Metal-organic photothermal conversion material, photothermal conversion layer, preparation method thereof and photothermal conversion device

Abstract

This invention discloses a metal-organic photothermal conversion material, a photothermal conversion layer, a preparation method thereof, and a solar photothermal conversion device. The structural formula of the metal-organic photothermal conversion material is: where n is a positive integer; R1 and R2 are each independently selected from H or alkyl groups; R3 is a phenyl group with a linking bond or alkoxy substitution; R4 is selected from one of the following structures: R5, R6, R7, R8, R9, R... 10 All are alkyl groups, and "★" indicates a linking site. This invention provides for the first time a platinum organometallic polymer with the aforementioned structure as a metal-organic photothermal conversion material. The metal-organic photothermal conversion material has good photon trapping ability and a large photon trapping range, covering the ultraviolet-visible-near-infrared band; at the same time, it has enhanced nonradiative transitions, allowing more energy to be released into the surrounding medium in the form of heat (molecular vibration), thus exhibiting high photothermal conversion efficiency.

Description

Technical Field

[0001] This invention relates to the field of photothermal conversion materials technology, and in particular to a metal-organic photothermal conversion material, a photothermal conversion layer, a preparation method thereof, and a photothermal conversion device thereof. Background Technology

[0002] Photothermal conversion technology can convert solar energy into thermal energy, which is an effective way to improve resource utilization and achieve sustainable energy development. It plays an important role in fields such as seawater desalination, wastewater purification, photothermal de-icing, photothermal therapy, and thermal energy storage. Low-cost, high-stability, and high-performance photothermal conversion materials are the core elements of this technology and a goal that academia and industry have been striving for. Common photothermal conversion materials include carbon-based materials, metal-based nanoparticles, polymer materials, inorganic semiconductor materials, and their composites. Compared with other materials, polymers have attracted widespread interest from scientists due to their unique advantages such as tunable molecular structure, abundant raw materials, low cost, low thermal conductivity, and environmental friendliness. However, high-performance polymer-based photothermal conversion materials are scarce, and most suffer from complex synthesis steps and low photothermal conversion efficiency, which limits their further application and development.

[0003] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a metal-organic photothermal conversion material, a photothermal conversion layer, a preparation method thereof, and a photothermal conversion device, aiming to enrich the types of polymer-based photothermal materials and solve the problem that the photothermal conversion efficiency of existing polymer-based photothermal conversion materials still needs to be further improved.

[0005] The technical solution of the present invention is as follows:

[0006] In a first aspect, the present invention provides a metal-organic photothermal conversion material, wherein the structural formula of the metal-organic photothermal conversion material is:

[0007]

[0008] Where n is a positive integer; R1 and R2 are each independently selected from H or alkyl; R3 is a phenyl group with a linking bond or alkoxy substitution; R4 is selected from one of the following structures:

[0009]

[0010] R5, R6, R7, R8, R9, R 10 All are alkyl groups. ★ "" indicates a connection point.

[0011] Optionally, the structural formula of R3 is:

[0012] Among them, R 11 R 12 All are alkyl groups.

[0013] Optionally, the metal-organic photothermal conversion material is selected from one of the following structures:

[0014]

[0015] A second aspect of the present invention provides a method for preparing the metal-organic photothermal conversion material as described above, comprising the steps of:

[0016] Will The metal-organic photothermal conversion material was obtained by a Sonogashira coupling reaction under the action of a catalyst.

[0017] Where R 13 It is a halogen atom.

[0018] Optionally, the preparation method of the metal-organic photothermal conversion material specifically includes the following steps:

[0019] Will The material is added to a first organic solvent, followed by triethylamine and a catalyst. After a Sonogashira coupling reaction at room temperature, methanol is added, and the mixture is filtered to obtain the metal-organic photothermal conversion material.

[0020] Optionally, the catalyst includes a palladium-based catalyst and a monovalent copper salt catalyst.

[0021] A third aspect of the present invention provides a photothermal conversion layer, comprising a substrate and a photothermal conversion material loaded on the substrate, wherein the photothermal conversion material is a metal-organic photothermal conversion material as described in the embodiments of the present invention and / or a metal-organic photothermal conversion material prepared by the preparation method described in the present invention.

[0022] Optionally, the substrate may be made of one of the following materials: polymer foam, polymer sponge, or wood.

[0023] A fourth aspect of the present invention provides a method for preparing the photothermal conversion layer of the present invention as described above, comprising the steps of:

[0024] The metal-organic photothermal conversion material is dispersed in a second organic solvent to obtain a dispersion.

[0025] The dispersion is applied to the substrate and dried to obtain the photothermal conversion layer.

[0026] In a fifth aspect, the present invention provides a solar photothermal conversion device, comprising a photothermal conversion layer as described above and / or a photothermal conversion layer prepared by the preparation method described above.

[0027] Beneficial Effects: This invention, through molecular structure design, provides for the first time a platinum-organic metal-organic polymer with the aforementioned structure as a metal-organic photothermal conversion material, enriching the variety of polymer-based photothermal conversion materials. The chemical structure of this metal-organic photothermal conversion material is easily tunable, and the interactions between the metal and ligands, as well as between ligands, enable the metal-organic photothermal conversion material to possess excellent light absorption and suitable energy levels. Compared with existing polymer-based photothermal conversion materials, the metal-organic photothermal conversion material provided by this invention has excellent photon trapping ability and a large photon trapping range, covering the ultraviolet-visible-near-infrared band; simultaneously, it exhibits enhanced nonradiative transitions, allowing more energy to be released into the surrounding medium in the form of heat (molecular vibration), thus achieving higher photothermal conversion efficiency. Attached Figure Description

[0028] Figure 1 The image shows the hydrogen nuclear magnetic resonance spectrum of Pt(II)(N,N)(O,O) in Example 1 of this invention.

[0029] Figure 2 The image shows the carbon NMR spectrum of Pt(II)(N,N)(O,O) in Example 1 of this invention.

[0030] Figure 3 This is the mass spectrum of Pt(II)(N,N)(O,O) in Example 1 of the present invention.

[0031] Figure 4 The image shows the hydrogen nuclear magnetic resonance spectrum of ffBT-2ET-2DT in Example 1 of this invention.

[0032] Figure 5 This is the carbon NMR spectrum of ffBT-2ET-2DT in Example 1 of the present invention.

[0033] Figure 6 This is the mass spectrum of ffBT-2ET-2DT in Example 1 of the present invention.

[0034] Figure 7a This is the Fourier transform infrared spectrum of PffBTPt(II) in Embodiment 1 of the present invention. Figure 7b The image shows the inductively coupled plasma emission spectrum test results of PffBTPt(II) in Embodiment 1 of the present invention.

[0035] Figure 8 The thermogravimetric curve of PffBTPt(II) in Embodiment 1 of the present invention is shown.

[0036] Figure 9 This is the solid diffuse scattering absorption spectrum of PffBTPt(II) in Example 1 of the present invention.

[0037] Figure 10 (a) is a physical image of the PU substrate in Embodiment 2 of the present invention, and (b) is a physical image of the PPU photothermal conversion layer.

[0038] Figure 11 (a) is an SEM image of the PU substrate in Embodiment 2 of the present invention, and (b) is an SEM image of the PPU photothermal conversion layer in Embodiment 2 of the present invention.

[0039] Figure 12 This is a diagram showing the photothermal conversion performance of the PU substrate and the PPU photothermal conversion layer in Embodiment 2 of the present invention.

[0040] Figure 13 This is a schematic diagram of the structure of the solar evaporator composed of a PPU photothermal conversion layer in Embodiment 2 of the present invention.

[0041] Figure 14 This is a graph showing the change in water mass over time when water is evaporated using a solar evaporator under simulated sunlight of different intensities in Embodiment 2 of the present invention.

[0042] Figure 15 The graph shows the evaporation rate and efficiency of water when evaporating water using a solar evaporator under simulated sunlight of different intensities in Embodiment 2 of the present invention.

[0043] Figure 16 This is a graph showing the mass changes over time of pure water, seawater, salt water with a NaCl concentration of 3.5 wt%, salt water with a NaCl concentration of 10 wt%, and salt water with a NaCl concentration of 20 wt% during evaporation using a solar evaporator in Embodiment 2 of the present invention.

[0044] Figure 17 The graph shows the evaporation rate results of pure water, seawater, salt water with a NaCl mass concentration of 3.5 wt%, salt water with a NaCl mass concentration of 10 wt%, and salt water with a NaCl mass concentration of 20 wt% in Embodiment 2 of the present invention.

[0045] Figure 18 This is a graph showing the change in surface temperature of the PPU photothermal conversion layer over time during the cycle of turning the light source on and off in Embodiment 2 of the present invention.

[0046] Figure 19 This is a graph showing the evaporation rate of water and seawater evaporated by the solar evaporator during the circulation process in Embodiment 2 of the present invention.

[0047] Figure 20The image shows the inductively coupled plasma emission spectrum test results of the evaporated water obtained in Example 2 of this invention. Detailed Implementation

[0048] This invention provides a metal-organic photothermal conversion material, a photothermal conversion layer, a preparation method thereof, and a photothermal conversion device. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0050] The depletion of global fossil fuels and the environmental pollution caused by their use have long plagued humanity. To address issues such as freshwater scarcity and the energy crisis, the development of efficient photothermal conversion materials is urgently needed. This invention aims to develop a new generation of metal-organic polymer-based photothermal conversion materials through molecular structure design, which can then be used to prepare efficient solar photothermal conversion devices. These devices can convert abundant and widely distributed solar energy into usable thermal energy, providing an effective solution to global challenges such as water pollution, seawater desalination, and energy shortages. Specifically, this invention provides a metal-organic photothermal conversion material, wherein the structural formula of the metal-organic photothermal conversion material is:

[0051]

[0052] Where n is a positive integer; R1 and R2 are each independently selected from H or alkyl; R3 is a phenyl group with a linking bond or alkoxy substitution; R4 is selected from one of the following structures:

[0053]

[0054] R5, R6, R7, R8, R9, R 10 All are alkyl groups. ★ "" indicates a connection point.

[0055] This invention, through molecular structure design, provides for the first time a platinum-organic metal-organic polymer with the aforementioned structure as a metal-organic photothermal conversion material, enriching the variety of polymer-based photothermal conversion materials. The chemical structure of this metal-organic photothermal conversion material is easily tunable, and the interactions between the metal and ligands, as well as between ligands themselves, enable the material to exhibit excellent light absorption and suitable energy levels. Compared to existing polymer-based photothermal conversion materials, the metal-organic photothermal conversion material provided by this invention possesses excellent photon trapping capability and a large photon trapping range, covering the ultraviolet-visible-near-infrared band. Simultaneously, it exhibits enhanced non-radiative transitions, allowing more energy to be released into the surrounding medium as heat (molecular vibrations), thus achieving higher photothermal conversion efficiency.

[0056] In this embodiment, n represents the degree of polymerization, which is a positive integer, such as 1, 3, 5, 10, 20, 50, 100, 500, 1000, etc. When R3 is a connecting bond, the structural formula of the metal-organic photothermal conversion material is:

[0057]

[0058] When R1 and R2 are alkyl groups, they can be straight-chain alkyl groups, such as methyl, ethyl, propyl, etc.; or they can be non-straight-chain alkyl groups, such as tert-butyl, etc.

[0059] When R5, R6, R7, R8, R9, R 10 When it is an alkyl group, it can be a straight-chain alkyl group or a non-straight-chain alkyl group.

[0060] In this embodiment, the metal-organic photothermal conversion material of the structure is composed of platinum metal complex units and organic acceptor units, and different electron-withdrawing capabilities are achieved by changing the structure of the acceptor units.

[0061] In some embodiments, the structural formula of R3 is:

[0062] Among them, R 11 R 12 All are alkyl groups, and "★" indicates a linking site. In this embodiment, R3 of the structure can increase the solubility of the platinum metal complex.

[0063] In some embodiments, the metal-organic photothermal conversion material is selected from one of the following structures:

[0064]

[0065] In this embodiment, these metal-organic photothermal conversion materials have the characteristics of ultraviolet-visible-near-infrared wide solar band absorption. Under one simulated sunlight irradiation, the surface temperature of the material rises from room temperature to above 65°C in about one minute, demonstrating highly efficient photothermal conversion performance.

[0066] Existing high-performance polymer-based photothermal conversion materials are scarce, and most suffer from complex synthesis procedures. Therefore, this invention also provides a method for preparing the metal-organic photothermal conversion material as described above, comprising the following steps:

[0067] Will The metal-organic photothermal conversion material was obtained through a Sonogashira coupling reaction under the action of a catalyst; wherein R 13 It is a halogen atom.

[0068] The embodiments of the present invention obtain the metal-organic photothermal conversion material through the Sonogashira coupling reaction. The preparation method is simple, the reaction conditions are mild, the yield is high, the cost is low, it is easy to promote, and it meets the conditions for industrial production. The prepared metal-organic photothermal conversion material has good photothermal stability and full-spectrum solar light utilization.

[0069] The specific structure of R4 in this embodiment can be found above, and will not be repeated here.

[0070] In some implementations, the R 13 It is Br.

[0071] In some embodiments, the preparation method of the metal-organic photothermal conversion material specifically includes the following steps:

[0072] Will The material is added to a first organic solvent (e.g., dioxane), followed by triethylamine and a catalyst. After a Sonogashira coupling reaction at room temperature, methanol is added, and the mixture is filtered to obtain the metal-organic photothermal conversion material.

[0073] In some embodiments, the catalyst comprises a palladium-based catalyst and a monovalent copper salt catalyst. The palladium-based catalyst includes, but is not limited to, tetrakis(triphenylphosphine)palladium, and the monovalent copper salt catalyst includes, but is not limited to, CuI.

[0074] In some implementations... The preparation method includes the following steps:

[0075] Will Potassium tetrachloroplatinate was added to a mixed solvent of acetonitrile and water, and after reflux, the following reaction was obtained:

[0076] Will 3,5-Di-tert-butylbenzylhydroquinone was added to dichloroethane, followed by the addition of sodium carbonate. After reacting overnight at 100°C, the following was obtained:

[0077] In some implementations... The preparation method includes the following steps:

[0078] Br-R4-Br and (trimethylsilyl)acetylene were added to tetrahydrofuran. After mixing, triethylamine was added, followed by cuprous iodide and bis(triphenylphosphine)palladium(II) chloride. The mixture was reacted at 50°C to obtain...

[0079] Under nitrogen protection, Add to tetrahydrofuran, then add a tetrabutylammonium fluoride tetrahydrofuran solution, stir at room temperature for 5 minutes, then quench the reaction with water to obtain...

[0080] This invention also provides a photothermal conversion layer, comprising a substrate and a photothermal conversion material loaded on the substrate. The photothermal conversion material is a metal-organic photothermal conversion material as described in this invention embodiment, or the photothermal conversion material is a metal-organic photothermal conversion material prepared by the preparation method described in this invention embodiment, or the photothermal conversion material is a combination of the metal-organic photothermal conversion material as described in this invention embodiment and the metal-organic photothermal conversion material prepared by the preparation method described in this invention embodiment.

[0081] In some embodiments, the substrate material includes one of polymer foam, polymer sponge, and wood. Specifically, the polymer foam substrate may be polyethylene foam, and the wood substrate may be filter paper, wood board, etc. When the substrate material is a porous material such as polymer foam or polymer sponge, that is, when the substrate is a polymer foam substrate or polymer sponge substrate, the metal-organic photothermal conversion material is loaded within the porous structure of the polymer foam substrate or polymer sponge substrate, and simultaneously loaded on the surface of the polymer foam substrate or polymer sponge substrate.

[0082] This invention also provides a method for preparing the photothermal conversion layer as described above, comprising the following steps:

[0083] The metal-organic photothermal conversion material is dispersed in a second organic solvent (e.g., isopropanol) to obtain a dispersion.

[0084] The dispersion is applied to the substrate and dried to obtain the photothermal conversion layer.

[0085] In this embodiment, when the substrate is made of polymer sponge or polymer foam, that is, when the substrate is a porous substrate, a portion of the dispersion will penetrate into the pores of the porous substrate.

[0086] This invention also provides a solar thermal conversion device, comprising a solar thermal conversion layer as described in the embodiments of this invention, or a solar thermal conversion layer prepared by the preparation method described in the embodiments of this invention, or a solar thermal conversion layer and a solar thermal conversion layer prepared by the preparation method described in the embodiments of this invention. The solar thermal conversion device can convert widely distributed solar energy into usable thermal energy and can be used for water vapor collection, seawater desalination, etc. Specifically, in this embodiment, the solar thermal conversion device can be a solar evaporator.

[0087] The following detailed description uses specific examples.

[0088] Example 1

[0089] This embodiment provides a metal-organic photothermal conversion material PffBTPt(II), the synthesis route of which is as follows:

[0090]

[0091] The synthetic route for the platinum metal complex Pt(II)(N,N)(O,O) is as follows:

[0092]

[0093] The synthetic route for the organic acceptor unit ffBT-2ET-2DT is as follows:

[0094]

[0095] According to the above synthetic route, the preparation method of the metal-organic photothermal conversion material PffBTPt(II) includes the following steps:

[0096] (1) Preparation of compound 1a: The preparation method is an existing method. For example, refer to A Fluorescent, Shape-Persistent Dendritic Host with Photoswitchable Guest Encapsulation and Intramolecular Energy Transfer, J.Am.Chem.Soc.2011,133,11194–11204.

[0097] (2) Preparation of compound 1b: The preparation method is an existing method. For example, see Improved synthesis of pyridyl–biaryl ring systems via benzidine rearrangements, Tetrahedron Letters 55 (2014) 3950–3953.

[0098] (3) Preparation of compound 3a: Under nitrogen protection, 200 mg of compound 2a and 250 mg of potassium tetrachloroplatinate were dissolved in 20 mL of a mixed solvent of acetonitrile:water (v:v = 9:1), and the mixture was refluxed at 100 °C for 12 h. The reaction mixture was then cooled to room temperature, and methanol was added for precipitation to obtain 300 mg of compound 3a as a dark green solid powder. No purification was required before proceeding to the next step of the reaction.

[0099] (4) Preparation of the platinum metal complex Pt(II)(N,N)(O,O): 300 mg of compound 3a and 110 mg of 3,5-di-tert-butylcatechol were dissolved in 30 mL of dichloroethane, and 300 mg of sodium carbonate was added. The reaction mixture was reacted overnight at 100 °C. The reaction mixture was then cooled to room temperature, extracted with dichloromethane, dried over anhydrous sodium sulfate, and the solvent was removed using a rotary evaporator. Finally, the reaction mixture was purified by silica gel column chromatography using a mixed solution of n-hexane and dichloromethane (v:v = 1:2) as the eluent to obtain 300 mg of Pt(II)(N,N)(O,O), which was a dark green solid powder. The 1H NMR spectrum of Pt(II)(N,N)(O,O) is as follows: 1 ¹H NMR (400MHz, Chloroform-d) δ 9.60 (d, J = 2.0Hz, 1H), 8.51 (d, J = 8.9Hz, 2H), 7.85–7.74 (m, 2H), 7.56 (d, J = 8.9Hz, 2H), 7.02 (d, J = 2.1Hz, 1H), 6.67 (d, J = 2.2Hz, 1H), 1.56 (s, 9H), 1.34 (s, 9H). The ¹H NMR spectrum of Pt(II)(N,N)(O,O) is shown below. Figure 1 As shown. The carbon NMR data for Pt(II)(N,N)(O,O) are as follows: 13C NMR (151MHz, CDCl3) δ=29.97,32.04,34.46,35.01,112.10,114.95,120.28,123.80,127.67,128.91,131.94,136.71,141.06,142.08,147.32,151.80,162.65,162.75,165.17. The C NMR spectrum of Pt(II)(N,N)(O,O) is shown below. Figure 2 As shown. The mass spectrometry data for Pt(II)(N,N)(O,O) are: MALDI-TOF MSm / z calcd.for C 25 H 27 Br2N3O2Pt[M] + :757.01Found:757.11. The mass spectrum of Pt(II)(N,N)(O,O) is as follows: Figure 3 As shown.

[0100] (5) Preparation of compounds 1b, 2b, 3b, and 4b: The preparation methods are existing methods. For example, see Synthesis of donor–acceptor copolymer using benzoselenadiazole as acceptor for OTFT, RSC Adv., 2016, 6, 4070.

[0101] (6) Preparation of compound 5b: Under nitrogen protection, 500 mg of compound 4b and 0.6 mL of (trimethylsilyl) acetylene were added to 100 mL of tetrahydrofuran solvent and mixed. Then, 10 mL of triethylamine was added, followed by 10 mg of cuprous iodide and 30 mg of bis(triphenylphosphine)palladium(II) chloride as catalysts. The reaction mixture was reacted overnight at 50 °C. The reaction mixture was then cooled to room temperature, extracted with dichloromethane, dried over anhydrous sodium sulfate, and the solvent was removed using a rotary evaporator. Finally, the reaction mixture was purified by silica gel column chromatography using a mixed solution of n-hexane:dichloromethane (v:v = 10:1) as the eluent to obtain 300 mg of compound 5b as an orange solid powder.

[0102] (7) Preparation of the organic acceptor unit ffBT-2ET-2DT: Under nitrogen protection, 300 mg of compound 5b was dissolved in 10 mL of tetrahydrofuran solvent, and then 0.5 mL of tetrabutylammonium fluoride (1 M) tetrahydrofuran solution was added. After stirring at room temperature for 5 minutes, a small amount of water was added to quench the reaction. The reaction mixture was extracted with dichloromethane, dried over anhydrous sodium sulfate, and the solvent was removed using a rotary evaporator. Finally, the reaction mixture was purified by silica gel column chromatography with a mixed solution of n-hexane:dichloromethane (v:v = 8:1) as the eluent to obtain 250 mg of ffBT-2ET-2DT as an orange solid powder. The 1H NMR spectrum of ffBT-2ET-2DT is as follows: 1 ¹H NMR (400MHz, Chloroform-d) δ 8.01 (s, 2H), 3.59 (s, 2H), 2.71 (d, J = 7.0Hz, 4H), 1.77 (p, J = 6.0Hz, 2H), 1.31 (t, J = 5.2Hz, 30H), 1.25 (d, J = 6.7Hz, 50H), 0.87 (td, J = 6.9, 2.4Hz, 12H). The ¹H NMR spectrum of ffBT-2ET-2DT is shown below. Figure 4 As shown. The carbon NMR spectrum data of ffBT-2ET-2DT are as follows: 13 C NMR (101 MHz, Chloroform-d) δ 148.48, 132.60, 131.46, 85.88, 39.12, 34.24, 33.57, 32.08, 30.17, 29.87, 29.85, 29.83, 29.52, 26.71, 22.85, 14.27. The C NMR spectrum of ffBT-2ET-2DT is shown below. Figure 5 As shown. The mass spectrometry data of the carbon NMR spectrum of ffBT-2ET-2DT are: MALDI-TOF MSm / zcalcd.for C 66 H 102 F2N2S3[M] + :1057.72Found:1057.53. The mass spectrum of ffBT-2ET-2DT is as follows: Figure 6 As shown. (8) Preparation of PffBTPt(II): Under nitrogen protection, 19 mg of platinum metal complex Pt(II)(N,N)(O,O) and 21 mg of organic acceptor unit ffBT-2ET-2DT were added to 3 mL of dioxane solvent and mixed. Then, 0.5 mL of triethylamine was added, followed by 2 mg of cuprous iodide and 5 mg of tetrakis(triphenylphosphine)palladium as catalysts. After reacting overnight at room temperature, 10 mL of methanol was added, and 33 mg of black solid powder was obtained by filtration.

[0103] The Fourier transform infrared spectrum of PffBTPt(II) is as follows: Figure 7a As shown, 2100cm -1 The characteristic absorption peak corresponding to the -C≡C- in the ffBT-2ET-2DT alkynyl group is 2190 cm⁻¹. -1 The corresponding absorption characteristic peaks are at 2920 and 2850 cm⁻¹ in the -C≡C- group of the PffBTPt(II) alkynyl group. -1 The characteristic absorption peak corresponding to CH on the alkyl group; 3100m -1 The characteristic absorption peak at 3100m corresponds to the CH group on the ffBT-2ET-2DT alkyne, while the peak at 3100m corresponds to the ffBT-2ET-2DT alkyne. -1 The disappearance of the characteristic peak at the point indicates that Pt(II)(N,N)(O,O) reacted successfully with ffBT-2ET-2DT.

[0104] Inductively coupled plasma optical emission spectroscopy (ICP-OES) testing of PffBTPt(II) is as follows: Figure 7b As shown, this confirms that the proportion of metal elements in the polymer is close to the theoretical value.

[0105] The thermogravimetric curve of PffBTPt(II) is as follows: Figure 8 As shown, when the heating temperature is 290℃, the weight decreases to 95%. The solid diffuse scattering absorption spectrum of PffBTPt(II) is as follows. Figure 9 As shown, the results indicate that PffBTPt(II) exhibits good absorption for light with wavelengths ranging from 400 to 1200 nm.

[0106] Example 2

[0107] This embodiment provides a method for preparing a photothermal conversion layer, including the following steps:

[0108] A polyethylene foam (PU) base is provided, with a diameter of 1.8 cm and a thickness of 4 mm;

[0109] The PffBTPt(II) from Example 1 was ultrasonically dispersed in isopropanol to obtain a dispersion with a PffBTPt(II) concentration of 0.2 mg / mL, an average particle size of about 250 nm, and a dispersibility of 0.26.

[0110] 20 mL of dispersion was drop-coated onto a PU substrate to form a PPU photothermal conversion layer.

[0111] The actual image of the PU substrate is shown below. Figure 10 As shown in (a), the physical image of the PPU photothermal conversion layer is as follows. Figure 10 As shown in (b).

[0112] SEM images of the PU substrate and the PPU photothermal conversion layer are shown below. Figure 11As shown in Figures (a) and (b), the surface of the skeleton in the PU substrate in Figure (a) is smooth, while as can be seen from Figure (b), PffBTPt(II) enters the porous structure of the PU substrate and attaches to the surface of the skeleton in the PU substrate.

[0113] In a simulated sunlight (intensity of 1000 W / m²) 2 Under irradiation, the photothermal conversion performance of the PU substrate and the PPU photothermal conversion layer is as follows: Figure 12 As shown, under simulated sunlight irradiation, the temperature of the PPU photothermal conversion layer can rise from 25.2℃ (room temperature) to 66.4℃ within 1 minute, demonstrating highly efficient photothermal conversion performance. In contrast, the temperature of the PU substrate, under simulated sunlight irradiation, only rises from 25℃ (room temperature) to 36.5℃ within 1 minute.

[0114] Assemble the PPU photothermal conversion layer as follows: Figure 13 The solar evaporator shown specifically involves placing a small beaker containing a liquid to be evaporated (such as water) inside a sealed large beaker. A PPU photothermal conversion layer floats on the liquid to be evaporated. An evaporation test is conducted using a xenon lamp (purchased from Beijing PLS-XSE300 Technology Co., Ltd.) to simulate a solar light source. The large beaker is used to collect the evaporated liquid vapor (such as water vapor).

[0115] The performance results of the solar evaporator evaporating water under simulated sunlight irradiation of different intensities are as follows: Figure 14 and 15 As shown, by Figure 14 It can be seen that solar evaporators can effectively evaporate water, and the amount of water evaporation gradually increases with the increase of sunlight intensity. Figure 15 It can be seen that (the horizontal axes 1sun, 2sun, and 3sun represent 1 simulated sun, 2 simulated suns, and 3 simulated suns, respectively), as the intensity of sunlight increases, the evaporation rate gradually increases, and the efficiency of water evaporation is greater than 75% under different intensities of sunlight.

[0116] Evaporation tests were conducted under simulated sunlight using pure water, seawater (the seawater sample was natural seawater from Shek O Beach, Hong Kong, hereinafter the same), saline solution with a NaCl concentration of 3.5 wt%, saline solution with a NaCl concentration of 10 wt%, and saline solution with a NaCl concentration of 20 wt%. The results are as follows. Figure 16 and 17 As shown. This solar evaporator can effectively evaporate water, seawater, and salt water with different NaCl concentrations. Figure 17(W, SW, 3.5B, 10B, and 20B represent pure water, seawater, salt water with a NaCl concentration of 3.5 wt%, salt water with a NaCl concentration of 10 wt%, and salt water with a NaCl concentration of 20 wt%, respectively.) It can be seen that the evaporation rate of pure water is 1.568 kg·m³. -2 ·h -1 The evaporation rate of seawater is 1.525 kg·m³. -2 ·h -1 The evaporation rate of a 3.5 wt% NaCl brine solution is 1.493 kg·m³. -2 ·h -1 The evaporation rate of a 10 wt% NaCl brine solution is 1.254 kg·m³. -2 ·h -1 The evaporation rate of a 20 wt% NaCl brine solution is 1.092 kg·m³. -2 ·h -1 .

[0117] The stability of the solar evaporator was tested under simulated sunlight, and the results are as follows: Figure 18 and 19 As shown, by Figure 18 It can be seen that during the cyclical opening and closing of the light source (with an opening and closing time interval of 5 minutes), the PPU photothermal conversion layer in the solar evaporator exhibits stable temperature rise performance. From... Figure 19 It can be seen that, in several evaporation cycles (15 cycles, each lasting 1 hour) of pure water and seawater respectively, the solar evaporator exhibits a stable evaporation rate for both. Simultaneously, the water vapor collected during seawater evaporation condenses to obtain evaporated water. Inductively coupled plasma atomic emission spectrometry (ICP-AES) analysis of the evaporated water yields the following results: Figure 20 As shown, the concentrations of calcium, potassium, magnesium, and sodium ions in the evaporated water are significantly lower than those in the original seawater. In particular, sodium ions in the evaporated water cannot be detected by inductively coupled plasma atomic emission spectrometry, indicating that the concentration of sodium ions in the evaporated water can be considered as 0. These results indicate that a solar evaporator containing a PPU photothermal conversion layer can effectively achieve seawater desalination.

[0118] In summary, this invention provides a metal-organic photothermal conversion material, a photothermal conversion layer, its preparation method, and a photothermal conversion device. This invention is the first to provide a platinum metal complex Pt(II)(N,N)(O,O) and an organic acceptor unit ffBT-2ET-2DT, along with their respective preparation methods. Furthermore, through molecular structure design, it is the first to provide a platinum metal-organic polymer with the aforementioned structure as a metal-organic photothermal conversion material and its preparation method. The chemical structure of this metal-organic photothermal conversion material is easily tunable, and the interactions between the metal and ligands, as well as between ligands, enable the metal-organic photothermal conversion material to possess excellent light absorption and suitable capabilities. Compared to existing polymer-based photothermal conversion materials, the metal-organic photothermal conversion material provided by this invention exhibits excellent photon trapping ability and a large photon trapping range, covering the ultraviolet-visible-near-infrared band. Simultaneously, it possesses enhanced non-radiative transitions, allowing more energy to be released into the surrounding medium in the form of heat (molecular vibration), thus achieving higher photothermal conversion efficiency. Moreover, the preparation method of the metal-organic photothermal conversion material provided by this invention is simple, has mild reaction conditions, high yield, low cost, is easy to promote, and meets the conditions for industrial production. The photothermal conversion device prepared using the aforementioned metal-organic photothermal conversion material can efficiently convert solar energy into thermal energy, and can be used for water pollution control, efficient water vapor collection, seawater desalination, etc., with broad application prospects.

[0119] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A metal-organic photothermal conversion material, characterized in that, The structural formula of the metal-organic photothermal conversion material is: ； Where n is a positive integer; R1 and R2 are each independently selected from H or alkyl; R3 is a phenyl group with a linking bond or alkoxy substitution; R4 is selected from one of the following structures: 、 、 ； R5, R6, R7, R8, R9, R 10 All are alkyl groups, and "★" indicates a linking site.

2. The metal-organic photothermal conversion material according to claim 1, characterized in that, The structural formula of R3 is: , where R 11 R 12 All are alkyl groups.

3. The metal-organic photothermal conversion material according to claim 1, characterized in that, The metal-organic photothermal conversion material is selected from one of the following structures: 、 、 、 、 、 。 4. A method for preparing a metal-organic photothermal conversion material as described in any one of claims 1-3, characterized in that, Including the following steps: Will and The metal-organic photothermal conversion material was obtained by a Sonogashira coupling reaction under the action of a catalyst. Where R 13 It is a halogen atom.

5. The preparation method according to claim 4, characterized in that, The preparation method of the metal-organic photothermal conversion material specifically includes the following steps: Will and The material is added to a first organic solvent, followed by triethylamine and a catalyst. After a Sonogashira coupling reaction at room temperature, methanol is added, and the mixture is filtered to obtain the metal-organic photothermal conversion material.

6. The preparation method according to claim 4, characterized in that, The catalysts include palladium-based catalysts and monovalent copper salt catalysts.

7. A photothermal conversion layer, characterized in that, The invention includes a substrate and a photothermal conversion material loaded on the substrate, wherein the photothermal conversion material is the metal-organic photothermal conversion material according to any one of claims 1-3 or the metal-organic photothermal conversion material prepared by the preparation method according to any one of claims 4-6.

8. The photothermal conversion layer according to claim 7, characterized in that, The substrate material includes one of the following: polymer foam, polymer sponge, and wood.

9. A method for preparing a photothermal conversion layer as described in any one of claims 7-8, characterized in that, Including the following steps: The metal-organic photothermal conversion material is dispersed in a second organic solvent to obtain a dispersion. The dispersion is applied to the substrate and dried to obtain the photothermal conversion layer.

10. A solar thermal conversion device, characterized in that, It includes the photothermal conversion layer as described in any one of claims 7-8 or the photothermal conversion layer prepared by the preparation method described in claim 9.

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