A ferroelectric polymer-based all-organic composite material for photothermal and photoelectric conversion, preparation method and application

Abstract

The present invention provides a ferroelectric polymer-based all-organic composite material for photothermal and photoelectric conversion, a preparation method, and its application. Ultra-small conjugated poly-Schiff base poly-4-amino-1-naphthaldehyde nanoparticles are mixed with ferroelectric PVDF-based polymers by solution blending and casting to simply prepare a nanocomposite film. The polarized composite film can generate strong photothermal and photoelectric conversion in a wide range of ultraviolet-visible-near infrared wavelengths, such as 100mW / cm 2 The 450nm light can produce a temperature change of about 23℃, and achieve an open circuit voltage of 42.4V and a capacitance of 501.5μAm by coupling the photothermal effect with the pyroelectric effect. ‑2 The composite material's photoelectric voltage of over 40V is significantly higher than the current mainstream semiconductor-based photoelectric voltage (~1V), which may be more conducive to the material's application in fields such as energy conversion and light detection.

Description

Technical Field

[0001] The present invention belongs to the field of new functional materials, and mainly relates to a ferroelectric polymer-based all-organic composite material for photothermal and photoelectric conversion, a preparation method and an application. The present invention prepares a new type of ultrasmall poly Schiff base nanoparticle that can produce strong photothermal conversion in a wide wavelength range of ultraviolet, visible and near infrared. By combining the nanoparticle with a ferroelectric polymer, a composite material that can produce strong photothermal and photoelectric conversion in a wide wavelength range of ultraviolet, visible and near infrared can be prepared. Background Art

[0002] Photothermal materials are a class of materials that can convert absorbed light energy into heat. With the advancement of optical technology, photothermal conversion materials have found increasingly widespread applications in chemical engineering, energy, sensing, and healthcare. In recent years, photothermal materials based on conjugated organic polymers have developed rapidly, particularly in energy harvesting and disease diagnosis and treatment. Classic organic photothermal materials include polyaniline, polypyrrole, polythiophene, and polydopamine. However, the main conjugated organic polymer photothermal materials currently used are hydrophilic and easily dispersed in aqueous solvents, while they are relatively difficult to disperse well in organic solvents. This makes it difficult to simply combine these materials with other functional polymers, such as ferroelectric polymers, via solution blending, potentially limiting their application in areas such as organic composites. Furthermore, the main conjugated organic polymer photothermal materials currently used focus on near-infrared energy conversion, and relatively few materials have been reported for visible light photothermal conversion. The development of materials with strong visible light absorption and photothermal conversion capabilities may facilitate visible light sensing and energy utilization.

[0003] Poly(Schiff base) polymers containing carbon-nitrogen double bonds typically possess a variety of properties, including nonlinear optical properties, intrinsic conductivity, and thermal stability. Their optical and electrical properties have become a research hotspot in recent years. Poly(Schiff base) materials are numerous and offer a wide range of options. Developing a robust photothermal response in these materials could expand their functionality and enrich the range of photothermal conversion materials.

[0004] Ferroelectric polymers are a typical class of functional polymer materials, with research and application areas focused on dielectrics, piezoelectrics, and pyroelectrics. The pyroelectric effect refers to the charge release phenomenon manifested by temperature-dependent changes in polarization intensity. Macroscopically, this temperature change results in a voltage or current generated across the material. Since the photothermal effect can be used to convert light energy into thermal energy, we are exploring the possibility of combining ferroelectric polymers with photothermal materials to achieve photoelectric conversion by coupling the photothermal and pyroelectric effects. In traditional semiconductor optoelectronic systems, the photoelectric voltage is typically limited by the material's band gap. However, materials constructed using this photothermal-pyroelectric mechanism, unconstrained by the inherent band gap, have the potential to achieve high photoelectric voltages far exceeding those of traditional semiconductor optoelectronic materials. If this mechanism can be exploited to generate a large photoelectric response in ferroelectric polymers, it could expand the functionality of ferroelectric materials and enrich the range of optoelectronic materials. These materials have potential applications in optoelectronic devices and artificial visual prostheses. Summary of the Invention

[0005] The present invention provides a ferroelectric polymer-based all-organic composite material for photothermal and photoelectric conversion, a preparation method and application. The present invention prepares a new type of ultrasmall poly-Schiff base (poly-4-amino-1-naphthaldehyde) nanoparticles that can produce strong photothermal conversion in a wide wavelength range of ultraviolet, visible and near infrared. We further attempt to simply prepare a nanocomposite film by using solution blending and casting methods to combine these ultrasmall conjugated poly-Schiff base nanoparticles with ferroelectric polyvinylidene fluoride (PVDF)-based polymers (such as a copolymer of vinylidene fluoride and trifluoroethylene P(VDF-TrFE)). In the final composite material, the nanoparticles can be evenly dispersed, and the composite material can exhibit strong photothermal conversion capabilities in a wide wavelength range of ultraviolet, visible and near infrared. Since ferroelectric polymers have pyroelectric responses, we attempt to achieve photoelectric conversion by coupling the photothermal effect with the pyroelectric effect. The polarized composite film can produce strong photoelectric conversion in a wide wavelength range of ultraviolet, visible and near infrared, such as at 100mW / cm 2 The 450nm light can produce a temperature change of about 23℃, and achieve an open circuit voltage of 42.4V and a capacitance of 501.5μAm by coupling the photothermal effect with the pyroelectric effect. -2 The short-circuit current density of this composite material exceeds 40V, significantly higher than the photoelectric voltage of current mainstream semiconductor-based materials (~1V), which may be more conducive to the application of the material in fields such as energy conversion and light detection. In addition, there is the possibility of blending poly (4-amino-1-naphthaldehyde) nanoparticles with other ferroelectric polymers to construct a composite material with high photoelectric response.

[0006] The present invention adopts the following technical solutions:

[0007] A method for preparing a ferroelectric polymer-based all-organic composite material for photothermal and photoelectric conversion includes the following steps: heating and refluxing the monomer 4-amino-1-naphthaldehyde in a first polar solvent under inert gas protection to cause dehydration and condensation to obtain poly-4-amino-1-naphthaldehyde; dissolving the poly-4-amino-1-naphthaldehyde and a ferroelectric PVDF-based polymer in a second polar solvent, casting and drying the solution, and polarizing under a high-voltage electric field to obtain the composite material. The film needs to exceed the coercive field of the ferroelectric PVDF-based polymer (>50MVm -1 ) under an external electric field (polarization time>1min).

[0008] In the present invention, the high voltage electric field is a field exceeding the coercive field (50MVm -1 For example, the high voltage electric field is greater than 50MVm -1 And less than or equal to 200MVm -1 electric field.

[0009] Furthermore, the first polar solvent is ethanol, ethyl acetate, N,N-dimethylformamide or N-methylpyrrolidone; and the second polar solvent is N,N-dimethylformamide or N-methylpyrrolidone.

[0010] Furthermore, based on the total weight of the poly-4-amino-1-naphthaldehyde and the ferroelectric PVDF-based polymer, the content of the poly-4-amino-1-naphthaldehyde is 0 to 40 wt%. For example, the content of the poly-4-amino-1-naphthaldehyde is 0, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, 8.5 wt%, 9 wt%, 9.5 wt%, 10 wt%, 10.5 wt%, 11 wt%, 11.5 wt%, 12 wt%, 12.5 wt%, 13 wt%. %, 13.5wt%, 14wt%, 14.5wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 21wt%, 22wt%, 23wt%, 24wt%, 25wt%, 26wt%, 27wt%, 28wt%, 29wt%, 30wt%, 31wt%, 32wt%, 33wt%, 34wt%, 35wt%, 36wt%, 37wt%, 38wt%, 39wt%, or 40wt%.

[0011] Furthermore, the reflux temperature is 25 to 200° C., and the reflux time is 12 to 54 hours. The reflux temperature is 25° C., 30° C., 35° C., 40° C., 45° C., 50° C., 55° C., 60° C., 65° C., 70° C., 75° C., 80° C., 90° C., 100° C., 110° C., 120° C., 130° C., 150° C., 160° C., 170° C., 180° C., 190° C., or 200° C., and the reflux time is 12, 18, 24, 36, 38, 40, 45, 50, or 54 hours.

[0012] The composite material obtained by the method according to any one of the above items is a film, and the thickness of the film is 5-200 μm. For example, the thickness of the film is 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31μm, 32μm, 33μm, 34μm, 35μm, 36μm, 37μm, 38μm, 39μm, 40μm, 50μm, 60μm, 70μm, 80 μm, 90μm, 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 170μm, 180μm, 190μm or 200μm.

[0013] The composite material prepared by the method described in any one of the above items or the application of the composite material described above in photothermal and photoelectric conversion.

[0014] Specifically, a method for preparing a ferroelectric polymer-based all-organic composite material for photothermal and photoelectric conversion comprises heating and refluxing the monomer 4-amino-1-naphthaldehyde in an ethyl acetate solution under argon protection to cause dehydration and condensation, and collecting the precipitate to obtain poly-4-amino-1-naphthaldehyde. Due to its low degree of polymerization and rigid chain structure, this conjugated poly-Schiff base material can spontaneously form ultra-small polymer nanoparticles and can be stably and uniformly dispersed in polar solvents such as DMF (N,N-dimethylformamide) and NMP (N-methylpyrrolidone). By dissolving poly-4-amino-1-naphthaldehyde and a ferroelectric PVDF-based polymer in a polar solvent such as DMF or NMP and casting and drying the solution, a composite material with uniformly dispersed poly-Schiff base nanoparticles can be obtained.

[0015] Using ferroelectric PVDF-based polymers with a coercive field exceeding 50 MVm -1 ) can generate strong photothermal and photoelectric conversion in a wide wavelength range of ultraviolet-visible-near infrared, such as 100mWcm -2Under 450nm light, it can produce a temperature change of about 23℃, an open circuit voltage of 42.4V and a capacitance of 501.5μAm. -2 In contrast, the photoelectric voltage of semiconductor photoelectric systems relying on the photovoltaic effect is often limited by the material's band gap, resulting in such materials typically absorbing only a specific wavelength range of light and typically having a maximum open-circuit voltage of approximately 1V. The composite material we prepared offers significant advantages in both the light-responsive wavelength range and open-circuit voltage.

[0016] Advantages and positive effects:

[0017] The nanocomposite material for photothermal and photoelectric conversion prepared by blending ultrasmall conjugated poly-Schiff base nanoparticles with photothermal conversion capability with a ferroelectric polymer with a pyroelectric effect has the following advantages:

[0018] (1) The synthesized novel conjugated poly-Schiff base: poly-4-amino-1-naphthaldehyde, can produce strong photothermal conversion in a wide wavelength range of ultraviolet, visible and near infrared. It is also ultra-small and easily dispersible. A composite material with uniformly dispersed nanoparticles can be prepared by simple solution blending and casting. The preparation method is highly operable and simple in process.

[0019] (2) The composite material has strong absorption in a wide wavelength range of ultraviolet-visible-near infrared, which is beneficial to improving the efficiency of light energy utilization;

[0020] (3) The optoelectronic composite material based on the coupling of photothermal and pyroelectric effects overcomes the voltage limitation of the optoelectronic system based on semiconductor materials and has an open circuit voltage value far exceeding that of other optoelectronic materials reported in the literature. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The invention relates to a method for obtaining poly-4-amino-1-naphthaldehyde by polymerizing monomer 4-amino-1-naphthaldehyde.

[0022] Figure 2 This is an ultrathin section TEM of a composite film of poly (4-amino-1-naphthaldehyde) ultrasmall nanoparticles (2 wt% content) and ferroelectric P (VDF-TrFE) copolymer.

[0023] Figure 3 Composite materials with different poly (4-amino-1-naphthaldehyde) contents at 100 mWcm -2 Open circuit voltage and short circuit current density curves under 405nm light.

[0024] Figure 4 The composite material with 2wt% poly 4-amino-1-naphthaldehyde content was -2 The 450nm light can produce a temperature change of about 23℃.

[0025] Figure 5 The composite material with 2wt% poly 4-amino-1-naphthaldehyde content was -2 Open circuit voltage and short circuit current density curves under 405-850nm light. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. However, the following embodiments are intended only to explain the present invention, and the scope of protection of the present invention should include the entire contents of the claims. Moreover, through the description of the following embodiments, those skilled in the art can fully implement the entire contents of the claims of the present invention.

[0027] The present invention proposes a composite thin film material of ultrasmall poly (4-amino-1-naphthaldehyde) nanoparticles and a ferroelectric P(VDF-TrFE) copolymer, which can be simply produced by casting a mixed solution. This composite material exhibits strong photothermal and photoelectric conversion capabilities over a wide wavelength range from ultraviolet to visible to near-infrared. The feasibility of this method is demonstrated using poly (4-amino-1-naphthaldehyde) (PANA) nanoparticles and P(VDF-TrFE) (7030).

[0028] Example 1: Synthesis of poly (4-amino-1-naphthaldehyde) nanoparticles.

[0029] 4-Amino-1-naphthaldehyde (0.58 g, 3.4 mmol) was dissolved in ethyl acetate (25 mL), and triethylamine (0.3 mL, 21 mmol) was added to provide an alkaline environment. The mixed solution was refluxed in argon at 70 ° C for 48 hours to obtain a dark brown solid residue. Figure 1 The solid residue was washed with ethanol and dried in vacuo to give 0.36 g (yield 62%) of poly(4-amino-1-naphthaldehyde).

[0030] Example 2: Preparation of a composite film of P(VDF-TrFE) copolymer and poly (4-amino-1-naphthaldehyde) by a casting method.

[0031] Poly(4-amino-1-naphthaldehyde) (PANA) and P(VDF-TrFE) (Piezotech, Arkema Group, France) prepared in Example 1 were dissolved in 4 mL of DMF and stirred overnight. The homogeneous mixture was then cast onto a clean glass plate and dried in an 80°C oven for 2 hours. After cooling naturally to room temperature, the composite film was peeled from the glass plate and dried in a vacuum oven at 135°C for 5 hours to remove residual solvent and increase crystallinity. The resulting composite film (20 μm thick) contained uniformly dispersed nanoparticles. Wherein poly (4-amino-1-naphthaldehyde) (PANA) and P (VDF-TrFE) are 0.2g in total, and based on the total mass of poly (4-amino-1-naphthaldehyde) and P (VDF-TrFE), the content of poly (4-amino-1-naphthaldehyde) is 0wt%, 0.5wt%, 1wt%, 2wt%, 5wt% and 10wt%, respectively, to obtain films with different contents of poly (4-amino-1-naphthaldehyde). Figure 2 As shown, the TEM image of the ultra-thin section of the composite film (the content of poly (4-amino-1-naphthaldehyde) is 2 wt%) after being stained with ruthenium tetroxide vapor, the thin film-like substance visible in the figure is the P (VDF-TrFE) matrix, and the nanoparticles are PANA nanoparticles.

[0032] Example 3: Photoelectric response of composite films with different poly (4-amino-1-naphthaldehyde) contents.

[0033] The composite film obtained in Example 2 was heated at 100 MVm -1 After polarization for 5 minutes under electric field strength, indium tin oxide (ITO) was plated on the composite film with a thickness of 100 nm for subsequent photoresponse testing. Composite materials with different nanoparticle contents all have good photoelectric responses, such as Figure 3 shown.

[0034] The composite material has a strong photothermal response in a wide wavelength range. The composite material with 2 wt% poly 4-amino-1-naphthaldehyde content has a strong photothermal response at 100 mWcm -2 The 450nm light can produce a temperature change of about 23℃, such as Figure 4 As shown in the infrared thermal image, the composite material with 2 wt% poly 4-amino-1-naphthaldehyde content is compared with that before illumination (left) at 100 mWcm -2 Under 450nm light (right), a temperature change of about 23°C can be generated. Due to the coupling of the photothermal effect of poly (4-amino-1-naphthaldehyde) nanoparticles and the pyroelectric effect of P (VDF-TrFE) copolymer, the 2wt% poly (4-amino-1-naphthaldehyde) content composite material can generate a temperature change of about 23°C under 100mW cm -2 It can show high open circuit voltage and short circuit current density under 405-850nm light, such as Figure 5 shown.

[0035] The present invention does not describe in detail parts that belong to the common knowledge of those skilled in the art. The above-described embodiments are merely descriptions of preferred embodiments of the present invention. The preferred embodiments do not describe all details in detail, nor do they limit the invention to the specific embodiments described. Without departing from the spirit of the present invention, various modifications and improvements made by those skilled in the art to the technical solution of the present invention should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing a ferroelectric polymer-based all-organic composite material for photothermal and photoelectric conversion, characterized in that: The method comprises the following steps: heating and refluxing the monomer 4-amino-1-naphthaldehyde in a first polar solvent under the protection of an inert gas to carry out dehydration condensation to obtain poly-4-amino-1-naphthaldehyde; dissolving the poly-4-amino-1-naphthaldehyde and a ferroelectric PVDF-based polymer in a second polar solvent at the same time; and casting and drying the solution to obtain the composite material.

2. The method according to claim 1, characterized in that The first polar solvent is ethanol, ethyl acetate, N,N-dimethylformamide, chloroform or N-methylpyrrolidone; the second polar solvent is N,N-dimethylformamide or N-methylpyrrolidone.

3. The method according to claim 1, characterized in that Based on the total mass of the poly (4-amino-1-naphthaldehyde) and the ferroelectric PVDF-based polymer, the content of the poly (4-amino-1-naphthaldehyde) is greater than 0 and less than or equal to 40 wt %.

4. The method according to claim 1, wherein The heating reflux temperature is 25 to 200° C., and the heating reflux time is 12 to 54 hours.

5. The composite material obtained by the method according to any one of claims 1 to 4, characterized in that The composite material is a film with a thickness of 5-200 μm.

6. The composite material according to claim 5, wherein The film needs to be polarized under an external electric field with a coercive field of the ferroelectric PVDF-based polymer of >50 MV / m, and the polarization time is >1 min.

7. Use of the composite material prepared by the method according to any one of claims 1 to 4 or the composite material according to claim 5 in photothermal or photoelectric conversion for non-diagnostic therapeutic purposes.

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