Organic near-infrared photothermal conversion material as well as preparation method and application thereof

Abstract

The invention discloses an organic near-infrared photothermal conversion material as well as a preparation method and application thereof, and belongs to the technical field of photothermal materials, the organic near-infrared photothermal conversion material is prepared through Suzuki coupling reaction and / or Sonogashira coupling reaction, 6-(2-ethylhexyl)-[1, 2, 5] thiadiazole [3, 4-F] benzotriazole or benzobisthiadiazole is used as an acceptor core, and the organic near-infrared photothermal conversion material is prepared through a one-step reaction. The same or different donor units are connected through a triple-bond pi bridge. The synthesis method of the organic near-infrared photothermal conversion material is simple, the molecular conjugated structure is prolonged and the intermolecular interaction is enhanced by introducing a triple bond pi bridge, and the organic near-infrared photothermal conversion material has longer-wavelength sunlight absorption capacity and excellent photothermal conversion capacity, can reach a high temperature of 300 DEG C or above under the action of laser and condensed sunlight, and has a wide application prospect. The method has a wide application prospect in the fields of photo-thermal device preparation, laser ignition, laser metal processing and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of photothermal materials, and in particular to an organic near-infrared photothermal conversion material and a preparation method and application thereof. Background Art

[0002] Photothermal effect refers to the property of materials that absorb light energy and release heat energy under the irradiation of sunlight or laser. Photothermal effect can not only realize the energy conversion of sunlight, but also give full play to the spatiotemporal controllability of light, and is applied to the fields of biotherapy, desalination, light-controlled intelligent soft robots, etc. Among the types of photothermal materials, compared with precious metals and inorganic semiconductor photothermal materials, organic photothermal materials have attracted more and more attention from researchers due to their advantages such as easy regulation of structure and performance and excellent processing performance.

[0003] In order to improve the photothermal conversion performance of organic photothermal materials, researchers often focus on the light absorption performance and photothermal conversion efficiency of materials in the current material development. Traditional organic photothermal materials usually use a large conjugated π plane or a classic donor (Donor)-acceptor (Acceptor) structure to give the material the absorption performance of long-wavelength light in the solar spectrum (200nm-2500nm). For example, the Chinese patent document with publication number CN115925641A discloses a DA structure organic small molecule photothermal material and its preparation method. The invention uses phthalonitrile as an electron acceptor (A) and diphenylamine as an electron donor (D) to prepare an organic small molecule photothermal material GDPA-QCN, which enhances the intermolecular charge transfer brought by the donor-acceptor structure and prolongs the molecular conjugation, thereby promoting the red shift of the spectrum. However, a strategy like this requires screening and replacement of electron donors and acceptors with more suitable performance, which makes the material preparation method more complicated, the structure and performance regulation are also more difficult, and the ultimate improvement of material performance is limited. Therefore, it is of great significance to develop a simple and universal method to prepare efficient organic photothermal materials, or to further improve the photothermal conversion performance of existing organic photothermal materials through molecular engineering.

[0004] At present, due to the limitations of their light absorption capacity, photothermal conversion performance and thermal stability, organic photothermal materials are usually difficult to reach very high temperatures under light. In the common application fields of organic photothermal materials such as photothermal therapy and seawater desalination, the photothermal temperature of the material usually does not exceed 70°C. Recently, a study used the [2+2] cycloaddition click reaction to prepare a high-temperature organic near-infrared photothermal material that can reach 450°C under an 808nm laser, and explored the application of organic high-temperature photothermal materials in laser ignition, metal processing, high-temperature shape memory and other fields (A Processible and Ultrahigh-temperature Organic Photothermal Material through Spontaneous and Quantitative [2+2] Cycloaddition–Cycloreversion, Angew. Chem. Int. Ed. 2024, e202406381), which to a certain extent reflects the application value and prospects of organic high-temperature photothermal materials. However, at this stage, research on such materials is still very rare, the types of materials need to be further expanded, and high-temperature applications need to be further explored. In summary, the preparation and application exploration of organic high-temperature photothermal conversion materials are of great significance. Summary of the invention

[0005] The present invention provides an organic near-infrared photothermal conversion material. The organic near-infrared photothermal conversion material uses 6-(2-ethylhexyl)-[1,2,5]thiadiazole[3,4-F]benzotriazole or benzobisthiadiazole as an acceptor core, connects the same or different donor units through a triple-bond π bridge, has long-wavelength light absorption capacity, high molar absorption coefficient, high photothermal conversion efficiency, and high photothermal conversion temperature, and has broad application prospects in the field of preparing photothermal devices.

[0006] The specific technical solutions adopted are as follows:

[0007] An organic near-infrared photothermal conversion material, the structural formula of which is shown in formula (I) to (IV):

[0008]

[0009] In formulae (I) to (IV), the donor units D1 and D2 are phenyl groups substituted with alkylamine, arylamine or heteroarylamine.

[0010] Preferably, the donor units D1 and D2 are each independently selected from one of the following formulae, and D1 and D2 are the same or different;

[0011]

[0012] Wherein, n is any integer from 1 to 10, R is hydrogen, fluorine, cyano, methoxy or C1 to C10 alkyl, and * indicates a substitution position.

[0013] The present invention also provides a method for preparing the organic near-infrared light-to-heat conversion material, including method one or method two;

[0014] Method 1 includes the following steps:

[0015] S01 uses a dihalogenated acceptor core compound and a donor compound substituted with boronic acid or boronic acid ester as raw materials, and undergoes a Suzuki coupling reaction at a molar ratio of 1:1.2-1.5 to obtain intermediate 1;

[0016] S02 uses the intermediate 1 and the alkynyl-substituted donor compound as raw materials, and conducts a Sonogashira coupling reaction at a molar ratio of 1:1.2 to 1.5 to obtain an organic near-infrared photothermal conversion material having a structural formula as shown in formula (I) or formula (III);

[0017] Method 2 includes the following steps:

[0018] S11 uses a dihalogenated acceptor core compound and an alkynyl-substituted donor compound as raw materials, and undergoes a Sonogashira coupling reaction at a molar ratio of 1:2.2 to 2.5 to obtain an organic near-infrared photothermal conversion material having a structural formula as shown in (II) or (IV).

[0019] Specifically, the structural formula of the dihalogenated receptor core compound is Wherein, X is Cl, Br or I.

[0020] In method 1, the structural formula of the donor compound substituted with boric acid or boric acid ester is The structural formula of the alkynyl-substituted donor compound is D1 and D2 are defined as above.

[0021] In method 2, the structural formula of the alkynyl-substituted donor compound is and D1 and D2 are defined as above.

[0022] Preferably, the conditions for the Suzuki coupling reaction are 60-120° C., 10-24 h.

[0023] Preferably, the Sonogashira coupling reaction is carried out at 60-100° C. for 10-24 h.

[0024] The present invention also provides the application of the organic near-infrared photothermal conversion material in the fields of solar energy conversion, solar energy storage, laser ignition, laser metal processing or light-controlled shape memory material processing.

[0025] The present invention also provides a solar light photothermal electric conversion device, including a photothermal coating made of the organic near-infrared photothermal conversion material. The organic near-infrared photothermal conversion material has long-wavelength light absorption capacity, high molar absorption coefficient, strong photothermal conversion capacity, and the prepared photothermal coating has excellent performance. The further prepared solar light photothermal electric conversion device has broad application prospects in the field of solar energy conversion and utilization.

[0026] The present invention also provides a concentrated solar energy molten inorganic salt heat storage device, including a photothermal coating made of the organic near-infrared photothermal conversion material. Based on its excellent photothermal conversion performance and excellent thermal stability under outdoor sunlight, the photothermal coating made of the organic near-infrared photothermal conversion material can reach a high photothermal conversion temperature of more than 300°C under the irradiation of outdoor concentrated sunlight, so that the inorganic salt loaded on the coating melts, converting solar energy into the phase change enthalpy of molten inorganic salt, and realizing solar energy energy storage.

[0027] In addition, based on its high photothermal conversion temperature, this organic near-infrared photothermal conversion material also has broad application prospects in the fields of photocontrolled metal processing and photocontrolled high-temperature shape memory.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The organic near-infrared photothermal conversion material provided by the present invention has a simple synthesis method, readily available raw materials, high yield, and is easy to prepare in large quantities. In addition, the organic near-infrared photothermal conversion material has a stable structure and a high thermal decomposition temperature.

[0030] (2) The present invention uses a triple bond as a π bridge between the donor unit and the acceptor unit in a traditional donor-acceptor structure organic molecule, which prolongs the molecular conjugation and enhances the intermolecular interaction, thereby significantly improving the light absorption capacity and photothermal conversion performance of the material.

[0031] (3) The organic near-infrared photothermal conversion material prepared by the present invention has excellent solar photothermal conversion capability. On the one hand, it can be applied to solar-driven photothermal-electrical conversion applications with high conversion efficiency; on the other hand, the material can reach a high temperature of more than 300°C under the action of concentrated sunlight, which is sufficient to achieve long-distance ignition of combustibles, processing of low-melting-point metals, and melting of some inorganic salts. It has broad application prospects in the fields of solar energy conversion and storage, laser ignition, laser metal processing, or light-controlled shape memory material processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the nuclear magnetic resonance hydrogen spectrum of the organic near-infrared photothermal conversion material prepared in Example 1 in deuterated dichloromethane.

[0033] Figure 2This is the UV-visible-near infrared absorption curve of the organic near-infrared photothermal conversion material solid powder prepared in Example 1.

[0034] Figure 3 This is a statistical diagram of the maximum photothermal temperature of the organic near-infrared photothermal conversion material prepared in Example 1 under 808nm lasers of different power densities.

[0035] Figure 4 This is the nuclear magnetic resonance hydrogen spectrum of the organic near-infrared photothermal conversion material prepared in Example 4 in deuterated dichloromethane.

[0036] Figure 5 This is the UV-visible-near infrared absorption curve of the organic near-infrared photothermal conversion material solid powder prepared in Example 4.

[0037] Figure 6 This is a statistical diagram of the maximum photothermal temperature of the organic near-infrared photothermal conversion material prepared in Example 4 under 808nm lasers of different power densities.

[0038] Figure 7 This is the photothermal conversion curve of the organic near-infrared photothermal conversion material prepared in Example 4 under simulated sunlight.

[0039] Figure 8 The voltage variation curve of the solar thermal-electric conversion device prepared in Application Example 1 under different simulated solar light powers.

[0040] Fig. 9 The temperature change curve of the concentrated solar molten inorganic salt heat storage device prepared in Application Example 4 with and without inorganic salt load. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the examples and drawings. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The operating methods in the following examples that do not specify specific conditions are usually carried out under conventional conditions or under conditions recommended by the manufacturer. Contents not described in detail in this specification belong to prior art known to professionals and technicians in the field.

[0042] Example 1

[0043] In this embodiment, the structural formula of the prepared organic near-infrared photothermal conversion material (BTAyA) is as follows:

[0044]

[0045] The synthetic route is as follows:

[0046]

[0047] (1) Weigh the dihalogenated acceptor core compound a (447 mg, 1 mmol), the boronic acid-substituted donor compound b (347 mg, 1.2 mmol), K2CO3 (829 mg, 6 mmol), and Pd(PPh3)4 (58 mg, 0.05 mmol) in a 100 mL two-necked bottle. Seal the small mouth of the two-necked bottle with a rubber stopper, connect the large mouth to a reflux condenser, and use a double-row tube to evacuate the system and fill it with nitrogen three times to drain the air in the two-necked bottle. Then, take 6 mL of tetrahydrofuran and 3 mL of deionized water in a single-necked bottle, and pass nitrogen for 30 min to drain the air in the solvent. Then, use a syringe to draw the reagents in the bottle and add them to the two-necked bottle, and react at 80°C for 12 h. After the reaction is completed, extract the reaction system with dichloromethane and deionized water and spin dry. The obtained crude product is purified and separated by silica gel chromatography to obtain intermediate c powder with a yield of 63%.

[0048] (2) Weigh the intermediate c (305 mg, 0.5 mmol), the alkynyl-substituted donor compound d (161 mg, 0.6 mmol), Pd(PPh3)4 (23 mg, 0.02 mmol), and CuI (8 mg, 0.04 mmol) into a 50 mL two-necked bottle equipped with a magnet. Seal the small mouth of the two-necked bottle with a rubber stopper, connect the large mouth to a reflux condenser, and use a double-row tube to evacuate the system and fill it with nitrogen three times to drain the air in the two-necked bottle. Then, add 3 mL of ultra-dry tetrahydrofuran and 3 mL of ultra-dry triethylamine to the reaction bottle and react at 80°C for 12 h. After the reaction is completed, extract the reaction system with dichloromethane and deionized water and spin dry. The obtained crude product is purified and separated by silica gel chromatography to obtain blue-black powder BTAyA with a yield of 80%.

[0049] Example 2

[0050] In this embodiment, the structural formula of the prepared organic near-infrared light-to-heat conversion material (BTMyM) is as follows:

[0051]

[0052] The synthetic route is as follows:

[0053]

[0054] (1) Weigh the dihalogenated acceptor core compound a (447 mg, 1 mmol), the boronic acid-substituted donor compound b (198 mg, 1.2 mmol), K2CO3 (829 mg, 6 mmol), and Pd(PPh3)4 (58 mg, 0.05 mmol) in a 100 mL two-necked bottle. Seal the small mouth of the two-necked bottle with a rubber stopper, connect the large mouth to a reflux condenser, and use a double-row tube to evacuate the system and fill it with nitrogen three times to drain the air in the two-necked bottle. Then, take 6 mL of tetrahydrofuran and 3 mL of deionized water in a single-necked bottle, and pass nitrogen for 30 min to drain the air in the solvent. Then, use a syringe to draw the reagents in the bottle and add them to the two-necked bottle, and react at 80°C for 12 h. After the reaction is completed, extract the reaction system with dichloromethane and deionized water and spin dry. The obtained crude product is purified and separated by silica gel chromatography to obtain intermediate c with a yield of 69%.

[0055] (2) Weigh the intermediate c (244 mg, 0.5 mmol), the alkynyl-substituted donor compound d (87 mg, 0.6 mmol), Pd(PPh3)4 (23 mg, 0.02 mmol), and CuI (8 mg, 0.04 mmol) into a 50 mL two-necked bottle equipped with a magnetic rod. Seal the small mouth of the two-necked bottle with a rubber stopper, connect the large mouth to a reflux condenser, and use a double-row tube to evacuate the system and fill it with nitrogen three times to drain the air in the two-necked bottle. Then, add 3 mL of ultra-dry tetrahydrofuran and 3 mL of ultra-dry triethylamine to the reaction bottle and react at 80°C for 12 h. After the reaction is completed, extract the reaction system with dichloromethane and deionized water and spin dry. The obtained crude product is purified and separated by silica gel chromatography to obtain black powder BTMyM with a yield of 73%.

[0056] Example 3

[0057] In this embodiment, the structural formula of the prepared organic near-infrared light-to-heat conversion material (BTCzyCz) is as follows:

[0058]

[0059] The synthetic route is as follows:

[0060]

[0061] (1) Weigh the dihalogenated acceptor core compound a (447 mg, 1 mmol), the boronic acid-substituted donor compound b (344 mg, 1.2 mmol), K2CO3 (829 mg, 6 mmol), and Pd(PPh3)4 (58 mg, 0.05 mmol) in a 100 mL two-necked bottle. Seal the small mouth of the two-necked bottle with a rubber stopper, connect the large mouth to a reflux condenser, and use a double-row tube to evacuate the system and fill it with nitrogen three times to drain the air in the two-necked bottle. Then, take 6 mL of tetrahydrofuran and 3 mL of deionized water in a single-necked bottle, and pass nitrogen for 30 min to drain the air in the solvent. Then, use a syringe to draw the reagents in the bottle and add them to the two-necked bottle, and react at 80°C for 12 h. After the reaction is completed, extract the reaction system with dichloromethane and deionized water and spin dry. The obtained crude product is purified and separated by silica gel chromatography to obtain intermediate c powder with a yield of 78%.

[0062] (2) Weigh the intermediate c (304 mg, 0.5 mmol), the alkynyl-substituted donor compound d (160 mg, 0.6 mmol), Pd(PPh3)4 (23 mg, 0.02 mmol), and CuI (8 mg, 0.04 mmol) into a 50 mL two-necked bottle equipped with a magnet. Seal the small mouth of the two-necked bottle with a rubber stopper, connect the large mouth to a reflux condenser, and use a double-row tube to evacuate the system and fill it with nitrogen three times to drain the air in the two-necked bottle. Then, add 3 mL of ultra-dry tetrahydrofuran and 3 mL of ultra-dry triethylamine to the reaction bottle and react at 80°C for 12 h. After the reaction is completed, extract the reaction system with dichloromethane and deionized water and spin dry. The obtained crude product is purified and separated by silica gel chromatography to obtain dark blue powder BTCzyCz with a yield of 75%.

[0063] Example 4

[0064] In this embodiment, the structural formula of the prepared organic near-infrared light-to-heat conversion material (BTDyA) is as follows:

[0065]

[0066] The synthetic route is as follows:

[0067]

[0068] Weigh the dihalogenated acceptor core compound a (447 mg, 1 mmol), alkynyl-substituted donor compound b (673 mg, 2.5 mmol), Pd(PPh3)4 (23 mg, 0.02 mmol), and CuI (8 mg, 0.04 mmol) in a 100 mL two-necked bottle equipped with a magnet. Seal the small mouth of the two-necked bottle with a rubber stopper, connect the large mouth to a reflux condenser, and use a double-row tube to evacuate the system and fill it with nitrogen three times to drain the air in the two-necked bottle. Then, take 6 mL of ultra-dry tetrahydrofuran and 6 mL of ultra-dry triethylamine and add them to a 100 mL single-necked bottle, and react at 80 ° C for 12 hours. After the reaction is completed, extract the reaction system with dichloromethane and deionized water and spin dry. The obtained crude product is purified and separated by silica gel chromatography to obtain a blue-black powder BTDyA with a yield of 71%.

[0069] Example 5

[0070] In this embodiment, the structural formula of the prepared organic near-infrared light-to-heat conversion material (BTDyCz) is as follows:

[0071]

[0072] The synthetic route is as follows:

[0073]

[0074] Weigh the dihalogenated acceptor core compound a (447 mg, 1 mmol), alkynyl-substituted donor compound b (668 mg, 2.5 mmol), Pd(PPh3)4 (23 mg, 0.02 mmol), and CuI (8 mg, 0.04 mmol) in a 100 mL two-necked bottle equipped with a magnet. Seal the small mouth of the two-necked bottle with a rubber stopper, connect the large mouth to a reflux condenser, and use a double-row tube to evacuate the system and fill it with nitrogen three times to drain the air in the two-necked bottle. Then, take 6 mL of ultra-dry tetrahydrofuran and 6 mL of ultra-dry triethylamine and add them to a 100 mL single-necked bottle, and react at 80 ° C for 12 hours. After the reaction is completed, extract the reaction system with dichloromethane and deionized water and spin dry. The obtained crude product is purified and separated by silica gel chromatography to obtain blue-black powder BTDyCz with a yield of 67%.

[0075] Example 6

[0076] In this embodiment, the structural formula of the prepared organic near-infrared photothermal conversion material (BTDyPT) is as follows:

[0077]

[0078] The synthetic route is as follows:

[0079]

[0080] Weigh the dihalogenated acceptor core compound a (447 mg, 1 mmol), alkynyl-substituted donor compound b (748 mg, 2.5 mmol), Pd(PPh3)4 (23 mg, 0.02 mmol), and CuI (8 mg, 0.04 mmol) in a 100 mL two-necked bottle equipped with a magnet. Seal the small mouth of the two-necked bottle with a rubber stopper, connect the large mouth to a reflux condenser, and use a double-row tube to evacuate the system and fill it with nitrogen three times to drain the air in the two-necked bottle. Then, take 6 mL of ultra-dry tetrahydrofuran and 6 mL of ultra-dry triethylamine and add them to a 100 mL single-necked bottle, and react at 80 ° C for 12 hours. After the reaction is completed, extract the reaction system with dichloromethane and deionized water and spin dry. The obtained crude product is purified and separated by silica gel chromatography to obtain black powder BTDyPT with a yield of 68%.

[0081] Example 7

[0082] In this embodiment, the structural formula of the prepared organic near-infrared light-to-heat conversion material (BBTDyA) is as follows:

[0083]

[0084] The synthetic route is as follows:

[0085]

[0086] Weigh the dihalogenated acceptor core compound a (352 mg, 1 mmol), alkynyl-substituted donor compound b (673 mg, 2.5 mmol), Pd(PPh3)4 (23 mg, 0.02 mmol), and CuI (8 mg, 0.04 mmol) in a 100 mL two-necked bottle equipped with a magnet. Seal the small mouth of the two-necked bottle with a rubber stopper, connect the large mouth to a reflux condenser, and use a double-row tube to evacuate the system and fill it with nitrogen three times to drain the air in the two-necked bottle. Then, take 6 mL of ultra-dry tetrahydrofuran and 6 mL of ultra-dry triethylamine and add them to a 100 mL single-necked bottle, and react at 80 ° C for 12 hours. After the reaction is completed, extract the reaction system with dichloromethane and deionized water and spin dry. The obtained crude product is purified and separated by silica gel chromatography to obtain a blue-black powder BBTDyA with a yield of 45%.

[0087] Application Example 1

[0088] In this application example, the organic near-infrared photothermal conversion material prepared in the embodiment is used as a raw material to prepare a solar photothermal conversion device. Taking BTDyA obtained in Example 4 as an example, the device preparation method of other materials is consistent with this. The specific preparation method is as follows:

[0089] BTDyA (50 mg) and commercially available polymethyl methacrylate (500 mg) were completely dissolved in dichloroethane, and the mixture was drop-coated on a bismuth telluride semiconductor thermoelectric device (commercially available). After the solvent was completely evaporated, a photothermal conversion device loaded with a photothermal coating was obtained.

[0090] Application Example 2

[0091] In this application example, the organic near-infrared photothermal conversion material prepared in the embodiment is used as a raw material to prepare a concentrated solar molten inorganic salt heat storage device. Taking BTDyA obtained in Example 4 as an example, the device preparation method of other materials is consistent with this. The specific preparation method is as follows:

[0092] BTDyA (50 mg) was melt-processed on a quartz plate (1 cm×1 cm) to obtain a photothermal conversion device loaded with a photothermal coating. Subsequently, a mixed inorganic salt of sodium nitrate and potassium nitrate was placed on the photothermal conversion device. The device was also equipped with a plano-convex lens to focus sunlight.

[0093] Sample analysis

[0094] Taking the organic near-infrared photothermal conversion materials BTAyA and BTDyA prepared in Example 1 and Example 4 as representatives, their nuclear magnetic resonance hydrogen spectra in deuterated dichloromethane are as follows: Figure 1 and Figure 4 As shown, the successful synthesis of the organic near-infrared photothermal conversion material is demonstrated.

[0095] The UV-Vis-NIR absorption spectrum of BTAyA powder is shown in Figure 2 As shown in the figure, it can be seen that its absorption spectrum covers the entire UV-visible light band and extends to the near-infrared region. The UV-visible-near-infrared absorption spectrum of BTDyA powder is shown in Figure 5 As shown in the figure, it can be seen that its absorption spectrum covers the entire ultraviolet-visible light band and can be further extended to beyond 1500nm in the near-infrared region, with excellent sunlight spectrum absorption ability.

[0096] The maximum photothermal temperature statistics of BTAyA powder under different power densities of 808nm laser are shown in the figure below. Figure 3 As shown in the figure, it can be seen that the BTAyA solid-state material has a power density of 1.4 W cm -2 The maximum photothermal temperature of BTDyA powder under different power densities of 808nm laser is as follows: Figure 6 As shown in the figure, it can be seen that the BTDyA solid-state material has a power density of 2.0 W cm -2 Under the 808nm laser, the maximum photothermal temperature can reach 370℃.

[0097] The photothermal conversion curve of BTDyA powder under simulated sunlight is as follows Figure 7 As shown in the figure, BTDyA powder has a high thermal conductivity at a power density of 100 mW cm -2 Under simulated sunlight, the maximum photothermal temperature can reach 50°C.

[0098] The voltage variation curve of BTDyA when applied to solar thermal power conversion is shown in the figure Figure 8 As shown in the figure, the prepared solar photothermal-electric conversion device has a power density of 100 mW cm -2 Under simulated sunlight, the open circuit voltage can reach 90mV.

[0099] The temperature variation curve of BTDyA applied to concentrated solar molten inorganic salt heat storage device is shown in Fig. 9 As shown. As can be seen from the figure, in the absence of inorganic salt loading (control group), the material can reach a high temperature of 320°C under concentrated sunlight. After loading inorganic salts, during the photothermal heating stage, an obvious inorganic salt molten heat storage stage can be observed; and during the cooling stage after the light is stopped, the slow heat energy release caused by the presence of molten inorganic salts can be clearly seen. The above applications prove the application prospects of this organic near-infrared photothermal conversion material in solar molten salt thermal energy storage.

[0100] In summary, the present invention prepares a highly efficient organic near-infrared photothermal conversion material by introducing a triple bond as a π bridge into a traditional donor-acceptor structure organic material. The material has the advantages of wide spectrum absorption, strong thermal stability, and high photothermal conversion temperature. Based on the above materials, the present invention further develops a concentrated solar molten inorganic salt heat storage device, which has excellent device performance and is expected to be applied to the storage and utilization of solar energy. In addition, the material also exhibits excellent performance and results in the field of solar thermal-electric conversion. In summary, the organic near-infrared photothermal conversion material prepared by the present invention has excellent performance and broad application prospects.

[0101] The embodiments described above provide a detailed description of the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An organic near-infrared photothermal conversion material, characterized in that: The structural formula is shown in formula (I) to (IV): In formulae (I) to (IV), the donor units D1 and D2 are phenyl groups substituted with alkylamine, arylamine or heteroarylamine.

2. The organic near-infrared photothermal conversion material according to claim 1, characterized in that: The donor units D1 and D2 are each independently selected from one of the following formulae, and D1 and D2 are the same or different; Wherein, n is any integer from 1 to 10, R is hydrogen, fluorine, cyano, methoxy or C1 to C10 alkyl, and * indicates a substitution position.

3. The method for preparing an organic near-infrared photothermal conversion material according to claim 1 or 2, characterized in that: Includes method 1 or method 2; Method 1 includes the following steps: S01 uses a dihalogenated acceptor core compound and a donor compound substituted with boronic acid or boronic acid ester as raw materials, and undergoes a Suzuki coupling reaction at a molar ratio of 1:1.2-1.5 to obtain intermediate 1; S02 uses the intermediate 1 and the alkynyl-substituted donor compound as raw materials, and conducts a Sonogashira coupling reaction at a molar ratio of 1:1.2 to 1.5 to obtain an organic near-infrared photothermal conversion material having a structural formula as shown in formula (I) or formula (III); Method 2 includes the following steps: S11 uses a dihalogenated acceptor core compound and an alkynyl-substituted donor compound as raw materials, and undergoes a Sonogashira coupling reaction at a molar ratio of 1:2.2 to 2.5 to obtain an organic near-infrared photothermal conversion material having a structural formula as shown in (II) or (IV).

4. The method for preparing an organic near-infrared photothermal conversion material according to claim 3, characterized in that: The structural formula of the dihalogenated acceptor core compound is Wherein, X is Cl, Br or I.

5. The method for preparing an organic near-infrared photothermal conversion material according to claim 3, characterized in that: In method 1, the structural formula of the donor compound substituted with boric acid or boric acid ester is The structural formula of the alkynyl-substituted donor compound is In method 2, the structural formula of the alkynyl-substituted donor compound is and D1 and D2 are defined as above.

6. The method for preparing an organic near-infrared photothermal conversion material according to claim 3, characterized in that: The conditions of the Suzuki coupling reaction are 60-120°C and 10-24h.

7. The method for preparing an organic near-infrared photothermal conversion material according to claim 3, characterized in that: The conditions of the Sonogashira coupling reaction are 60-100°C and 10-24h.

8. Application of the organic near-infrared photothermal conversion material according to claim 1 or 2 in the fields of solar energy conversion, solar energy storage, laser ignition, laser metal processing or photo-controlled shape memory material processing.

9. A solar light-to-thermoelectric conversion device, characterized in that: A photothermal coating comprising the organic near-infrared photothermal conversion material according to claim 1 or 2.

10. A concentrated solar energy molten inorganic salt heat storage device, characterized in that: A photothermal coating comprising the organic near-infrared photothermal conversion material according to claim 1 or 2.

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