Method for enhancing photoluminescence of monolayer tungsten disulfide by acid and application of method

Abstract

The invention discloses a method for enhancing photoluminescence of single-layer tungsten disulfide through acid and application of the method, and particularly relates to the field of two-dimensional semiconductor materials. The method comprises the following steps: bonding a plurality of WS2 layered samples on a first substrate, forming a WS2 sheet layer on the surface of the first substrate, evaporating a metal film on the surface of the WS2 sheet layer, and forming a WS2 layer-metal film layer on the surface of the first substrate; transferring the WS2-metal film layer to a second substrate, and depositing on the second substrate to obtain a WS2 layer-metal film layer; removing the metal film layer by using an etching solution to obtain a WS2 sample on the surface of the second substrate; the second substrate with the WS2 sample attached to the surface is placed in a hydrobromic acid aqueous solution, and the acid-enhanced single-layer tungsten disulfide is obtained. According to the method, WS2 is subjected to acid treatment, and Br can fill up sulfur vacancies and reduce non-radiative recombination centers, so that a PL peak is close to intrinsic emission energy, and PLQY is improved.

Description

Technical Field

[0001] The present application relates to the field of two-dimensional semiconductor materials, and in particular to a method for acid-enhanced monolayer tungsten disulfide photoluminescence and its application. Background Art

[0002] Two-dimensional transition metal dichalcogenides (TMDs) have attracted significant attention in fundamental research and optoelectronics due to their unique intralayer sandwich lattice structure, thickness-dependent band gap, excellent optoelectronic properties, and strong spin-orbit coupling. They are considered one of the most promising two-dimensional semiconductor materials. Unlike III-V semiconductors, the optical properties of TMDs are dominated by excitons with strong binding energies (approximately hundreds of meV). Photoluminescence (PL), one of the most iconic exciton effects, plays a crucial role in studying the properties of these excitons. However, TMDs exhibit weak PL, characterized by low photoluminescence quantum yields (PLQYs). Currently, methods for manipulating the optoelectronic properties of TMDs primarily include electric field modulation, stress engineering, doping, and defect engineering. However, these methods remain plagued by unstable effects, complex operations, and high costs. Doping is the most common and effective method for modifying the properties of traditional semiconductor materials and has recently been used to manipulate the carrier behavior of two-dimensional TMDs. Unlike substitutional doping, which is introduced by foreign dopant atoms in the crystal lattice, charge transfer doping utilizes the carrier barrier between the host material and the surface dopant to regulate carrier injection and recombination. Charge transfer at the interface can lead to so-called "n-type" (electron-accepting) or "p-type" (electron-donating) doping effects, thereby changing the optoelectronic properties of monolayer TMDs.

[0003] Existing dopants will cause surface defects during the doping process. On the one hand, the existence of defects will capture carriers such as electrons and holes during the electron transition process, dissipating the energy in a non-radiative recombination manner. On the other hand, it will induce non-uniformity of photoluminescence, resulting in line width widening, thereby leading to low PLQY. Summary of the Invention

[0004] The main purpose of this application is to provide a method for acid-enhanced monolayer tungsten disulfide photoluminescence and its application, aiming to solve the problem of low PLQY of existing two-dimensional TMDs.

[0005] To achieve the above-mentioned purpose, the present application provides a method for acid-enhanced single-layer tungsten disulfide photoluminescence, comprising: bonding multiple WS2 layered samples on a first substrate to form a WS2 sheet on the surface of the first substrate, evaporating a metal film on the surface of the WS2 sheet to form a WS2 layer-metal film layer on the surface of the first substrate; transferring the WS2-metal film layer to a second substrate, and depositing a WS2 layer-metal film layer on the second substrate; removing the metal film layer by using an etching solution to obtain a WS2 sample on the surface of the second substrate; placing the second substrate with the WS2 sample attached to the surface in a hydrobromic acid aqueous solution to obtain an acid-enhanced single-layer tungsten disulfide; wherein the mass fraction of hydrobromic acid in the hydrobromic acid aqueous solution is 24%, the treatment time is 3 minutes, and the treatment temperature is 25-70°C.

[0006] Optionally, the method for forming a WS2 layer on the surface of the first substrate is: evenly distribute multiple WS2 layered samples on the blue film, stick a layer of double-sided tape on the first substrate, transfer the WS2 layered samples on the blue film to the double-sided tape, and form a WS2 layer on the surface of the first substrate.

[0007] Optionally, during the evaporation process, the pressure in the evaporation chamber is 5×10 -4 -6×10 -4 Pa, the evaporation rate is 0.2-0.4Å / s, and the thickness of the metal film is 40 nm.

[0008] Optionally, the method for depositing a WS2 layer-metal film layer on a second substrate is: using a thermal release tape to bond the WS2 layer-metal film layer to separate the WS2 layer-metal film layer from the first substrate; bonding the thermal release tape bonded with the WS2 layer-metal film layer to the second substrate, and heating it on a substrate at 120°C~140°C to form a WS2 layer-metal film layer on the surface of the second substrate.

[0009] Optionally, the metal film layer is removed by: immersing the second substrate on which the WS2 layer-metal film layer is deposited in a mixed aqueous solution of KI and I2 for 5 to 10 minutes to obtain a WS2 sample on the surface of the second substrate; Optionally, the mass ratio of KI to I2 is 1:0.25.

[0010] Optionally, the first substrate is glass, the second substrate is a SiO2 / Si substrate, the thickness of the SiO2 layer is 300 nm, and the thickness of the Si layer is 500 μm.

[0011] Optionally, the metal film is a gold film.

[0012] To achieve the above objectives, the present application also provides an acid-enhanced monolayer tungsten disulfide, which is prepared according to the method of acid-enhanced monolayer tungsten disulfide photoluminescence. The PL intensity of the acid-enhanced monolayer tungsten disulfide is 163.43 au-3759.86 au, and the fluorescence lifetime is 0.3345 ns-0.4227 ns. After exposure for 200 days, its PL intensity is 663.5 au.

[0013] To achieve the above objectives, the present application also provides an application of acid-enhanced monolayer tungsten disulfide in optoelectronic devices.

[0014] Compared with the prior art, the present invention has the following advantages: The method for acid-enhanced monolayer tungsten disulfide photoluminescence of the present invention adopts a gold-assisted mechanical exfoliation method to prepare a large area of ​​2H phase 1L-WS2, and can effectively suppress the trapped exciton state through HBr treatment, and fill the exciton and charged exciton emission, effectively improving sulfur vacancies and significantly improving the PL intensity of the monolayer WS2 (more than 23 times) without destroying the surface structure of the original two-dimensional material; the average fluorescence lifetime of the obtained acid-enhanced monolayer tungsten disulfide is increased from 0.3345 ns to 0.4227 ns, and after 200 days of exposure, its growth multiple can still reach 3.3 times, with good fluorescence stability; the strong photoluminescence characteristics under low pump power can be used as a raw material for preparing optoelectronic devices based on two-dimensional semiconductor materials such as light-emitting diodes, lasers and solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of a process for acid-enhanced photoluminescence of a monolayer tungsten disulfide; Figure 2 This is an optical photograph of the 1L-WS2 sample obtained in Example 1; Figure 3 PL enhancement scatter plots without acid treatment and Example 1; Figure 4 This is a graph showing the changes in the photoluminescence peak intensity and half-height width of 1L-WS2 at different concentrations and temperatures in this application; Figure 5 PL spectra without acid treatment and PL spectra of Example 1; Figure 6 : The fluorescence lifetime diagram without acid treatment and the fluorescence lifetime diagram of Example 1; Figure 7 : Raman spectra without acid treatment and Raman spectra of Example 1; Figure 8 The spatially resolved fluorescence distribution graphs without acid treatment and the spatially resolved fluorescence distribution graphs of Example 1; Figure 9 PL spectra without acid treatment and PL spectra of Example 1; The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0016] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0017] The first embodiment of the present invention provides a method for acid-enhanced photoluminescence of a monolayer of tungsten disulfide, such as Figure 1 As shown, the specific steps include: Step S1, bonding a plurality of WS2 layered samples onto a first substrate to form WS2 sheets on the surface of the first substrate; Before bonding the WS2 layered samples, the first substrate was ultrasonically cleaned for 10 minutes using acetone, water, and isopropyl alcohol, followed by a nitrogen purge. The specific bonding method involved evenly distributing multiple WS2 layered samples on a blue film, applying a layer of double-sided tape to the first substrate, and then transferring the WS2 layered samples from the blue film to the double-sided tape.

[0018] Step S2, evaporating a metal film on the surface of the WS2 layer to form a WS2 layer-metal film layer on the surface of the first substrate; wherein the metal film is a gold film; during the evaporation process, the pressure in the evaporation chamber is 5×10 -4 ~6×10 -4 Pa, the evaporation rate is 0.2 Å / s, and the thickness of the metal film is 40 nm.

[0019] Specifically, the tungsten boat containing pure gold particles and the first substrate with the WS2 layer adhered thereto were placed in the vacuum chamber of the vacuum evaporation machine, and the chamber door was closed; the evaporation chamber of the vacuum coating machine was evacuated to 5×10 -4 ~6×10 -4 Pa; when the film thickness monitor reading stabilized at 0.2 Å / s, the damper was opened to begin evaporation; when the film thickness monitor indicated a thickness of 400 Å, evaporation was stopped. After venting, the chamber door was opened and the sample was removed. The resulting sample consisted of Au / WS2 / double-sided tape / first substrate. Because the WS2 layer may not completely cover the double-sided tape surface, the gold film may partially cover the double-sided tape surface. The film material used for the gold layer evaporated in the vacuum coating machine is 99.999% gold particles.

[0020] Step S3, transferring the WS2-metal thin film layer onto a second substrate, and depositing the WS2 layer-metal thin film layer on the second substrate; Specifically, the thermal release tape is cut into the same size and shape as the second substrate, and the thermal release tape is used to bond the WS2 layer-metal film layer to separate the WS2 layer-metal film layer from the first substrate; the thermal release tape bonded with the WS2 layer-metal film layer is bonded to the second substrate. At this time, the structure is thermal release tape / Au / WS2 / second substrate. The structure is heated at 120°C to deposit the WS2 layer-metal film layer on the surface of the second substrate.

[0021] Step S4, removing the metal film layer using an etching solution to obtain a WS2 sample on the surface of the second substrate; Specifically, a second substrate, with a WS2 layer and a metal film layer deposited on its surface, was wet-etched for 5 minutes in a mixed aqueous solution of KI and I2, resulting in a WS2 sample layer on the second substrate surface. The mass ratio of KI to I2 was 1:0.25. The mixed aqueous solution of KI and I2 was prepared by dissolving KI and I2 in a mass ratio of 1:0.25 in deionized water, stirring with a glass rod, and sonicating to achieve complete dissolution. For example, the etching solution was prepared by dissolving 5 g of potassium iodide and 1.25 g of elemental iodine in 50 ml of deionized water, stirring with a glass rod, and sonicating for 5 minutes to achieve complete dissolution. The etched product was then rinsed with acetone, deionized water, and isopropanol for 10 minutes to remove residue and obtain a large-area monolayer. The surface was then purged with N2 to obtain a large-area 1L-WS2 (monolayer WS2).

[0022] Step S5, placing the second substrate with the WS2 sample attached to the surface in a hydrobromic acid aqueous solution to obtain an acid-enhanced monolayer tungsten disulfide; wherein the mass fraction of hydrobromic acid in the hydrobromic acid aqueous solution is 4.8-48%, and the treatment temperature is 25-70°C.

[0023] In this example, acid treatment allows Br⁻ to fill sulfur vacancies, reducing non-radiative recombination centers and shifting the PL peak closer to the intrinsic emission energy, thereby improving the PLQY. The photoluminescence (PL) spectrum of the acid-enhanced monolayer tungsten disulfide was measured by exciting the sample surface with a 532 nm continuous laser at an excitation power of 100 µW and an excitation time of 1000 ms. The PL spectra of the acid-enhanced monolayer tungsten disulfide obtained by acid treatment at different concentrations, temperatures, and times were measured.

[0024] A second embodiment of the present invention provides an acid-enhanced monolayer tungsten disulfide, prepared according to a method for photoluminescence of acid-enhanced monolayer tungsten disulfide. The acid-enhanced monolayer tungsten disulfide has an average fluorescence lifetime of 0.4227 ns and exhibits a stability that can maintain a 3.3-fold increase in fluorescence after 200 days of exposure to atmospheric air.

[0025] Example 1 Step 1: Use metal tweezers to peel off several WS2 layered samples with a size of approximately 3 mm × 3 mm from a high-purity WS2 crystal source, and place each WS2 layered sample in parallel on a 1.5 cm × 1.5 cm blue film specially used for mechanical peeling; stick a layer of 1 cm × 5 cm 3M double-sided tape on the glass, align the WS2 layered sample on each blue film with the position of the 3M double-sided tape on the slide, and press gently, then remove the blue film at a relatively fast speed and transfer the WS2 layered sample to the double-sided tape; repeat the above steps to obtain multiple thicker WS2 layers on the glass; Step 2: Place the tungsten boat containing pure gold particles and the glass with WS2 layer attached into the vacuum chamber of the vacuum deposition machine and pump the vacuum degree to 5×10 -4 Pa, turn on the vacuum evaporator, and evaporate about 40 nm of gold film on the surface of the double-sided tape and WS2 layer at a rate of 0.2 Å / s.

[0026] Step 3: Use 0.5 cm × 2 cm thermal release tape to remove the gold film and WS2 layer from the double-sided tape and transfer them to the pre-prepared SiO2 / Si substrate. Then, place it on a heating table at 120°C and heat it to deposit the gold film and WS2 layer on the SiO2 / Si substrate. That is, a WS2 layer-metal film layer is deposited on the second substrate. Step 4: The second substrate with the WS2 layer-metal film layer deposited on the surface was immersed in a mixed aqueous solution of KI and I2 with a mass ratio of 1:0.25 and wet-etched for 5 min to remove the surface gold film of the SiO2 / Si substrate. The substrate was then taken out and rinsed with acetone, deionized water and isopropanol for 10 min respectively. Finally, the surface was purged with N2 to obtain the second substrate with the WS2 sample attached to the surface, i.e., the WS2 sample. Figure 2 , Figure 2 (a) is a sample image observed under a 20x lens. The light green part is a single layer of WS2. Figure 2 (b) shows a single-layer WS2 sample observed at 50x magnification. This image demonstrates the successful production of large-scale, large-area (micrometer-scale) single-layer WS2 (1L-WS2) through gold-assisted mechanical exfoliation. Observation under the aforementioned microscope identified suitable single-layer WS2 samples for subsequent testing, including spatially resolved PL fluorescence, Raman spectroscopy, and lifetime spectroscopy.

[0027] Step 5, use deionized water and hydrobromic acid solution (48%) to prepare 4.8%, 14.4%, 24%, 33.6%, and 48% (wt% in H2O) solutions; place the WS2 sample in 6 ml of each HBr solution of the above concentration, and treat it at room temperature (25 ℃) for 2 min, 3 min, 4 min, and 5 min in sequence to obtain different acid-enhanced monolayer tungsten disulfide.

[0028] For the acid-enhanced monolayer tungsten disulfide obtained above with different concentrations, temperatures and times, a 532 nm continuous laser was used to excite the sample surface, with the excitation power set to 100 µw and the excitation time set to 1000 ms, and the PL spatially resolved fluorescence was measured. In addition, a 532 nm continuous laser was used to measure the Raman spectra before and after acid treatment at an excitation power of 5 mw and an excitation time of 15000 ms. A 473 nm pulsed laser was used at 10 MHz to measure the fluorescence lifetime before and after acid treatment.

[0029] Example 2 Steps 1-4 are the same as in Example 1; In step 5, the WS2 sample was placed in a 24% HBr solution and treated at different temperatures (30°C, 40°C, 50°C, 60°C, 70°C, and 80°C) for 3 min, 5 min, and 8 min, respectively, to obtain different acid-enhanced monolayer tungsten disulfide.

[0030] The PL spatially resolved fluorescence, Raman spectrum and fluorescence lifetime of the different acid-enhanced monolayer tungsten disulfide obtained in Example 2 were measured.

[0031] The measurement results of Example 1 and Example 2 are as follows.

[0032] The steady-state transient photoluminescence spectra of WS2 samples and different acid-enhanced monolayer tungsten disulfide were tested, and the test results are as follows: Figure 3 As shown, the single PL spectra of different concentrations are as follows: Figure 3As can be seen in Figures (a-b), the photoluminescence enhancement effect is most pronounced at a 24% HBr concentration (wt % inH₂O). The PL peak undergoes a redshift, with the average peak position redshifting from 614.2 nm (σ=0.41) to 615.1 nm (σ=0.40). The PL half-width (FWHM) narrows, decreasing from 8.16 nm (σ=0.18) to 8.04 nm (σ=0.22). The PL intensity counts increase from 306.89 au to 1840.48 au. This redshift in the PL peak indicates a shift in the band gap of the monolayer WS₂ material. This is likely due to Br⁻ filling sulfur vacancies, reducing nonradiative recombination centers and shifting the PL peak closer to the intrinsic emission energy. The narrowing FWHM suggests that the acid removes surface-adsorbed impurities or oxides, reducing nonradiative recombination channels, improving material quality, and reducing defect-related nonradiative recombination, thereby increasing quantum efficiency. Narrow half-width means more monochromatic light emission, which is beneficial to the performance optimization of optoelectronic devices (such as LEDs and lasers).

[0033] PL single spectra at different temperatures are shown in Figure 2. Figure 3 In (d), from Figure 3 In (d), it can be seen that the photoluminescence after treatment at a temperature of 70°C, a concentration of 24% (wt% in H2O), and a treatment time of 3 min becomes stronger overall, and the photoluminescence enhancement effect is most obvious. The PL peak position undergoes a red shift, and the average peak position red shifts from 614.88 nm (σ= 1.18) to 615.16 nm (σ= 0.59). The PL half-peak width becomes narrower, and the average half-peak width decreases from 8.48 nm (σ= 0.54) to 7.97 nm (σ= 0.30). σ refers to the standard deviation of the data, and the calculated data comes from Figure 3 (a) (c). PL intensity counts increased from 163.43 au to 3759.86 au.

[0034] The changes in the photoluminescence peak intensity and half-height width of 1L-WS2 at different concentrations (4.8%, 14.4%, 24%, 33.6%, 48% (wt% in H2O) HBr) and different temperatures (25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 60°C, 70°C) are shown in Figure 2. Figure 4 , from the figure Figure 4 (a) It can be seen that when the HBr concentration is 24%, the treatment time is 4 minutes, and the temperature is room temperature, the PL growth intensity is the strongest (290.74 au-2241.08 au). Figure 4 (b) It can be seen that when the HBr concentration is 48% and the treatment time is 6 minutes, the half-height width decreases the most (8.59 nm-7.43 nm). Figure 4(c) It can be seen that when the HBr concentration is 24%, the treatment time is 3 minutes, and the temperature is 70 degrees, the PL growth intensity is the strongest (122.49 au-3729.3 au). Figure 4 (d) The maximum reduction in FWHM (from 8.6 nm to 7.3 nm) is observed at 24% HBr concentration, 5 minutes of treatment, and 40°C. This decrease in FWHM indicates higher crystal quality, and the increase in PL intensity indicates that the acid treatment neutralizes dangling bonds or unsaturated coordination sites (sulfur vacancies) on the surface, reducing non-radiative recombination centers. This increases the quantum yield (PL efficiency) and enhances the intrinsic luminescence capability of WS2.

[0035] The PL spectra of 1L-WS2 before and after acid treatment are shown in Figure 5 The PL spectrum of untreated 1L-WS2 is shown in blue, while the PL spectrum of 1L-WS2 treated at 70°C, with a 24% HBr concentration (wt% in H2O) for 3 minutes is shown in red. Fitting the spectra using a Lorentzian function reveals that the PL peak position undergoes a 0.7 nm red shift (from 614.2 nm to 614.9 nm) and the full width at half maximum narrows by 0.6 nm (from 8.55 nm to 7.95 nm) after treatment.

[0036] The fluorescence lifetime diagrams of 1L-WS2 before and after acid treatment are shown in Figure 6 , Figure 6 (a) TRPL of untreated 1L-WS2, Figure 6 (b) TRPL spectrum of 1L-WS2 treated at 70°C, 24% HBr concentration (wt% in H2O), and 3 minutes. The average fluorescence lifetime increases from 0.3345 ns to 0.4227 ns, a 26.38% improvement. This improvement in lifetime indicates a reduction in defect-assisted recombination.

[0037] Raman spectra of 1L-WS2 before and after acid treatment, see Figure 7 The Raman spectrum of untreated 1L-WS2 is shown in red; the Raman spectrum of 1L-WS2 treated at 70 °C, 24% HBr concentration (wt% in H2O) and 3 min is shown in blue. 1 2g The peak position is from 349.19 cm -1 Redshifted to 345.95 cm -1 , A 1 g From 415.48cm -1 Redshifted to 414.67 cm -1The red shift of HBr to lower wavenumbers indicates that the acidic environment provides electrons (H⁺ reduction), causing the Fermi level to shift upward, weakening the phonon-electron coupling, and resulting in the red shift of the Raman peak.

[0038] Spatially resolved fluorescence distribution of 1L-WS2 before and after acid treatment, see Figure 8 Figures (a, c) show the spatial distribution of the fluorescence intensity and luminescence peak position of untreated 1L-WS2; (b, d) show the spatial distribution of the fluorescence intensity and luminescence peak position of 1L-WS2 treated at 70°C, 24% HBr concentration (wt% in H2O), and for 3 minutes. Fluorescence intensity and peak position distribution of the samples. It can be seen that the photoluminescence intensity is stronger overall after treatment, with the peak at 614.21 nm (standard deviation 0.41135) red-shifting to 614.93 nm (standard deviation 0.4311), and the peak integrated intensity increasing from 1640.08 au to 37345.90 au.

[0039] PL spectra of 1L-WS2 before and after acid treatment at different times, see Figure 9 The PL spectrum of untreated 1L-WS2 is shown in black. The PL spectrum of 1L-WS2 measured immediately after acid treatment at 70°C, 24% HBr concentration (wt% in H2O), and 3 min is shown in blue. The PL spectra of 1L-WS2 measured after acid treatment in air for 48, 165, and 200 days are shown in red, orange, and purple, respectively. The figure shows that the PL enhancement factor still reaches 7-fold after 48 days of exposure, 6.4-fold after 165 days of exposure, and 3.3-fold after 200 days of exposure. This confirms the excellent stability of this fluorescence enhancement strategy in air. Furthermore, optical microscopy observations revealed that the morphology of 1L-WS2 did not change during the acid enhancement process. The treated 1L-WS2 exhibits strong photoluminescence at low pump powers, paving the way for the development of efficient optoelectronic devices based on two-dimensional semiconductor materials, such as light-emitting diodes, lasers, and solar cells.

[0040] A third embodiment of the present invention provides an application of an acid-enhanced monolayer tungsten disulfide in a photoelectric device.

[0041] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for acid-enhanced photoluminescence of a monolayer of tungsten disulfide, characterized in that: include: bonding a plurality of WS2 layered samples onto a first substrate to form WS2 sheets on the surface of the first substrate; Vapor-depositing a metal thin film on the surface of the WS2 layer to form a WS2 layer-metal thin film layer on the surface of the first substrate; Transferring the WS2-metal thin film layer to a second substrate, and depositing a WS2 layer-metal thin film layer on the second substrate; Removing the metal film layer using an etching solution to obtain a WS2 sample on the surface of the second substrate; The second substrate with the WS2 sample attached to the surface is placed in a hydrobromic acid aqueous solution to obtain an acid-enhanced monolayer tungsten disulfide; wherein the mass fraction of hydrobromic acid in the hydrobromic acid aqueous solution is 24%, the treatment time is 3 minutes, and the treatment temperature is 25-70°C.

2. The method for acid-enhanced monolayer tungsten disulfide photoluminescence according to claim 1, characterized in that: The method for forming the WS2 layer on the surface of the first substrate is: Multiple WS2 layered samples are evenly distributed on the blue film, a layer of double-sided tape is pasted on the first substrate, and the WS2 layered samples on the blue film are transferred to the double-sided tape to form a WS2 layer on the surface of the first substrate.

3. The method for acid-enhanced monolayer tungsten disulfide photoluminescence according to claim 1, characterized in that: During the evaporation process, the pressure in the evaporation chamber is 5×10 -4 -6×10 -4 Pa, the evaporation rate is 0.2-0.4Å / s, and the thickness of the metal film is 40 nm.

4. The method for acid-enhanced monolayer tungsten disulfide photoluminescence according to claim 1, characterized in that: The method for depositing the WS2 layer-metal thin film layer on the second substrate is: Using a thermal release tape to bond the WS2 layer to the metal film layer, so that the WS2 layer and the metal film layer are separated from the first substrate; The thermal release tape with the WS2 layer-metal film layer bonded thereto is bonded to the second substrate and heated on a base plate at 120° C. to 140° C. to form a WS2 layer-metal film layer on the surface of the second substrate.

5. The method for acid-enhanced photoluminescence of a single-layer tungsten disulfide according to claim 1, characterized in that: The method for removing the metal film layer is as follows: The second substrate with a WS2 layer-metal thin film layer deposited on the surface was immersed in a mixed aqueous solution of KI and I2 for 5 to 10 minutes to obtain a WS2 sample on the surface of the second substrate.

6. The method for acid-enhanced monolayer tungsten disulfide photoluminescence according to claim 5, characterized in that: The mass ratio of KI to I2 is 1:0.

25.

7. The method for acid-enhanced photoluminescence of a single-layer tungsten disulfide according to claim 1, characterized in that: The first substrate is glass, the second substrate is a SiO2 / Si substrate, the thickness of the SiO2 layer is 300 nm, and the thickness of the Si layer is 500 μm.

8. The method for acid-enhanced photoluminescence of a single-layer tungsten disulfide according to claim 1, characterized in that: The metal thin film is a gold thin film.

9. An acid-enhanced monolayer tungsten disulfide, characterized in that: The method for acid-enhanced monolayer tungsten disulfide photoluminescence according to any one of claims 1 to 8 is prepared, wherein the PL intensity of the acid-enhanced monolayer tungsten disulfide is 163.43 au-3759.86 au, the fluorescence lifetime is 0.3345 ns-0.4227 ns, and after exposure for 200 days, the PL intensity is 663.5 au.

10. Use of the acid-enhanced monolayer tungsten disulfide according to claim 9 in a photoelectric device.

Images