Application of self-powered flexible SERS probe in bronze cultural relic detection

Abstract

The invention relates to the technical field of flexible electronics, and discloses an application of a self-powered flexible SERS probe in bronze cultural relic detection, and the self-powered flexible SERS probe comprises a flexible substrate layer composed of a high-molecular polymer; the piezoelectric functional layer is attached to the upper surface of the flexible substrate layer and is made of a piezoelectric material; the SERS active layer covers the upper surface of the piezoelectric functional layer and is composed of a noble metal nanostructure array; the conductive electrode layer comprises a first electrode and a second electrode which are respectively arranged on the upper surface and the lower surface of the piezoelectric functional layer and are connected with an external circuit; the energy storage module is connected with the conductive electrode layer through a wire; and the packaging layer is made of a transparent flexible material and covers the outer surfaces of the SERS active layer and the piezoelectric functional layer. Through the piezoelectric functional layer and the miniature capacitor, mechanical deformation energy is converted into electric energy to be stored, laser detection is driven, limitation of an external power source is eliminated, the energy utilization rate is high, storage and detection are completed through single pressing, and portability is improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of flexible electronics, and particularly relates to an application of a self-powered flexible SERS probe in bronze cultural relic detection. BACKGROUND

[0002] In the field of cultural relic protection and detection, surface enhanced Raman scattering (SERS) technology has become an important means for bronze cultural relic corrosion product detection due to its high sensitivity, non-destructive micro-area analysis and other characteristics. Through the enhancement effect of noble metal nanostructure on Raman signals, the composition of trace chemical substances on the surface of cultural relics can be identified, and the technology has key application value in the fields of bronze ware disease diagnosis and protection material compatibility evaluation.

[0003] In the existing SERS detection scheme, the mainstream probe structure is usually composed of a rigid substrate, a noble metal nano active layer and an external laser excitation system. Among them, the laser light source and the signal acquisition module need to rely on an external power supply for driving, which leads to a large volume of the entire equipment, and there are problems such as complex cable connection and complicated operation process. For example, when the traditional rigid SERS probe is used for detection at an outdoor archaeological site, a portable power generation device or a large-capacity battery pack needs to be additionally carried, and the total weight of the equipment is often more than 5 kg, which is difficult to meet the single-person portable operation requirement. At the same time, the line transmission between the external power supply and the probe will introduce energy loss, and the laser light source needs to be continuously powered to maintain stable output, so the energy consumption of single detection is high, and the energy utilization rate is generally less than 30%.

[0004] The present application inventors found in the research that the existing technology at least has the technical problems of poor portability of the detection equipment and low energy utilization rate due to the dependence on an external power supply. SUMMARY

[0005] In view of the deficiencies of the prior art, the application provides an application of a self-powered flexible SERS probe in bronze cultural relic detection, which solves the technical problems of poor portability of the detection equipment and low energy utilization rate due to the dependence on an external power supply.

[0006] To achieve the above object, the application is implemented by the following technical scheme: a self-powered flexible SERS probe, comprising:

[0007] A flexible substrate layer composed of a high polymer;

[0008] A piezoelectric functional layer attached to the upper surface of the flexible substrate layer and composed of a piezoelectric material;

[0009] A SERS active layer covering the upper surface of the piezoelectric functional layer and composed of a noble metal nanostructure array;

[0010] A conductive electrode layer including a first electrode and a second electrode, which are respectively arranged on the upper and lower surfaces of the piezoelectric functional layer and connected with an external circuit.

[0011] an energy storage module connected with the conductive electrode layer through a wire, for storing the electric energy generated by the piezoelectric functional layer;

[0012] an encapsulation layer composed of transparent flexible material, covering the outer surface of the SERS active layer and the piezoelectric functional layer;

[0013] wherein the lower surface of the flexible substrate layer is a curved surface structure in direct contact with the detection surface.

[0014] By adopting the above technical solution, the poor portability and low energy utilization rate caused by the dependence on external power supply in the prior art are solved through the collaborative design of multiple components. The flexible substrate layer is made of high molecular polymer (such as PDMS), and the curved surface structure (curvature radius 0.5-5 mm, adhesion error ≤10%) of the lower surface can closely adhere to the micron-level gap of bronze cultural relics. When pressed, the piezoelectric functional layer converts mechanical energy into electric energy, which is stored in the micro solid-state capacitor (0.1-10 μF) through the conductive electrode. A single press can drive the laser light source (532 nm / 785 nm) to work, freeing it from external power supply restrictions, and the energy utilization rate is improved to more than 65%. The SERS active layer (gold / silver nanoparticle array, EF = 10 7 -10 8 ) combined with the molecular modification layer realizes high-sensitivity detection of trace corrosion products (detection limit 10 -8 mol / L), and the ultra-thin transparent encapsulation layer (1-10 μm, transmittance ≥90%) protects the device while supporting repeated use of more than 50 times, with signal attenuation <3%, significantly improving the detection portability and reliability.

[0015] Preferably, the thickness of the flexible substrate layer is 50-200 μm, and the material is selected from polydimethylsiloxane, polyimide or polyvinyl alcohol.

[0016] Preferably, the material of the piezoelectric functional layer is polyvinylidene fluoride or zinc oxide, and the thickness is 10-100 μm.

[0017] Preferably, the noble metal nanostructure array is composed of gold or silver nanoparticles, the particle size of the nanoparticles is 20-100 nm, and the arrangement distance is 5-50 nm.

[0018] Preferably, the material of the encapsulation layer is polydimethylsiloxane or silica gel, the thickness is 1-10 μm, and the visible light transmittance is ≥90%.

[0019] Preferably, the energy storage module is a micro solid-state capacitor, the capacitance value is 0.1-10 μF, and the working voltage is 1-5 V.

[0020] Preferably, the curvature radius of the curved surface structure is 0.5-5mm, and the fitting error with the concave-convex surface of the bronze cultural relic is ≤10%.

[0021] Preferably, the noble metal nanostructure surface of the SERS active layer is modified with a benzene thiol or rhodamine B molecular layer, and the thickness of the molecular layer is 1-5nm.

[0022] Preferably, the application of the self-powered flexible SERS probe in bronze cultural relic detection comprises the following steps: the probe is attached to the surface of the bronze cultural relic, the piezoelectric functional layer is used to convert mechanical deformation energy into electrical energy, and the SERS active layer is used to enhance and detect the Raman signal of the corrosion product on the surface of the cultural relic.

[0023] Preferably, the detection comprises the following steps:

[0024] S1, contacting the curved surface structure of the flexible substrate layer of the probe with the surface of the bronze cultural relic;

[0025] S2, applying a pressure of 0.1-1N to generate an electric charge in the piezoelectric functional layer;

[0026] S3, the stored electrical energy drives the laser light source to emit 532nm or 785nm wavelength laser light;

[0027] S4, collecting the Raman scattering signal enhanced by the SERS active layer through the packaging layer.

[0028] The application provides an application of a self-powered flexible SERS probe in bronze cultural relic detection.

[0029] 1. The application stores the mechanical deformation energy into electrical energy through the piezoelectric functional layer and the micro capacitor, drives the laser detection, gets rid of the external power supply limitation, has high energy utilization rate, completes the storage and detection through single pressing, and improves portability.

[0030] 2. The lower surface curved surface structure of the application is reversely modeled, has a fitting error of ≤10% with the cultural relic, can be embedded into a micron-level gap, has a flexible material to increase a contact area and avoid scratching the cultural relic, solves the problem of poor contact of the rigid probe, and improves detection reliability.

[0031] 3. The noble metal nanostructure array of the application is combined with a molecular modification layer, has a Raman enhancement factor of 10 7 -10 8 , and has a detection limit as low as 10 -8 mol / L. The corrosion product can be specifically adsorbed, micro-area high signal-to-noise ratio characteristic peak identification is realized, and the fine detection requirement is met.

[0032] 4、The 1-10 mu m thick packaging layer of the present application has a visible light transmittance of greater than or equal to 90%, low signal loss, firm edge bonding, bending resistance, protection of the active layer, support for repeated use of 50 times, signal attenuation of less than 3%, and consideration of durability and detection efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a perspective view of a self-powered flexible SERS probe of the present application.

[0034] Figure 2 It is a flow chart of the application of a self-powered flexible SERS probe of the present application in bronze cultural relic detection. DETAILED DESCRIPTION

[0035] The technical solutions of the present application will be described in detail below with reference to the drawings of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0036] Please refer to the drawings of the present application Figure 1 The present application provides a self-powered flexible SERS probe, which comprises:

[0037] The flexible substrate layer is composed of a high molecular polymer;

[0038] The piezoelectric functional layer is attached to the upper surface of the flexible substrate layer and is composed of a piezoelectric material;

[0039] The SERS active layer covers the upper surface of the piezoelectric functional layer and is composed of a noble metal nanostructure array;

[0040] The conductive electrode layer includes a first electrode and a second electrode, which are respectively arranged on the upper and lower surfaces of the piezoelectric functional layer and connected to an external circuit;

[0041] The energy storage module is connected to the conductive electrode layer through a wire and is used to store the electrical energy generated by the piezoelectric functional layer;

[0042] The packaging layer is composed of a transparent flexible material and covers the outer surfaces of the SERS active layer and the piezoelectric functional layer;

[0043] The lower surface of the flexible substrate layer is a curved surface structure in direct contact with the detection surface.

[0044] Specifically, the flexible substrate layer is made of polydimethylsiloxane (PDMS) or polyimide (PI) material, prepared by mold casting method, with a thickness of 50-200 μm. The lower surface of the substrate layer is reverse-modeled by three-dimensional laser scanning bronze cultural relic surface topography data, combined with soft lithography technology to replicate a curved surface structure with a radius of curvature of 0.5-5 mm, ensuring that the fitting error with the concave-convex topography of the cultural relic surface is ≤10%. The curved surface design enables the probe to closely fit the micron-level gap (≤10 μm) on the surface of the bronze ware, avoiding signal attenuation caused by poor contact during detection.

[0045] The piezoelectric functional layer is formed by solution casting method on the upper surface of the flexible substrate layer to form a polyvinylidene fluoride (PVDF) film, or by a magnetron sputtering process to deposit a zinc oxide (ZnO) film, with a thickness of 10-100 μm. The PVDF film is polarized by a high-voltage electric field of 50-100 kV / cm during preparation, with a piezoelectric constant d33≥20 pC / N; the crystal orientation of the ZnO film is controlled by sputtering parameters to grow preferentially in the (002) direction, with a piezoelectric response sensitivity of 15-25 mV / N. The piezoelectric layer can generate an output voltage of 1-5 V under a pressure of 0.1-1 N, and the electric charge is collected by the upper and lower surface electrodes.

[0046] The SERS active layer is prepared by chemical vapor deposition on the surface of the piezoelectric functional layer to form an array of gold nanoparticles, with a particle size of 20-100 nm and a spacing of 5-50 nm between adjacent particles. The specific process includes: spin-coating a single layer of polystyrene microspheres (particle size 200 nm) as a template on the surface of the piezoelectric layer, removing the template after sputtering a 50 nm thick gold film to form a hexagonal close-packed nanopore structure, and then annealing at 400°C for 10 minutes to spheroidize the gold film into nanoparticles. The array surface is immersed in 1 mM benzene thiol ethanol solution for 30 minutes to form a 1-3 nm thick molecular modification layer, with a Raman enhancement factor (EF) of 10^7-10^8, and a detection limit of bronze corrosion products as low as 10^-8 mol / L.

[0047] The conductive electrode layer is composed of silver paste coated on the upper and lower surfaces of the piezoelectric layer, with an upper electrode thickness of 100-500 nm and a lower electrode bonded to the flexible substrate layer by epoxy resin glue. The electrode ends are connected to a miniature solid-state capacitor (barium titanate dielectric material, capacitance value 0.1-10 μF, size 2 mm×2 mm×1 mm) through a 0.1 mm diameter copper wire, and the capacitor is embedded in the groove reserved in the probe sidewall, with a charge and discharge efficiency of ≥85%, and the surface resistance of the electrode layer is ≤0.1 Ω / sq after sintering at 150°C, ensuring that the piezoelectric charge transmission loss is <5%.

[0048] The encapsulation layer is a 1-10 pm thick transparent PDMS film coated on the surface of the SERS active layer by spin coating. The transmittance of visible light (400-800 nm) is greater than or equal to 90%, and the edge is seamlessly bonded to the flexible substrate layer after oxygen plasma treatment (power 50 W, time 30 s) (peeling strength greater than or equal to 5 N / cm). The surface roughness of the encapsulation layer is less than or equal to 10 nm, avoiding laser scattering. Its flexible characteristics allow the probe to withstand more than 1,000 bends (curvature radius 3 mm) without cracking.

[0049] The adaptability of the curved structure is verified by a three-dimensional profiler: after the probe is attached to the surface of the bronze ware, the pressure distribution of the contact area is measured using a pressure-sensitive film (Fuji Prescale film). The results show that the pressure value of more than 90% of the area is greater than or equal to 0.05 MPa, indicating that the curved structure and the surface topography of the cultural relics meet the detection requirements. The probe can be cleaned by ethanol wiping and ultraviolet ozone treatment (wavelength 254 nm, power 30 W, 10 minutes) to remove surface contaminants, and the SERS signal intensity attenuates by less than 3% after 50 times of repeated use.

[0050] The self-powered working process is as follows: when the probe is pressed on the bronze surface, the piezoelectric layer deforms to generate an electric charge, which is transmitted to the capacitor through the electrode for storage; when the stored energy reaches 1 V threshold, the integrated laser (wavelength 532 nm / 785 nm, power 10 mW) is automatically triggered to emit laser, which penetrates the encapsulation layer to excite the SERS active layer, and the enhanced Raman signal is conducted to the spectrometer (resolution 2 cm-1) by the built-in optical fiber (core diameter 200 pm, NA=0.22). The entire detection process does not require external power supply, and a single press (pressure 1 N, duration 3 s) can support continuous spectral acquisition for greater than or equal to 30 s.

[0051] The thickness of the flexible substrate layer is 50-200 pm, and the material is selected from polydimethylsiloxane, polyimide or polyvinyl alcohol; the material of the piezoelectric functional layer is polyvinylidene fluoride or zinc oxide, and the thickness is 10-100 pm; the noble metal nanostructure array is composed of gold or silver nanoparticles, the particle size of the nanoparticles is 20-100 nm, and the arrangement interval is 5-50 nm.

[0052] Specifically, the flexible substrate layer is prepared by mold casting, and the material is selected from polydimethylsiloxane (PDMS), polyimide (PI) or polyvinyl alcohol (PVA), and the thickness is accurately controlled within the range of 50-200 pm.

[0053] The PDMS base layer is prepared by mixing SYLGARD 184 silicone pre-polymer and curing agent at a mass ratio of 10:1, vacuum degassing, and then injecting into a mold with inverse bronze surface topography, and then heating and curing at 80°C for 2 hours to form a curved structure with a radius of curvature of 0.5-5 mm and a fitting error of ≤10%; the PI base layer is prepared by spin coating a 15% polyamide acid solution (solvent: N-methyl pyrrolidone) on the surface of the mold, and then imidizing by stepwise heating to 350°C, with a thickness uniformity deviation of <5%; the PVA base layer is prepared by spreading an 8wt% polyvinyl alcohol aqueous solution on the mold by flow casting, and then drying at 50°C to form a flexible curved surface. The piezoelectric functional layer is made of polyvinylidene fluoride (PVDF) or zinc oxide (ZnO) material: the PVDF film is prepared by dissolving PVDF powder in DMAC solvent (concentration 20wt%), flow casting on the surface of the base layer, drying at 60°C, and then polarizing under a high voltage electric field of 100kV / cm for 30 minutes to form a β-phase film with a thickness of 10-100μm and a piezoelectric constant d33≥25pC / N; the ZnO film is prepared by magnetron sputtering process in an argon-oxygen mixed atmosphere (Ar:O2=4:1), with a substrate temperature of 200°C and a sputtering power of 150W, to obtain a 50-100μm thick film with (002) crystal direction preferential growth, with a piezoelectric response sensitivity of 20mV / N.

[0054] The noble metal nanostructure array is composed of gold or silver nanoparticles, which is prepared by nanosphere lithography: spin coating a single layer of polystyrene microspheres (particle size 200nm) as a template on the surface of the piezoelectric layer, sputtering a 50nm thick gold or silver film, and then ultrasonically removing the template to form a hexagonal close-packed structure, and then annealing at 400°C for 10 minutes to spheroidize the metal film into nanoparticles with a particle size of 20-100nm, with an adjacent particle spacing of 5-50nm controlled by the template size, and a surface plasmon resonance peak covering the 532nm and 785nm laser wavelength bands, with a Raman enhancement factor (EF) of 10^7-10^8. The gold nanoparticles are further modified with 1mM benzene thiol ethanol solution for 30 minutes to form a 1-3nm thick molecular layer, which is used for specific adsorption of sulfur / chlorine-containing groups in the corrosion products of bronze cultural relics.

[0055] The encapsulation layer is made of polydimethylsiloxane or silicone, with a thickness of 1-10μm and a visible light transmittance of ≥90%; the energy storage module is a micro solid-state capacitor with a capacitance of 0.1-10μF and a working voltage of 1-5V; the curved structure has a radius of curvature of 0.5-5mm and a fitting error of ≤10% with the concave-convex topography of the bronze cultural relics surface; the SERS active layer is modified with a benzene thiol or rhodamine B molecular layer on the surface of the noble metal nanostructure, with a molecular layer thickness of 1-5nm.

[0056] Specifically, the encapsulation layer adopts polydimethylsiloxane or silica gel, and a 1-10 μm thick film is formed on the surface of the SERS active layer by a spin coating process: after mixing the PDMS prepolymer and the curing agent at a mass ratio of 10:1, spin coating is performed at a speed of 3000 rpm for 30 seconds, and curing is performed at 80°C for 2 hours. The visible light band (400-800 nm) transmittance is ≥92%, and the surface roughness is ≤10 nm. The silica gel encapsulation layer is uniformly covered by spraying, and after curing at 60°C, the thickness deviation is <5%. The edge of the encapsulation layer is seamlessly bonded to the flexible substrate layer after oxygen plasma treatment (power 50 W, time 30 seconds), and the peeling strength is ≥5 N / cm, which can withstand 1000 bends (curvature radius 3 mm) without cracking.

[0057] The energy storage module is a miniature solid-state capacitor, which is composed of alternating layers of barium titanate (BaTiO3) dielectric layer and silver-palladium (Ag-Pd) electrode (single-layer dielectric thickness 1 μm, electrode thickness 200 nm), with a size of 2 mm x 2 mm x 1 mm, a capacitance value of 0.1-10 μF adjusted by the number of layers, a working voltage range of 1-5 V, a charge and discharge efficiency of ≥85%, and a single press (1 N pressure) storage energy that can drive a 785 nm laser to work continuously for ≥30 seconds.

[0058] The curvature radius of the curved structure is 0.5-5 mm, which is modeled by three-dimensional laser scanning (accuracy ±1 μm) of the surface morphology data of the bronze cultural relics, and is replicated to the PDMS mold by soft lithography technology, so that the contact error between the probe substrate and the surface of the cultural relics is ≤10% (the contact area is ≥95% detected by a pressure-sensitive film), and the adaptation depth of the corrosion micropore is ≤10 μm. The surface modification of the noble metal nanostructure of the SERS active layer is realized by immersion method: the probe is immersed in 1 mM benzene thiol ethanol solution or 0.1 mM rhodamine B aqueous solution for 30 minutes, and a 1-5 nm thick molecular layer is formed after nitrogen blowing. Among them, benzene thiol specifically adsorbs Cu2(OH)3Cl in the corrosion product of bronze through thiol (-SH), and rhodamine B captures SnO particles through electrostatic interaction; the thickness of the molecular layer is calibrated by the sputtering etching rate of X-ray photoelectron spectroscopy (XPS), and the fluctuation of the surface enhanced Raman signal intensity is ≤5%.

[0059] An application of a self-powered flexible SERS probe in bronze cultural relic detection, including attaching the probe to the surface of the bronze cultural relic, converting mechanical deformation energy into electrical energy through the piezoelectric functional layer, and driving the SERS active layer to enhance the detection of the Raman signal of the corrosion product on the surface of the cultural relic.

[0060] Specifically, the curved structure (curvature radius 0.5-5mm) of the probe flexible substrate layer is attached to the bronze cultural relics to be tested, a vertical pressure of 0.1-1N is applied to make the piezoelectric functional layer (PVDF or ZnO film) mechanically deform, generate a voltage of 1-5V and transmit to the micro solid capacitor (capacitance value 0.1-10μF) for storage through the conductive electrode layer; when the stored energy voltage reaches 1V threshold, the integrated laser module (wavelength 532nm or 785nm, power 10mW, spot diameter 50μm) is automatically triggered to emit laser, the laser penetrates the transparent packaging layer (PDMS, thickness 1-10μm, transmittance ≥90%) and irradiates to the noble metal nanostructure array (Au / Ag nanoparticles, particle size 20-100nm, spacing 5-50nm) of the SERS active layer, and the Raman signal of the corrosion product molecules on the surface of the cultural relics is excited; the enhanced signal is collected by the optical fiber probe (core diameter 200μm, numerical aperture NA=0.22) through the packaging layer and transmitted to the spectrometer (resolution 2cm -1 , detection range 200-2000cm -1 ), and the qualitative and quantitative analysis of the corrosion product is realized by combining the preset database (containing Cu2(OH)3Cl, Cu2S, SnO characteristic peak position) to achieve a detection limit of 10 -8 mol / L and a characteristic peak recognition accuracy of ≥98%; after the detection is completed, the probe is removed and the surface adsorbed molecules are removed by ethanol wiping and ultraviolet ozone treatment (wavelength 254nm, power 30W, time 10 minutes) to restore the SERS active layer to the initial state, and the signal attenuation is less than 3% after 50 times of repeated use.

[0061] Please refer to the attached Figure 2 , the detection includes the following steps:

[0062] S1, the curved structure of the probe flexible substrate layer is in contact with the surface of the bronze cultural relics;

[0063] S2, a pressure of 0.1-1N is applied to make the piezoelectric functional layer generate electric charge;

[0064] S3, the stored electric energy drives the laser light source to emit 532nm or 785nm wavelength laser;

[0065] S4, the Raman scattering signal enhanced by the SERS active layer is collected through the packaging layer.

[0066] Specifically, S1, the curved structure of the probe flexible substrate layer is aligned with the target area of the bronze cultural relics surface by a three-dimensional positioning clamp, a pre-pressure of 0.5N is applied to make the substrate curved surface fully contact with the corrosion micropores on the surface of the cultural relics, and the contact area is determined to be ≥95% by Fuji Prescale pressure sensitive film;

[0067] S2, press the probe with 0.1-1N vertical pressure for 3 seconds, the piezoelectric functional layer (PVDF film d33≥25pC / N or ZnO film piezoelectric response sensitivity≥20mV / N) generates 1-5V pulse voltage, which is transmitted to the micro solid-state capacitor (barium titanate dielectric layer, capacitance value 0.1-10μF, charge and discharge efficiency≥85%) through the silver paste electrode (square resistance≤0.1Ω / sq), and triggers the circuit switch after storing energy to 1V threshold value;

[0068] S3, the capacitor releases electric energy to drive the integrated laser (wavelength 532nm / 785nm optional, power 10mW±5%, spot diameter 50μm, pulse frequency 1Hz) to emit laser, the laser is vertically incident to the SERS active layer (gold nanoparticles with a particle size of 20-100nm and a spacing of 5-50nm) through the packaging layer (PDMS thickness 1-10μm, transmittance≥90%), and the surface adsorbed corrosion product molecules (including Cu2(OH)3Cl, Cu2S, SnO) are excited to generate Raman signals, and the enhancement factor reaches 10^7-10^8;

[0069] S4, the enhanced Raman scattering signals are transmitted through the packaging layer, conducted to the spectrometer (Andor SR-500 type, resolution 2cm -1 , grating line 1200 lines / mm) by the integrated optical fiber probe (core diameter 200μm, numerical aperture NA=0.22, collection efficiency≥80%), and after the signals are subjected to baseline correction and Savitzky-Golay smoothing processing, compared with a standard corrosion product database (containing Cu-O bond stretching vibration peak 480cm -1 , S-S bond peak 470cm -1 , Sn-O peak 630cm -1 ), qualitative and quantitative analysis of the composition is realized, the detection limit is≤10 -8 mol / L, the single detection time is≤30 seconds, and the repeatability error is<5%; after detection, the probe is soaked in ethanol and treated by ultraviolet ozone (254nm, 30W, 10 minutes) to remove the adsorbed molecules, and the signal intensity attenuates by less than 3% after 50 cycles of use.

[0070] Example One

[0071] The self-powered flexible SERS probe of the embodiment is prepared and applied in the following manner:

[0072] The flexible substrate layer was selected from polydimethylsiloxane (PDMS, SYLGARD 184), and the prepolymer was mixed with the curing agent at a mass ratio of 10:1, then was injected into a bronze surface reverse mold with a curvature radius of 2 mm, and was cured at 80°C for 2 hours to form a curved substrate with a thickness of 100 μm, and the error of the fitting degree was ≤8%; the piezoelectric functional layer was formed by a solution casting method on the PDMS surface to form a 50 μm thick PVDF film, and after high voltage polarization at 80 kV / cm, the piezoelectric constant d33 was 28 pC / N; the SERS active layer was formed by a nanosphere lithography method (polystyrene template 200 nm) to sputter a 50 nm gold film, and after annealing, a gold nanoparticle array with a particle size of 60 nm and a spacing of 20 nm was formed, and the surface was modified with 1 mM benzene sulfenyl ethanol solution for 30 minutes, the molecular layer thickness was 2 nm, and the enhancement factor (EF) reached 1.2 x 10 8 ; the conductive electrode layer was composed of 300 nm thick silver paste coated on the upper and lower surfaces, and was connected to a 5 μF barium titanate solid-state capacitor; the packaging layer was spin-coated with 5 μm thick PDMS (transmittance 93%), and after oxygen plasma bonding, the peeling strength was ≥6 N / cm.

[0073] Detection application: the probe was fitted on the Cu2(OH)3Cl region of the bronze ding surface, 0.5 N pressure was applied for 3 seconds, the capacitor was energized to 1.5 V, then a 785 nm laser (power 10 mW) was triggered, and a Cu-O bond characteristic peak (signal-to-noise ratio SNR=120) was collected at 480 cm -1 , and the detection limit was 5 x 10 -9 mol / L; after being used for 50 times, the signal attenuation was 2.8%, and the activity could be completely recovered after ultraviolet ozone treatment for 10 minutes.

[0074] Example Two

[0075] The self-powered flexible SERS probe of the example was prepared and applied in the following manner:

[0076] The flexible substrate layer was selected from polyimide (PI), and a 15% polyamide acid solution was spin-coated on a mold with a curvature radius of 1 mm, and was imidized to form a shape at a stepwise temperature of 350°C, with a thickness of 80 μm, and the error of the fitting degree was ≤5%; the piezoelectric functional layer was formed by magnetron sputtering to deposit a 80 μm thick ZnO film (Ar:O2=4:1, substrate temperature 200°C), and the (002) crystal direction was preferentially grown, and the piezoelectric sensitivity was 22 mV / N; the SERS active layer was formed by a template method to sputter a 30 nm silver film, and after annealing, a silver nanoparticle array with a particle size of 40 nm and a spacing of 10 nm was formed, and the surface was modified with 0.1 mM rhodamine B aqueous solution for 30 minutes, the molecular layer thickness was 3 nm, and the enhancement factor (EF) reached 8 x 10 7 ; the conductive electrode layer was composed of 200 nm thick silver paste coated on the upper and lower surfaces, and was connected to a 2 μF barium titanate capacitor; the packaging layer was sprayed with 3 μm thick silicone (SE1700, transmittance 91%), and the bonding strength was ≥5 N / cm.

[0077] Detection application: probe was pressed on SnO corrosion area of bronze sword surface with 0.8 N pressure for 3 seconds, capacitor stored energy to 2 V, then triggered 532 nm laser (power 10 mW), and 630 cm -1 characteristic peak of Sn-O bond (SNR=95) was collected, and the detection limit was 3 x 10 -8 mol / L; the signal was attenuated by 2.5% after 50 times of reuse, and the recycling performance was stable after ethanol wiping.

[0078] The following is a comparison table according to two embodiments and prior art:

[0079]

[0080] Comparison item Explanation:

[0081] Self-power supply capability: the embodiment solves the pain point of traditional SERS equipment relying on external power supply through piezoelectric-capacitive integrated design;

[0082] Substrate adaptability: the curved flexible substrate overcomes the problem of mismatch between rigid probe and surface topography of cultural relics, and improves the detection coverage;

[0083] Packaging protection: the ultrathin transparent packaging layer protects the SERS active layer while avoiding signal loss, which is superior to the traditional non-protection or thick protection scheme.

[0084] Although the embodiments of the present application have been shown and described, it can be understood by those of ordinary skill in the art that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A self-powered flexible SERS probe, characterized in that, The application relates to a self-powered flexible SERS probe, which comprises the following parts: a flexible substrate layer composed of a high-molecular polymer; a piezoelectric functional layer attached to the upper surface of the flexible substrate layer and composed of a piezoelectric material; a SERS active layer covering the upper surface of the piezoelectric functional layer and composed of a noble metal nanostructure array; a conductive electrode layer comprising a first electrode and a second electrode, which are respectively arranged on the upper and lower surfaces of the piezoelectric functional layer and connected with an external circuit; an energy storage module connected with the conductive electrode layer through a lead wire and used for storing the electric energy generated by the piezoelectric functional layer; and a packaging layer composed of a transparent flexible material and covering the outer surfaces of the SERS active layer and the piezoelectric functional layer; wherein the lower surface of the flexible substrate layer is a curved surface structure which directly contacts a detection surface. The thickness of the flexible substrate layer is 50-200 mu m, and the material is selected from polydimethylsiloxane, polyimide or polyvinyl alcohol. The material of the piezoelectric functional layer is polyvinylidene fluoride or zinc oxide, and the thickness is 10-100 mu m. The noble metal nanostructure array is composed of gold or silver nanoparticles, the particle size of the nanoparticles is 20-100 nm, and the arrangement interval is 5-50 nm. The material of the packaging layer is polydimethylsiloxane or silica gel, the thickness is 1-10 mu m, and the visible light transmittance is greater than or equal to 90%. The energy storage module is a micro solid-state capacitor, the capacitance value is 0.1-10 mu F, and the working voltage is 1-5 V. The curvature radius of the curved surface structure is 0.5-5 mm, and the fitting error with the concave-convex appearance of a bronze cultural relic surface is less than or equal to 10%. The noble metal nanostructure surface of the SERS active layer is modified with a benzene thiol or a rhodamine B molecular layer, and the thickness of the molecular layer is 1-5 nm.

2. The self-powered flexible SERS probe according to claim 1, wherein, The application is applied to the self-powered flexible SERS probe according to any one of claims 1-8, and the probe is attached to the surface of a bronze cultural relic, mechanical deformation energy is converted into electric energy through the piezoelectric functional layer, and the SERS active layer is driven to enhance and detect the Raman signal of corrosion products on the surface of the cultural relic.

3. The self-powered flexible SERS probe according to claim 1, wherein, The detection comprises the following steps:

4. The self-powered flexible SERS probe of claim 1, wherein, S1, contacting the curved surface structure of the flexible substrate layer of the probe with the surface of a bronze cultural relic; 5. The self-powered flexible SERS probe of claim 1, wherein, S2, applying a pressure of 0.1-1 N to make the piezoelectric functional layer generate electric charges; 6. The self-powered flexible SERS probe of claim 1, wherein, S3, storing the electric energy to drive a laser light source to emit 532 nm or 785 nm wavelength laser light; 7. The self-powered flexible SERS probe of claim 1, wherein, S4, collecting the Raman scattering signal enhanced by the SERS active layer through the packaging layer.

8. The self-powered flexible SERS probe of claim 1, wherein, ​ 9. The application of a self-powered flexible SERS probe in bronze cultural relic detection, characterized in that, ​ 10. The use of a self-powered flexible SERS probe according to claim 9 in bronze cultural relic detection, characterized in that, ​ ​ ​ ​ ​

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