Photothermal-hydrophobic synergistic effect wide spectrum plasmonic core-shell material and device preparation method

Abstract

The application provides a photothermal-water-voltaic synergistic effect wide-spectrum plasmonic core-shell material and a device preparation method. In the synthesis process, anisotropic plasmonic nanostructures respectively undergo aggregation in a plane and overlap in a vertical direction, which respectively causes red shift and blue shift of a surface plasmon resonance (SPR) resonance peak, and breaks through the diffraction limit to achieve wide-spectrum absorption. The thin film prepared by the application has good photothermal effect, and the existence of the oxide shell can effectively protect the plasmonic metal core from deformation caused by chemical reaction with the outside world when the temperature rises. In addition, the prepared thin film has good water-voltaic power generation capacity, and can improve the water-voltaic power generation output by using the photothermal effect under illumination.

Description

Technical Field

[0001] This invention relates to the fields of plasmons, photothermal, metal nanostructures, self-powered devices and thin-film devices, and specifically to a method for preparing a broadband plasmon core-shell material and device with photothermal-water photovoltaic synergistic effect. Background Technology

[0002] With the increasingly severe environmental and energy problems facing human society, much effort has been devoted to research on green energy technologies, including photovoltaic power generation, piezoelectricity, thermoelectricity, and the recently popular hydrovoltaic power generation. Functional materials in hydrovoltaic power generation devices can spontaneously absorb water molecules from the surrounding environment. The hydration of these materials generates an ion concentration gradient that drives the directional movement of charge carriers in an external circuit, thereby generating energy for external power supply. Hydrovoltaic power generation devices can directly utilize water that is ubiquitous in the natural environment (evaporation, respiration, transpiration, sublimation, etc.) to generate electricity, demonstrating their convenience as portable functional devices. Materials suitable for hydrovoltaic power generation mainly include inorganic carbon, inorganic solid oxides, organic polymers, and natural biomaterials. There are no reports of introducing plasmon metals into the field of hydrovoltaic power generation, even though plasmon metals themselves are excellent light-absorbing materials.

[0003] Currently, the output of hydro-voltaic power generation devices is relatively low, often requiring multiple devices to operate simultaneously to power practical applications. Therefore, improving the output of hydro-voltaic power generation is a key research focus in this field. Among numerous methods to increase output, introducing a photovoltaic (PV) effect synergistic approach can both enhance the output of hydro-voltaic power generation and utilize abundant solar energy from nature. The output of a hydro-voltaic power generation device as a power source or its sensing speed as a sensor is closely related to the water evaporation rate; increasing the evaporation rate can effectively improve the device's output performance. Among the factors in the natural environment that affect the water evaporation rate (such as temperature, wind speed, and humidity), wind speed and humidity are difficult to change, or require energy to change. However, temperature can be easily changed by sunlight, and there is extensive research experience with photovoltaic materials. Therefore, introducing a photovoltaic effect is a suitable direction for enhancing the output performance of hydro-voltaic power generation while effectively utilizing natural solar energy. However, there is not much research on such photovoltaic power generation devices with photothermal synergy. The materials used are often independent photovoltaic power generation materials and light absorption materials combined by mechanical mixing or thin film stacking. The photovoltaic effect and the photothermal effect are separate, and there are no reports of combining the two effects with a single material.

[0004] In photovoltaic (PV) power generation devices that combine photothermal and optical energy, light-absorbing materials are a crucial component. The temperature rise of the device under illumination determines the degree to which photothermal energy enhances the PV power output. Besides carbon-based materials, commonly used broadband absorbers include plasmonic metals. When light shines on the surface of noble metals (such as Ag, Au, and Pt), a localized surface plasmon resonance phenomenon occurs, enhancing spectral selectivity. This spectral response varies with morphology and size, absorbing light in different wavelength bands. Broadband absorption can be achieved by controlling the morphology and structure to match optical absorption. Furthermore, the thermal conductivity of plasmons is higher than that of the surrounding medium, resulting in a high degree of localized thermal effect and better photothermal conversion efficiency. However, current traditional anisotropic plasmonic nanostructures exhibit weak absorption in the short wavelength range, with narrow SPR resonance peaks. Additionally, the in-plane aggregation of traditional nanostructures causes a redshift in the spectrum, failing to overcome the deficiency of weak short-wavelength absorption. Furthermore, exposed plasmonic nanostructures, due to their fragility, begin to deform when the temperature rises to 60°C, failing to maintain their original shape and thus being destroyed. Therefore, there is a need to prepare a material that can enhance the short-wavelength light absorption capability of plasmonic nanostructures, achieving broad-spectrum absorption, and addressing the poor high-temperature resistance of metallic nanomaterials. Summary of the Invention

[0005] Technical Problem: The purpose of this invention is to solve the problems of poor short-wavelength absorption, inability to achieve broad-spectrum absorption, and poor high-temperature resistance of traditional anisotropic surface plasmonic metal nanostructures, as well as the fact that existing materials used in the field of hydrovoltaic power generation do not involve plasmonic metal materials. This invention proposes a method for fabricating a broad-spectrum absorbing plasmonic metal-metal oxide core-shell structure and thin-film device with hydrovoltaic-photothermal synergistic effect. This material can achieve broad-spectrum absorption and excellent high-temperature resistance, realizing excellent photothermal synergistic hydrovoltaic power generation on a single material.

[0006] Technical Solution: To solve the above-mentioned technical problems, this invention proposes a broadband plasmonic core-shell material and device with photothermal-hydrovoltaic synergistic effect, the preparation method of which includes the following steps:

[0007] Prepare an ethanol solution I of ligand A and an ethanol solution II of oxide precursor B to prepare an anisotropic surface plasmon metal nanostructure ethanol solution III.

[0008] An ethanol solution of ligand A was added to an ethanol solution III of plasmonic metal nanostructures, and the mixture was stirred for 10–60 min. Under the action of ligand A, the anisotropic surface plasmonic metal nanostructures agglomerated, clustering on the plane and overlapping in the longitudinal direction to obtain agglomerated anisotropic surface plasmonic nanostructures. The supernatant was then removed by centrifugation, and an oxide precursor ethanol solution II was added to dilute the solution and sonicate it. Then, a pH adjuster C was added to adjust the pH of the solution to 7.5–9, and the solution was sealed and reacted for 2–8 h to obtain an ethanol solution IV of plasmonic core-shell material.

[0009] Preparation of plasmonic core-shell material suspension V;

[0010] Conductive carbon paste electrodes are drawn on a hydrophilic insulating substrate E. After the electrodes dry, a suspension of plasmonic core-shell material V is coated using methods such as drop coating, scraping coating, or screen printing. During the natural evaporation and drying process of the solvent, capillary-driven uniformly mixed nanoparticles self-assemble to obtain a plasmonic core-shell material film. Subsequently, the obtained film is surface modified by oxygen plasma cleaning. The cleaning power is set to 0.5-50W and the cleaning time is 0.1-1min to obtain a broadband plasmonic core-shell material nanofilm device with photothermal-hydrovoltaic synergistic effect.

[0011] in,

[0012] The anisotropic surface plasmon metal nanostructures include materials such as gold, silver, or gold-silver alloys, and morphologies such as nanoplates, nanodiscs, nanodecahedrons, or nanorods. The monodisperse anisotropic surface plasmon metal nanostructures have narrow-band resonance peaks of surface plasmon resonance effect, with positions selectable between 400-1000 nm. The molar concentration of the ethanol solution III is between 0.0012-0.12 M.

[0013] The ligand A is a thiol-containing ligand such as 16-mercaptohexadecyl acid, N,ALPHA-dimethyl-2-thiopheneethylamine hydrochloride, and N-acetylcysteine. The spacing between the aggregates of the anisotropic surface plasmon metal nanostructures obtained by ligands with different chain lengths is different. The oxide precursor B is a metal oxide precursor such as tetraethyl silicate, tetrabutyl titanate, and aluminum trichloride. The pH regulator C is dimethylamine or ammonia.

[0014] The molar concentration of ligand A in the anisotropic surface plasmon nanostructure ethanol solution IV is 0.02-2 mM, and the molar concentration of the oxide precursor ethanol solution II is 0.6-60 mM.

[0015] During stirring, the anisotropic surface plasmon metal nanostructures undergo planar aggregation and longitudinal stacking under the influence of specific concentrations and chain length ligand A. The spacing between the aggregates is randomly distributed within 0-30 nm, and the number of overlaps is randomly distributed within 1-5, which correspond to continuous red shift and blue shift in the core-shell structure spectrum, respectively, thus extending the single-peak absorption of the anisotropic surface plasmon metal nanostructures to a broad spectrum of absorption.

[0016] The anisotropic surface plasmon metal nanostructures described herein have a planar dimension of 50-200 nm and a longitudinal thickness of 10-50 nm.

[0017] By controlling the concentration of ethanol solution II of oxide precursor B during the coating process, the thickness of the grown shell can be controlled within the range of 5-40 nm, ensuring that the hot electrons generated by the core plasmon nanostructure can be transferred to the outer shell surface under illumination.

[0018] The organic solvent D, which is highly volatile at room temperature, includes ethanol, methanol, or acetone, and the hydrophilic insulating substrate E used includes a plastic sheet, glass, or alumina plate.

[0019] The specific steps for preparing plasmonic core-shell material suspension V include: centrifuging the ethanol solution of plasmonic core-shell material IV, taking the precipitate, drying it, grinding it, and then uniformly dispersing it in a highly volatile organic solvent D at a ratio of 0.05-5 g / mL to obtain plasmonic core-shell material suspension V.

[0020] The formation principle and hydrovoltaic power generation method of this invention are as follows: Monodisperse anisotropic plasmonic nanostructures have a distinct main resonance peak and a weaker secondary resonance peak in their spectrum, corresponding to in-plane (lateral) and out-of-plane (vertical) plasmonic resonance modes, respectively. In this case, the color of the nanostructure is determined by the wavelength of the main resonance peak, and its broadband absorption capability is relatively weak. After adding ligands with thiol bonds to an ethanol solution of the anisotropic surface plasmonic nanostructures, the monodisperse nanostructures aggregate together under the influence of the ligands. When the ligand concentration is low, this aggregation generally only occurs in the plane; however, when the ligand concentration reaches a certain level, the nanostructures are also attracted and overlap in the vertical direction. Under the influence of ligands of specific concentrations and chain lengths, the distance between the in-plane aggregated nanostructures continuously and randomly varies within a certain range, generally between 0-30 nm, and some overlap may occur, corresponding to a continuous redshift in the spectrum. When the nanostructures overlap vertically, the anisotropy weakens, and the number of superimposed structures is randomly distributed, resulting in a continuous blueshift in the spectrum. Under the influence of the aforementioned random characteristic structure, the spectra of isolated anisotropic surface plasmon nanostructures undergo continuous redshift and blueshift, respectively. Furthermore, by controlling the main SPR peak of the anisotropic surface plasmon nanostructures to be distributed between 400-1000 nm, the spectra undergo relatively uniform blueshift and redshift, ultimately achieving broad-spectrum absorption. Figure 1 A schematic diagram of the aggregation process of anisotropic surface plasmon nanostructures and the corresponding spectral changes is presented.

[0021] Compared to single-effect water-based photovoltaic devices, the plasmonic core-shell material nanofilm device prepared in this invention exhibits a photothermal effect. Relying on the plasmonic metal core with broad-spectrum absorption capabilities, it can convert absorbed light energy into heat energy, which then promotes water evaporation, thereby enhancing the water-based photovoltaic power generation effect. The generation of water-based photovoltaic power mainly relies on the metal oxide shell of the plasmonic core-shell material. When in contact with water, the surface of the metal oxide acquires a charge; the sign and amount of this charge are determined by the material type. This charge determines the zeta potential of the material, and thus the magnitude of the potential generated during water-based photovoltaic power generation. Figure 4A schematic diagram illustrating the principle of plasmonic metal-metal oxide core-shell thin-film hydrovoltaic power generation is presented. The core-shell structure carries a positive charge on its surface. Driven by capillary force, water rises along the film surface. As it passes through the nanochannels inside the film, the ions in the water are repelled by the Coulomb force of the surface charge, allowing only negative charges to pass. At the ends of the nanochannels, water evaporates, leaving behind accumulated negative charges, creating a potential difference across the nanochannels. The output of this evaporation-driven hydrovoltaic power generation is proportional to the speed at which water flows through the nanochannels. Therefore, when the film is illuminated, the core of the plasmonic metal-metal oxide core-shell structure absorbs light, causing the film temperature to rise, accelerating water evaporation and flow, thus increasing the hydrovoltaic power output. The presence of the metal oxide shell further enhances the light intensity, raising the film temperature even higher and further increasing the hydrovoltaic power output. Utilizing this photothermal synergistic hydrovoltaic output, the broadband plasmonic core-shell device with photothermal-hydrovoltaic synergy can be used as a power source. Furthermore, thanks to the good contact between the core-shell structure plasmon metal core and the metal oxide shell, the thermal electrons generated by light can cross the shell and reach the surface of the metal oxide to participate in hydrovolt power generation. These rapidly changing photogenerated thermal electrons can be used in fast-response light intensity sensors.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0023] 1. A plasmonic core-shell material thin film with synergistic water-voltaic and photothermal effects is proposed. Traditional evaporation-driven water-voltaic power generation thin films generally require nanomaterials with sizes within 100-1000 nm. When the material size reaches the micrometer scale, water tends to rise to a lower height in the film, and the ion filtering capacity of the internal nanochannels decreases. The anisotropic surface plasmonic metal nanostructure used in this invention is ultrathin in one direction, approximately 10 nm, and its size remains within 100 nm when it is stacked longitudinally. It can overcome the diffraction limit for spectral control, and the size of the plasmonic metal core of the prepared core-shell structure is in the range of 100-300 nm, which meets the requirements of water-voltaic power generation for nanomaterial size, has good water-voltaic power generation capability, and expands the material selection in the field of water-voltaic power generation.

[0024] 2. A broadband-absorbing plasmonic core-shell material is proposed. Traditional anisotropic surface plasmonic metal nanostructures exhibit weak absorption in the short wavelength range, with narrow SPR resonance peaks. Furthermore, the in-plane aggregation of traditional nanostructures causes a redshift in the spectrum, failing to address the deficiency of weak short-wavelength absorption. This invention prepares a nanomaterial structure in which monodisperse anisotropic surface plasmonic metal nanostructures possess narrow-band SPR resonance peaks, selectable between 400-1000 nm. During aggregation, lateral aggregation and vertical overlap occur, resulting in redshift and blueshift of the spectrum, respectively, covering a spectral range of 400-1100 nm.

[0025] 3. A strategy using an oxide shell to protect the metal core is proposed to prevent deformation of the metal nanostructure at high temperatures. In photovoltaic power generation with photothermal synergy, the material temperature rises with increasing light intensity. Traditional exposed anisotropic surface plasmon metal nanostructures, due to their fragility, begin to react chemically with external substances such as oxygen and water after the temperature rises to 60°C, failing to maintain their original shape and resulting in nanostructure damage. By encasing the anisotropic surface plasmon metal nanostructure with an oxide shell, the metal core can be effectively protected from high temperatures under the constraint of the shell, preventing deformation and loss of properties, and improving high-temperature resistance. The method described in this invention enables the mass production and low-cost fabrication of plasmon core-shell materials with good high-temperature resistance, and can further enhance the output power within the same area at higher temperatures (by using lenses to further focus and increase the temperature) through photothermal effects.

[0026] 4. In commonly used methods for preparing metal oxide photovoltaic thin films, the mixed materials are often subjected to simple mechanical mixing. This method suffers from problems such as uncontrollable dispersion and unstable processes. Furthermore, the contact between materials depends on electrostatic forces and other interactions, leading to uncontrollable device performance. The plasmonic core-shell material prepared in this invention exhibits good contact between the core and shell, and a stable electron transport channel, which facilitates the transfer of hot electrons generated by plasmonic metals under illumination to the metal oxide shell to participate in the photovoltaic power generation process. Attached Figure Description

[0027] Figure 1 A schematic diagram of the microstructure and spectrum of anisotropic surface plasmon metal nanostructures from dispersion to aggregation. The solid line represents the original position of the SPR resonance peak, and the dashed line represents the position of the SPR resonance peak after shift.

[0028] Figure 2 Transmission electron microscopy (TEM) images of plasmonic core-shell materials. Image A corresponds to the longitudinal overlap of plasmonic metal nanostructures on anisotropic surfaces, while image B corresponds to the planar aggregation of plasmonic metal nanostructures on anisotropic surfaces.

[0029] Figure 3 Fabrication process of plasmonic core-shell devices.

[0030] Figure 4 A schematic diagram of the principle of hydrovoltaic power generation by a plasmonic core-shell device. A lens is used to focus sunlight onto the surface of the device to utilize solar energy. This method can further increase the surface temperature of the device.

[0031] Figure 5 A schematic diagram of the negative response of a plasmonic core-shell device at the instant the light source is turned off. At this moment, the negative response disappears and the voltage instantly rises. Detailed Implementation

[0032] The present invention will be further illustrated below through specific embodiments:

[0033] Example 1

[0034] Step 1: Precursor Preparation

[0035] Ethanol solution I containing 4 mM 16-mercaptohexadecyl acid (MHA) and ethanol solution II containing 6 mM tetraethyl silicate (TEOS) were prepared to prepare ethanol solution III of silver nanoplates.

[0036] Step 2: Preparation of Plasmon Core-Shell Materials

[0037] 1.16 ml of MHA ethanol solution I was added to silver nanoplate ethanol solution III and stirred for 30 min. Under the action of MHA, the silver nanoplates aggregated, forming clusters on the plane and overlapping each other in the longitudinal direction, resulting in aggregated silver nanoplates. The supernatant was then removed by centrifugation, diluted with TEOS ethanol solution II, and sonicated. Dimethylamine was then added to adjust the pH to approximately 8, and the mixture was sealed and reacted for 4 h to obtain silver-silica core-shell structure ethanol solution IV.

[0038] Step 3: Preparation of Plasmon Core-Shell Material Suspension

[0039] After centrifuging the silver-silica core-shell structure ethanol solution IV, the precipitate was collected, dried, and ground. Then, it was uniformly dispersed in ethanol, which is highly volatile at room temperature, at a ratio of 0.5 g / mL to obtain silver-silica core-shell structure suspension V.

[0040] Step 4: Fabrication of plasmonic core-shell material nanofilm devices

[0041] A silver-silica core-shell structure suspension V was screen-printed onto a hydrophilic PET substrate with pre-drawn electrodes. During the natural solvent evaporation and drying process, capillary-driven uniformly mixed nanoparticles self-assembled to obtain a plasmonic metal-metal oxide thin film. The resulting film was then surface-modified by oxygen plasma cleaning at a power of 0.5 W for 20 s, yielding a silver-silica core-shell structure nanofilm device.

[0042] Example 2

[0043] Step 1: Precursor Preparation

[0044] An ethanol solution I containing 4 mM 16-mercaptohexadecyl acid (MHA) and an ethanol solution II containing 6 mM tetraethyl silicate (TEOS) were prepared to prepare an ethanol solution III of silver-gold-silver alloy nanorods.

[0045] Step 2: Preparation of Plasmon Core-Shell Materials

[0046] 1.16 ml of MHA ethanol solution I was added to silver-gold-silver alloy nanorod ethanol solution III and stirred for 30 min. Under the action of MHA, the silver-gold-silver alloy nanorods aggregated, forming clusters on the plane and overlapping each other in the longitudinal direction, resulting in aggregated silver nanoplates. The supernatant was then removed by centrifugation, diluted with TEOS ethanol solution II, and sonicated. Dimethylamine was then added to adjust the pH to approximately 8, and the mixture was sealed and reacted for 4 h to obtain silver-gold-silver alloy nanorod-silica core-shell structure ethanol solution IV.

[0047] Step 3: Preparation of Plasmon Core-Shell Material Suspension

[0048] After centrifuging the ethanol solution IV containing silver-gold-silver alloy nanorods and silica core-shell structure, the precipitate was dried, ground, and then uniformly dispersed in ethanol, which is highly volatile at room temperature, at a ratio of 1 g / mL to obtain silver-silica core-shell structure suspension V.

[0049] Step 4: Fabrication of plasmonic core-shell material nanofilm devices

[0050] A suspension of silver-gold-silver alloy nanorods-silica core-shell structure (SVS) was drop-coated onto a hydrophilic glass substrate with pre-drawn electrodes. During the natural solvent evaporation and drying process, capillary-driven uniformly mixed nanoparticles self-assembled to obtain a plasmonic metal-metal oxide thin film. The resulting film was then surface-modified by oxygen plasma cleaning at a power of 0.5 W for 20 s, yielding a silver-silica core-shell nanofilm device.

[0051] Example 3

[0052] Step 1: Precursor Preparation

[0053] Ethanol solution I containing 0.4 mM 16-mercaptohexadecyl acid (MHA) and ethanol solution II containing 6 mM tetraethyl silicate (TEOS) were prepared to prepare ethanol solution III of silver nanoplates.

[0054] Step 2: Preparation of Plasmon Core-Shell Materials

[0055] Add 0.116% MHA in ethanol solution I to silver nanoplate ethanol solution III and stir for 30 min. Under the action of MHA, the silver nanoplates aggregate, forming clusters on the plane and overlapping each other in the longitudinal direction, resulting in aggregated silver nanoplates. Then, centrifuge to remove the supernatant, dilute with TEOS ethanol solution II and sonicate, then add dimethylamine to adjust the pH to about 8 and seal the reaction for 4 h to obtain silver-silica core-shell structure ethanol solution IV.

[0056] Step 3: Preparation of Plasmon Core-Shell Material Suspension

[0057] After centrifuging the silver-silica core-shell structure ethanol solution IV, the precipitate was collected, dried, and ground. Then, it was uniformly dispersed in ethanol, which is highly volatile at room temperature, at a ratio of 0.5 g / mL to obtain silver-silica core-shell structure suspension V.

[0058] Step 4: Fabrication of plasmonic core-shell material nanofilm devices

[0059] A silver-silica core-shell structure suspension V was screen-printed onto a hydrophilic PET substrate with pre-drawn electrodes. During the natural solvent evaporation and drying process, capillary-driven uniformly mixed nanoparticles self-assembled to obtain a plasmonic metal-metal oxide thin film. The resulting film was then surface-modified by oxygen plasma cleaning at a power of 0.5 W for 20 s, yielding a silver-silica core-shell structure nanofilm device.

[0060] Plasmon metal-metal oxide core-shell nanofilms were prepared according to Examples 1-3, and their rapid response to light source switching was investigated. As a power supply device, the output power can change rapidly with the light source, and this change can be reflected in the load device. Taking driving an LED lamp as an example, when the light source is turned off, the output voltage generates a rapidly rising spike, including the following steps:

[0061] Step 1: Connect the circuit

[0062] Multiple plasmonic core-shell material nanofilms were prepared, and based on the calculation of output voltage and internal resistance, multiple units were connected together in series and parallel to form a hydroelectric power generation unit, which was then connected to both ends of an LED lamp.

[0063] Step 2: Turn on the light source and illuminate the LED light.

[0064] Plasmon core-shell material nanofilms were inserted into water. After the water rose along the surface of the film and stabilized, the light source was turned on to illuminate the surface of the film and the output voltage of the hydrovolt generator was stabilized. Then, the LED lights were turned on.

[0065] Step 3: Quickly switch the light source on and off

[0066] Use an obstruction to quickly block the light source or quickly switch the power on and off, and observe the frequency of changes in the LED light brightness to count the number of times the light is blocked or switched on.

[0067] Furthermore, those skilled in the art may make other changes within the spirit of this invention, and of course, all such changes made in accordance with the spirit of this invention should be included within the scope of protection claimed by this invention.

Claims

1. A method for preparing a broadband plasmonic core-shell material with photothermal-hydrovoltaic synergistic effect, characterized in that, Includes the following steps: Prepare an ethanol solution I of ligand A and an ethanol solution II of oxide precursor B to prepare an anisotropic surface plasmon metal nanostructure ethanol solution III. An ethanol solution of ligand A was added to an ethanol solution III of plasmonic metal nanostructures, and the mixture was stirred for 10–60 min. Under the action of ligand A, the anisotropic surface plasmonic metal nanostructures agglomerated, clustering on the plane and overlapping in the longitudinal direction to obtain agglomerated anisotropic surface plasmonic nanostructures. The supernatant was then removed by centrifugation, and an oxide precursor ethanol solution II was added to dilute the solution and sonicate it. Then, a pH adjuster C was added to adjust the pH of the solution to 7.5–9, and the solution was sealed for 2–8 h to obtain an ethanol solution IV of plasmonic core-shell material. Wherein, ligand A is 16-mercaptohexadecyl acid, N,ALPHA-dimethyl-2-thiopheneethylamine hydrochloride, or N-acetylcysteine; the spacing between aggregates of anisotropic surface plasmon metal nanostructures obtained by ligands with different chain lengths is different; oxide precursor B is tetraethyl silicate, tetrabutyl titanate, or aluminum trichloride; pH regulator C is dimethylamine or ammonia. The anisotropic surface plasmon metal nanostructures described herein have a planar dimension of 50-200 nm and a longitudinal thickness of 10-50 nm. By controlling the concentration of ethanol solution II of oxide precursor B during the coating process, the thickness of the grown shell can be controlled within the range of 5-40 nm, ensuring that the hot electrons generated by the core plasmon nanostructure can be transferred to the outer shell surface under illumination.

2. The method for preparing a broadband plasmon core-shell material with photothermal-hydrovoltaic synergistic effect as described in claim 1, characterized in that, The materials included in the anisotropic surface plasmon polariton metal nanostructures are gold, silver or gold-silver alloys, and the morphologies include nanoplates, nanodiscs, nanodecahedrons or nanorods. The monodisperse anisotropic surface plasmon polariton metal nanostructures have narrow-band resonance peaks of surface plasmon resonance effect, with positions selectable between 400-1000 nm, and the molar concentration of ethanol solution III is between 0.0012-0.12 M.

3. The method for preparing a broadband plasmon core-shell material with photothermal-hydrovoltaic synergistic effect as described in claim 1, characterized in that, The molar concentration of ligand A in ethanol solution IV of anisotropic surface plasmon nanostructures was 0.02-2 mM, and the molar concentration of oxide precursor ethanol solution II was 0.6-60 mM.

4. The method for preparing a broadband plasmon core-shell material with photothermal-hydrovoltaic synergistic effect as described in claim 1, characterized in that, During stirring, anisotropic surface plasmon metal nanostructures undergo planar aggregation and longitudinal stacking under the action of chain-length ligand A. The spacing between the aggregates is randomly distributed within 0-30 nm, and the number of overlaps is randomly distributed within 1-5, which correspond to continuous red shift and blue shift in the core-shell structure spectrum, respectively. This extends the single-peak absorption of the anisotropic surface plasmon metal nanostructures to a broad spectrum.

5. The method for preparing a broadband plasmon core-shell material with photothermal-hydrovoltaic synergistic effect as described in claim 1, characterized in that, It also includes the step of fabricating the device: Preparation of plasmonic core-shell material suspension V; Conductive carbon paste electrodes were drawn on a hydrophilic insulating substrate E. After the electrodes dried, plasmonic core-shell material V was coated. During the natural evaporation and drying process of the solvent, capillary-driven uniformly mixed nanoparticles were self-assembled to obtain a plasmonic core-shell material thin film. Subsequently, the obtained thin film was surface modified by oxygen plasma cleaning. The cleaning power was set to 0.5-50 W and the cleaning time was 0.1-1 min to obtain a broadband plasmonic core-shell material nanofilm device with photothermal-hydrovoltaic synergistic effect.

6. The method for preparing a broadband plasmon core-shell material with photothermal-hydrovoltaic synergistic effect as described in claim 5, characterized in that, The specific steps for preparing plasmonic core-shell material suspension V include: centrifuging the ethanol solution of plasmonic core-shell material IV, taking the precipitate, drying it, grinding it, and then uniformly dispersing it in a volatile organic solvent D at room temperature at a ratio of 0.05-5 g / mL to obtain plasmonic core-shell material suspension V.

7. The method for preparing a broadband plasmon core-shell material with photothermal-hydrovoltaic synergistic effect as described in claim 6, characterized in that, The volatile organic solvent D used at room temperature includes ethanol, methanol, or acetone, and the hydrophilic insulating substrate E used includes plastic sheet, glass, or alumina sheet.

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