A method for preparing large-area palladium sulfide or / and palladium disulfide nanofilm

Abstract

The present invention discloses a method for preparing large-area palladium sulfide and / or palladium disulfide nanofilms. Using electron beam evaporation and chemical vapor deposition methods, by varying the thickness of a pre-deposited palladium metal nanofilm, palladium sulfide, palladium disulfide, or a mixed-phase nanofilm of palladium sulfide and palladium disulfide can be controllably prepared. The method comprises: 1. Using an electron beam evaporation coating apparatus, palladium metal nanofilms of varying thicknesses are evaporated onto a silicon dioxide substrate. 2. Sulfur powder is placed in the first temperature zone of a tube furnace, and the growth substrate is placed in the second temperature zone. Large-area palladium sulfide, palladium disulfide, or a mixed-phase nanofilm of palladium sulfide and palladium disulfide is controllably grown using atmospheric pressure chemical vapor deposition. Due to their unique physical and chemical properties, palladium sulfide and palladium disulfide nanofilms have broad application prospects in various industrial and technological fields, such as catalysts, acid-resistant high-temperature electrodes, and solar cells. The present invention enables the industrial production of palladium sulfide, palladium disulfide, or a mixed-phase nanofilm of palladium sulfide and palladium disulfide.

Description

Technical Field

[0001] The invention relates to palladium-based sulfide, and in particular to a method for preparing a large-area palladium sulfide or / and palladium disulfide nanofilm. Background Art

[0002] Palladium sulfide (PdS, PdS2, Pd x S y ) is widely used in a variety of industrial and technological fields, such as photodetectors, catalysts, sensors, acid-resistant high-temperature electrodes, solar cells, etc. Among them, palladium sulfide is a tetragonal n-type semiconductor with a band gap energy of 1.6eV. It has excellent physical and chemical properties, such as thermoelectricity, photoelectrochemistry, photovoltaic properties, etc. These properties make it used in catalysts and acid-resistant high-temperature electrodes. Palladium disulfide is a member of the 10th group transition metal dihalide family and has a unique pentagonal crystal structure. Unlike other common two-dimensional materials, each palladium atom is bonded to four sulfur atoms in the same layer, and two adjacent sulfur atoms are bonded into a covalent bond, and the layers are held together by van der Waals forces. Monolayer palladium disulfide is an indirect band gap semiconductor with a band gap of about 1.28eV and an electron mobility of up to 258.06cm 2 v -1 s -1 . As the number of layers increases, the band gap of palladium disulfide gradually decreases and eventually turns into a semi-metallic phase. Due to these interesting properties, it has potential application prospects in the fields of two-dimensional functional devices such as field effect transistors and gas sensors. At present, the preparation methods of palladium sulfide include photochemical method, aerosol assisted method, chemical vapor deposition method and direct sulfurization method, while the commonly used preparation methods of palladium disulfide include mechanical exfoliation, liquid phase exfoliation, physical vapor deposition, etc. However, these preparation methods are complicated to operate, have high preparation costs, and poor controllability, and cannot be applied industrially. The preparation of large-area palladium sulfide, palladium disulfide or mixed phase nanofilms of palladium sulfide and palladium disulfide is still very challenging. Summary of the Invention

[0003] In response to the technical problems of existing palladium-based sulfide preparation methods, such as complex operation, high preparation cost, and poor controllability, which make industrial application difficult, the present invention provides a method for preparing large-area palladium sulfide or / and palladium disulfide nanofilms. By combining electron beam evaporation coating with atmospheric pressure chemical vapor deposition, large-area, high-quality palladium sulfide, palladium disulfide, or a mixed-phase nanofilm of palladium sulfide and palladium disulfide is prepared. The preparation method is highly controllable, and the resulting palladium sulfide, palladium disulfide, or a mixed-phase nanofilm of palladium sulfide and palladium disulfide has broad application prospects in the fields of light detection, catalysts, sensors, acid-resistant high-temperature electrodes, solar cells, etc., and the palladium sulfide and palladium disulfide nanofilms are very stable under normal temperature atmospheric conditions, which provides a guarantee for further research on the physical properties of palladium sulfide and palladium disulfide nanomaterials.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A method for preparing a large-area palladium sulfide or / and palladium disulfide nanofilm comprises the following steps:

[0006] 1) depositing palladium metal nanofilms of different thicknesses onto a substrate using an electron beam evaporation coating apparatus;

[0007] 2) placing the alumina boat containing sulfur powder in the center of the first heating zone, and placing the silica substrate with palladium vapor deposited thereon in the center of the second heating zone of the dual-temperature-zone tubular furnace;

[0008] 3) introducing argon gas into the reaction chamber of the tube furnace for cleaning;

[0009] 4) Raise the temperature of the tube furnace to raise the temperature of the first temperature zone to 200°C-300°C and the temperature of the second temperature zone to 400°C-600°C for vulcanization;

[0010] 5) After the growth is completed, the temperature is naturally cooled to room temperature, and the argon gas is turned off to obtain a palladium sulfide or / and palladium disulfide nanofilm.

[0011] Furthermore, the thickness of the palladium metal nanofilm is one of 1 nanometer, 2 nanometers, 4 nanometers or 10 nanometers.

[0012] Furthermore, in step 1), the area of ​​the substrate can reach 3 cm×3 cm.

[0013] Furthermore, the substrate is one of soda-lime glass, fluorphlogopite substrate, sapphire, graphene, molybdenum disulfide, tungsten disulfide, molybdenum diselenide, and tungsten diselenide.

[0014] Furthermore, in step 2), the amount of sulfur powder increases with the temperature in the first temperature zone. At 200°C, the amount of sulfur powder is 0.8-1.0g. For every 20°C increase in temperature, the mass of sulfur powder increases by 0.1g. The purity of the sulfur powder is above 99.5%.

[0015] Furthermore, in step 3), the flow rate of argon gas is 50-100 sccm.

[0016] Furthermore, in step 4), the growth time is 10 to 60 minutes.

[0017] Furthermore, in the step 5), when the palladium metal film with a thickness of 1 nm is evaporated on the substrate in step 1), the sulfide product is pure palladium disulfide; when the palladium metal film with a thickness of 2 nm is evaporated on the substrate, the sulfide product is a mixed phase film of palladium disulfide and palladium sulfide, and the area ratio of palladium disulfide to palladium sulfide is 30-40%:70-60%; when the palladium metal film with a thickness of 4 nm is evaporated on the substrate, the sulfide product is a mixed phase film of palladium disulfide and palladium sulfide, and the area ratio of palladium disulfide to palladium sulfide is 2%-7%:98%-93%; when the palladium metal film with a thickness of 10 nm is evaporated on the substrate, the sulfide product is a pure palladium sulfide film.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1) By combining electron beam evaporation coating with atmospheric pressure chemical vapor deposition, large-area, high-quality palladium sulfide or / and palladium disulfide nanofilms can be controllably prepared.

[0020] 2) Traditional methods for synthesizing palladium sulfide and palladium disulfide involve the use of H2S gas or vacuum-sealed quartz tube devices. These preparation methods are complex to operate, and H2S gas is toxic. However, this method has strong operational flexibility and high safety.

[0021] 3) The use of atmospheric pressure chemical vapor deposition method can achieve the precise synthesis of large-area, highly uniform, high-quality nano-thin films of palladium sulfide, palladium disulfide or mixed phase nano-thin films of palladium sulfide and palladium disulfide.

[0022] 4) The palladium disulfide nanofilm prepared on the silicon dioxide substrate can be used to prepare a thin film field effect transistor (TFT) array with uniform performance using semiconductor technology.

[0023] 5) Different materials can be selected for the evaporation substrate, so that application exploration in different fields can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1This is a digital photo of a palladium disulfide nanofilm prepared by electron beam evaporation (the palladium metal nanofilm deposition thickness is 1 nm) and chemical vapor deposition methods corresponding to Example 1;

[0025] Figure 2 The optical microscope characterization and Raman spectroscopy characterization results of the palladium disulfide nanofilm prepared by electron beam evaporation coating (the palladium metal nanofilm deposition thickness is 1 nm) and chemical vapor deposition method corresponding to Example 1;

[0026] Figure 3 The optical microscope characterization and Raman spectroscopy characterization results of the mixed phase nanofilm of palladium sulfide and palladium disulfide prepared by electron beam evaporation coating (the palladium metal nanofilm deposition thickness is 2 nanometers) and chemical vapor deposition method corresponding to Example 6;

[0027] Figure 4 The optical microscope characterization and Raman spectroscopy characterization results of the mixed phase nanofilm of palladium sulfide and palladium disulfide prepared by electron beam evaporation coating (the palladium metal nanofilm deposition thickness is 4 nanometers) and chemical vapor deposition method corresponding to Example 7;

[0028] Figure 5 The optical microscope characterization and Raman spectroscopy characterization results of the palladium sulfide nanofilm prepared by electron beam evaporation coating (the palladium metal nanofilm deposition thickness is 10 nanometers) and chemical vapor deposition method corresponding to Example 8;

[0029] Figure 6 The atomic force microscope and Kelvin probe microscope characterization results of the palladium disulfide nanofilm prepared by electron beam evaporation (the palladium metal nanofilm deposition thickness is 1 nm) and chemical vapor deposition methods corresponding to Example 1;

[0030] Figure 7 Atomic force microscopy and Kelvin probe microscopy characterization results of the mixed phase nanofilm of palladium sulfide and palladium disulfide prepared by electron beam evaporation (the palladium metal nanofilm deposition thickness is 4 nm) and chemical vapor deposition methods corresponding to Example 7;

[0031] Figure 8 Atomic force microscopy and Kelvin probe microscopy characterization results of the palladium sulfide nanofilm prepared by electron beam evaporation (the palladium metal nanofilm deposition thickness is 10 nm) and chemical vapor deposition methods corresponding to Example 8;

[0032] Figure 9 The Raman spectrum scanning characterization results of the palladium disulfide nanofilm prepared by electron beam evaporation coating (the palladium metal nanofilm deposition thickness is 1 nm) and chemical vapor deposition method corresponding to Example 1;

[0033] Figure 10 The Raman spectrum scanning characterization results of the mixed phase nanofilm of palladium sulfide and palladium disulfide prepared by electron beam evaporation coating (the palladium metal nanofilm deposition thickness is 2 nm) and chemical vapor deposition method corresponding to Example 6;

[0034] Figure 11 The Raman spectrum scanning characterization results of the mixed phase nanofilm of palladium sulfide and palladium disulfide prepared by electron beam evaporation coating (the palladium metal nanofilm deposition thickness is 4 nm) and chemical vapor deposition method corresponding to Example 7;

[0035] Figure 12 The Raman spectrum scanning characterization results of the palladium sulfide nanofilm prepared by electron beam evaporation coating (the palladium metal nanofilm deposition thickness is 10 nanometers) and chemical vapor deposition method corresponding to Example 8;

[0036] Figure 13 Transmission electron microscopy and high-resolution transmission electron microscopy characterization results of the palladium disulfide nanofilm prepared by electron beam evaporation coating (the palladium metal nanofilm deposition thickness is 1 nm) and chemical vapor deposition method corresponding to Example 1;

[0037] Figure 14 Transmission electron microscopy and high-resolution transmission electron microscopy characterization results of the palladium sulfide nanofilm prepared by electron beam evaporation coating (palladium metal nanofilm deposition thickness is 10 nanometers) and chemical vapor deposition methods corresponding to Example 8;

[0038] Figure 15 The transistor array corresponding to Example 1 is prepared by using a semiconductor process using a palladium disulfide nanofilm prepared by electron beam evaporation coating (the palladium metal nanofilm deposition thickness is 1 nanometer) and chemical vapor deposition. DETAILED DESCRIPTION

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the present invention is not limited thereto.

[0040] Palladium metal thin film evaporation of different thicknesses

[0041] Palladium metal films of different thicknesses (1 nm, 2 nm, 4 nm, 10 nm) were deposited onto silicon dioxide substrates using an electron beam evaporation coating apparatus.

[0042] Example 1

[0043] A 1-nanometer palladium thin film was deposited onto a silica substrate using an electron beam evaporation coating apparatus. The substrate was then placed in the second zone of a dual-zone tubular furnace, and an alumina boat containing 0.8g of sulfur powder was placed in the first zone. Argon gas (500 sccm) was then introduced into the reaction chamber to purge the chamber and expel any remaining air. The purge lasted 30 minutes. The temperature was then programmed to reach a designated temperature of 200°C in the first zone and 400°C in the second zone. Argon gas (50g) was used as a carrier gas to transport the sulfur vapor to the growth substrate, allowing the growth of the palladium disulfide nanofilm to proceed for 30 minutes. After the growth was complete, the tubular furnace was allowed to cool naturally to room temperature, the argon gas was turned off, and the growth substrate was removed.

[0044] The obtained PdS2 nanofilm samples were characterized by optical microscopy, Raman spectroscopy, atomic force microscopy, Kelvin probe microscopy, and transmission electron microscopy. Figure 2 、 Figure 6 、 Figure 9 and Figure 13 As shown. The optical microscope characterization data shows that the palladium disulfide nanofilm is very uniform. The Raman spectrum characterization data shows that 299cm -1 and 425cm -1 The two characteristic peaks at correspond to the E g and A g Peak. Atomic force microscopy and Kelvin probe microscopy data indicate that the thickness of the PdS2 nanofilm is approximately 3.3 nanometers, the potential difference between the PdS2 nanofilm and the silicon dioxide substrate is approximately 40 mV, and the surface potential distribution is uniform. Raman spectroscopy surface scanning characterization indicates that the surface of the PdS2 sample is uniform. High-resolution transmission electron microscopy data indicate that the lattice distance corresponding to the (102) plane in PdS2 is 0.3164 nanometers. Figure 1 This is a digital photo comparing before and after the experiment in Example 1. Figure 15 These are digital and optical photos of a transistor array fabricated using a semiconductor process using the palladium disulfide thin film obtained in Example 1.

[0045] Example 2

[0046] The palladium disulfide nanofilm can also be obtained by changing the temperature of the first temperature zone in Example 1 to 250° C., changing the amount of sulfur powder to 1.0 g, and keeping other preparation conditions unchanged.

[0047] Example 3

[0048] The palladium disulfide nanofilm can also be obtained by changing the temperature of the second temperature zone in Example 1 to 450° C. while keeping other preparation conditions unchanged.

[0049] Example 4

[0050] The palladium disulfide nanofilm can also be obtained by changing the temperature of the second temperature zone in Example 1 to 500° C. and keeping other preparation conditions unchanged.

[0051] Example 5

[0052] The palladium disulfide nanofilm can also be obtained by changing the temperature of the second temperature zone in Example 1 to 600° C. and keeping other preparation conditions unchanged.

[0053] Example 6

[0054] The substrate plated with 1 nanometer palladium metal in Example 1 is replaced with a substrate plated with 2 nanometer palladium metal, and other preparation conditions remain unchanged, to obtain a mixed phase nanofilm of palladium sulfide and palladium disulfide.

[0055] The obtained PdS and PdS2 mixed phase nanofilm samples were characterized by optical microscopy, Raman spectroscopy, and Raman spectroscopy surface scanning. Figure 3 and Figure 10 As shown in Figure 2, optical microscopy data indicate that the products are two different substances. Combined with Raman spectroscopy, this indicates that one is palladium sulfide and the other is palladium disulfide. This is further confirmed by Raman spectroscopy scan data.

[0056] Example 7

[0057] The substrate plated with 1 nanometer palladium metal in Example 1 is replaced with a substrate plated with 4 nanometer palladium metal, and other preparation conditions remain unchanged, to obtain a mixed phase nanofilm of palladium sulfide and palladium disulfide.

[0058] The obtained PdS and PdS2 mixed phase nanofilm samples were characterized by optical microscopy, Raman spectroscopy, atomic force microscopy, Kelvin probe microscopy, and Raman spectroscopy surface scanning. Figure 4 、 Figure 7 and Figure 11 As shown. Optical microscopy data indicate that the products are two different substances. Combined with Raman spectroscopy, this indicates that one is palladium sulfide and the other is palladium disulfide. Raman spectroscopy surface scanning data further confirms this. Atomic force microscopy and Kelvin probe microscopy data indicate that the potential difference between palladium sulfide and palladium disulfide is approximately 10 mV, with a uniform surface potential distribution.

[0059] Example 8

[0060] The palladium sulfide nanofilm can be obtained by replacing the substrate plated with 1 nanometer palladium metal in Example 1 with a substrate plated with 10 nanometer palladium metal, while keeping other preparation conditions unchanged.

[0061] The obtained palladium sulfide nanofilm samples were characterized by optical microscopy, Raman spectroscopy, atomic force microscopy, Kelvin probe microscopy, Raman spectroscopy surface scanning, and transmission electron microscopy. Figure 5 、 Figure 8 、 Figure 12 and Figure 14 As shown. The optical microscope characterization data shows that the palladium sulfide nanofilm is very uniform. The Raman spectroscopy characterization results show that 134cm -1 and 334cm -1 The two characteristic peaks at g and B g Atomic force microscopy and Kelvin probe microscopy data demonstrate that the thickness of the PdS nanofilm is approximately 27 nanometers, the potential difference between the PdS nanofilm and the silicon dioxide substrate is approximately 58 mV, and the surface potential distribution is uniform. Raman spectroscopy surface scanning characterization indicates that the surface of the PdS sample is uniform. High-resolution transmission electron microscopy data indicate that the lattice distance corresponding to the (101) plane in PdS is 0.4801 nanometers.

[0062] Examples 9-16

[0063] The silicon dioxide substrate in Example 1 is replaced by two-dimensional layered materials such as soda-lime glass, sapphire, fluorphlogopite base, graphene, molybdenum disulfide, tungsten disulfide, molybdenum diselenide, and tungsten diselenide.

Claims

1. A method for preparing a large-area palladium sulfide or / and palladium disulfide nanofilm, characterized in that: The steps include: 1) Palladium metal nanofilms of different thicknesses are deposited onto the substrate using an electron beam evaporation coating apparatus; 2) Place the alumina boat containing sulfur powder in the center of the first heating zone, and place the silica substrate with palladium vapor deposited in the center of the second heating zone of the dual-temperature tube furnace; 3) Introduce argon gas into the reaction chamber of the tube furnace for cleaning; 4) Raise the temperature of the tube furnace to raise the temperature of the first temperature zone to 200℃-300℃ and the temperature of the second temperature zone to 400℃-600℃ for vulcanization; 5) After the growth is completed, the temperature is naturally cooled to room temperature, and the argon gas is turned off to obtain palladium sulfide and / or palladium disulfide nanofilm; Among them, when the substrate is evaporated with a palladium metal film with a thickness of 1 nanometer, the sulfide product is pure palladium disulfide; when the substrate is evaporated with a palladium metal film with a thickness of 2 nanometers, the sulfide product is a mixed phase film of palladium disulfide and palladium sulfide, and the area ratio of palladium disulfide to palladium sulfide is 40%~60%: 60%~50%; when the substrate is evaporated with a palladium metal film with a thickness of 4 nanometers, the sulfide product is a mixed phase film of palladium disulfide and palladium sulfide, and the area ratio of palladium disulfide and palladium sulfide is 1%~3%: 99%~97%; when the substrate is evaporated with a palladium metal film with a thickness of 10 nanometers, the sulfide product is a pure palladium sulfide film.

2. The method for preparing a large-area palladium sulfide or / and palladium disulfide nanofilm according to claim 1, wherein: In step 1), the area of ​​the substrate can reach 3 cm × 3 cm.

3. The preparation method of large-area palladium sulfide and / or palladium disulfide nanofilm according to claim 1, wherein The substrate is one of soda-lime glass, fluorphlogopite substrate, sapphire, graphene, molybdenum disulfide, tungsten disulfide, molybdenum diselenide and tungsten diselenide.

4. The method for preparing a large-area palladium sulfide or / and palladium disulfide nanofilm according to claim 1, wherein: In the step 2), the amount of sulfur powder increases with the temperature in the first temperature zone. At 200°C, the amount of sulfur powder is 0.8-1.0g. For every 20°C increase in temperature, the mass of sulfur powder increases by 0.1g. The purity of the sulfur powder is above 99.5%.

5. The method for preparing a large-area palladium sulfide or / and palladium disulfide nanofilm according to claim 1, wherein: In step 3), the flow rate of argon gas is 50-100 sccm.

6. The method for preparing a large-area palladium sulfide or / and palladium disulfide nanofilm according to claim 1, wherein: In step 4), the growth time is 10 to 60 minutes.

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