The SEM results of other embodiments are similar to those of this embodiment.

[0056] Figure 2 is the XRD pattern of Ag2Se / GO of Example 2, Figure 2 It can be seen that the Ag2Se synthesized by the present invention is consistent with the standard PDF (Ag2Se PDF#24-1041), indicating that the preparation method of the present invention can successfully prepare Ag2Se with good crystallinity. The SEM results of other examples are similar to those of this example.

[0057] Figure 3 The thermoelectric performance diagram of Ag2Se / GO of Example 3 is shown in FIG. Figure 3 It can be seen that the Ag2Se / GO film synthesized in the present invention has high conductivity and excellent thermoelectric performance. The SEM results of other embodiments are similar to those of this embodiment.

[0058] Table 1 Statistics of thermoelectric properties of thin films obtained in Examples 1 to 3 and Comparative Example 1

[0059]

[0060] As can be seen from Table 1, the Ag2Se / GO films obtained in Examples 1 to 3 of the present invention have higher electrical conductivity and room temperature power factor than a single Ag2Se film, indicating that the prepared Ag2Se / GO films have more excellent thermoelectric properties.

[0061] In summary, the Ag2Se composite film prepared by the preparation method of the present invention has good crystallinity, smooth surface morphology, and excellent thermoelectric performance.

[0062] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. An Ag2Se composite film, characterized in that: It comprises silver selenide and graphene oxide doped in the silver selenide; the mass ratio of the graphene oxide to the silver selenide is (0.0001-0.001):

1.

2. The method for preparing the Ag2Se composite thin film according to claim 1, characterized in that: The following steps are involved: A selenium source, a soluble silver salt, graphene oxide and an alcohol solvent are mixed to carry out an oxidation-reduction reaction, wherein the selenium source and the soluble silver salt form silver selenide, the graphene oxide is doped into the silver selenide, and the obtained reaction liquid is filtered to obtain a silver selenide-graphene oxide filter membrane; the ratio of the mass of the graphene oxide to the theoretical mass of the silver selenide is (0.0001-0.001):1; The silver selenide-graphene oxide filter membrane is hot-pressed to obtain the Ag2Se composite film.

3. The preparation method according to claim 2, characterized in that: The molar ratio of Se in the selenium source to Ag in the soluble silver salt is 1:(2-4).

4. The preparation method according to claim 2 or 3, characterized in that: The selenium source includes selenium nanowires; and the soluble silver salt includes silver nitrate or silver fluoride.

5. The preparation method according to claim 2 or 3, characterized in that: The concentration of the selenium source in the alcohol solvent is 0.0002-0.002 g / mL.

6. The preparation method according to claim 2 or 3, characterized in that: The temperature of the oxidation-reduction reaction is 30-100° C. and the time is 2-3 hours.

7. The preparation method according to claim 6, characterized in that: The redox reaction is carried out under stirring conditions; the stirring speed is 500-2000 rad / min.

8. The preparation method according to claim 2, characterized in that: The hot pressing pressure is 0.8-1.5 MPa.

9. The preparation method according to claim 2 or 8, characterized in that: The temperature of the hot pressing is 170-250° C., and the time is 30-90 minutes.

10. Use of the Ag2Se composite film according to claim 1 or the Ag2Se composite film prepared by any one of the preparation methods of claims 2 to 9 in thermoelectric materials.

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