High-performance pure organic magnetic composite material and preparation method thereof

Abstract

The application discloses a kind of high-performance pure organic magnetic composite material and preparation method thereof, the composite material is poly (3-hexyl thiophene) as electron donor, using fullerene as electron acceptor, synthesis poly (3-hexyl thiophene) / fullerene composite charge transfer object.Then after 4" -n-pentyl-4-cyanotriphenyl subsequent doping, poly (3-hexyl thiophene) / fullerene / 4" -n-pentyl-4-cyanotriphenyl composite material.The method and material used in the application enhance the degree of charge transfer between pure organic composite material and solid state structure order, so that composite material obtains high room temperature ferromagnetism and Curie temperature, overcome the shortcoming that organic magnetic material is unstable in performance in air, low Curie temperature.Through poly (3-hexyl thiophene), fullerene and 4" -n-pentyl-4-cyanotriphenyl three composite, provide a kind of simple operation, solid state structure packing order, good stability high magnetic pure organic component composite material preparation new method.

Description

Technical Field

[0001] This invention relates to the field of novel energy material preparation technology, specifically to a high-performance pure organic magnetic composite material poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanoterphenyl and its preparation method. Background Technology

[0002] With the advancement of modern technology, magnetic materials have a wide range of applications in electronic communications, information storage, and life sciences. Traditional magnetic materials are mostly inorganic materials such as metals, alloys, and minerals with 3d or 4f orbital electrons. However, due to their high density, hardness, complex synthesis processes, susceptibility to corrosion, and high magnetic loss, they can no longer meet the requirements of certain high-tech and cutting-edge scientific fields. In recent years, with the continuous progress in superconducting material preparation technology, the preparation of organic magnetic materials has attracted much attention. Organic magnets have advantages such as flexibility, light weight, low magnetic loss, and good biocompatibility, and are expected to lead major technological innovations in aerospace, information, military, and life sciences.

[0003] Pure organic magnetic materials refer to organic compounds composed of low-Z elements such as C, H, O, and N. Their magnetism originates from the long-range order of the electron spins in the s and p orbitals. The synthesis of high-spin organic magnets requires two conditions: the presence of paramagnetic units (spins); and ferromagnetic interactions between the spins. During molecular synthesis, paramagnetic centers with unpaired electrons, including free radicals, spin solitons, and polarons, are introduced into the molecular backbone to regulate intermolecular interactions, resulting in ordered spin arrangement and macroscopic ferromagnetism. Therefore, pure organic magnets possess structural diversity, good stability, and high plasticity, enabling the creation of multifunctional magnetic materials that combine optical, electrical, and mechanical properties.

[0004] Common organic magnetic materials mainly include organic free radical polymers, high-spin cross-linked macromolecules, and spin-doped conjugated polymers. Common free radical-containing organic magnets derive their magnetism from the ferromagnetic exchange interaction between the main-chain carbon atoms and the side-chain free radicals. However, they are chemically reactive and completely lose their magnetism after exposure to air for a few seconds. Furthermore, these organic magnets typically exhibit magnetism only at extremely low temperatures. Ovchinnikov reported the first experimentally synthesized pure organic magnet, poly(2,2,6,6-tetramethyl-4-hydroxy-1-oxopiperidine)butadiyne (polyBIPO), a discovery that overturned the established notion that organic materials are insulated from magnetism. However, Fang et al. found in their experiments that although some free radicals exhibit magnetism due to the presence of lone pairs of electrons, they are chemically reactive. Only under sufficiently stable conditions can free radicals be prepared, separated, and characterized. Moreover, due to the inherent chemical reactivity of free radicals, the reported organic ferromagnets are usually unstable and completely lose their magnetism after exposure to air for a few seconds.

[0005] Rational molecular design is crucial for obtaining stable organic π-conjugated magnetic frameworks, aiming to stabilize their spin centers and maintain a highly magnetically ordered state. Rajca et al. synthesized conjugated polymers with large magnetic moments by alternately linking free radical modules with different spin quantum numbers and high crosslinking densities. However, the magnetism of this material only tends to stabilize below 10 K, making it difficult to meet practical standards. Phan et al. found that adjacent free radicals are ferromagnetically coupled in covalently linked porous organic free radical frameworks. 1,3,5-triazine chain porous organic free radical frameworks obtained through thermal or microacid-assisted polymerization exhibit spontaneous magnetization and hysteresis at room temperature, with an ordering temperature above 450 K. Mahmood et al. reported a room-temperature ferromagnetic triazine network polymer formed by the self-polymerization of 7,7,8,8-tetracyanoquinoline dimethane (TCNQ). Its glassy state can capture highly stable free radicals generated by spin, thus giving the polymer ferromagnetic order. Purposeful spin assembly and control through structural design is an effective way to obtain pure organic magnets, but problems such as high synthesis difficulty, poor reproducibility and low yield still need to be solved.

[0006] Besides the aforementioned free radical compounds, some classic conjugated polymers, such as polyaniline, polypyrrole, regio-irregular poly(3-alkylthiophene), and substituted polyacetylene, also exhibit ferromagnetism after doping. Paula synthesized ClO using an electrochemical method. 4- The key to ferromagnetism in doped, non-metallic P3TH lies in the charge transfer induced by doping, which generates polarons with unpaired electrons. Yang et al. prepared a composite exciton solution by mixing P3HT and PCBM, and the resulting film exhibited strong room-temperature ferromagnetism with a saturation magnetization of approximately 0.65 emu / g. Vandeleene et al. reported the magnetism of neutral (undoped) polythiophenes with different side chains, particularly exploring the effects of substituent properties, substitution modes, and regioregularity on the magnetism. However, due to the large spin distance, spin coupling was impossible, resulting in weak magnetism. To date, no purely organic magnets with excellent and stable performance at room temperature have been found among organic materials composed solely of C, H, O, and N.

[0007] Based on the above analysis, a pure organic magnetic material with excellent room-temperature ferromagnetism and air stability is urgently needed in this industry. Summary of the Invention

[0008] The purpose of this invention is to solve the above-mentioned problems existing in the prior art and provide a high-performance pure organic magnetic composite material and its preparation method. This invention involves pre-assembling poly(3-hexylthiophene) powder in a mixed solvent; then doping the poly(3-hexylthiophene) system with fullerene to form a charge-transfer composite; and finally post-treating with 4″-n-pentyl-4-cyanoterphenyl to prepare a poly(3-hexylthiophene) / fullerene / 4″-n-pentyl-4-cyanoterphenyl composite material. This composite material is a pure organic magnetic composite material with excellent room-temperature ferromagnetism and air stability.

[0009] The technical solution adopted in this invention is as follows: A method for preparing a high-performance pure organic magnetic composite material, comprising the following steps:

[0010] S1. Poly(3-hexylthiophene) powder, o-dichlorobenzene and acetonitrile are pretreated with solvent to obtain a poly(3-hexylthiophene) solution, and then fullerene is added to prepare a mixed solution;

[0011] S2. Prepare a silicon wafer substrate and clean the silicon wafer with a polar solvent; drop the mixed solution from S1 onto the cleaned silicon wafer substrate, cover it with a petri dish, and dry it slowly to obtain a poly(3-hexylthiophene) / fullerene composite charge transfer film.

[0012] S3: The poly(3-hexylthiophene) / fullerene composite charge transfer film obtained in S2 was subsequently doped with 4”-n-pentyl-4-cyanoterphenyl to obtain a poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanoterphenyl composite material.

[0013] Preferably, in step S1, poly(3-hexylthiophene) powder is dissolved in o-dichlorobenzene, and after ultrasonic dissolution and uniform mixing, a poly(3-hexylthiophene) / o-dichlorobenzene solution is obtained, and then acetonitrile is added to prepare a poly(3-hexylthiophene) solution.

[0014] Preferably, the poly(3-hexylthiophene) powder has a purity of 95-99%.

[0015] Preferably, the concentration of the poly(3-hexylthiophene) / o-dichlorobenzene solution is 5-50 mg / mL.

[0016] Preferably, the volume ratio of the acetonitrile to the poly(3-hexylthiophene) / o-dichlorobenzene solution is 5%-25%.

[0017] In a further preferred embodiment, the mass ratio of poly(3-hexylthiophene) powder to fullerene in S1 is 10:1 to 1:1.

[0018] Further preferably, the polar solvent in S2 is one of ethanol, isopropanol, and acetone.

[0019] More preferably, the volume ratio of the poly(3-hexylthiophene) / fullerene composite charge transfer film to 4”-n-pentyl-4-cyanoterphenyl in S3 is 1:1 to 1:10.

[0020] The present invention also provides a high-performance pure organic magnetic composite material prepared by the above preparation method, wherein the high-performance pure organic magnetic composite material is a poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanoterphenyl composite material.

[0021] The beneficial effects of this invention are as follows:

[0022] 1. This invention prepares a pure organic magnetic composite material, namely a poly(3-hexylthiophene) / fullerene / 4″-n-pentyl-4-cyanoterphenyl composite material. In this ternary composite material, the closed-shell structure of the poly(3-hexylthiophene) system is broken by regulating charge transfer, and pure spin density is obtained. Furthermore, 4″-n-pentyl-4-cyanoterphenyl is used to improve the orderliness of the molecular chains and enhance the crystallinity of the film, thereby effectively enhancing the room temperature ferromagnetism and air stability of the composite material.

[0023] 2. The preparation method of the composite material in this invention is mild, simple, and rapid, and can stably obtain a pure organic magnetic composite material with excellent room temperature ferromagnetism and air stability, which is suitable for large-scale industrial production. Attached Figure Description

[0024] Figure 1 This is a digital photograph of poly(3-hexylthiophene) solution B in Example 3 of the present invention;

[0025] Figure 2 Raman spectra of poly(3-hexylthiophene), fullerene, and poly(3-hexylthiophene) / fullerene charge transfer complex in Example 3 of the present invention;

[0026] Figure 3 The infrared spectra of the 4”-n-pentyl-4-cyanotriphenyl, poly(3-hexylthiophene) / fullerene and poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanotriphenyl composite films in Example 3 of the present invention are shown below.

[0027] Figure 4 The XRD patterns of the poly(3-hexylthiophene) / fullerene and poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanoterphenyl composite films in Example 3 of the present invention are shown below.

[0028] Figure 5 The hysteresis loop of the poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanoterphenyl composite film newly prepared in Example 3 of the present invention and after being placed in air for 3 months. Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0030] Example 1

[0031] Poly(3-hexylthiophene) powder P3HT with a purity of 95% was weighed and dissolved in o-dichlorobenzene solvent. After ultrasonic dissolution and homogenization, a 5 mg / mL poly(3-hexylthiophene) / o-dichlorobenzene solution A was obtained. Then, a certain amount of acetonitrile (V) was added to solution A. CAN :V o-DCB =5%), after ultrasonic treatment and uniform mixing, it is left to stand at room temperature to obtain poly(3-hexylthiophene) solution B.

[0032] A certain mass of fullerene was added to solution B, with a fullerene to poly(3-hexylthiophene) mass ratio of 1:1.5. After ultrasonic treatment and homogenization, the mixture was allowed to stand at room temperature to obtain poly(3-hexylthiophene) / fullerene solution C. A silicon substrate was ultrasonically washed in acetone for 5 min, and then air-dried in a vacuum oven at low temperature for later use. Solution C was drop-coated onto a clean substrate, covered with a petri dish, and slowly dried at room temperature to obtain a poly(3-hexylthiophene) / fullerene composite charge transfer film D.

[0033] Subsequent doping was performed using 1 ml of 4”-n-pentyl-4-cyanotriphenyl, covered with a petri dish, and slowly dried at room temperature to obtain a poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanotriphenyl composite film.

[0034] Example 2

[0035] P3HT powder with a purity of 95% was weighed and dissolved in o-dichlorobenzene solvent. After ultrasonic dissolution and homogenization, a poly(3-hexylthiophene) / o-dichlorobenzene solution A with a concentration of 8 mg / mL was obtained. Then, a certain amount of acetonitrile (V) was added to solution A. CAN :V o-DCB =7%), after ultrasonic treatment and uniform mixing, it is left to stand at room temperature to obtain poly(3-hexylthiophene) solution B.

[0036] A certain mass of fullerene was added to solution B, with a fullerene to poly(3-hexylthiophene) mass ratio of 1:1. After ultrasonic treatment and homogenization, the mixture was allowed to stand at room temperature to obtain poly(3-hexylthiophene) / fullerene solution C. A silicon wafer substrate was ultrasonically washed in anhydrous ethanol for 5 min, and then air-dried in a vacuum oven at low temperature for later use. Solution C was drop-coated onto a clean substrate, covered with a petri dish, and slowly dried at room temperature to obtain a poly(3-hexylthiophene) / fullerene composite charge transfer film D.

[0037] Subsequent doping was performed using 1.5 ml of 4”-n-pentyl-4-cyanotriphenyl, covered with a petri dish, and slowly dried at room temperature to obtain a poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanotriphenyl composite film.

[0038] Example 3

[0039] P3HT powder with a purity of 99% was weighed and dissolved in o-dichlorobenzene solvent. After ultrasonic dissolution and homogenization, a 5 mg / mL poly(3-hexylthiophene) / o-dichlorobenzene solution A was obtained. Then, a certain amount of acetonitrile (V) was added to solution A. CAN :V o-DCB =15%), after ultrasonic treatment and thorough mixing, and then allowed to stand at room temperature, poly(3-hexylthiophene) solution B is obtained. The solution is dark red. Figure 1 This is a digital photograph of solution B prepared in this embodiment.

[0040] A certain mass of fullerene was added to solution B, with a fullerene to poly(3-hexylthiophene) mass ratio of 1:2.5. After ultrasonic treatment and homogenization, the mixture was allowed to stand at room temperature to obtain poly(3-hexylthiophene) / fullerene solution C. A silicon substrate was ultrasonically washed once in acetone and isoacetone for 5 min, and then air-dried at low temperature in a vacuum oven for later use. Solution C was drop-coated onto a clean substrate, covered with a petri dish, and slowly dried at room temperature to obtain a poly(3-hexylthiophene) / fullerene composite charge transfer film D.

[0041] Figure 2 The images show the Raman spectra of poly(3-hexylthiophene), fullerene, and the poly(3-hexylthiophene) / fullerene charge-transfer complex in this embodiment. The excitation wavelength for the Raman spectra was 532 nm. Fullerenes exhibited excitation wavelengths of 1421, 1471, and 1574 cm⁻¹. -1 Characteristic peaks. In composite film D, all characteristic Raman peaks of fullerenes disappear. The negative charge of fullerenes leads to a decrease in the concentration of neutral molecules, and the electrical characteristics of fullerene molecules are relatively dispersed, masked by the strong signal peak of P3HT. 1350–1500 cm⁻¹ -1 The spectral bands are highly sensitive to the conjugation length within the molecular chain and the degree of π electron delocalization

[31] . Among them, 1380 cm⁻¹ -1 and 1450cm -1 These are the intra-ring C-C and C=C stretching vibration peaks, respectively. Compared to poly(3-hexylthiophene), the intensity of the poly(3-hexylthiophene)-related Raman peaks in composite film D is significantly increased, while the corresponding full width at half maximum (FWHM) decreases. The Raman spectrum intensity is proportional to the square of the induced dipole moment, indicating that there is effective charge transfer between poly(3-hexylthiophene) and fullerene in film D, affecting the properties of the C=C bond and the charge distribution of the S element.

[0042] Subsequent doping was performed using 2 ml of 4”-n-pentyl-4-cyanotriphenyl, covered with a petri dish, and slowly dried at room temperature to obtain a poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanotriphenyl composite film.

[0043] Figure 3 The images show the infrared spectra of the 4”-n-pentyl-4-cyanotriphenyl, poly(3-hexylthiophene) / fullerene, and poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanotriphenyl composite films in this embodiment. Compared to (3-hexylthiophene) / fullerene, the poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanotriphenyl composite film contains I 1510 / I 1460 The increase in the ratio indicates that 4”-n-pentyl-4-cyanoterphenyl helps to enhance the conjugated order of the molecular chains in the composite film. Figure 4 The XRD patterns of the poly(3-hexylthiophene) / fullerene and poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanoterphenyl composite films in Example 3 of this invention are shown. After near-4”-n-pentyl-4-cyanoterphenyl doping, the crystallinity of the composite film is significantly improved, and the π-π stacking distance of the poly(3-hexylthiophene) molecular chains is shortened. This facilitates more efficient charge transfer and stronger, more stable polaron spin coupling, which is key to the high magnetization of the poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanoterphenyl composite films. The poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanoterphenyl composite films were exposed to air for three months, and the magnetic properties of the aged films were characterized to investigate the effect of external conditions on magnetism. Figure 5 The figures show the hysteresis loops of the newly prepared poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanoterphenyl composite film and the film after being exposed to air for 3 months in this embodiment. At 300 K, the poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanoterphenyl composite film exhibits typical hysteresis characteristics and thus exhibits ferromagnetism, with an out-of-plane saturation magnetization of approximately 80 emu. -1 The magnetic properties are significantly higher than those reported for poly(3-hexylthiophene). After aging treatment, the magnetic properties of the poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanoterphenyl composite film decreased to some extent, but it still maintained a high saturation magnetization of 60 emu.g. -1 .

[0044] Example 4

[0045] P3HT powder with a purity of 98% was weighed and dissolved in o-dichlorobenzene solvent. After ultrasonic dissolution and homogenization, a 10 mg / mL poly(3-hexylthiophene) / o-dichlorobenzene solution A was obtained. Then, a certain amount of acetonitrile (V) was added to solution A.CAN :V o-DCB =15%), after ultrasonic treatment and uniform mixing, it is left to stand at room temperature to obtain poly(3-hexylthiophene) solution B.

[0046] A certain mass of fullerene was added to solution B, with a fullerene to poly(3-hexylthiophene) mass ratio of 1:4.5. After ultrasonic treatment and homogenization, the mixture was allowed to stand at room temperature to obtain poly(3-hexylthiophene) / fullerene solution C. A silicon substrate was ultrasonically washed in isoacetone for 15 min, and then air-dried in a vacuum oven at low temperature for later use. Solution C was drop-coated onto a clean substrate, covered with a petri dish, and slowly dried at room temperature to obtain a poly(3-hexylthiophene) / fullerene composite charge transfer film D.

[0047] Subsequent doping was performed using 5 ml of 4”-n-pentyl-4-cyanotriphenyl, covered with a petri dish, and slowly dried at room temperature to obtain a poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanotriphenyl composite film.

[0048] The specification and drawings of this invention are intended to be illustrative rather than restrictive. Based on this invention, those skilled in the art can make substitutions and modifications to some of the technical features without creative effort, and all such modifications are within the scope of protection of this invention.

Claims

1. A method for preparing a high-performance pure organic magnetic composite material, characterized in that, Includes the following steps: S1. Poly(3-hexylthiophene) powder, o-dichlorobenzene and acetonitrile are pretreated with solvent to obtain a poly(3-hexylthiophene) solution, and then fullerene is added to prepare a mixed solution; S2. Prepare a silicon wafer substrate and clean the silicon wafer with a polar solvent; drop the mixed solution from S1 onto the cleaned silicon wafer substrate, cover it with a petri dish, and dry it slowly to obtain a poly(3-hexylthiophene) / fullerene composite charge transfer film. S3: The poly(3-hexylthiophene) / fullerene composite charge transfer film obtained in S2 was subsequently doped with 4”-n-pentyl-4-cyanoterphenyl to obtain a poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanoterphenyl composite material.

2. The preparation method according to claim 1, characterized in that, In step S1, poly(3-hexylthiophene) powder is dissolved in o-dichlorobenzene, and after ultrasonic dissolution and uniform mixing, a poly(3-hexylthiophene) / o-dichlorobenzene solution is obtained. Acetonitrile is then added to prepare a poly(3-hexylthiophene) solution.

3. The preparation method according to claim 2, characterized in that, The purity of the poly(3-hexylthiophene) powder is 95-99%.

4. The preparation method according to claim 2, characterized in that, The concentration of the poly(3-hexylthiophene) / o-dichlorobenzene solution is 5–50 mg / mL.

5. The preparation method according to claim 2, characterized in that, The volume ratio of acetonitrile to poly(3-hexylthiophene) / o-dichlorobenzene solution is 5%-25%.

6. The preparation method according to claim 1, characterized in that, The mass ratio of poly(3-hexylthiophene) powder to fullerene in S1 is 10:1 to 1:

1.

7. The preparation method according to claim 1, characterized in that, The polar solvent in S2 is one of ethanol, isopropanol, and acetone.

8. The preparation method according to claim 1, characterized in that, The volume ratio of the poly(3-hexylthiophene) / fullerene composite charge transfer film in S3 to 4”-n-pentyl-4-cyanoterphenyl is 1:1 to 1:

10.

9. The high-performance pure organic magnetic composite material prepared by the preparation method according to any one of claims 1-8, wherein the high-performance pure organic magnetic composite material is a poly(3-hexylthiophene) / fullerene / 4”-n-pentyl-4-cyanoterphenyl composite material.

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