CN112409998A

CN112409998A - Photo-thermal conversion eutectic material containing N, N, N, N-tetramethyl-p-phenylenediamine and preparation method thereof

Info

Publication number: CN112409998A
Application number: CN202011346697.XA
Authority: CN
Inventors: 李明德; 陈文斌; 孙姗姗; 党丽; 陈业韬; 朱升
Original assignee: Shantou University
Current assignee: Shantou University
Priority date: 2020-11-26
Filing date: 2020-11-26
Publication date: 2021-02-26
Anticipated expiration: 2040-11-26
Also published as: CN112409998B

Abstract

The invention relates to the field of material preparation, and discloses a photothermal conversion eutectic material formed by combining N, N, N, N-tetramethyl-p-phenylenediamine serving as an electron donor and an electron acceptor. The TMPD-containing photothermal conversion eutectic material has excellent photothermal conversion performance, and particularly has high photothermal conversion efficiency in a near infrared region. In addition, the eutectic material is composed of small organic molecules, and has the advantages of mild and simple preparation conditions and low cost, so the eutectic material has good application prospects in sewage treatment, seawater desalination, photothermal imaging and photothermal treatment.

Description

Photo-thermal conversion eutectic material containing N, N, N, N-tetramethyl-p-phenylenediamine and preparation method thereof

Technical Field

The invention relates to the field of material preparation, in particular to a photothermal conversion eutectic material containing N, N, N, N-tetramethyl-p-phenylenediamine and a preparation method thereof.

Background

The strategy of converting solar Energy into heat Energy is the simplest and most effective way of utilizing the solar Energy, has remarkable advantages in the industries with intensive Energy sources such as sewage treatment, seawater desalination and the like (Nano Energy,2020,68, 104324), and also has important application prospects in the fields of photothermal therapy, photothermal electric equipment, shape memory materials and the like. Compared with inorganic photothermal conversion materials such as metal materials, carbon-based materials and semiconductor materials, the organic photothermal conversion functional material has the advantage of photothermal conversion in a near-infrared band with low energy and strong penetrating power, so that the organic photothermal conversion functional material has great application potential in the fields of photothermal therapy (PTT), photothermal/photoacoustic (PT/PA) imaging and the like, and attracts the interest of numerous researchers (chem.Soc.Rev.,2019,48, 2053). So far, the organic photothermal materials mainly include porphyrin nanovesicles, indocyanine, and polymers such as polyaniline and polypyrrole. There are two general strategies to improve these organic photothermal materials, one is to enhance the infrared absorption by extending the molecular conjugation length or covalently linking electron donor and electron acceptor fragments (Small,2016,12, 24-31.), and the other is to inhibit the radiative transition process by enhancing the quenching effect or increasing the concentration of free radicals (j.am. chem. soc.2017,139, 1921-1927.). However, the complicated design and complicated synthesis steps of the organic photothermal material have limited the development of the organic photothermal material. In recent years, an organic eutectic photo-thermal material composed of two components of small organic molecules with intermolecular Charge Transfer (CT) property has attracted attention due to its advantages of simple preparation process and low cost. And theoretically, the rational design of the eutectic can be achieved by controlling CT between the electron donor and acceptor molecules, such as CT degree ρ, dynamic processes of ground state and excited state, and control of generation, separation, and recombination processes of charges (Nature,2013,500,435.).

Currently, studies on the composition of photothermal eutectic materials comprising tetrathiafulvalene (TTF) and Diphenyltetrathiafulvalene (DBTTF) as electron donors and electron acceptors are more frequent, including DBTTF-TCNB eutectic (angelw. chem. int. ed.,2014,57, 3963-. Researchers also explore the application of the organic photothermal eutectic crystal and succeed in the application of the organic photothermal eutectic crystal, and show the application prospect of the organic photothermal eutectic crystal.

At present, the photothermal conversion efficiency of the organic photothermal eutectic material, particularly the photothermal conversion efficiency in the near infrared region, is not very high. Wherein the photothermal conversion efficiency of the DBTTF-TCNB eutectic in the near infrared (808nm) is 18.8% (Angew. chem. int. Ed.,2018,57, 3963-; the photothermal conversion efficiency of TTF-Tri-PDMI eutectic (chem. Commun.,2020,56, 5223-5226) under 808nm illumination is only 15.0%. The photo-thermal conversion efficiency of the covalent organic framework PyBPy +. cndot-material can reach 63.80%, and the photo-thermal conversion efficiency of the oligomer nanoparticle F8-PEG material can reach 82%, but the photo-thermal conversion efficiency is difficult to further improve. Therefore, there is a need to develop new photothermal materials to meet the increasing demand for photothermal applications.

Disclosure of Invention

The invention aims to provide an organic photothermal eutectic material with high photothermal conversion performance, especially excellent photothermal conversion efficiency in a near infrared region, based on the defect of low photothermal conversion efficiency in the prior art.

In order to solve the technical problems, the invention adopts the following technical scheme:

the photothermal conversion eutectic material is formed by combining N, N, N, N-tetramethyl-p-phenylenediamine serving as an electron donor and an electron acceptor.

Preferably, the electron acceptor comprises one or more of pyromellitic dianhydride, tetrachloro-p-phenylene quinone, tetrabromo-phenylene quinone and tetrafluoro-p-phenylene quinone.

The invention adopts N, N, N, N-tetramethyl in which 1, 4-position on benzene ring is substituted by dimethylaminoP-phenylenediamine (TMPD) as an electron donor, wherein SP³The hybridized N is a strongly electron-donating group, and thus is electron-rich on the benzene ring (i.e., the electrostatic potential is negative). On the other hand, pyromellitic dianhydride (PMDA), Tetrachloroterephthaloquinone (TCBQ), Tetrabromophenanthroquinone (TBBQ), and Tetrafluoroterephthaloquinone (TFBQ) having a strong electron-withdrawing group are preferable as electron acceptors, and the benzene ring is electron-deficient (electrostatic potential is positive). When the above electron donor is combined with an electron acceptor, an electron may be delocalized from the donor to the acceptor. Both form a Charge Transfer (CT) state, which in turn broadens the absorption spectrum of the system, enabling more efficient use of light in a wider wavelength band. When the CT compound is directionally arranged to form a eutectic crystal through non-covalent bonding force among molecules, absorbed light energy can be mainly released in a non-radiative transition form such as vibration relaxation, and photo-thermal conversion can be effectively carried out.

Preferably, the electron donor and the electron acceptor are combined in a molar ratio of 1:1 to form the photothermal conversion eutectic material.

The preparation method of the photothermal conversion eutectic material containing the N, N, N, N-tetramethyl-p-phenylenediamine comprises a solvent volatilization method and a solid phase grinding method.

Preferably, the solvent evaporation method comprises the following steps:

A. weighing N, N, N, N-tetramethyl-p-phenylenediamine solid according to a proportion, adding a low-boiling-point soluble solvent, and performing ultrasonic oscillation to completely dissolve the solid;

B. weighing the electron acceptor solid according to a proportion, adding a low-boiling-point soluble solvent, and performing ultrasonic oscillation to completely dissolve the electron acceptor solid;

C. mixing the solutions obtained in the step A and the step B to generate an intermolecular charge transfer complex;

D. removing the low-boiling-point soluble solvent, and precipitating the intermolecular charge transfer compound by forming a eutectic to obtain the photothermal conversion eutectic material containing the N, N, N, N-tetramethyl-p-phenylenediamine.

Preferably, the solvent evaporation method comprises the following steps:

A. weighing N, N, N, N-tetramethyl-p-phenylenediamine solid according to a ratio, placing the N, N, N-tetramethyl-p-phenylenediamine solid in a beaker, adding 4.5-5.5 mL of acetone, and carrying out ultrasonic oscillation for 4-6 minutes to completely dissolve the acetone, wherein the ultrasonic oscillation can be carried out at room temperature without additional means for controlling the temperature of a system, such as heating and the like;

B. weighing the electron acceptor solid according to a ratio, placing the electron acceptor solid in a beaker, adding 5-10mL of acetone, and carrying out ultrasonic oscillation for 3-5 minutes to completely dissolve the acetone; the acetone exists as a solvent and is enough to completely dissolve the electron donor and the electron acceptor without precise control;

C. uniformly mixing the acetone solution obtained in the step A and the acetone solution obtained in the step B, and generally shaking up to generate a black intermolecular charge transfer compound;

D. volatilizing acetone under normal pressure or reduced pressure by using a rotary evaporator, and precipitating the intermolecular charge transfer compound by forming eutectic;

E. and collecting the precipitated eutectic in a mode of suction filtration or scraping off the inner wall of the container after completely volatilizing acetone to obtain the photo-thermal conversion eutectic material containing the N, N, N, N-tetramethyl-p-phenylenediamine.

Preferably, the solid phase milling method comprises the steps of:

A. weighing N, N, N, N-tetramethyl-p-phenylenediamine solid according to a proportion;

B. weighing the electron acceptor solid according to the proportion;

C. mixing the N, N, N, N-tetramethyl-p-phenylenediamine solid with the electron acceptor solid to form a solid mixture, and contacting the two components to start forming an electron donor-electron acceptor intermolecular CT complex;

D. milling the solid mixture during which time contact between the two components is more complete and ordered self-assembly of the CT complex in the lowest energy form is promoted to form a eutectic;

E. and obtaining the photothermal conversion eutectic material containing the N, N, N, N-tetramethyl-p-phenylenediamine after grinding.

Preferably, the solid phase milling method comprises the steps of:

B. weighing the electron acceptor solid according to the proportion;

C. uniformly mixing the N, N, N, N-tetramethyl-p-phenylenediamine solid and the electron acceptor solid to form a solid mixture, simply stirring or shaking to form a primary contact, and enabling the two components to contact with each other to start forming an intermolecular CT compound of an electron donor-electron acceptor;

D. transferring the solid mixture into a mortar or a ball mill, and carrying out pressure grinding for 10-20min, wherein the solid mixture can be manually ground or mechanically ground, and the applied pressure does not need to be finely controlled, so long as the contact between the two components is ensured to be more sufficient in the period, and the CT compound is promoted to orderly self-assemble in a form with lowest energy to form eutectic;

E. and after the grinding is finished, obtaining the photothermal conversion eutectic material containing the N, N, N, N-tetramethyl-p-phenylenediamine in the form of powder.

Use of the photothermal conversion eutectic material containing N, N-tetramethyl-p-phenylenediamine according to claim 1 in photothermal conversion reactions.

Preferably, the method comprises the fields of sewage treatment, seawater desalination, photothermal imaging, photothermal therapy and the like which apply photothermal conversion reaction.

Compared with the prior art, the implementation of the invention has the following beneficial effects:

(1) the invention prepares the photothermal eutectic material containing TMPD. TMPD as an electron donor component forms a charge transfer complex with an electron acceptor component and self-assembles to form a co-crystal. At present, no other eutectic photothermal conversion materials containing TMPD are reported.

(2) The electron acceptor component can be one or a mixture of more of PMDA, TCBQ, TBBQ and TFBQ.

(3) The photothermal eutectic material containing TMPD can be prepared by a simple solvent volatilization or solid phase grinding process, does not need strict condition control, and is suitable for wide popularization and use.

(4) The prepared photothermal eutectic material containing TMPD has excellent photothermal conversion performance, and is represented by i) the absorption band can reach 250-1500nm, and light in a wide waveband can be effectively utilized; ii) the material has higher photo-thermal conversion efficiency, especially the near infrared photo-thermal conversion efficiency can reach 87.2 percent, which is the highest value reported.

(5) The excellent photo-thermal conversion performance of the prepared TMPD-containing photo-thermal eutectic material is closely related to a charge transfer compound consisting of TMPD and an electron donor component and a structure formed by the compound in an oriented arrangement mode.

(6) The invention provides a TMPD-containing photothermal conversion eutectic material and a preparation method thereof. In addition, the eutectic material is composed of small organic molecules, and has the advantages of mild and simple preparation conditions and low cost, so the eutectic material has good application prospects in sewage treatment, seawater desalination, photothermal imaging and photothermal treatment.

Drawings

FIG. 1 is a schematic view of a solvent volatilization and solid phase grinding process for preparing the co-crystal;

FIG. 2 shows the electron donor and acceptor chemical formula and electrostatic potential distribution of the composition eutectic;

FIG. 3 is a PXRD spectrum of a TMPD-containing photothermal eutectic crystal prepared by a solvent volatilization process;

FIG. 4 is a PXRD spectrum of a TMPD-containing photothermal eutectic crystal (TMPD-TCBQ) prepared by a solid phase grinding process and a solvent volatilization process;

FIG. 5 is a schematic representation of the crystal structure of a photothermal eutectic of TMPD (TMPD-PMDA) and its internal intermolecular non-covalent interactions, shown from different angles (a-d);

FIG. 6 is a chart of the UV-vis-NIR absorption spectra of TMPD-containing co-crystal (TMPD-PMDA) and TMPD and PMDA;

fig. 7 is a diagram showing a photothermal conversion experiment result of a photothermal conversion eutectic material (TMPD-PMDA) containing TMPD, in which, (a) a temperature rise-decrease process diagram, (b) a cyclic temperature rise-decrease experiment result diagram, (c) a temperature rise-decrease result diagram of different illumination powers, and (d) a temperature change-incident light power linear fitting diagram;

FIG. 8 is a graph of the results of ultrafast spectroscopy experiments on a photothermal conversion eutectic material (TMPD-PMDA) containing TMPD, wherein (a) and (b) are femtosecond transient absorption spectra of the eutectic material, (c) is a graph of kinetic fitting results, and (d) is a schematic diagram of the excitation and relaxation paths of the eutectic material;

FIG. 9 is a graph showing the results of a photothermal conversion experiment for a photothermal conversion eutectic material containing TMPD (TMPD-TCBQ, TMPD-TBBQ, TMPD-PMDA, and TMPD-TFBQ).

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings.

Example 1

As shown in fig. 1, the present example employs a solvent evaporation process route, and the detailed steps of the solvent evaporation process route for preparing the photothermal conversion eutectic material containing TMPD are as follows:

(1) 41.0mg of TMPD solid was weighed into a beaker, about 5mL of acetone was added, and TMPD was dissolved well by sonication at room temperature for about 5 minutes.

(2) 54.5mg of solid electron acceptor component PMDA is weighed and placed in a beaker, 5-10mL of acetone is added, and the PMDA is fully dissolved by ultrasonic treatment for 3-5 minutes at room temperature.

(3) The TMPD was mixed well with an acetone solution of the electron acceptor component to form a black intermolecular charge transfer complex.

(4) The acetone solvent is volatilized at normal pressure or under reduced pressure using a rotary evaporator, and the formed intermolecular charge transfer complex forms a eutectic and precipitates.

(5) The precipitated eutectic can be collected by suction filtration or scraping the solvent from the inner wall of the container after completely volatilizing the solvent, and the black photothermal conversion eutectic material containing TMPD can be obtained.

Example 2

(2) Weighing 61.5mg of the solid TCBQ as the electron acceptor component, placing the solid in a beaker, adding 5-10mL of acetone, and carrying out ultrasonic treatment at room temperature for 3-5 minutes to fully dissolve the PMDA.

Example 3

(2) 105.9mg of the electron acceptor component TBBQ solid is weighed and placed in a beaker, 5-10mL of acetone is added, and the PMDA is fully dissolved by ultrasonic treatment at room temperature for 3-5 minutes.

Example 4

(2) Weighing 45.0mg of solid TFBQ as an electron acceptor component, placing the solid in a beaker, adding 5-10mL of acetone, and carrying out ultrasonic treatment at room temperature for 3-5 minutes to fully dissolve PMDA.

Example 5

As shown in fig. 1, the solid phase grinding process route is adopted in the present embodiment, and the detailed steps of the solid phase grinding process route for preparing the photothermal conversion eutectic material containing TMPD are as follows:

(1) 41.0mg of TMPD solid was weighed out.

(2) 54.5mg of the solid electron acceptor component PMDA was weighed out.

(3) The TMPD and the electron acceptor component solids are intimately mixed, wherein the TMPD and the electron acceptor component in contact with each other begin to form an electron donor-electron acceptor intermolecular CT complex.

(4) Transferring the solid mixture in (3) into a mortar or ball mill, and grinding for 10-20min under certain pressure, wherein the contact between the two components is more sufficient, and the CT complex is promoted to orderly self-assemble in a form with lowest energy to form eutectic crystals.

(5) And after the grinding is finished, the photothermal conversion eutectic material containing TMPD can be obtained in a powder form.

Example 6

(1) 41.0mg of TMPD solid was weighed out.

(2) The electron acceptor component TCBQ was weighed out as a solid (61.5 mg).

Example 7

(1) 41.0mg of TMPD solid was weighed out.

(2) The electron acceptor component TBBQ was weighed out as a solid (105.9 mg).

Example 8

(1) 41.0mg of TMPD solid was weighed out.

(2) The electron acceptor component TFBQ was weighed out as a solid (45.0 mg).

Example 9

The electrostatic potential distributions of the electron donor and the electron acceptor selected in examples 1 to 8 were observed, and the results are shown in FIG. 2.

As can be seen from FIG. 2, the present invention employs N, N, N, N-tetramethylp-phenylenediamine (TMPD) having dimethylamino groups substituted at the 1-and 4-positions of the benzene ring, respectively, as an electron donor, wherein SP is³The hybridized N is a strongly electron-donating group, and thus is electron-rich on the benzene ring (i.e., the electrostatic potential is negative). On the other hand, pyromellitic dianhydride (PMDA), Tetrachloroterephthaloquinone (TCBQ), Tetrabromophenanthroquinone (TBBQ), and Tetrafluoroterephthaloquinone (TFBQ) having a strong electron-withdrawing group are preferable as electron acceptors, and the benzene ring is electron-deficient (electrostatic potential is positive). When the above electron donor is combined with an electron acceptor, an electron may be delocalized from the donor to the acceptor. Both form a Charge Transfer (CT) state, which in turn broadens the absorption spectrum of the system, enabling more efficient use of light in a wider wavelength band. When the CT compound is directionally arranged to form a eutectic crystal through non-covalent bonding force among molecules, absorbed light energy can be mainly released in a non-radiative transition form such as vibration relaxation, and photo-thermal conversion can be effectively carried out.

Example 10

The results of crystal observation of the photothermal eutectic containing TMPD obtained in examples 1 to 4 are shown in fig. 3.

As can be seen from FIG. 3, the prepared materials all have sharp and clear X-ray diffraction peaks, which indicates that the materials are long-range ordered, anisotropic crystals and have good crystallinity.

Example 11

The results of crystal observation of the photothermal co-crystals containing TMPD obtained in examples 2 and 6 are shown in fig. 4.

As can be seen from fig. 4, the photothermal conversion eutectic material containing TMPD obtained by the solid phase milling process is only slightly different from the eutectic material obtained by the solvent evaporation process in terms of crystal size and growth orientation, and the crystal structure, i.e., the specific arrangement or stacking form of the molecules, is not changed.

Example 12

The crystal structure of the photothermal eutectic containing TMPD obtained in example 1 was analyzed, and the results are shown in fig. 5.

FIG. 5 shows the molecular arrangement and stacking pattern of TMPD-PMDA eutectic and shows the presence of intermolecular non-covalent interaction forces such as intermolecular hydrogen bonding and pi-pi stacking. The eutectic crystal prepared by the invention is formed by the TMPD and the electron acceptor PMDA in an oriented arrangement mode.

Example 13

The photothermal conversion performance of the TMPD-containing photothermal eutectic obtained in example 1 was examined, and the results are shown in fig. 6.

Fig. 6 shows the uv-vis-nir absorption spectra of TMPD-PMDA and compared with the spectra of TMPD and PMDA. Therefore, after the TMPD and the electron acceptor component form a eutectic structure, the absorption spectrum of the eutectic material is expanded to 250-1500 nm. The eutectic material is made narrow and dense in excited state electron transition energy levels relative to the individual TMPD and electron acceptor components, i.e., the eutectic material is able to efficiently utilize light over a wide wavelength band.

Example 14

The photothermal conversion efficiency of the prepared TMPD-containing photothermal eutectic was measured by a method reported in the reference (angelw. chem. int. ed.,2018,57, 3963-. 8mg of a photothermal conversion eutectic material of TMPD-PMDA was weighed, dispersed on a square quartz plate having a size of 1.2cm, and fixed using a double-sided tape. The mass of the photothermal conversion eutectic material and the quartz piece was about 0.36 g. The power density of the system is 0.23W cm^-2Under the irradiation of near infrared laser with the wavelength of 808nm, the method can be usedThe temperature was raised to about 69 ℃ in 200 seconds. The photothermal conversion efficiency of the photothermal conversion eutectic material is calculated to be 87.2% through a temperature reduction curve, and is the highest value reported at present. The photothermal conversion efficiency of other photothermal conversion eutectic materials is shown in table 1.

TABLE 1 conversion efficiency of photothermal conversion material

Type of material	Efficiency of photothermal conversion
		TMPD-containing organic cocrystal (TMPD-PMDA)	87.20％
Organic eutectic crystal containing DBTTF (DBTTF-TCNB)	18.80％
		Gold nano-rod	21.00％
Metal organic framework material based on perylene diimide	52.30％
		Covalent organic framework (PyBPy +. cndot. -)	63.80％
Oligomer nanoparticles (F8-PEG NPs)	82.00％

Example 15

The photothermal conversion eutectic material of TMPD-PMDA of example 14 was subjected to 6 temperature rise-fall cycle tests, and the results are shown in fig. 7.

As can be seen from fig. 7, good photothermal conversion stability is maintained in 6 heating-cooling cycles, and the heating temperature and the power of the incident laser have a good linear relationship, i.e., the temperature of the photothermal conversion eutectic material can be accurately controlled by controlling the power of the incident laser.

Example 16

Ultrafast spectrum observation of the TMPD-PMDA eutectic crystal obtained in example 1, the result is shown in FIG. 8.

As can be seen from fig. 8, the TMPD-PMDA eutectic rapidly decays within 1ps after absorption of the optical excitation, and the kinetic results show that the process accounts for 94.4% of the total relaxation process. The prepared TMPD-containing photothermal eutectic material can rapidly release energy to relax to the ground state after being excited, mainly in a non-radiative transition mode, and light energy is effectively converted into heat energy in the process, so that the TMPD-containing photothermal eutectic material has excellent photothermal conversion efficiency.

Example 17

The photothermal conversion performance test was performed on the photothermal eutectic containing TMPD prepared in examples 1 to 4, and the results are shown in fig. 9.

As can be seen from FIG. 9, the power density of the photothermal conversion eutectic material containing TMPD prepared by different electron donors is 0.18w/cm^-2FIG. 7 shows the results of the photothermal conversion test under 808nm infrared light irradiation. It can be seen that the photothermal eutectic materials containing TMPD all rapidly increase the temperature to about 60-77 ℃ within 200 seconds, and show excellent photothermal conversion performance.

The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the scope of the present invention, therefore, the present invention is not limited by the appended claims.

Claims

1. The photothermal conversion eutectic material is formed by combining N, N, N, N-tetramethyl-p-phenylenediamine serving as an electron donor and an electron acceptor.

2. The photothermal conversion eutectic material containing N, N-tetramethyl-p-phenylenediamine according to claim 1, wherein said electron acceptor comprises one or more of pyromellitic dianhydride, tetrachloro-p-phenylenediamine, tetrabromo-p-phenylenediamine, tetrafluoro-p-phenylenediamine.

3. The photothermal conversion eutectic material containing N, N-tetramethyl-p-phenylenediamine according to claim 1, wherein said electron donor and said electron acceptor are combined in a molar ratio of 1:1 to form said photothermal conversion eutectic material.

4. The method for preparing a photothermal conversion eutectic material containing N, N, N, N-tetramethyl-p-phenylenediamine according to claim 1, which comprises a solvent evaporation method and a solid-phase grinding method.

5. The method for preparing the photothermal conversion eutectic material containing N, N, N, N-tetramethyl-p-phenylenediamine according to claim 4, wherein the solvent evaporation method comprises the following steps:

6. The method for preparing the photothermal conversion eutectic material containing N, N, N, N-tetramethyl-p-phenylenediamine according to claim 5, wherein the solvent evaporation method comprises the following steps:

A. weighing N, N, N, N-tetramethyl-p-phenylenediamine solid according to a ratio, placing the solid in a beaker, adding 4.5-5.5 mL of acetone, and ultrasonically vibrating for 4-6 minutes to completely dissolve the acetone;

B. weighing the electron acceptor solid according to a ratio, placing the electron acceptor solid in a beaker, adding 5-10mL of acetone, and carrying out ultrasonic oscillation for 3-5 minutes to completely dissolve the acetone;

C. uniformly mixing the acetone solution obtained in the step A and the acetone solution obtained in the step B to generate a black intermolecular charge transfer compound;

7. The method for preparing the photothermal conversion eutectic material containing N, N, N, N-tetramethyl-p-phenylenediamine according to claim 4, wherein the solid phase milling method comprises the following steps:

B. weighing the electron acceptor solid according to the proportion;

8. The method for preparing the photothermal conversion eutectic material containing N, N, N, N-tetramethyl-p-phenylenediamine according to claim 7, wherein the solid phase milling method comprises the following steps:

B. weighing the electron acceptor solid according to the proportion;

C. uniformly mixing the N, N, N, N-tetramethyl-p-phenylenediamine solid and the electron acceptor solid to form the solid mixture, and enabling the two components to contact with each other to start to form an intermolecular CT (computed tomography) compound of an electron donor-electron acceptor;

D. transferring the solid mixture into a mortar or a ball mill, and carrying out pressure grinding for 10-20min, wherein the contact between the two components is more sufficient, and the CT compound is promoted to orderly self-assemble in a form with lowest energy to form eutectic;

9. The use of the photothermal conversion eutectic material containing N, N-tetramethyl-p-phenylenediamine according to claim 1 in a photothermal conversion reaction.

10. The use of the photothermal conversion eutectic material containing N, N-tetramethyl-p-phenylenediamine according to claim 1, comprising sewage treatment, desalination of sea water, photothermal imaging, photothermal therapy.