Silver-sulfur-based plastic inorganic semiconductor and method for achieving super-high plastic deformation of silver-sulfur-based plastic inorganic semiconductor

Abstract

This invention discloses a method for preparing a silver-sulfur-based plastic inorganic semiconductor with ultra-high plastic deformation, comprising: cold working a silver-sulfur-based material; annealing the cold-worked silver-sulfur-based material under an inert gas atmosphere or vacuum environment; repeating the above steps to obtain a silver-sulfur-based plastic inorganic semiconductor material with ultra-high deformation; wherein the silver-sulfur-based material is Ag. 2‑x Cu x S 1‑y M y Where M is Se and / or Te, x = 0–0.5, y = 0.3–0.8. This invention also discloses a silver-sulfur-based plastic inorganic semiconductor prepared using this method, which exhibits extremely high plastic deformation.

Description

Technical Field

[0001] This invention relates to plastic inorganic semiconductor materials, specifically to a silver-sulfur-based plastic inorganic semiconductor and a method for achieving ultra-high plastic deformation of the silver-sulfur-based plastic inorganic semiconductor. Background Technology

[0002] Semiconductors, due to their unique physical properties, are widely researched and applied in communications, the Internet of Things, and health monitoring devices. However, traditional inorganic semiconductors typically exhibit brittle fracture under external forces, which greatly limits their processing methods and application scenarios.

[0003] In recent years, silver-sulfur-based semiconductors have been reported to possess excellent plastic deformation capabilities, with compressive strain exceeding 50% (Xun Shi et al.) and tensile strain exceeding 12% (Shiyang He et al.). Furthermore, compared to traditional organic semiconductors, silver-sulfur-based inorganic semiconductors exhibit high electrical transport properties, with mobilities ranging from 100 to 1000 cm⁻¹. 2 / (V·s), therefore it has great application potential in the field of flexible electronics.

[0004] Patent application CN115096935A discloses a silver-based chalcogenide metal-insulator phase-change flexible semiconductor thermistor and its application technology. This patent application uses silver-based chalcogenides as the temperature-sensitive material, designs its thermistor coefficient, Seebeck coefficient, and metal-insulator phase-change characteristics through material composition, and fabricates it into a flexible self-supporting film or low-dimensional filament material through precision machining for further fabrication of discrete or array-type devices. By combining the negative resistance-temperature coefficient thermistor characteristics of silver-based chalcogenides, the metal-insulator phase change, and the Seebeck coefficient, it achieves applications in temperature sensing, thermal switching, and high-precision thermal disturbance detection. The provided technology has considerable application value in intelligent temperature sensing, infrared detection, thermal disturbance detection, thermal switching, and surge current suppression, and can achieve device flexibility.

[0005] However, compared to traditional metallic materials, the plastic deformation capability of the silver-sulfur-based semiconductors disclosed in the aforementioned patent application is still not outstanding, and the single plastic deformation is very limited. When the plastic deformation exceeds a certain amount, obvious cracks will appear in the silver-sulfur-based semiconductors, making it difficult to obtain silver-sulfur-based semiconductors of various shapes and specific shapes using traditional plastic processing methods.

[0006] Currently, the processing methods for silver-sulfur-based inorganic semiconductors are still limited to cutting, which not only leads to serious material loss and limited processing accuracy, but also makes it difficult to obtain complex shapes, and the plasticity of silver-sulfur-based semiconductors has not been fully utilized.

[0007] With the rapid development of flexible electronics and the Internet of Things, there is an urgent need to obtain semiconductor products that meet specific application scenarios and specific shapes and sizes in a fast and efficient manner. Therefore, it is particularly critical and urgent to develop a method that can achieve the ultra-high plastic deformation of current silver-sulfur-based plastic inorganic semiconductors. Summary of the Invention

[0008] This invention provides a method for achieving ultra-high plastic deformation in silver-sulfur-based plastic inorganic semiconductors, which can be used to prepare silver-sulfur-based plastic inorganic semiconductor materials with ultra-high plastic deformation.

[0009] This invention provides a method for preparing silver-sulfur-based plastic inorganic semiconductors with ultra-high plastic deformation, comprising:

[0010] (1) Cold working of silver-sulfur-based materials;

[0011] (2) Anneal the cold-processed silver-sulfur-based material in an inert gas atmosphere or vacuum environment;

[0012] (3) Repeat (1)-(2) to achieve ultra-high deformation of silver-sulfur-based plastic inorganic semiconductor material;

[0013] The silver-sulfur-based material is Ag. 2-x Cu x S 1-y M y Where M is Se and / or Te, x = 0-0.5, y = 0.2-0.7.

[0014] This invention introduces appropriate amounts of Se and / or Te elements with large radii, enabling silver-sulfur-based materials to become amorphous after cold working with a large deformation rate. At the same time, by controlling the ratio of Ag and Cu, the generation of pores is avoided, which would affect the plasticity of the silver-sulfur-based materials after annealing. This allows for better restoration of the plasticity of the silver-sulfur-based materials, preparing them for the next cold working. Through multiple iterations, the ultra-high deformation amount required by this invention is obtained.

[0015] Furthermore, the annealing temperature in step (2) is above the phase transformation temperature but below 750°C, and the annealing time is at least 5 minutes. The phase transformation temperature is the temperature at which the silver-sulfur-based material transforms from an amorphous state to a crystalline state, and is obtained through DSC testing. This invention controls the annealing temperature above the phase transformation temperature, enabling the silver-sulfur-based material to transform from an amorphous state to a crystalline state, thereby better restoring the plastic properties of the silver-sulfur-based material. Furthermore, by controlling the annealing time, sufficient time is provided for the phase transformation to obtain a crystalline structure with good plasticity.

[0016] Furthermore, the annealing temperature in step (2) is 300-700℃. By providing a suitable annealing temperature, this invention transforms the amorphous structure obtained after cold working into a cubic crystalline phase, thereby restoring the plasticity of the silver-sulfur-based material and minimizing the transformation into a monoclinic crystalline phase with poor plasticity.

[0017] Furthermore, the annealing temperature in step (2) is 350-500℃, and the annealing time is 5-120 min. By further controlling the annealing temperature and annealing time, this invention can ensure the formation of a silver-sulfur-based material with good plasticity, while also avoiding the precipitation and volatilization of Ag, Cu, and S materials with low solid solubility, which would affect the performance of the semiconductor material.

[0018] Furthermore, in step 1, the stretching rate is below 50%, the roll deformation rate is below 200%, or the drawing diameter reduction is below 50%. By controlling the deformation rate, burrs or even direct breakage of the silver-sulfur-based material at the edges after a single processing step are avoided.

[0019] Furthermore, cooling methods after annealing include air cooling, water cooling, and furnace cooling.

[0020] This invention controls the cooling method to keep the cooling rate within a reasonable range, thereby reducing the formation of a brittle second phase in the silver-sulfur-based material during the phase transformation process, thus giving the silver-sulfur-based material better plasticity.

[0021] Further preferred cooling methods are air cooling and water cooling. Compared with other cooling methods, air cooling and water cooling produce the fewest second phases in silver-sulfur-based materials and avoid the formation of monoclinic crystal phases with poor plasticity, thus resulting in the best plasticity.

[0022] Furthermore, the pressure of the inert gas is 0-100 MPa to control the volatilization of S / Te elements.

[0023] Furthermore, the cold working in step (2) is cold rolling, cold forging, cold drawing, cold heading, or cold bending.

[0024] On the other hand, the present invention also provides a method for preparing silver-sulfur-based plastic inorganic semiconductors by means of the aforementioned method for achieving ultra-high plastic deformation.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] This invention enables silver-sulfur-based materials to undergo an amorphous transformation after cold working by providing appropriate amounts of Se and / or Te elements. Then, an annealing process is used to induce a crystalline phase transformation in the amorphous silver-sulfur-based materials, thereby restoring the plasticity of the silver-sulfur-based materials. At the same time, the amounts of Se and / or Te elements and Cu elements are controlled to avoid affecting the plasticity properties of the annealed silver-sulfur-based materials. Since plasticity recovery is performed after each cold working, the silver-sulfur-based materials will not crack or develop burrs during multiple cold working processes. This achieves the goal of obtaining silver-sulfur-based plastic inorganic semiconductor materials with ultra-high deformation capacity. Attached Figure Description

[0027] Figure 1 A schematic diagram of the rolling operation provided in Example 1, and a photograph of the sample fractured after a single rolling deformation.

[0028] Figure 2 Images of silver-sulfur-based inorganic semiconductors prepared under different iteration numbers as provided in Example 1, and images of silver-sulfur-based inorganic semiconductors prepared under a single large-volume rolling process as provided in Comparative Example 1.

[0029] Figure 3 This is a microstructure diagram of the silver-sulfur-based inorganic semiconductor prepared in Example 1.

[0030] Figure 4 A comparison chart showing the amount of plastic deformation obtained by a single stretching test in Comparative Example 2 and by the iterative stretching-annealing method in Example 2.

[0031] Figure 5 This is a schematic diagram of the pull-out operation in Example 3, and a photograph of the semiconductor line obtained by the iterative pull-annealing method.

[0032] Figure 6 The image shows an irregular semiconductor surface obtained by the iterative deformation-annealing method in Example 4.

[0033] Figure 7 The XRD pattern and microstructure of the silver-sulfur-based inorganic semiconductor prepared in Example 10 are shown.

[0034] Figure 8 The XRD pattern and optical photograph of the silver-sulfur-based inorganic semiconductor prepared in Example 11 are shown.

[0035] Figure 9 An optical photograph of the silver-sulfur-based inorganic semiconductor prepared in Comparative Example 3.

[0036] Figure 10 The XRD pattern and microstructure of the silver-sulfur-based inorganic semiconductor prepared in Comparative Example 4 are shown.

[0037] Figure 11This is a photograph of the morphology of the silver-sulfur-based inorganic semiconductor prepared in Comparative Example 5 after rolling.

[0038] Figure 12 The XRD pattern, microstructure, and compressive stress-strain curve of the silver-sulfur-based inorganic semiconductor prepared in Comparative Example 6 are shown. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the embodiments.

[0040] Example 1

[0041] Rolling can induce continuous plastic deformation in materials; a schematic diagram is shown below. Figure 1 The original size of Ag2Te was 2mm × 6mm × 10mm. 0.6 S 0.4 Semiconductor samples were rolled at room temperature using a rolling mill (Hefei Kejing, MSK-HRP-04UL).

[0042] When Ag2Te 0.6 S 0.4 The rolling deformation rate of the semiconductor sample was 141%, that is, the rolling was stopped after the sample was reduced from 2.05 mm to 0.85 mm. The sample was then transferred to a quartz tube, sealed in an argon atmosphere, placed in a muffle furnace and heated to 400°C for annealing for 20 minutes. It was then cooled to room temperature in air at a cooling rate of about 50 K / min. The rolling-annealing process was repeated four times. Figure 2 This demonstrates the dimensional changes and final state of the samples after each roll-annealing process. Ag2Te 0.6 S 0.4 The semiconductor sample achieved a final thickness of 0.02 mm, a plastic elongation of 10150%, and smooth edges without cracks. Its plastic deformation was significantly higher than that of samples subjected to a single rolling process. Figure 2 As shown in (a). The final Ag2Te 0.6 S 0.4 The crystal phase structure of semiconductor samples, such as Figure 3 As shown in (a) and (b), the EDS results indicate that the compositions of Ag, Te, and S are basically in the nominal proportions, proving that the volatilization of the metal elements and S is relatively low. Figure 3 As shown in (c) and (d), the synthesized silver-sulfur-based inorganic semiconductor is a cubic crystalline phase, but the diffraction peaks disappear after cold processing, indicating an amorphous transformation.

[0043] Comparative Example 1

[0044] Rolling can induce continuous plastic deformation in materials; a schematic diagram is shown below. Figure 1 The original size of Ag2Te was 2mm × 6mm × 10mm. 0.6 S 0.4Semiconductor samples were subjected to room temperature rolling using a rolling mill (Hefei Kejing, MSK-HRP-04UL). Semiconductor samples deformed in a single rolling pass fractured after the rolling deformation rate reached 1100%, and dense cracks appeared at the sample edges, such as... Figure 2 As shown in (b).

[0045] Example 2

[0046] For Ag2Te 0.6 S 0.4 Semiconductor undergoes room temperature biaxial stretching. Deformation region dimensions: thickness 1.2mm, width 4mm, length 8mm.

[0047] When Ag2Te 0.6 S 0.4 The tensile deformation rate of the semiconductor deformation region reached 30%, that is, it was stretched from 8 mm to 11 mm and then the stretching was stopped. The sample was transferred to a quartz tube, sealed in an argon atmosphere, placed in a muffle furnace and heated to 360°C for annealing for 5 minutes, and then cooled to room temperature in air. After three iterations of stretching-annealing, the tensile deformation rate was close to 100% and the fracture occurred. Its plastic deformation was twice the elongation of the sample after a single stretching.

[0048] Comparative Example 2

[0049] For Ag2Te 0.6 S 0.4 Semiconductors undergo room-temperature biaxial stretching. Deformation region dimensions (within...) Figure 4 (Circled in the image): Thickness 1.2mm, width 4mm, length 8mm. Tensile testing was performed using a Shanghai Jujing JVJ-20S universal testing machine. After a single tensile deformation, the sample fractured at a tensile deformation rate close to 50%. Figure 4 As shown in (a).

[0050] Example 3

[0051] Ag2Te with a diameter of 2.6 mm and a length of 20 mm 0.6 S 0.4 Semiconductor samples are drawn at room temperature using a wire drawing plate. A schematic diagram of the drawing process is shown below. Figure 5 As shown in (a). When the diameter was reduced by 20%, from 2.6 mm to 2.0 mm, the sample was transferred to a quartz tube, sealed under an argon atmosphere, and annealed in a muffle furnace at 400 °C for 10 minutes, followed by cooling to room temperature in air. After three iterations of drawing-annealing, the sample diameter reached 0.45 mm, and the obtained semiconductor wire still exhibited good plasticity and bending ability, such as... Figure 5 As shown in (b) and (c).

[0052] Example 4

[0053] The original size of Ag2Te was 4mm×6mm×9mm. 0.6 S 0.4 Semiconductor samples were rolled to obtain a 0.9 mm thick sheet. The sheet was transferred to a quartz tube, sealed under an argon atmosphere, and annealed in a muffle furnace at 400°C for 30 minutes, followed by air cooling to room temperature. The sheet was then forged into a school emblem pattern using cold forging and dies, such as... Figure 6 As shown.

[0054] Example 5

[0055] The difference compared to Example 1 is that the silver-sulfur-based material is Ag. 1.6 Cu 0.4 S 0.4 Te 0.6 The deformation rate of a single roll is 49%.

[0056] Example 6

[0057] The difference compared to Example 1 is that the silver-sulfur-based material is Ag₂S. 0.5 Se 0.5 The deformation rate of a single roll is 83%, and after iterative annealing, the final deformation reaches 5650%.

[0058] Comparative Example 3

[0059] The difference compared to Example 5 is that the silver-sulfur-based material is Ag. 1.2 Cu 0.8 S 0.4 Te 0.6 ,like Figure 9 As shown, the prepared material has voids and exhibits brittle fracture characteristics, lacking the ability to undergo plastic deformation.

[0060] Example 7

[0061] The difference compared to Example 1 is that the silver-sulfur-based material is Ag₂S. 0.6 Te 0.4 The single-pass roll deformation rate was 140%. After iterative annealing, the final roll deformation rate reached 6767%.

[0062] Example 8

[0063] The difference compared to Example 1 is that the silver-sulfur-based material is Ag₂S. 0.8 Te 0.2 The single-pass roll deformation rate was 153%. After iterative annealing, the final roll deformation rate reached 7067%.

[0064] Example 9

[0065] Compared to Example 1, the cooling method was water cooling at a rate of approximately 200 K / min, with a single roll deformation rate of 150%. After iterative annealing, the final roll deformation rate reached 6800%.

[0066] Example 10

[0067] Compared to Example 1, the difference is that the cooling method is furnace cooling, the cooling rate before 250°C is approximately 6 K / min, and the single roll deformation rate is 14%. Figure 7 (a) and Figure 7 As shown in (b), a monoclinic structure is formed at a lower cooling rate, and a certain amount of brittle second phase is generated in the microstructure.

[0068] Example 11

[0069] Compared to Example 1, the protective gas pressure was 0 MPa, the annealing temperature was 700°C, and the annealing time was 120 min. Figure 8 (a) and Figure 8 As shown in (b), a small amount of metallic Ag was found to be precipitated on the sample surface in XRD and optical photographs. This was due to the high annealing temperature, long annealing time, and lack of protective gas pressure, which led to the volatilization of a small amount of S and Te.

[0070] Comparative Example 4

[0071] Compared to Example 1, the difference is that the cooling method is slow cooling, which is achieved by program-controlled furnace cooling rate, controlled at 0.4 K / min. For example... Figure 10 (a) and Figure 10 (b) XRD and SEM characterization revealed a large number of brittle second-phase structures in the sample, which led to microcracks and made cold working impossible.

[0072] Comparative Example 5

[0073] Unlike Example 1, the silver-sulfur-based material is Ag₂S. 0.2 Te 0.8 The deformation rate of a single cold working is 23%, such as Figure 11 As shown, the silver-sulfur-based material produced cracks after a single cold working.

[0074] Comparative Example 6

[0075] Unlike Example 1, the annealing temperature was 250°C, such as Figure 12 As shown, the sample's phase structure transforms into a monoclinic structure, resulting in brittle fracture at room temperature. Cold working methods such as rolling are not feasible. Figure 12 The secondary electrons and backscattering show that the sample after low-temperature annealing developed a large number of microcracks and underwent brittle fracture after polishing.

Claims

1. A method of achieving a silver-sulfur-based plastic inorganic semiconductor super-high plasticity deformation amount, characterized by, The method comprises: (1) cold working silver-sulfur-based material; (2) annealing the cold worked silver-sulfur-based material in an inert gas atmosphere or vacuum environment; (3) repeating (1)-(2) to achieve super high deformation of silver-sulfur-based plastic inorganic semiconductor material. The silver sulfur-based material is Ag 2-x Cu x S 1-y M y wherein M is Se and / or Te, x = 0-0.5, y = 0.2-0.7; The annealing temperature of step (2) is 350-500℃, and the annealing time is 5-120min.

2. The method of achieving a silver-sulfur-based plastic inorganic semiconductor super-high plasticity deformation amount according to claim 1, characterized by, The tensile rate of step 1 is below 50%, the rolling deformation rate is below 200%, or the diameter reduction is below 50%.

3. The method of achieving a super-high plasticity deformation amount of a silver-sulfur-based plastic inorganic semiconductor according to claim 1, characterized by, The cooling method after annealing includes air cooling, water cooling and furnace cooling.

4. The method of achieving a silver-sulfur-based plastic inorganic semiconductor super-high plasticity deformation amount according to claim 3, characterized by, The cooling method after annealing is air cooling and water cooling.

5. A silver-sulfur-based plastic inorganic semiconductor prepared by the method of any one of claims 1-4 to achieve super high plastic deformation of silver-sulfur-based plastic inorganic semiconductor.

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