Light-emitting up-conversion nanoparticle-based iron-phosphorus-sulfur / tungsten diselenide heterojunction photoelectric detector, and preparation method and application of light-emitting up-conversion nanoparticle-based iron-phosphorus-sulfur / tungsten diselenide heterojunction photoelectric detector
By combining iron phosphorus sulfur/tungsten diselenide heterojunction with upconversion nanoparticles, the problem of insufficient performance of existing photodetectors in the near-infrared band is solved, efficient near-infrared photodetection is achieved, and photoelectric performance is improved.
Patent Information
- Application Number
- CN202510768937.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-10
- Publication Date
- 2025-09-05
AI Technical Summary
Existing near-infrared photodetectors based on upconversion nanoparticles have not reached ideal levels in terms of performance parameters, especially the insufficient light response performance in the near-infrared band, and the low electron-hole pair generation efficiency of two-dimensional materials in the infrared region.
By combining an iron phosphorus sulfur/tungsten diselenide heterojunction with upconversion nanoparticles, a built-in electric field is generated at the interface of tungsten diselenide and iron phosphorus sulfur, and the upconversion nanoparticles are used to convert near-infrared light into visible light. The photogenerated carriers are separated under the action of the built-in electric field at the heterojunction interface, forming a near-infrared selective photodetector based on iron phosphorus sulfur/tungsten diselenide-upconversion nanoparticles.
The photoelectric performance of the photodetector at 980nm has been significantly improved, and selective detection of the near-infrared has been achieved. The process is simple and the quality is stable, and it has certain application potential.
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Figure CN120603338A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of micro-nano optoelectronic device manufacturing. More specifically, it relates to a photoelectric detector based on a two-dimensional iron-phosphorus-sulfur-tungsten diselenide heterojunction of luminescent upconversion nanoparticles, as well as a preparation method and application thereof, which is particularly suitable for wavelength-selective detection in the near-infrared band. Background Art
[0002] Photodetectors are key components in modern optoelectronic systems, playing a vital role in converting optical signals into detectable electrical signals. They hold broad application prospects in fields such as optical communications, biosensing, environmental monitoring, and military reconnaissance. Diversified market demands are driving the functionalization of photodetectors. Near-infrared selective photodetectors, a popular research topic in the near-infrared region, have garnered widespread attention. Currently, methods for achieving wavelength-selective detection include designing materials with specific absorption wavelengths, modifying device structures, enhancing narrowband absorption through surface plasmon resonance, and suppressing carrier collection efficiency in non-target light absorption bands.
[0003] In recent years, the strategy of combining upconversion nanoparticles with two-dimensional materials has opened up new possibilities in the field of near-infrared selective photodetection. The innovation of this approach lies in that it circumvents the traditional technical route of adjusting the material absorption spectrum by doping impurities or constructing hybrid structures, thereby retaining the advantages of two-dimensional semiconductor materials and having advantages such as simple preparation, special wavelength selectivity, and flexibility. Upconversion nanoparticles act as energy transfer media, capable of converting low-energy photons or long-wavelength light (primarily near-infrared light) into high-energy photons or short-wavelength light (such as visible light or ultraviolet light). Two-dimensional materials act as energy receivers, exhibiting high photosensitivity and high sensitivity in the visible light range. However, due to the limitation of the band gap, they suffer greater losses in the infrared region, and the efficiency of generating electron-hole pairs is seriously reduced. The stable, intense, and wavelength-tunable upconversion luminescence properties of upconversion nanoparticles well compensate for the insufficient photoresponse performance of iron phosphorus sulfur in the near-infrared band. However, due to the low quantum efficiency and high pumping threshold of upconversion nanoparticles, the performance parameters of photodetectors based on the combination of the two have not reached the ideal level compared with the performance of two-dimensional material photodetectors in the visible light region.
[0004] Iron phosphorus sulfur (FePS3) is an emerging class of transition metal sulfide phosphates with the general formula MPX3 (a chalcogenide where M is a transition metal, P is phosphorus, and X = S or Se). Compared to other transition metal chalcogenides, FePS3 has a lower cleavage energy, making it easier to exfoliate layered materials. Furthermore, FePS3 exhibits not only good responsivity in the UV range but also, because its band edge lies in the Vis-NIR region, enables broadband photoresponse from the UV-Vis to the NIR. Summary of the Invention
[0005] To address the shortcomings and drawbacks of the aforementioned prior art, the present invention aims to provide an iron-phosphorus-sulfur-tungsten diselenide two-dimensional heterojunction photodetector based on upconversion nanoparticle luminescence. This photodetector utilizes a tungsten diselenide and iron-phosphorus-sulfur heterojunction to enhance photodetection performance in the visible light spectrum. Furthermore, through coupling with upconversion nanoparticles, a near-infrared selective photodetector based on the iron-phosphorus-sulfur / tungsten diselenide-upconversion nanoparticles is formed. This combines the advantages of heterojunction photodetectors and upconversion nanoparticles to achieve selective detection in the near-infrared spectrum.
[0006] Another object of the present invention is to provide a method for preparing the aforementioned iron phosphide tungsten diselenide two-dimensional heterojunction photodetector based on upconversion nanoparticle luminescence. This method utilizes the luminescence properties of nanoparticles to enhance the weak infrared light response of the iron phosphide tungsten diselenide heterojunction photodetector.
[0007] Another object of the present invention is to provide an application of the above-mentioned iron phosphorus sulfur diselenide two-dimensional heterojunction photodetector based on upconversion nanoparticle luminescence.
[0008] The purpose of the present invention is achieved through the following technical solutions:
[0009] A photodetector based on an iron phosphorus sulfur / tungsten diselenide heterojunction of luminescent upconversion nanoparticles includes, from bottom to top, a silicon dioxide / silicon substrate, a tungsten diselenide nanosheet / iron phosphorus sulfur nanosheet heterojunction, a metal electrode layer, and an upconversion nanoparticle layer; the tungsten diselenide nanosheet partially overlaps with the iron phosphorus sulfur nanosheet, and metal electrode layers are respectively provided at both ends of the tungsten diselenide nanosheet and the iron phosphorus sulfur nanosheet.
[0010] Preferably, the thickness of the tungsten diselenide nanosheet is 25-35 nm, the thickness of the iron phosphorus sulfur nanosheet is 29-35 nm, the metal electrode layer is titanium and gold, with thicknesses of 10-15 nm and 60-65 nm respectively; the thickness of the upconversion nanoparticle layer is 100-150 nm.
[0011] The method for preparing the photodetector of the iron phosphorus sulfur / tungsten diselenide heterojunction based on luminescent upconversion nanoparticles comprises the following specific steps:
[0012] S1. Mechanically exfoliating single-crystalline tungsten diselenide onto a 300nm silicon oxide layer substrate to obtain tungsten diselenide nanosheets;
[0013] S2. The iron phosphorus sulfur single crystal was mechanically peeled off onto a silicon substrate having a 300nm oxide layer to obtain iron phosphorus sulfur nanosheets;
[0014] S3. Transferring the iron phosphorus sulfur nanosheets to the tungsten diselenide nanosheets by a polyvinyl alcohol (PVA) polymer-assisted transfer method to form an overlapping portion to prepare an iron phosphorus sulfur / tungsten diselenide heterojunction;
[0015] S4. Preparing electrodes at both ends of the iron phosphorus sulfur / tungsten diselenide heterojunction by electron beam evaporation or thermal evaporation;
[0016] S5. Spin-coat an upconversion nanoparticle solution on the iron phosphorus sulfur / tungsten diselenide heterojunction and dry it to produce an iron phosphorus sulfur / tungsten diselenide heterojunction photodetector based on luminescent upconversion nanoparticles.
[0017] Preferably, step S3 is specifically titrating PVA on polydimethylsiloxane (PDMS), and drying it at 55-60°C for 11-13 minutes to form a PVA film; placing the PDMS with the PVA film on a quartz wafer, aligning it with the silicon dioxide / silicon substrate layer with iron, phosphorus and sulfur through a two-dimensional material transfer table, and heat treating it at 92-96°C for 4-6 minutes to make the PVA / PDMS adhere to iron, phosphorus and sulfur nanosheets; then aligning the PVA / PDMS with the iron, phosphorus and sulfur nanosheets through a two-dimensional material transfer table with the silicon dioxide / silicon substrate layer with tungsten diselenide, so that the iron, phosphorus and sulfur nanosheets and the tungsten diselenide nanosheets partially overlap, placing it on a heating table and baking it at 97-102°C for 6-8 minutes; finally, placing it in deionized water at 55-60°C until the PVA is completely dissolved to obtain an iron, phosphorus and sulfur / tungsten diselenide heterojunction.
[0018] Preferably, the specific method in step S4 is to drop a positive photoresist on a silicon dioxide / silicon substrate layer having an iron phosphorus sulfur / tungsten diselenide heterojunction and spin-coat it in a coater for 1 to 1.5 minutes, and bake it at 100 to 105° C. on a drying table for 4 to 5 minutes; align it with a photolithography machine, perform ultraviolet exposure using a mask, develop it with a developer, and dry it to photoetch an electrode pattern; then use an electron beam or thermal evaporation method to evaporate 10 to 15 nm of Ti and 60 to 65 nm of Au on its surface; finally, place it in an acetone solution to remove excess gold and photoresist, remove residual acetone with deionized water, blow dry it, and then heat treat it at 150 to 160° C. in a nitrogen atmosphere for 30 to 35 minutes to obtain electrodes at both ends of the iron phosphorus sulfur / tungsten diselenide heterojunction.
[0019] Preferably, the absorption peak of the upconversion nanoparticles in step S5 is 970-990 nm, the emission peak is 550-590 nm, and the concentration of the upconversion nanoparticle solution is 100-110 mg / mL; the spin coating speed is 500-1000 rpm / min, the spin coating time is 2-3 min, the drying temperature is 55-65° C., and the drying time is 3-6 min.
[0020] The application of the photoelectric detector of the iron phosphorus sulfur / tungsten diselenide heterojunction based on luminescent upconversion nanoparticles in the field of near-infrared detection.
[0021] Compared with the prior art, the present invention has the following beneficial effects:
[0022] 1. The present invention uses iron phosphorus sulfur / tungsten diselenide as a heterojunction. The built-in electric field generated at the iron phosphorus sulfur / tungsten diselenide interface can effectively separate photogenerated electron-hole pairs under visible light, which is beneficial to improving detection under weak light with low optical power density.
[0023] 2. The photodetector of the present invention forms a heterojunction between tungsten diselenide and iron phosphorus sulfur to improve the photoelectric detection performance under visible light, and forms a near-infrared selective photodetector based on iron phosphorus sulfur / tungsten diselenide-upconversion nanoparticles through the coupling of upconversion nanoparticles. It can combine the advantages of heterojunction photodetectors and upconversion nanoparticles, greatly improving the photoelectric performance of the device at 980nm, realizing selective detection in the near-infrared, with simple process, stable quality, and certain application potential.
[0024] 3. The photodetector of the present invention comprises a silicon dioxide / silicon substrate, tungsten diselenide nanosheets, iron-phosphorus-sulfur nanosheets, metal electrodes on both sides, and upconversion nanoparticles. The upconversion nanoparticles have an absorption peak between 970 and 990 nm and an emission peak between 500 and 540 nm. Under 980 nm illumination, the upconversion nanoparticles convert near-infrared light into visible light that is absorbed by the upper tungsten diselenide layer. The built-in electric field at the iron-phosphorus-sulfur / tungsten diselenide heterojunction interface effectively separates photogenerated carriers, generating a photocurrent, significantly improving photodetection performance at 980 nm. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 It is a schematic structural diagram of the photodetector of the iron phosphorus sulfur / tungsten diselenide heterojunction (FePS3 / WSe2) of the luminescent upconversion nanoparticles of the present invention;
[0026] Figure 2 is an optical microscope photograph of iron phosphorus sulfur nanosheets and tungsten diselenide nanosheets prepared by mechanical exfoliation in Example 1;
[0027] Figure 3is a current-voltage curve diagram of the iron phosphorus sulfur / tungsten diselenide photodetector of Example 1 at different light power densities at 532 nm;
[0028] Figure 4 is a graph showing the relationship between optical power density, photoresponsivity, and specific detectivity of the iron phosphorus sulfur / tungsten diselenide photodetector at 532 nm in Example 1;
[0029] Figure 5 is a current-voltage curve diagram of the iron phosphorus sulfur / tungsten diselenide upconversion nanoparticle photodetector under different light power densities at 980 nm in Example 1;
[0030] Figure 6 The optical power density of the iron phosphorus sulfur / tungsten diselenide upconversion nanoparticle photodetector and the iron phosphorus sulfur / tungsten diselenide detector under 980nm light irradiation is 114mW / cm 2 Time-resolved image of .
[0031] Figure 7 is an optical microscope photograph of iron phosphorus sulfur nanosheets and tungsten diselenide nanosheets prepared by mechanical exfoliation in Example 2;
[0032] Figure 8 is a current-voltage curve diagram of the iron phosphorus sulfur / tungsten diselenide photodetector at different light power densities at 532 nm in Example 2;
[0033] Figure 9 is a graph showing the relationship between optical power density, photoresponsivity, and specific detectivity at 532 nm based on an iron phosphorus sulfur / tungsten diselenide photodetector according to Example 2;
[0034] Figure 10 The current-voltage curves of the photodetector based on iron phosphorus sulfur / tungsten diselenide photodetector and iron phosphorus sulfur / tungsten diselenide-upconversion nanoparticles under 980 nm light irradiation at the same light power density in Example 2 are shown;
[0035] Figure 11 The optical power density of the photodetector based on iron phosphorus sulfur / tungsten diselenide upconversion nanoparticles and the photodetector based on iron phosphorus sulfur / tungsten diselenide at 980 nm is 115 mW / cm 2 Time-resolved image of . DETAILED DESCRIPTION
[0036] The present invention will be further described below in conjunction with specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.
[0037] Example 1
[0038] Figure 1 This is a schematic diagram of the structure of the photodetector based on the iron phosphorus sulfur / tungsten diselenide heterojunction (FePS3 / WSe2) of the present invention based on luminescent upconversion nanoparticles, wherein: 1-silicon dioxide / silicon substrate; 2-tungsten diselenide nanosheets; 3-iron phosphorus sulfur nanosheets; 4-metal electrode layer; 5-upconversion nanoparticle layer. Figure 1 As shown, the photodetector based on the iron phosphorus sulfur / tungsten diselenide heterojunction (FePS3 / WSe2) of luminescent upconversion nanoparticles is provided with a silicon dioxide / silicon substrate 1, a tungsten diselenide / iron phosphorus sulfur heterojunction formed by iron phosphorus sulfur nanosheets 2 and tungsten diselenide nanosheets 3, a metal electrode layer 4 and an upconversion nanoparticle layer 5 in sequence from bottom to top; the tungsten diselenide nanosheets partially overlap with the iron phosphorus sulfur nanosheets, and metal electrode layers 4 are respectively provided at both ends of the tungsten diselenide nanosheets and the iron phosphorus sulfur nanosheets, and the metal electrode layer 4 is in asymmetric contact with the two two-dimensional materials (iron phosphorus sulfur nanosheets and tungsten diselenide nanosheets); the overlapping area accounts for 30-40%; the thickness of the iron phosphorus sulfur nanosheets 2 is 32±3nm, the thickness of the tungsten diselenide nanosheets 3 is 30±5nm, the metal electrode layer 4 is 10nm thick titanium and 60nm thick gold, and the thickness of the upconversion nanoparticle layer 5 is 100-150nm.
[0039] The specific preparation method is as follows:
[0040] 1. Cut the silica / silicon substrate layer 1 into 15 mm x 15 mm pieces and ultrasonically clean it in acetone for 12 minutes to remove any organic matter attached to its surface. Then, ultrasonically clean it in anhydrous ethanol for 12 minutes to remove any residual acetone solution on the silica / silicon substrate layer 1. Finally, ultrasonically clean it in deionized water for 10 minutes to remove any residual ethanol and particles on the surface of the substrate 1. After cleaning, blow dry it with high-purity nitrogen gas.
[0041] 2. The single crystal iron phosphorus sulfur is peeled off onto the silicon dioxide / silicon substrate layer by mechanical exfoliation to obtain a few layers of iron phosphorus sulfur nanosheets.
[0042] 3. The single crystal tungsten diselenide is peeled off onto the silicon dioxide / silicon substrate layer by mechanical peeling to obtain a few-layer tungsten diselenide nanosheets.
[0043] 3. Transfer the tungsten diselenide nanosheets onto the iron phosphorus sulfur nanosheets to form a tungsten diselenide / iron phosphorus sulfur heterojunction, such as Figure 2As shown. A polyvinyl alcohol (PVA) solution was dripped onto a polydimethylsiloxane (PDMS) film and dried at 55°C for 11 minutes to form a thin film. The PDMS with the PVA film was placed on a quartz glass slide and aligned with a silicon dioxide / silicon substrate layer containing iron, phosphorus and sulfur using a two-dimensional material transfer platform. Heat treatment was performed at 94°C for 4 minutes to adhere iron, phosphorus and sulfur nanosheets to the PVA. The PVA / PDMS with the iron, phosphorus and sulfur nanosheets was then aligned with a silicon dioxide / silicon substrate layer containing tungsten diselenide nanosheets using a two-dimensional material transfer platform, so that the iron, phosphorus and sulfur nanosheets partially overlapped. The film was then placed on a heating platform and baked at 98°C for 6 minutes. It was then immersed in deionized water at 55°C for 20 minutes to completely dissolve the PVA, thereby forming a tungsten diselenide / iron, phosphorus and sulfur heterojunction.
[0044] 4. A positive photoresist was dripped onto the silicon dioxide / silicon substrate of the iron-phosphorus-sulfur / tungsten diselenide heterojunction and spin-coated at 3000 rpm / min for 1 minute using a spin coater. The sample was then baked at 100°C for 4 minutes on a hot plate. The electrode pattern was then photolithographically patterned using a photolithography machine for alignment, UV exposure of the mask, development with a developer, and drying. 10nm of Ti and 60nm of Au were deposited on the surface using electron beam or thermal evaporation. The sample was then placed in an acetone solution to remove excess gold and photoresist. After drying, the sample was heat-treated at 150°C for 30 minutes in a nitrogen atmosphere using a defect passivation device, forming electrodes at both ends of the iron-phosphorus-sulfur / tungsten diselenide heterojunction.
[0045] 5. Spin-coat the upconversion nanoparticle solution (concentration of 100 mg / mL) on the tungsten diselenide / iron phosphorus sulfur heterojunction at a spin-coating speed of 500 rpm / min for 2-3 minutes and a drying temperature of 65°C for 3 minutes to obtain a tungsten diselenide / iron phosphorus sulfur-upconversion nanoparticle photodetector device.
[0046] The photoelectric detection device of the tungsten diselenide / iron phosphorus sulfur upconversion nanoparticles prepared in Example 1 was tested, and the results were as follows: Figure 3-6 shown. Figure 3 The current-voltage curves of the tungsten diselenide / iron phosphorus sulfur photodetector device at different light power densities at 532 nm are shown in Example 1. Figure 3 It can be seen that the tungsten diselenide / iron phosphorus sulfur heterojunction exhibits a rectification ratio of more than 150, which is caused by the Schottky contact between the iron phosphorus sulfur nanosheets and the tungsten diselenide nanosheets. The heterojunction achieves a 1.5×10 2 The switching ratio. Figure 4 The relationship between the optical power density, photoresponsivity and specific detectivity of the photodetector device based on tungsten diselenide / iron phosphorus sulfur at 532 nm in Example 1 is shown in FIG. Figure 4 It can be seen that the response rate of the device reached 370.97 mA / W, and the specific detection rate was 1.08×1011 Jones, heterojunctions exhibit excellent detection performance of photodetectors. Figure 5 The current-voltage curves of the photodetector of the iron phosphorus sulfur / tungsten diselenide upconversion nanoparticles of Example 1 at different light power densities at 980 nm are shown in FIG. Figure 5 It can be seen that the photodetector based on iron phosphorus sulfur / tungsten diselenide upconversion nanoparticles exhibits obvious photoresponse at 980nm. Figure 6 The time-resolved optical diagram of the iron phosphorus sulfur / tungsten diselenide upconversion nanoparticle photodetector and the iron phosphorus sulfur / tungsten diselenide photodetector at the same optical power density at 980nm is shown in Example 1. Figure 6 It can be seen that after adding upconversion nanoparticles, the optical circuit of the tungsten diselenide / iron phosphorus sulfur photodetector device is greatly improved, proving that there is energy transfer between the iron phosphorus sulfur / tungsten diselenide heterojunction and the upper layer upconversion nanoparticles, and it has excellent photodetection performance at 980nm.
[0047] Example 2
[0048] The difference from Example 1 is that the thickness of the iron phosphorus sulfur nanosheets in the iron phosphorus sulfur layer 2 is 28±2nm, the thickness of the tungsten diselenide nanosheets in the tungsten diselenide layer 3 is 30±3nm, the thickness of the upconversion nanoparticle layer 5 is 100-130nm, and the metal electrode layer 4 is 13nm thick titanium and 63nm thick gold.
[0049] The specific preparation method is as follows:
[0050] 1. Cut the silica / silicon substrate layer 1 into 15 mm x 15 mm pieces and ultrasonically clean it in acetone for 12 minutes to remove any organic matter attached to its surface. Then, ultrasonically clean it in anhydrous ethanol for 12 minutes to remove any residual acetone solution on the silica / silicon substrate layer 1. Finally, ultrasonically clean it in deionized water for 10 minutes to remove any residual ethanol and particles on the surface of the substrate 1. After cleaning, blow dry it with high-purity nitrogen gas.
[0051] 2. The single crystal iron phosphorus sulfur is peeled off onto the silicon dioxide / silicon substrate layer by mechanical exfoliation to obtain a few layers of iron phosphorus sulfur nanosheets.
[0052] 3. The single crystal tungsten diselenide is peeled off onto the silicon dioxide / silicon substrate layer by mechanical peeling to obtain a few-layer tungsten diselenide nanosheets.
[0053] 4. Transfer the tungsten diselenide nanosheets to the silicon dioxide / silicon substrate layer with iron phosphorus sulfur to form a tungsten diselenide / iron phosphorus sulfur heterojunction, such as Figure 7As shown. A polyvinyl alcohol (PVA) solution was titrated onto a polydimethylsiloxane (PDMS) film and dried at 58°C for 12 minutes to form a thin film. The PDMS with the PVA film was placed on a quartz glass slide and aligned with a silicon dioxide / silicon substrate layer containing iron, phosphorus and sulfur using a two-dimensional material transfer platform. Heat treatment was performed at 92°C for 5 minutes to adhere iron, phosphorus and sulfur nanosheets to the PVA. The PVA / PDMS with iron, phosphorus and sulfur nanosheets was then aligned with a silicon dioxide / silicon substrate layer containing tungsten diselenide using a two-dimensional material transfer platform, so that the iron, phosphorus and sulfur and tungsten diselenide partially overlapped. The film was then placed on a heating table and baked at 102°C for 7 minutes. It was then immersed in deionized water at 58°C for 20 minutes to completely dissolve the PVA, thereby forming a tungsten diselenide / iron, phosphorus and sulfur heterojunction.
[0054] 5. A positive photoresist was dripped onto the silicon dioxide / silicon substrate of the iron-phosphorus-sulfur / tungsten diselenide heterojunction and spin-coated at 3000 rpm / min for 1.3 minutes using a spin coater. The film was then baked on a hot plate at 103°C for 5 minutes. The electrode pattern was then photolithographically patterned using a photolithography machine for alignment, UV exposure of the mask, development with a developer, and drying. 13nm of Ti and 63nm of Au were deposited on the surface using electron beam or thermal evaporation. The sample was then placed in an acetone solution to remove excess gold and photoresist. After drying, the sample was heat-treated at 155°C for 32 minutes in a nitrogen atmosphere using a defect passivation device, forming electrodes at both ends of the iron-phosphorus-sulfur / tungsten diselenide heterojunction.
[0055] 6. Spin-coat the tungsten diselenide / iron phosphorus sulfur heterojunction with an upconversion nanoparticle solution (concentration of 100 mg / mL) at a spin-coating speed of 750 rpm / min for 2-3 min and a drying temperature of 58°C for 5 min to obtain a tungsten diselenide / iron phosphorus sulfur-upconversion nanoparticle photodetector device.
[0056] The photoelectric detection device of the tungsten diselenide / iron phosphorus sulfur upconversion nanoparticles prepared in Example 2 was tested, and the results were as follows: Figure 8-11 shown. Figure 8 The current-voltage curves of the photodetector device based on tungsten diselenide / iron phosphorus sulfur under 532nm light irradiation at different light power densities in Example 2 are shown in FIG. Figure 8 It can be seen that the tungsten diselenide / iron phosphorus sulfur heterojunction exhibits a rectification ratio exceeding 110, which is caused by the Schottky contact between iron phosphorus sulfur and tungsten diselenide. The heterojunction achieves a 1.1×10 2 The switching ratio. Figure 9 The following is a graph showing the relationship between different optical power densities, photoresponsivity, and specific detection rate at 532 nm based on the tungsten diselenide / iron phosphorus sulfur photodetector device in Example 2. Figure 9 It can be seen that the response rate of the device reached 355.46 mA / W, and the specific detection rate was 2.93×10 11Jones, heterojunctions exhibit excellent detection performance of photodetectors. Figure 10 The current-voltage curves of the iron phosphorus sulfur / tungsten diselenide photodetector (FePS3 / WSe2) and the iron phosphorus sulfur / tungsten diselenide-upconversion nanoparticle photodetector (FePS3 / WSe2-UCNPS) at the same light power density at 980nm are shown in Example 2. Figure 10 It can be seen that the iron phosphorus sulfur / tungsten diselenide photodetector exhibits a more obvious photoresponse at 980nm after coupling with upconversion nanoparticles. Figure 11 The time-resolved image of the iron phosphorus sulfur / tungsten diselenide heterojunction-upconversion nanoparticle photodetector and the iron phosphorus sulfur / tungsten diselenide photodetector at the same light power density at 980nm is shown in Example 2. Figure 11 It can be seen that after the addition of upconversion nanoparticles, the photocurrent of the tungsten diselenide / iron phosphorus sulfur photodetector device increased significantly, proving that there is energy transfer between the iron phosphorus sulfur / tungsten diselenide heterojunction and the upper layer upconversion nanoparticles, and it has excellent photodetection performance at 980nm.
[0057] The above embodiments are preferred implementations of the present invention, but the implementations of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.
Claims
1. A photodetector based on an iron phosphorus sulfur / tungsten diselenide heterojunction of luminescent upconversion nanoparticles, characterized in that: The photodetector includes, from bottom to top, a heterojunction of a silicon dioxide / silicon substrate, a tungsten diselenide nanosheet / iron phosphorus sulfur nanosheet, a metal electrode layer, and an upconversion nanoparticle layer; the tungsten diselenide nanosheet partially overlaps with the iron phosphorus sulfur nanosheet, and metal electrode layers are respectively provided at both ends of the tungsten diselenide nanosheet and the iron phosphorus sulfur nanosheet.
2. The photodetector based on the iron phosphorus sulfur / tungsten diselenide heterojunction of luminescent upconversion nanoparticles according to claim 1, characterized in that: The thickness of the tungsten diselenide nanosheet is 25-35nm, the thickness of the iron phosphorus sulfur nanosheet is 29-35nm, the metal electrode layer is titanium and gold, with thicknesses of 10-15nm and 60-65nm respectively; the thickness of the upconversion nanoparticle layer is 100-150nm.
3. The method for preparing a photodetector based on an iron phosphorus sulfur / tungsten diselenide heterojunction of luminescent upconversion nanoparticles according to claim 1 or 2, characterized in that: The specific steps include: S1. Mechanically exfoliating single-crystalline tungsten diselenide onto a 300nm silicon oxide layer substrate to obtain tungsten diselenide nanosheets; S2. The iron phosphorus sulfur single crystal was peeled off by mechanical exfoliation onto a silicon substrate having a 300nm oxide layer to obtain iron phosphorus sulfur nanosheets; S3. Transferring the iron-phosphorus-sulfur nanosheets to the tungsten diselenide nanosheets by a polyvinyl alcohol polymer-assisted transfer method to form an overlapping portion to prepare an iron-phosphorus-sulfur / tungsten diselenide heterojunction; S4. Preparing electrodes at both ends of the iron phosphorus sulfur / tungsten diselenide heterojunction by electron beam evaporation or thermal evaporation; S5. Spin-coat an upconversion nanoparticle solution on the iron phosphorus sulfur / tungsten diselenide heterojunction and dry it to produce an iron phosphorus sulfur / tungsten diselenide heterojunction photodetector based on luminescent upconversion nanoparticles.
4. The method for preparing a photodetector based on an iron phosphorus sulfur / tungsten diselenide heterojunction of luminescent upconversion nanoparticles according to claim 3, characterized in that: Step S3 specifically comprises titrating PVA on PDMS, drying at 55-60°C for 11-13 minutes to form a PVA film; placing the PDMS with the PVA film on a quartz wafer, aligning it with a silicon dioxide / silicon substrate layer with iron, phosphorus and sulfur through a two-dimensional material transfer platform, and heat treating it at 92-96°C for 4-6 minutes to make the PVA / PDMS adhere to iron, phosphorus and sulfur nanosheets; then aligning the PVA / PDMS with the iron, phosphorus and sulfur nanosheets through a two-dimensional material transfer platform with a silicon dioxide / silicon substrate layer with tungsten diselenide, so that the iron, phosphorus and sulfur nanosheets and the tungsten diselenide nanosheets partially overlap, placing it on a heating table and baking it at 97-102°C for 6-8 minutes; finally, placing it in deionized water at 55-60°C until the PVA is completely dissolved to obtain an iron, phosphorus and sulfur / tungsten diselenide heterojunction.
5. The method for preparing a photodetector based on an iron phosphorus sulfur / tungsten diselenide heterojunction of luminescent upconversion nanoparticles according to claim 3, characterized in that: The specific method in step S4 is to drop a positive photoresist on a silicon dioxide / silicon substrate layer with an iron phosphorus sulfur / tungsten diselenide heterojunction, spin-coat it in a coater for 1 to 1.5 minutes, and bake it in a drying table at 100 to 105° C. for 4 to 5 minutes; perform alignment using a photolithography machine, perform ultraviolet exposure using a mask, develop with a developer, and dry it to photoetch an electrode pattern; then evaporate 10 to 15 nm of Ti and 60 to 65 nm of Au on the surface using an electron beam or thermal evaporation method; finally, place it in an acetone solution to remove excess gold and photoresist, remove residual acetone with deionized water, blow dry it, and then heat treat it at 150 to 160° C. in a nitrogen atmosphere for 30 to 35 minutes to obtain electrodes at both ends of the iron phosphorus sulfur / tungsten diselenide heterojunction.
6. The method for preparing a photodetector based on an iron phosphorus sulfur / tungsten diselenide heterojunction of luminescent upconversion nanoparticles according to claim 3, characterized in that: The absorption peak of the upconversion nanoparticles in step S5 is 970-990 nm, the emission peak is 550-590 nm, and the concentration of the upconversion nanoparticle solution is 100-110 mg / mL; the spin coating speed is 500-1000 rpm / min, the spin coating time is 2-3 min, the drying temperature is 55-65° C., and the drying time is 3-6 min.
7. Application of the iron phosphorus sulfur / tungsten diselenide heterojunction photodetector based on luminescent upconversion nanoparticles according to claim 1 or 2 in the field of near-infrared detection.