Transition metal compound fluorescence enhanced heterostructure, preparation method and use

Abstract

The present invention provides a transition metal compound fluorescence-enhancing heterostructure, a preparation method, and uses thereof. The transition metal compound fluorescence-enhancing heterostructure comprises a stacked transition metal compound layer, a porous alumina template layer, and a metal substrate layer; the transition metal compound layer exhibits curved depressions with a depth of 3 nm or greater at the pores of the porous alumina template layer. By constructing a fluorescence-enhancing heterostructure comprising a stacked transition metal compound layer, a porous alumina template layer, and a metal substrate layer, the present invention can effectively enhance the fluorescence intensity of the transition metal compound and achieve regulation of its optical properties. The resulting fluorescence-enhancing heterostructure can be widely used in high-performance low-dimensional material devices, optoelectronic devices, flexible electronic devices, and other fields.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanophotonics and relates to a heterostructure, in particular to a transition metal compound fluorescence enhancement heterostructure, a preparation method and use thereof. Background Art

[0002] Transition metal dichalcogenides (TMDs) are layered two-dimensional materials with tunable band gaps, emerging after graphene. Their in-plane bonds are connected by strong covalent bonds, while the interlayers interact via weak van der Waals forces. Their unique structure and excellent optoelectronic properties hold great potential for applications in light harvesting, photodetection, light-emitting diodes, and nanolasers.

[0003] As the number of layers in transition metal compounds decreases, their bandgap increases and shifts from an indirect bandgap to a direct bandgap. However, ultra-thin monolayer atomic structures cannot effectively generate energy level excitation and transition processes, thus limiting their light absorption rate and quantum emission efficiency. Combining plasmonic optical structures with transition metal compounds or creating more localized electric field enhancement by fabricating metal micro-nano periodic structures is an effective means to improve the efficiency of fluorescence enhancement.

[0004] CN 113481007A discloses a method for enhancing the fluorescence of molybdenum disulfide (MoS2) based on a double-L-shaped metasurface structure. Using a monolayer of MoS2 as the luminescent material, the double-L-shaped metasurface structure excites surface plasmon resonance, generating dual resonances in the excitation and emission bands to enhance the light absorption efficiency of MoS2. Based on the chiral structure of the metasurface, this invention can enhance the photoluminescence of MoS2 and further explore the physics of valley spins to regulate the fluorescence polarization state.

[0005] CN 108176393A discloses a method for preparing ordered, high-density Ag-Al2O3-MoS2 nanostructures. This method directly uses ordinary optical glass as a substrate, with molybdenum trioxide (MoO3) and elemental sulfur as the molybdenum and sulfur sources, respectively. A monolayer of molybdenum disulfide is grown on the substrate, which is then transferred to the prepared high-density, ordered Ag-Al2O3 nanocore-shell structure via a wet transfer method. After removing the transfer support layer, a working electrode is obtained that can be used in the field of photocatalytic hydrogen production.

[0006] While all of the aforementioned approaches utilize the structural and optoelectronic properties of transition metal compounds to fabricate optoelectronic devices, the fluorescence intensity of these compounds still falls short of expectations and remains unsuitable for large-scale industrial production. To address these shortcomings, there is an urgent need for a simple, easily fabricated heterostructure that enhances the photoluminescence intensity of transition metal compounds. Summary of the Invention

[0007] The purpose of the present invention is to provide a transition metal compound fluorescence-enhancing heterostructure, preparation method and use. By constructing a stacked heterostructure of a transition metal compound, a porous alumina template and a metal substrate, the fluorescence intensity of the transition metal compound can be effectively enhanced. The preparation method provided by the present invention is simple to operate and has lower costs compared to traditional micro-nano processing. The resulting transition metal compound fluorescence-enhancing heterostructure can be widely used in high-performance optoelectronic devices and flexible electronic devices.

[0008] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a transition metal compound fluorescence enhanced heterostructure, wherein the transition metal compound fluorescence enhanced heterostructure comprises a stacked transition metal compound layer, a porous alumina template layer, and a metal substrate layer;

[0010] The transition metal compound layer has a curved depression with a depth of ≥3 nm at the pores of the porous alumina template layer.

[0011] The present invention enhances the fluorescence intensity of the transition metal compound by constructing a heterostructure of a stacked transition metal compound layer, a porous alumina template layer, and a metal substrate layer. The transition metal compound layer is suspended on the porous alumina template layer, causing the dielectric environment of the transition metal compound to change and the exciton resonance intensity to increase. The transition metal compound layer bends and sinks along the pores of the porous alumina template layer, causing the energy band structure of the transition metal compound to change, thereby enhancing its photoluminescence signal.

[0012] The porous alumina template layer is evenly distributed with holes, and the transition metal compound layer has a curved depression with a depth of ≥3nm at the holes of the porous alumina template layer, for example, it can be 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 12nm, 13nm, 14nm or 15nm, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 5-15nm.

[0013] The depth of the bending and sinking in the present invention refers to the maximum value of the depression of the transition metal compound layer at the hole.

[0014] Preferably, the porous alumina template layer comprises holes periodically distributed in a hexagonal honeycomb shape, and the openings of the holes are bowl-shaped structures.

[0015] Preferably, in the porous alumina template layer, the periodic interval D of the holes is intThe thickness is 80-120 nm, for example, 80 nm, 90 nm, 100 nm, 110 nm or 120 nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] The periodic interval mentioned in the present invention refers to the distance between the center axes of adjacent holes.

[0017] Preferably, the pore size D of the porous alumina template layer is p The thickness is 30-90 nm, for example, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm or 90 nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0018] The pore diameter of the pores in the porous alumina template layer is an equivalent circle diameter.

[0019] Preferably, the depth of the pores in the porous alumina template layer is ≥30 nm, for example, it can be 30 nm, 50 nm, 100 nm, 200 nm, 500 nm, 1000 nm, 2000 nm, 5000 nm, 10000 nm, 20000 nm or 30000 nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] In the fluorescence-enhanced heterostructure, the hole size and the metal particle size must match to allow the metal particles to enter the hole. If the hole depth is too small, the metal particles cannot enter the hole to form an integrated metal particle array.

[0021] Preferably, the thickness of the transition metal compound layer is 0.6-10 nm, for example, 0.6 nm, 0.8 nm, 1 nm, 1.5 nm, 2 nm, 3 nm, 5 nm, 8 nm or 10 nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] The transition metal compound layer of the present invention is a single layer or a few layers of transition metal compound (the number of layers is ≤ 10, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 layers), and has a thickness of 0.6-10 nm. If the thickness is greater than 10 nm, the transition metal compound layer is too thick to form a curved depression of ≥ 3 nm in the pores of the porous alumina template layer, thereby failing to enhance the fluorescence intensity.

[0023] Preferably, the transition metal compound in the transition metal compound layer includes any one of molybdenum disulfide (MoS2), molybdenum diselenide (MoSe2), molybdenum ditelluride (MoTe2), tungsten disulfide (WS2), tungsten diselenide (WSe2), rhenium disulfide (ReS2) or rhenium diselenide (ReSe2), or a combination of at least two of them. Typical but non-limiting combinations include a combination of molybdenum disulfide and molybdenum diselenide, a combination of tungsten disulfide and tungsten diselenide, a combination of rhenium disulfide and rhenium diselenide, a combination of molybdenum disulfide, molybdenum diselenide and molybdenum ditelluride, or a combination of tungsten disulfide, tungsten diselenide, rhenium disulfide and rhenium diselenide.

[0024] Preferably, the metal substrate layer comprises an aluminum substrate layer.

[0025] Preferably, metal particles are distributed in the pores of the porous alumina template layer.

[0026] Preferably, the metal in the metal particles includes any one of Au, Ag, Cu or Pt or a combination of at least two of them. Typical but non-limiting combinations include a combination of Au and Ag, a combination of Ag and Cu, a combination of Ag and Pt, a combination of Cu and Pt, a combination of Au, Ag and Pt, or a combination of Au, Ag, Cu and Pt; preferably any one of Au, Ag or Pt or a combination of at least two of them.

[0027] Preferably, the metal particles are distributed in a single layer.

[0028] Preferably, the size of the metal particles is 20-80 nm, for example, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm or 80 nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] The size of the metal particles can be selected so that they can be embedded in the pores of the porous alumina template layer. If the metal particles are too large or too small, they cannot form an integrated metal particle array, thereby losing the function of the metal particles in enhancing the fluorescence intensity of the transition metal compound.

[0030] Preferably, the metal particles are any one or a combination of at least two of metal nanospheres, metal nanocubes or metal nanotriangular sheets synthesized by a solution method. Typical but non-limiting combinations include a combination of metal nanospheres and metal nanocubes, a combination of metal nanocubes and metal nanotriangular sheets, or a combination of metal nanospheres, metal nanocubes and metal nanotriangular sheets.

[0031] When the metal particles are metal nanospheres, the size of the metal particles is the diameter of the metal nanospheres.

[0032] When the metal particles are metal nanocubes, the size of the metal particles is the side length of the metal nanocubes.

[0033] When the metal particles are metal nano-triangular flakes, the size of the metal particles is the side length of the metal nano-triangular flakes.

[0034] Preferably, the integration degree of the metal particles in the porous alumina template layer is ≥95%, for example, it can be 95%, 96%, 97%, 98%, 99% or 100%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] The integration degree of metal particles in the porous alumina template layer described herein refers to the percentage of pores containing metal particles relative to the total number of pores in the porous alumina template layer. The higher the integration degree of metal particles in the porous alumina template layer, the better the fluorescence enhancement effect of the resulting fluorescence-enhancing heterostructure. However, the process difficulty increases with the integration degree. To achieve the desired fluorescence enhancement effect, a metal particle integration degree of ≥95% in the porous alumina template layer is sufficient.

[0036] Preferably, the distribution density of the metal particles is ≥10 10 pieces / cm 2 , for example it can be 10 10 pieces / cm 2 、11 10 pieces / cm 2 , 12 10 pieces / cm 2 , 13 10 pieces / cm 2 or 14 10 pieces / cm 2 , but not limited to the listed values, other unlisted values ​​within the numerical range are also applicable.

[0037] In a second aspect, the present invention provides a method for preparing the transition metal compound fluorescence-enhanced heterostructure as described in the first aspect, the preparation method comprising the following steps:

[0038] (1) depositing a transition metal compound layer on the substrate layer, then coating an electron beam photoresist on the surface of the transition metal compound layer, and heating and curing the layer to form an electron beam photoresist layer;

[0039] (2) removing the base layer by etching with an alkaline solution, and then immersing and cleaning the transition metal compound layer provided with the electron beam photoresist layer;

[0040] (3) removing the floating transition metal compound layer from the porous alumina template layer, drying it, and immersing it in an organic solvent to remove the electron beam photoresist layer on the surface of the transition metal compound layer;

[0041] (4) washing and air-drying in sequence to obtain the transition metal compound fluorescence enhanced heterostructure.

[0042] The present invention first deposits a transition metal compound layer, which is then suspended on the surface of a porous alumina template layer through wet transfer to construct a stacked transition metal compound fluorescence-enhancing heterostructure. This structure has an excellent effect on enhancing the fluorescence signal, can improve the fluorescence efficiency of the transition metal compound, and achieve regulation of its optical properties.

[0043] The substrate in step (1) can be any substrate capable of depositing a transition metal compound layer, including but not limited to a Si / SiO2 substrate.

[0044] Preferably, the deposition method in step (1) includes chemical vapor deposition and / or physical vapor deposition.

[0045] Preferably, the coating method in step (1) comprises spin coating.

[0046] Preferably, the spin coating speed is 2800-3200 rpm, and the time is 40-60 s.

[0047] The spin coating rotation speed is 2800-3200 rpm, for example, 2800 rpm, 2900 rpm, 3000 rpm, 3100 rpm or 3200 rpm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0048] The spin coating time is 40-60 s, for example, 40 s, 45 s, 50 s, 55 s or 60 s, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0049] Preferably, the temperature of the heating and curing in step (1) is 70-80°C, for example, 70°C, 72°C, 75°C, 76°C, 78°C or 80°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0050] Preferably, the heating and curing time in step (1) is 4-6 minutes, for example, 4 minutes, 4.5 minutes, 5 minutes, 5.5 minutes or 6 minutes, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0051] The present invention converts the coated electron beam photoresist into an electron beam photoresist layer by heating and curing.

[0052] Preferably, the thickness of the electron beam photoresist layer in step (1) is 280-320 nm, for example, 280 nm, 290 nm, 300 nm, 310 nm or 320 nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0053] If the thickness of the electron beam photoresist layer is too large, it is difficult to remove; if the thickness is too small, it cannot play its supporting role. Therefore, the present invention controls the appropriate thickness of the resist layer to effectively ensure its supporting effect.

[0054] Preferably, the electron beam photoresist in step (1) includes PMMA electron beam glue and / or PDMS electron beam glue.

[0055] Preferably, the alkaline solution in step (2) includes NaOH solution and / or KOH solution.

[0056] Preferably, the organic solvent in step (3) comprises any one or a combination of at least two of acetone, methanol, ethanol or diethyl ether. Typical but non-limiting combinations include a combination of acetone and methanol, a combination of methanol and ethanol, a combination of ethanol and diethyl ether, a combination of acetone, methanol and ethanol, a combination of methanol, ethanol and diethyl ether, or a combination of acetone, methanol, ethanol and diethyl ether.

[0057] The porous alumina template layer in step (3) of the present invention is a porous alumina template layer comprising a metal substrate layer, preferably a porous alumina template layer comprising an aluminum substrate layer. When the porous alumina template layer in step (3) is a porous alumina template layer comprising an aluminum substrate layer, the porous alumina template layer is prepared by a conventional two-step anodization method in the art using aluminum.

[0058] Preferably, metal particles are distributed in the pores of the porous alumina template layer in step (3), and the method for distributing metal particles in the pores includes the following steps: dripping a metal particle dispersion on the surface of the porous alumina template layer, and completing the distribution of the metal particles in the pores after the solvent evaporates.

[0059] The metal particles are dispersed in a solvent and evenly drop-coated on the surface of the porous alumina template layer. They enter the pores of the template layer through capillary force and geometric constraints. As the solvent evaporates, the metal particles are integrated into the pores of the template layer.

[0060] The solvent used to disperse the metal particles includes water and / or alcohol solvents; the alcohol solvents include methanol and / or ethanol.

[0061] Preferably, the drying temperature in step (3) is 20-50°C, for example, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C or 50°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0062] Preferably, the drying time in step (3) is 10-14 hours, for example, 10 hours, 11 hours, 12 hours, 13 hours or 14 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0063] Preferably, the cleaning agent used in step (4) comprises ethanol and / or deionized water.

[0064] Preferably, the air drying in step (4) is performed using a protective gas, and the protective gas includes nitrogen and / or an inert gas.

[0065] As a preferred technical solution of the preparation method described in the second aspect of the present invention, the preparation method comprises the following steps:

[0066] (1) depositing a transition metal compound layer on the substrate layer, and then spin-coating an electron beam glue on the surface of the transition metal compound layer, heating and curing at 70-80° C. for 4-6 minutes to form an electron beam glue layer with a thickness of 280-320 nm; the spin coating speed is 2800-3200 rpm, and the time is 40-60 seconds;

[0067] (2) removing the base layer by etching with an alkaline solution, and then immersing and cleaning the transition metal compound layer provided with the electron beam gel layer;

[0068] (3) Remove the floating transition metal compound layer from the porous alumina template layer, dry it at 20-50°C for 10-14 hours, and then immerse it in an organic solvent to remove the electron beam gel layer on the surface of the transition metal compound layer;

[0069] (4) washing with ethanol and deionized water and drying with nitrogen gas in sequence to obtain the transition metal compound fluorescence enhanced heterostructure.

[0070] Further preferably, the preparation method comprises the following steps:

[0071] (1) depositing a transition metal compound layer on the substrate layer, and then spin-coating PMMA electron beam glue on the surface of the transition metal compound layer, heating and curing at 70-80° C. for 4-6 minutes to form a PMMA electron beam glue layer with a thickness of 280-320 nm; the spin coating speed is 2800-3200 rpm, and the time is 40-60 seconds;

[0072] (2) removing the base layer by etching with a saturated NaOH solution, and then immersing the transition metal compound layer provided with the PMMA electron beam gel layer in deionized water for cleaning;

[0073] (3) using a porous alumina template layer connected to the aluminum substrate layer to fish out the floating transition metal compound layer, drying it at 20-50° C. for 10-14 hours, and then immersing it in acetone until the PMMA electron beam gel layer on the surface of the transition metal compound layer is removed;

[0074] (4) washing with ethanol and deionized water and drying with nitrogen gas in sequence to obtain the transition metal compound fluorescence enhanced heterostructure.

[0075] In a third aspect, the present invention provides a use of the transition metal compound fluorescence-enhanced heterostructure as described in the first aspect, wherein the transition metal compound fluorescence-enhanced heterostructure is used to prepare a light-emitting device, a photodetection device, or an electronic flexible device.

[0076] Compared with the prior art, the present invention has the following beneficial effects:

[0077] The present invention prepares a transition metal compound layer by deposition, and suspends it on the surface of a porous alumina template layer by wet transfer to construct a transition metal compound fluorescence-enhanced heterostructure comprising a stacked transition metal compound layer, a porous alumina template layer, and a metal substrate layer. The fluorescence intensity of the transition metal compound in the obtained transition metal compound fluorescence-enhanced heterostructure can be enhanced by up to 22 times compared to that of the SiO2 substrate layer, thereby achieving regulation of its optical properties. The preparation method of the present invention is low-cost and easy to operate, and the obtained fluorescence-enhanced heterostructure can be widely used in fields such as high-performance low-dimensional material devices, optoelectronic devices, or flexible electronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 A schematic structural diagram of the porous alumina template layer provided by the present invention;

[0079] Figure 2 A schematic diagram of the top view of the porous alumina template layer provided by the present invention;

[0080] Figure 3 A schematic side view of the porous alumina template layer provided by the present invention;

[0081] Figure 4 Schematic diagram of the transition metal compound fluorescence enhanced heterostructure provided in Examples 6, 7, and 8.

[0082] Among them: 1, metal substrate layer; 2, porous alumina template layer; 3, transition metal compound layer; 4, metal particles. DETAILED DESCRIPTION

[0083] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0084] Control Example

[0085] This control example provides a fluorescence-enhancing heterostructure, which differs from Example 1 in that the fluorescence-enhancing heterostructure includes a molybdenum disulfide layer and a Si / SiO2 substrate layer, and the fluorescence-enhancing heterostructure is obtained by chemical vapor deposition of a molybdenum disulfide layer on the Si / SiO2 substrate layer; the molybdenum disulfide layer is a single layer of molybdenum disulfide with a thickness of 0.65 nm; the rest is the same as Example 1.

[0086] The transition metal compound fluorescence-enhanced heterostructures provided in the following examples and comparative examples were tested for fluorescence intensity, and the fluorescence intensity results obtained in the examples and comparative examples were compared with those in the control example.

[0087] Example 1

[0088] This embodiment provides a transition metal compound fluorescence enhancement heterostructure, which includes a stacked transition metal compound layer 3, a porous alumina template layer 2, and a metal substrate layer 1; the transition metal compound layer 3 is a molybdenum disulfide layer, a porous alumina template layer, and the metal substrate layer 1 is an aluminum substrate layer;

[0089] The molybdenum disulfide layer is a single layer of molybdenum disulfide with a thickness of 0.65 nm. The depth of its bending and sinking at the hole of the porous alumina template layer 2 is 10 nm. The holes of the porous alumina template layer 2 are periodically distributed in a hexagonal honeycomb shape, and the hole openings are bowl-shaped structures (see Figure 1 ); period interval D int 100nm (see Figure 2 ), depth is 130nm, pore diameter D p 85nm (see Figure 3 ).

[0090] The transition metal compound fluorescence enhanced heterostructure is obtained by the following preparation method, which comprises the following steps:

[0091] (1) A molybdenum disulfide layer was chemically vapor deposited on the SiO2 substrate layer, and then PMMA electron beam glue was spin-coated on the surface of the molybdenum disulfide layer and heated and cured at 75°C for 5 minutes to form a PMMA electron beam glue layer with a thickness of 300 nm; the spin coating speed was 3000 rpm and the time was 50 seconds;

[0092] (2) removing the SiO2 substrate layer by etching with a saturated NaOH solution, and then immersing the molybdenum disulfide layer provided with the PMMA electron beam gel layer in deionized water for cleaning;

[0093] (3) Using the porous alumina template layer 2 connected to the aluminum substrate layer, the floating molybdenum disulfide layer was fished out, dried at 30°C for 12 hours, and then immersed in acetone to remove the PMMA electron beam gel layer on the surface of the molybdenum disulfide layer;

[0094] (4) washing with ethanol and deionized water and drying with nitrogen gas in sequence to obtain the transition metal compound fluorescence enhanced heterostructure.

[0095] The fluorescence intensity of molybdenum disulfide in the transition metal compound fluorescence-enhanced heterostructure obtained in this example is 19 times that of the control example.

[0096] Example 2

[0097] This embodiment provides a transition metal compound fluorescence enhancement heterostructure, which includes a stacked transition metal compound layer 3, a porous aluminum oxide template layer 2, and a metal substrate layer 1; the transition metal compound layer 3 is a molybdenum disulfide layer, and the metal substrate layer 1 is an aluminum substrate layer;

[0098] The molybdenum disulfide layer is a single layer of molybdenum disulfide with a thickness of 0.65 nm. The depth of its bending and sinking at the hole of the porous alumina template layer 2 is 5 nm. The holes of the porous alumina template layer 2 are periodically distributed in a hexagonal honeycomb shape, and the hole openings are bowl-shaped structures (see Figure 1 ); period interval D int 80nm (see Figure 2 ), with a depth of 30 nm and a pore diameter of 30 nm (see Figure 3 ).

[0099] The transition metal compound fluorescence enhanced heterostructure is obtained by the following preparation method, which comprises the following steps:

[0100] (1) A molybdenum disulfide layer was chemically vapor deposited on the SiO2 substrate layer, and then PMMA electron beam glue was spin-coated on the surface of the molybdenum disulfide layer and heated and cured at 70°C for 6 minutes to form a PMMA electron beam glue layer with a thickness of 280 nm. The spin coating speed was 2800 rpm and the spin coating time was 60 seconds.

[0101] (2) removing the SiO2 substrate layer by etching with a saturated NaOH solution, and then immersing the molybdenum disulfide layer provided with the PMMA electron beam gel layer in deionized water for cleaning;

[0102] (3) Using the porous alumina template layer 2 connected to the aluminum substrate layer, the floating molybdenum disulfide layer was fished out, dried at 20°C for 14 h, and then immersed in acetone to remove the PMMA electron beam gel layer on the surface of the molybdenum disulfide layer;

[0103] (4) washing with ethanol and deionized water and drying with nitrogen gas in sequence to obtain the transition metal compound fluorescence enhanced heterostructure.

[0104] The fluorescence intensity of molybdenum disulfide in the transition metal compound fluorescence-enhanced heterostructure obtained in this example is 10 times that of the control example.

[0105] Example 3

[0106] This embodiment provides a transition metal compound fluorescence enhancement heterostructure, which includes a stacked transition metal compound layer 3, a porous aluminum oxide template layer 2, and a metal substrate layer 1; the transition metal compound layer 2 is a molybdenum disulfide layer, and the metal substrate layer is an aluminum substrate layer;

[0107] The molybdenum disulfide layer is a single layer of molybdenum disulfide with a thickness of 0.65 nm. The depth of its bending and sinking at the hole of the porous alumina template layer 2 is 15 nm. The holes of the porous alumina template layer 2 are periodically distributed in a hexagonal honeycomb shape, and the hole openings are bowl-shaped structures (see Figure 1 ); period interval D int 120nm (see Figure 2 ), depth is 150nm, pore diameter D p 100nm (see Figure 3 ).

[0108] The transition metal compound fluorescence enhanced heterostructure is obtained by the following preparation method, which comprises the following steps:

[0109] (1) A molybdenum disulfide layer was chemically vapor deposited on the SiO2 substrate layer, and then PMMA electron beam glue was spin-coated on the surface of the molybdenum disulfide layer and heated and cured at 80°C for 4 minutes to form a PMMA electron beam glue layer with a thickness of 320 nm. The spin coating speed was 3200 rpm and the spin coating time was 40 seconds.

[0110] (2) removing the SiO2 substrate layer by etching with a saturated NaOH solution, and then immersing the molybdenum disulfide layer provided with the PMMA electron beam gel layer in deionized water for cleaning;

[0111] (3) Using the porous alumina template layer 2 connected to the aluminum substrate layer, the floating molybdenum disulfide layer was fished out, dried at 50°C for 10 h, and then immersed in acetone to remove the PMMA electron beam gel layer on the surface of the molybdenum disulfide layer;

[0112] (4) washing with ethanol and deionized water and drying with nitrogen gas in sequence to obtain the transition metal compound fluorescence enhanced heterostructure.

[0113] The fluorescence intensity of molybdenum disulfide in the transition metal compound fluorescence-enhanced heterostructure obtained in this example is 22 times that of the control example.

[0114] Example 4

[0115] This embodiment provides a transition metal compound fluorescence enhanced heterostructure. Except for adjusting the parameters for preparing molybdenum disulfide so that the molybdenum disulfide layer is a few-layer molybdenum disulfide with a thickness of 2.6 nm and a depth of 5 nm at the pores of the porous alumina template layer 2, the rest is the same as Example 1.

[0116] The fluorescence intensity of molybdenum disulfide in the transition metal compound fluorescence-enhanced heterostructure obtained in this example is 8 times that of the control example.

[0117] Example 5

[0118] This embodiment provides a transition metal compound fluorescence-enhanced heterostructure. Except for adjusting the parameters for preparing molybdenum disulfide so that the molybdenum disulfide layer is a few-layer molybdenum disulfide with a thickness of 6.5 nm and a depth of 3 nm at the pores of the porous alumina template layer 2, everything else is the same as in Example 1.

[0119] The fluorescence intensity of molybdenum disulfide in the transition metal compound fluorescence-enhanced heterostructure obtained in this example is 5 times that of the control example.

[0120] Example 6

[0121] This embodiment provides a Figure 4 The transition metal compound fluorescence enhanced heterostructure shown is different from Example 1 in that metal particles 4 with a diameter of 80 nm are distributed in the pores of the porous alumina template layer 2 , and the metal particles 4 are Au particles.

[0122] The Au particles are dispersed in a 1 mg / mL CH3-PEG-SH ethanol solution and drop-coated on the surface of the porous alumina template layer 2 to complete the distribution in the pores. The integration degree of the platinum particles is ≥95%, and the distribution density is ≥10 10 pieces / cm 2 , the rest are the same as in Example 1.

[0123] The fluorescence intensity of molybdenum disulfide in the transition metal compound fluorescence-enhanced heterostructure obtained in this example is 13 times that of the control example.

[0124] Example 7

[0125] This embodiment provides a Figure 4 The transition metal compound fluorescence enhanced heterostructure shown is different from Example 2 in that metal particles 4 with a diameter of 20 nm are distributed in the pores of the porous alumina template layer 2, and the metal particles 4 are Au particles.

[0126] The Au particles are dispersed in a 1 mg / mL CH3-PEG-SH ethanol solution and drop-coated on the surface of the porous alumina template layer 2 to complete the distribution in the pores. The integration degree of the platinum particles is ≥95%, and the distribution density is ≥10 10 pieces / cm 2 , the rest are the same as in Example 2.

[0127] The fluorescence intensity of molybdenum disulfide in the transition metal compound fluorescence-enhanced heterostructure obtained in this example is 10 times that of the control example.

[0128] Example 8

[0129] This embodiment provides a Figure 4 The transition metal compound fluorescence enhanced heterostructure shown is different from Example 3 in that metal particles 4 with a diameter of 90 nm are distributed in the pores of the porous alumina template layer 2 , and the metal particles 4 are Au particles.

[0130] The Au particles are dispersed in a 1 mg / mL CH3-PEG-SH ethanol solution and drop-coated on the surface of the porous alumina template layer 2 to complete the distribution in the pores. The integration degree of the platinum particles is ≥95%, and the distribution density is ≥10 10 pieces / cm 2 , the rest are the same as in Example 3.

[0131] The fluorescence intensity of molybdenum disulfide in the transition metal compound fluorescence-enhanced heterostructure obtained in this example is 18 times that of the control example.

[0132] Comparative Example 1

[0133] This comparative example provides a transition metal compound fluorescence-enhanced heterostructure, which differs from Example 1 in that, in addition to adjusting the parameters for preparing molybdenum disulfide so that the molybdenum disulfide layer is a few-layer molybdenum disulfide layer, the thickness of the molybdenum disulfide layer is 7.8 nm, and the depth of its bending and sinking at the holes of the porous alumina template layer 2 is 1 nm, the rest is the same as Example 1.

[0134] The fluorescence intensity of molybdenum disulfide in the transition metal compound fluorescence enhanced heterostructure obtained in this comparative example is three times that of the control example.

[0135] In summary, the present invention prepares a transition metal compound layer by deposition, and suspends it on the surface of a porous alumina template layer by wet transfer to construct a transition metal compound fluorescence-enhanced heterostructure comprising a stacked transition metal compound layer, a porous alumina template layer, and a metal substrate layer. The fluorescence intensity of the transition metal compound in the obtained transition metal compound fluorescence-enhanced heterostructure can be enhanced up to 22 times compared to the SiO2 substrate layer, thereby achieving regulation of its optical properties. The preparation method of the present invention has low cost and is easy to operate. The obtained transition metal compound fluorescence-enhanced heterostructure can be widely used in high-performance low-dimensional material devices, optoelectronic devices, flexible electronic devices, and other fields.

[0136] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A transition metal compound fluorescence enhanced heterostructure, characterized in that: The transition metal compound fluorescence enhancement heterostructure comprises a stacked transition metal compound layer, a porous alumina template layer, and a metal substrate layer; the porous alumina template layer comprises holes periodically distributed in a hexagonal honeycomb pattern; the openings of the holes are bowl-shaped; The transition metal compound layer is suspended on the porous alumina template layer; In the porous alumina template layer, the periodic interval of the holes is D int 80-120nm; In the porous alumina template layer, the pore size D p 30-90nm; The thickness of the transition metal compound layer is 0.6-10 nm; The transition metal compound in the transition metal compound layer includes any one of molybdenum disulfide, molybdenum diselenide, molybdenum ditelluride, tungsten disulfide, tungsten diselenide, rhenium disulfide or rhenium diselenide, or a combination of at least two thereof; The transition metal compound layer has a curved depression with a depth of ≥3nm at the pores of the porous alumina template layer; metal particles are distributed in the pores of the porous alumina template layer; the metal particles are distributed in a single layer; and the size of the metal particles is 20-80nm.

2. The transition metal compound fluorescence enhanced heterostructure according to claim 1, characterized in that: The depth of the bent depression is 5-15 nm.

3. The transition metal compound fluorescence enhanced heterostructure according to claim 1, characterized in that: In the porous alumina template layer, the depth of the holes is ≥30 nm.

4. The transition metal compound fluorescence enhanced heterostructure according to claim 1, characterized in that: The metal substrate layer includes an aluminum substrate layer.

5. The transition metal compound fluorescence enhanced heterostructure according to claim 1, characterized in that: The metal in the metal particles includes any one of Au, Ag, Cu or Pt, or a combination of at least two of them.

6. The transition metal compound fluorescence enhanced heterostructure according to claim 5, characterized in that: The metal in the metal particles is any one of Au, Ag or Pt, or a combination of at least two of them.

7. The transition metal compound fluorescence enhanced heterostructure according to claim 1, characterized in that: The integration degree of the metal particles in the porous alumina template layer is ≥95%.

8. The transition metal compound fluorescence enhanced heterostructure according to claim 1, characterized in that: The distribution density of the metal particles is ≥10 10 pieces / cm 2 .

9. A method for preparing a transition metal compound fluorescence-enhanced heterostructure according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: (1) depositing a transition metal compound layer on the substrate layer, then coating the surface of the transition metal compound layer with an electron beam photoresist, and heating and curing the layer to form an electron beam photoresist layer; (2) removing the base layer by etching with an alkaline solution, and then immersing and cleaning the transition metal compound layer provided with the electron beam photoresist layer; (3) Remove the floating transition metal compound layer from the porous alumina template layer, dry it, and immerse it in an organic solvent to remove the electron beam photoresist layer on the surface of the transition metal compound layer; (4) After washing and air-drying, the transition metal compound fluorescence enhanced heterostructure is obtained.

10. The preparation method according to claim 9, characterized in that The deposition method in step (1) includes chemical vapor deposition and / or physical vapor deposition.

11. The preparation method according to claim 9, characterized in that The coating method in step (1) includes spin coating.

12. The preparation method according to claim 11, characterized in that The spin coating has a rotation speed of 2800-3200 rpm and a time of 40-60 s.

13. The preparation method according to claim 9, characterized in that The thickness of the electron beam photoresist layer in step (1) is 280-320 nm.

14. The preparation method according to claim 9, characterized in that The electron beam photoresist in step (1) includes PMMA electron beam glue and / or PDMS electron beam glue.

15. The preparation method according to claim 9, characterized in that The organic solvent in step (3) includes any one of acetone, methanol, ethanol or ether, or a combination of at least two of them.

16. The preparation method according to claim 9, characterized in that In step (3), metal particles are distributed in the pores of the porous alumina template layer. The method for distributing the metal particles in the pores comprises the following steps: a metal particle dispersion is drop-coated on the surface of the porous alumina template layer, and after the solvent evaporates, the metal particles are distributed in the pores.

17. The preparation method according to claim 9, characterized in that The preparation method comprises the following steps: (1) chemical vapor deposition of a transition metal compound layer on the substrate layer, and then spin coating an electron beam photoresist on the surface of the transition metal compound layer, heating and curing to form an electron beam photoresist layer with a thickness of 280-320 nm; the spin coating speed is 2800-3200 rpm, and the time is 40-60 s; (2) removing the base layer by etching with an alkaline solution, and then immersing and cleaning the transition metal compound layer provided with the electron beam photoresist layer; (3) Remove the floating transition metal compound layer from the porous alumina template layer, dry it, and immerse it in acetone to remove the electron beam photoresist layer on the surface of the transition metal compound layer; (4) After washing and air-drying, the transition metal compound fluorescence enhanced heterostructure is obtained.

18. Use of the transition metal compound fluorescence enhancement heterostructure according to any one of claims 1 to 8, characterized in that: The transition metal compound fluorescence enhanced heterostructure is used for preparing light-emitting devices, photoelectric detection devices or electronic flexible devices.

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