A fully flexible blue-green light detection material and its preparation method and application

Abstract

The present invention relates to the technical field of blue-green light detection materials, and in particular to a fully flexible blue-green light detection material, a preparation method thereof, and an application thereof. The fully flexible blue-green light detection material of the present invention utilizes the unique photoisomerization reaction of pseudostilbene azobenzene groups to blue-green light. The dynamic disorder of the molecular shape drives the microscopic contraction of the film fiber network, stimulating the piezoelectric polymer to output a voltage signal on a macroscopic scale, which can be amplified and detected by an electrometer to realize the detection of the blue-green light intensity. The present invention prepares a fiber film composite material with a microstructure through a material forming method that is simple to operate and can be continuously manufactured on a large area. The present invention utilizes light signals to cause the accumulation of mechanical stress inside the material system, which is further converted into an electric potential difference between the material surfaces through the piezoelectric effect, thereby establishing a continuous transmission mechanism of optical-mechanical-electrical signals, and can prepare a large-area, fast-response, long-life, self-driven intrinsic flexible blue-green light detector.

Description

Technical Field

[0001] The present invention relates to the technical field of blue-green light detection materials, and in particular to a fully flexible blue-green light detection material and a preparation method and application thereof. Background Art

[0002] Blue-green light, which refers to the 450-550nm wavelength range of the electromagnetic spectrum, exhibits a lower attenuation coefficient and greater propagation distance in marine environments. Due to the pressing demands of military activities and resource development and utilization, wireless optical communication systems based on blue-green light have attracted significant attention for their application in underwater sensors, underwater robots, submersibles, and other detection equipment. Furthermore, the blue-green light band exhibits sensitive reflection effects on surface blood vessels in human skin and excellent resistance to stray light interference. This has led to significant progress in real-time monitoring of health data such as heart rate and blood oxygen saturation on integrated devices such as smart wearables and mobile terminals.

[0003] At present, the sensitive elements of blue-green light detectors are mainly inorganic semiconductor materials (such as silicon-germanium crystals, perovskites, organic-inorganic heterojunctions, etc.), but they generally have complex and cumbersome preparation processes, strict requirements on raw material purity and production environment, etc., which significantly affect the production efficiency of the materials and greatly increase the manufacturing cost of the detectors. At the same time, semiconductor hard sheets that are only tens of microns in size after processing are precision materials. They are usually very fragile, afraid of falling and collisions, and have weak resistance to external interference. They are difficult to meet the requirements of future dynamic use scenarios for material elasticity, bendability, and stability. Therefore, the development of a new material system and the design and preparation of flexible blue-green light detection devices based on a new light-to-electricity conversion mechanism are the inevitable development trend to reduce the bit error rate of communication systems during movement and improve the fit to human body parts.

[0004] As an emerging technology with great potential, fully flexible electronic devices based on organic polymers are rapidly developing in applications such as sensors and actuators, electronic skin, and micro-integrated systems. They are leading a new revolution in electronic technology across fields such as information, energy, health, and national defense, and have become a research hotspot within interdisciplinary fields in recent years. Therefore, expanding the material systems and design strategies for fully flexible blue-green photodetectors that are inherently flexible and can be fabricated over large areas through simple and controllable material forming processes is of great scientific significance and a major research challenge in this field. Summary of the Invention

[0005] In order to solve the above technical problems of the present invention, the present invention provides a fully flexible blue-green light detection material and a preparation method and application thereof.

[0006] According to a first aspect of the present invention, a fully flexible blue-green light detection material is provided, which uses a pseudostilbene azobenzene liquid crystal elastomer that specifically responds to blue-green light as a sensitive unit and a piezoelectric polymer as a matrix.

[0007] The present invention discovered that pseudostilbene azobenzene liquid crystal elastomers are extremely sensitive to incident light stimulation due to the synergistic effects of liquid crystal orientation and polymer networks, as well as a unique rapid thermal relaxation effect. The energy generated by the photoinduced cis-trans isomerization of even a small number of pseudostilbene azobenzene molecules can cause a transient change in the overall orientation of the material. Without light exposure, the deformation is quickly released and the material returns to its initial state, combining the advantages of sensitive response with high mechanical stability.

[0008] The present invention compounds the pseudostilbene azobenzene liquid crystal elastomer with a piezoelectric polymer matrix. The optical signal first causes the accumulation of mechanical stress inside the material system, which is further converted into an electric potential difference between the material surfaces using the piezoelectric effect, thereby establishing a continuous transmission mechanism of optical-mechanical-electrical signals. This produces an intrinsically flexible blue-green light detection material with high wavelength selectivity, large area, fast response, and long life, and further a fully flexible blue-green light detector.

[0009] Furthermore, the pseudostilbene azobenzene liquid crystal elastomer includes poly{11-[N-methyl-N-(4-(4'-succinimidyl ester phenylazo)phenyl)amino]undecyl methacrylate} (CPADB-P11NAz), 6-[N-methyl-N-(4-(4'-succinimidyl ester phenylazo)phenyl)amino]hexyl methacrylate, poly(ethylene glycol)-block-poly{11-[N-methyl-N-(4-(4'-succinimidyl ester phenylazo)phenyl)amino]undecyl methacrylate} One or more of poly{11-[N-methyl-N-(4-(4'-succinimidyl ester phenylazo)phenyl)amino]undecyl methacrylate}, poly{2-[N-ethyl-N-(4-(4'-succinimidyl ester phenylazo)phenyl)amino]ethyl methacrylate}; preferably, the pseudostilbene azobenzene liquid crystal elastomer is poly{11-[N-methyl-N-(4-(4'-succinimidyl ester phenylazo)phenyl)amino]undecyl methacrylate} (CPADB-P11NAz).

[0010] In the above scheme, the succinimide active ester group at the tail end of the side chain of the pseudostilbene azobenzene liquid crystal polymer used in the present invention can undergo a mild and rapid chemical reaction with the amino-rich crosslinking agent at room temperature to form a lightly crosslinked liquid crystal elastomer.

[0011] Furthermore, the piezoelectric polymer is selected from one or more of polyvinylidene fluoride, polyvinylidene fluoride-trifluoroethylene copolymer, and polyvinylidene fluoride-hexafluoroethylene copolymer.

[0012] Furthermore, the fully flexible blue-green light detection material has a tensile strength exceeding 2 MPa and an elongation at break exceeding 30%.

[0013] According to a second aspect of the present invention, the present invention provides a method for preparing the above-mentioned fully flexible blue-green light detection material, comprising the following steps:

[0014] The fiber film matrix is prepared by blending pseudostilbene azobenzene liquid crystal elastomer and piezoelectric polymer;

[0015] The prepared fiber film substrate is immersed in a crosslinking agent solution for a period of time to crosslink the pseudostilbene azobenzene polymer in the pseudostilbene azobenzene liquid crystal elastomer to form a lightly chemically crosslinked liquid crystal elastomer composite fiber film.

[0016] Furthermore, the mass ratio of the pseudostilbene azobenzene liquid crystal elastomer to the piezoelectric polymer is 1:1 to 1:10.

[0017] In the present invention, the reversible isomerization reaction of the pseudo-stilbene azobenzene liquid crystal elastomer under blue-green light drives the piezoelectric polymer to produce microscopic deformation, causing the relative transfer of internal positive and negative charge centers to produce polarization phenomena, thereby gathering bound charges of equal size and opposite sign on the upper and lower surfaces of the material, and ultimately outputting the mechanical stress generated by the blue-green light in the form of a voltage signal. In addition, the voltage value can be used as a response variable and can also provide energy for the measurement circuit to achieve zero-power self-driven light detection. By limiting the mass ratio of the pseudo-stilbene azobenzene liquid crystal elastomer and the piezoelectric polymer to a reasonable range of values, the pseudo-stilbene azobenzene liquid crystal elastomer and the piezoelectric polymer can play a better synergistic role.

[0018] In some preferred embodiments, the pseudostilbene azobenzene liquid crystal elastomer is selected from poly{11-[N-methyl-N-(4-(4'-succinimidyl ester phenylazo)phenyl)amino]undecyl methacrylate} (CPADB-P11NAz), and the mass ratio of the pseudostilbene azobenzene liquid crystal elastomer to the piezoelectric polymer is 1:1 to 1:10.

[0019] Further preferably, the piezoelectric polymer is polyvinylidene fluoride-trifluoroethylene copolymer (P(VDF-TrFE)), and the mass ratio of the pseudostilbene azobenzene liquid crystal elastomer to the piezoelectric polymer is 1:1 to 1:5.

[0020] Furthermore, the cross-linking agent is one or more polyamine macromolecular compounds with a molecular weight of 600 to 70,000 g / mol.

[0021] In the present invention, the addition of polyethyleneimine with the aforementioned molecular weight strengthens the bonding between the pseudostilbene azobenzene liquid crystal elastomer and the piezoelectric polymer matrix, facilitating the accumulation and conduction of photoinduced stress within the material, further enhancing photoelectric conversion efficiency. Crosslinkers with molecular weights in other ranges, however, either exhibit excessive rigidity, limiting the photoinduced deformation of the pseudostilbene azobenzene molecules, or exhibit excessive flexibility, exacerbating stress dissipation, and thus fail to achieve the desired effect.

[0022] Furthermore, the fiber film matrix is prepared by a spinning method or a 3D printing method; wherein the spinning method is selected from one of solution spinning, melt spinning, phase separation spinning, jet spinning, electrospinning and microfluidic spinning.

[0023] In the above scheme, a fiber film matrix with excellent performance and stable structure can be obtained by selecting a suitable preparation method.

[0024] Further preferably, the spinning method is electrospinning. The positive DC voltage used in the spinning process is 10 to 20 kV, and the negative DC voltage is -3 to -10 kV; the volume of the solution in the syringe is 0.5 to 5 mL, and the speed of the solution in the syringe is 0.5 to 2 mL / h; the receiving device is a flat plate or roller with a layer of aluminum foil attached to the surface, and the roller rotates at a speed of 50 to 3000 rpm; the distance between the needle and the receiving device is 5 to 15 cm. The mixed solution is continuously electrospun to obtain a fiber film with a thickness of 10 to 150 μm. After spinning is completed, the fiber film can be torn off with pointed tweezers and cut into any shape and size with surgical scissors.

[0025] The spinning method of the present invention can produce a large-area, washable, stretchable, foldable, highly breathable, and uniform fiber film. The high-voltage electrostatic field stretching effect of the electrospinning process and the centripetal force of the high-speed drum not only promote the highly oriented alignment of the pseudostilbene azobenzene mesogens, but also promote the crystallization transformation of the α phase in the piezoelectric polymer to the β phase with a high dipole moment and high spontaneous polarization strength, thereby improving the material's piezoelectric properties without the need for a subsequent high-voltage poling step.

[0026] In some preferred embodiments, the method for preparing a fully flexible blue-green light detection material specifically comprises the following steps:

[0027] 1) A certain amount of the pseudostilbene azobenzene liquid crystal elastomer and the piezoelectric polymer are mixed and dissolved in a co-solvent, stirred at 35-45°C for 14-24 hours using a magnetic stirrer to fully disperse the mixture to form a uniform viscous solution, and a flexible nanofiber oriented film substrate is prepared by the spinning method. More preferably, the co-solvent is one or more of N,N-dimethylformamide (DMF), acetone, tetrahydrofuran (THF), ethanol, and chloroform.

[0028] 2) The active amino crosslinker is prepared into a dispersion, and the nanofiber oriented film substrate is immersed in the dispersion for 6 to 12 hours to form a new chemical covalent bond between the succinimide group at the end of the side chain of the polymer repeating unit and the polyamine group. After washing away the residual crosslinker, the film is placed in a fume hood to dry, thereby obtaining a flexible liquid crystal elastomer composite fiber film, i.e., a fully flexible blue-green light detection material. Further preferably, the crosslinker dispersion concentration is 0.5 to 3 mg / mL, and the dispersion solvent is one or more of ethanol, methanol, and deionized water.

[0029] Furthermore, the raw materials for preparing the fiber film matrix also include a thermoplastic elastomer, and the added amount of the thermoplastic elastomer is 0 to 50% of the mass of the piezoelectric polymer; preferably, the thermoplastic elastomer includes one or more of thermoplastic polyurethane, hydrogenated styrene-butadiene copolymer, and ethylene propylene diene monomer rubber.

[0030] In the above scheme, the pseudostilbene azobenzene liquid crystal elastomer is blended with the above thermoplastic elastomer, which can significantly improve the elongation at break and mechanical properties of the material, while utilizing the resilience to shorten the recovery time required for stress release after light is turned off.

[0031] According to the third aspect of the present invention, the present invention also provides a fully flexible blue-green light detector, which is prepared using the fully flexible blue-green light detection material described in the claim or the fully flexible blue-green light detection material prepared by the above preparation method.

[0032] According to a fourth aspect of the present invention, the present invention also provides applications of the above-mentioned fully flexible blue-green light detector in light source positioning, health monitoring, artificial intelligence, wearable devices, wireless optical communications, and health data analysis. Further preferred applications include the preparation of underwater photoelectric sensors, light-driven biomimetic actuators, electronic skin, smart wearable devices, and other IoT-related fields.

[0033] Furthermore, the system model constructed by the application of the fully flexible blue-green light detector in light source positioning is composed of a plurality of the fully flexible blue-green light detectors arranged at equal intervals to form an array, and the number of the fully flexible blue-green light detectors in the array is 4 to 12;

[0034] The system model constructed for the application of the fully flexible blue-green light detector in health detection is to combine the fully flexible blue-green light detector with a carrier substrate with excellent biocompatibility, high air permeability, low skin sensitivity and high elasticity; the carrier substrate includes one or more of medical bandages, wound dressings, polydimethylsiloxane and silicone.

[0035] In this scheme, multiple fully flexible blue-green light detectors are evenly spaced on the surface of a cylindrical buoy, forming a detector array system for light source positioning. When incident light strikes a detector from different directions and distances, only that detector outputs a voltage signal of a certain intensity. This basic positioning of the incident light source is achieved by leveraging the detector's inherent orientation information during installation and inferring the distance corresponding to the current signal strength using a voltage-distance calibration curve.

[0036] The fully flexible blue-green light detector is combined with a carrier substrate with excellent biocompatibility, high air permeability, low skin sensitivity and high elasticity to build a health detection system that can monitor heart rate and pulse in real time and analyze the wearer's physiological movement status. After the visible light of a specific wavelength is reflected by tissues such as the skin, fat, muscle, and blood vessels, it carries relevant information about the periodic changes in arterial volume. After this information is received by the pseudo-stilbene azobenzene liquid crystal elastomer blue-green light detector, it can realize practical functions such as counting pulse beats, monitoring heart rate, analyzing exercise intensity, quantitatively calculating physiological indicators, and preliminary screening for blood circulation system diseases. It has huge application potential in the fields of medical care, health warning, etc. In some preferred embodiments, the placement position of the fully flexible blue-green light detector can be one or more of the radial artery at the wrist, the brachial artery at the elbow, and the common carotid artery in the neck.

[0037] Furthermore, the light source positioning system and health detection system of the fully flexible blue-green light detector are connected to the control chip circuit of the Arduino Uno microcontroller, and the Bluetooth module is connected. Then, Android software for receiving and displaying Bluetooth transmission information is created using programs such as MIT App Inventor. The current measurement results can be wirelessly transmitted to the mobile phone through the Bluetooth protocol built into the microcontroller, building an IoT intelligent system that can remotely monitor data and remotely receive information.

[0038] The technical solution provided by the present invention has the following beneficial effects:

[0039] The fully flexible blue-green light detection material of the present invention utilizes the unique photoisomerization reaction of pseudostilbene azobenzene groups to blue-green light. The dynamic disorder of the molecular shape drives the microscopic contraction of the film fiber network, stimulating the piezoelectric polymer to output a macroscopic voltage signal. The blue-green light intensity can be detected through amplification and detection by an electrometer.

[0040] Due to the unique characteristics and applications of blue-green light, as well as the demand for intrinsically flexible blue-green light detection materials, the present invention cleverly uses a blue-green light-responsive pseudostilbene azobenzene liquid crystal elastomer as a sensitive unit, and organically compounds it with other piezoelectric polymers or thermoplastic elastomer matrix materials to construct a suitable optical-mechanical-electrical conversion system. The results show that it has a blue-green light detection capability with fast response, high linearity, and dynamic environmental stability. Compared with traditional semiconductor photoelectric sensors, blue-green light detectors based on polymer materials have advantages that semiconductor materials cannot match in terms of mass production, cost, and flexible wearable applications. On this basis, combined with Internet of Things technologies such as single-chip microcomputers, Bluetooth modules, and mobile phone / computer software, the fully flexible blue-green light detector prepared using the fully flexible blue-green light detection material of the present invention is used for functions such as information detection, transmission, and autonomous processing, which is of great significance in artificial intelligence fields such as wearable devices, wireless optical communication systems, underwater light source positioning, and health data monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 Schematic diagram of the molecular structure of the pseudostilbene azobenzene polymer, the piezoelectric polymer, and the polyethyleneimine crosslinker in Example 1 of the present invention;

[0043] Figure 2 This is the process flow for preparing the fully flexible blue-green light detection material according to Example 1 of the present invention;

[0044] Figure 3 Scanning electron microscope photographs of the surface of the original fully flexible blue-green light detection material and the surface of the fully flexible blue-green light detection material after spin coating with silver nanowire ethanol solution in Example 10 of the present invention;

[0045] Figure 4 The open circuit voltage-time curve of the fully flexible blue-green light detector in Example 10 of the present invention under blue-green light irradiation of different intensities, and the light intensity-voltage simulation curve after linear regression;

[0046] Figure 5 The arrangement of the detector array of the light source positioning system in Example 19 of the present invention, and the response results to incident light from different directions;

[0047] Figure 6 It is the pulse signal output by the health detection system in Example 20 of the present invention. DETAILED DESCRIPTION

[0048] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0049] In the present invention, all instruments and other materials used, unless the manufacturer is indicated, are conventional products available through regular channels. Methods described are conventional methods unless otherwise specified, and raw materials described are commercially available unless otherwise specified. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in the field or in accordance with the product instructions were used.

[0050] Example 1

[0051] In this embodiment, the pseudostilbene azobenzene polymer used is specifically poly{11-[N-methyl-N-(4-(4'-succinimidyl ester phenylazo)phenyl)amino]undecyl methacrylate} (CPADB-P11NAz) synthesized in the laboratory, the piezoelectric polymer used is polyvinylidene fluoride-trifluoroethylene copolymer (P(VDF-TrFE)), and the cross-linking agent used is PEI. The molecular structures of CPADB-P11NAz, P(VDF-TrFE) and PEI are shown in the following figure. Figure 1 shown.

[0052] This example provides a method for preparing a fully flexible blue-green light detection material. The specific steps are as follows:

[0053] 1) Electrospinning of Flexible Fiber Films: Pseudostilbene azobenzene polymer powder and piezoelectric polymer powder were weighed at a mass ratio of 1:3 using an analytical balance and poured into a glass vial containing a magnet. N,N-dimethylformamide and tetrahydrofuran solvents at a volume ratio of 3:2 were drawn into the vial using a syringe. The mixed solution was stirred at 42°C for 16 hours using a magnetic stirrer until the solutes were completely dissolved and a homogeneous mixed solution was formed. The mixed solution was transferred to a syringe for electrospinning. A positive DC voltage of 15 kV and a negative DC voltage of -5 kV were applied. The syringe volume was 1 mL and the solution was fed at a rate of 1 mL / h. The receiving device was a high-speed roller with an aluminum foil layer attached, rotating at 2800 rpm. The distance between the needle and the receiving device was 10 cm. The mixed solution was continuously electrospun to produce a 50 μm thick flexible fiber film. After spinning, the film was removed using pointed tweezers and allowed to dry overnight at room temperature and atmospheric pressure. The size of the spun film is 55 mm × 250 mm, and it has a certain electrostatic adsorption ability to the skin and gloves. It is cut into 25 mm × 15 mm rectangular strips with surgical scissors for use.

[0054] 2) Liquid crystal elastomer crosslinking: Prepare a 2 mg / L polyethyleneimine (molecular weight 10000 g / mol) anhydrous ethanol solution in a beaker and place it in an ultrasonic cleaner for 30 minutes to fully disperse it to obtain a uniform and transparent polyethyleneimine solution. Soak the fiber film strip obtained in the previous step in the crosslinker solution for 7.5 hours to fully crosslink the pseudostilbene azobenzene polymer. Figure 2 The sample was removed, the residual crosslinker was washed off, and the film was dried in a vacuum oven overnight to obtain a lightly crosslinked liquid crystal elastomer composite fiber film, a fully flexible blue-green light detection material with excellent mechanical properties, a tensile strength exceeding 18 MPa, and an elongation at break exceeding 60%, meeting the basic performance requirements of wearable devices for stretching and folding.

[0055] Example 2

[0056] This example provides a method for preparing a fully flexible blue-green light detection material, which differs from Example 1 in that poly(ethylene glycol)-block-poly{11-[N-methyl-N-(4-(4'-succinimidylphenylazo)phenyl)amino]undecyl methacrylate} (PEO-b-P11NAz) is used instead of CPADB-P11NAz.

[0057] Example 3

[0058] This example provides a method for preparing a fully flexible blue-green light detection material, which differs from Example 1 in that poly{2-[N-ethyl-N-(4-(4'-succinimidylphenylazo)phenyl)amino]ethyl methacrylate} (CPADB-P2NAz) is used instead of CPADB-P11NAz.

[0059] Example 4

[0060] This example provides a method for preparing a fully flexible blue-green light detection material, which is different from Example 1 in that the weight ratio of CPADB-P11NAz to P(VDF-TrFE) is 1:1.

[0061] Example 5

[0062] This example provides a method for preparing a fully flexible blue-green light detection material, which is different from Example 1 in that the weight ratio of CPADB-P11NAz to P(VDF-TrFE) is 1:10.

[0063] Example 6

[0064] This example provides a method for preparing a fully flexible blue-green light detection material, which is different from Example 1 in that the weight ratio of CPADB-P11NAz to P(VDF-TrFE) is 1:5.

[0065] Example 7

[0066] This example provides a method for preparing a fully flexible blue-green light detection material, which is different from Example 1 in that the molecular weight of PEI is 1800 g / mol.

[0067] Example 8

[0068] This example provides a method for preparing a fully flexible blue-green light detection material, which is different from Example 1 in that the molecular weight of PEI is 600 g / mol.

[0069] Example 9

[0070] This example provides a method for preparing a fully flexible blue-green light detection material, which differs from Example 1 in that: in step 1) electrospinning to prepare a flexible fiber film, the preparation raw materials also include a thermoplastic elastomer, specifically thermoplastic polyurethane (TPU), and the addition amount thereof is 20% of the mass of the piezoelectric polymer.

[0071] The fully flexible blue-green light detection materials prepared in Examples 1-9 were subjected to tensile strength and elongation at break tests. The tests were conducted in accordance with the relevant criteria of the national standard GB / T 1040.3-2006, with a tensile rate of 3 mm / min. The test results are shown in Table 1 below.

[0072] Table 1

[0073] Fully flexible blue-green light detection material Tensile strength / MPa Elongation at break / % Example 1 18.8 63.2 Example 2 17.1 63.4 Example 3 15.5 62.6 Example 4 15～18 50～60 Example 5 10～12 30～40 Example 6 12～15 40～50 Example 7 2.3 45.9 Example 8 2.2 36.8 Example 9 4.5 105.1

[0074] It can be seen from the results in Table 1 that the fully flexible blue-green light detection material prepared by the preparation method of the present invention has good mechanical properties, and the tensile strength and elongation at break can meet the basic performance requirements of wearable devices for stretching and folding.

[0075] Example 10-18 Fully flexible blue-green photodetector preparation process and photovoltage detection

[0076] This embodiment provides a method for preparing a fully flexible blue-green light detection material prepared in Examples 1-9 by encapsulating it into a fully flexible blue-green light detector, and detecting the voltage change across the device using a digital ammeter. The specific steps are as follows:

[0077] (1) Preparation of fully flexible blue-green light detector: Take the fully flexible blue-green light detection material sample in Example 1-9, completely stick double-sided conductive copper tape on one side of it, place it in a coating machine, and use a silver nanowire / anhydrous ethanol solution with a volume ratio of 1:2 to spin coat 1 to 2 times to form a surface transparent electrode with a resistance of 50Ω. The scanning electron microscope photo of the surface of the composite fiber film device is shown as follows: Figure 3 As shown by Figure 3 It can be seen that the highly oriented nanofibers are neatly arranged along the same axis. After spin coating, the elongated silver nanowires overlap each other on the fiber surface, forming a transparent and complete conductive path. Two copper wires were then adhered to the copper tape near the long end of the spline and the surface of the transparent electrode using conductive silver paste. After the conductive silver paste diluent completely evaporated, the copper wire attachment points were sealed with double-sided tape, resulting in a fully flexible blue-green light detection device with a light-receiving area of 20mm×10mm.

[0078] A digital meter detects device voltage changes: The blue-green light intensity detection system consists of a digital meter (Keithley 6517B) and its accessories, a blue-green light source (460nm and 520nm), and a computer. The two copper wires of the fully flexible blue-green light detector prepared in the previous step are connected to the positive and negative terminals of the digital meter. Under illumination with blue-green light of varying intensities, the digital meter detects voltage changes in real time and displays them on the computer screen. Data such as time, output voltage, and blue-green light intensity are recorded. Linear regression is then used to analyze the light intensity-voltage relationship and generate a fitted curve.

[0079] The fully flexible blue-green light detection material prepared in Example 1 is encapsulated into a fully flexible blue-green light detector. The output voltage-time curve under the irradiation of blue-green light of different intensities is shown in FIG. Figure 4 As shown. Figure 4It can be seen that when the mass ratio of pseudostilbene azobenzene liquid crystal elastomer to piezoelectric polymer is 1:3, the blue-green light intensity range that the device can detect is 20-350 mW / cm 2 , the open circuit voltage is 138.1mV, and the response time is 3.6 seconds. Similarly, the fully flexible blue-green light detection material prepared in Example 2-9 is encapsulated into a fully flexible blue-green light detector, and the blue-green light intensity range that can be detected is also 20 to 350mW / cm 2 The open-circuit voltage and response time are shown in Table 2 below. From the experimental data in Table 2, it can be seen that the fully flexible blue-green light detector of the present invention has a wide light intensity detection range, fast response speed, excellent and stable performance, and can meet the detection of blue-green light intensity in most daily life, wireless optical communication, light source positioning, health data monitoring and other fields.

[0080] Table 2 Test results of fully flexible blue-green light detectors prepared using the fully flexible blue-green light detection materials of Examples 1-9

[0081]

[0082] Example 19 Design and Application of Detector Array of Light Source Positioning System

[0083] This example provides a method for forming an array-type light source positioning system using multiple fully flexible blue-green light detectors obtained in Example 10. The basic positioning of incident light is achieved by sequentially determining the direction and distance. The specific steps are as follows:

[0084] 1) Construction of an array-type light source positioning system: The light source positioning system consists of a fully flexible blue-green light detector array, a digital electric meter (Keithley 6517B) and its accessories, a blue light source (460nm), and a computer. Eight fully flexible blue-green light detectors from Example 10 are evenly spaced and fixed to the surface of the cylinder. Each detector can independently receive light within ±22.5° on both sides of its plane normal, forming a 360° blue light detector array. Each detector corresponds to a direction. By numbering the eight detectors in counterclockwise order, an association can be established between the detector number and the two-dimensional plane coordinate of the incident light. For example, number 1 is the (0, -Y) axial direction, number 2 is the (X, -Y) angular bisector direction, and so on.

[0085] 2) Light source positioning: When the incident light illuminates detectors with different numbers from different angles and distances, only the corresponding detector outputs a voltage signal with a negative exponential relationship with the distance length, while the remaining detectors in the array maintain the baseline state, such as Figure 5As shown in the figure, after turning on a blue light source at an unknown location, detectors 1 through 8 operate sequentially for 10 seconds, recording whether a detection signal is input. The only detector with a valid signal is selected, and according to the aforementioned numbering logic, the direction of the light source is directly determined. The voltage-distance calibration curve is also used to infer the distance corresponding to the current signal strength, which together form the light source's position coordinates in the XY two-dimensional plane.

[0086] Example 20 Design and Application of Health Detection System

[0087] This example provides a method for real-time pulse detection using the fully flexible blue-green light detector obtained in Example 10, and counting and statistically analyzing the pulse signals using software. The specific steps are as follows:

[0088] 1) Construction of the Health Monitoring System: The health monitoring system consists of an improved fully flexible blue-green photodetector, a digital ammeter (Keithley 6517B) and its accessories, a green light source (520 nm), and a computer. The fully flexible blue-green photodetector from Example 10 was fixed to a highly elastic, low-sensitivity, breathable bandage with a copper tape electrode attached. A polyethylene terephthalate (PET) insulating film was then applied to the upper side of the silver nanowire transparent electrode. The PET and carrier bandage were affixed together using double-sided tape, ensuring that the insulating layer was as close to the pseudostilbene azobenzene liquid crystal elastomer blue-green photodetector as possible to prevent moisture and other impurities from entering the gap and affecting the detection results.

[0089] 2) Real-time pulse detection: straighten your arm and place it flat on the detection table, place the above health detection system near the brachial artery at the elbow, turn on the 520nm green light source and hold it close to the skin and the detector at the same time. Adjust the position of the detector back and forth, and slightly rotate your arm to maximize the pulse signal amplitude displayed on the computer screen. After 30 seconds of stable measurement (can fluctuate up and down for 10 seconds), the heart rate can be calculated based on the number of pulse peaks within the detection time, such as Figure 6 shown.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A fully flexible blue-green light detection material, characterized in that: A pseudostilbene azobenzene liquid crystal elastomer that specifically responds to blue-green light is used as a sensitive unit, and a piezoelectric polymer is used as a matrix; the pseudostilbene azobenzene liquid crystal elastomer includes one or more of poly{11-[N-methyl-N-(4-(4'-succinimidyl ester phenylazo)phenyl)amino]undecyl methacrylate}, 6-[N-methyl-N-(4-(4'-succinimidyl ester phenylazo)phenyl)amino]hexyl methacrylate, poly(ethylene glycol)-block-poly{11-[N-methyl-N-(4-(4'-succinimidyl ester phenylazo)phenyl)amino]undecyl methacrylate}, and poly{2-[N-ethyl-N-(4-(4'-succinimidyl ester phenylazo)phenyl)amino]ethyl methacrylate}; The preparation method of the fully flexible blue-green light detection material comprises the following steps: The fiber film matrix is prepared by blending pseudostilbene azobenzene liquid crystal elastomer and piezoelectric polymer; The prepared fiber film matrix is immersed in a crosslinker solution for a period of time to crosslink the pseudostilbene azobenzene polymer in the pseudostilbene azobenzene liquid crystal elastomer to form a chemically crosslinked liquid crystal elastomer composite fiber film; the crosslinker is one or more polyamine macromolecular compounds with a molecular weight of 600 to 70,000 g / mol.

2. The fully flexible blue-green light detection material according to claim 1, characterized in that: The pseudostilbene azobenzene liquid crystal elastomer is poly{11-[N-methyl-N-(4-(4'-succinimidyl ester phenylazo)phenyl)amino]undecyl methacrylate}.

3. The fully flexible blue-green light detection material according to claim 1, characterized in that: The piezoelectric polymer is selected from one or more of polyvinylidene fluoride, polyvinylidene fluoride-trifluoroethylene copolymer, and polyvinylidene fluoride-hexafluoroethylene copolymer.

4. The fully flexible blue-green light detection material according to claim 1, characterized in that: The fully flexible blue-green light detection material has a tensile strength exceeding 2 MPa and an elongation at break exceeding 30%.

5. The method for preparing the fully flexible blue-green light detection material according to any one of claims 1 to 4, characterized in that: The steps include: The fiber film matrix is prepared by blending pseudostilbene azobenzene liquid crystal elastomer and piezoelectric polymer; The prepared fiber film substrate is immersed in a crosslinking agent solution for a period of time to crosslink the pseudostilbene azobenzene polymer in the pseudostilbene azobenzene liquid crystal elastomer to form a chemically crosslinked liquid crystal elastomer composite fiber film.

6. The preparation method according to claim 5, characterized in that The mass ratio of the pseudostilbene azobenzene liquid crystal elastomer to the piezoelectric polymer is 1:1 to 1:10; And / or, the cross-linking agent is polyethyleneimine with a molecular weight of 1800 to 10000 g / mol.

7. The preparation method according to claim 5, characterized in that The fiber film matrix is prepared by a spinning method or a 3D printing method; wherein the spinning method is selected from one of solution spinning, melt spinning, phase separation spinning, jet spinning, electrospinning and microfluidic spinning; And / or, the raw materials for preparing the fiber film matrix further include a thermoplastic elastomer, and the added amount of the thermoplastic elastomer is 0 to 50% of the mass of the piezoelectric polymer.

8. The preparation method according to claim 7, characterized in that The thermoplastic elastomer includes one or more of thermoplastic polyurethane, hydrogenated styrene-butadiene copolymer, and ethylene propylene diene monomer rubber.

9. A fully flexible blue-green light detector, characterized in that: The method is prepared by using the fully flexible blue-green light detection material described in any one of claims 1 to 4 or the fully flexible blue-green light detection material prepared by the preparation method described in any one of claims 5 to 8.

10. Application of the fully flexible blue-green light detector according to claim 9 in light source positioning, artificial intelligence, wearable devices and wireless optical communications.

11. The use according to claim 10, characterized in that The application of the fully flexible blue-green light detector in light source positioning refers to an array composed of multiple fully flexible blue-green light detectors arranged at equal intervals, and the number of fully flexible blue-green light detectors in the array is 4 to 12.

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