Ionic elastomer photoelectric sensor based on triplet-triplet annihilation up-conversion and preparation method thereof

Abstract

The invention discloses an ionic elastomer photoelectric sensor based on triplet-triplet annihilation up-conversion and a preparation method of the ionic elastomer photoelectric sensor, and belongs to the technical field of functional materials and photoelectric sensing. The photosensitizer and the luminescence agent form a triplet state-triplet state annihilation up-conversion system. The preparation method comprises the following steps: respectively forming the ionic conductive phase and the optical active phase, mixing the ionic conductive phase and the optical active phase to form a homogeneous system, and curing and molding through photo-initiation polymerization. Under the optical excitation condition of a specific wave band, the ion elastomer can generate measurable electric signal output, so that conversion from an optical signal to an electric signal is realized. The flexible photoelectric sensor can be prepared by curing the material on the surface of an electrode, can work under the condition of no external bias voltage or low bias voltage, has the characteristics of good wavelength selectivity, excellent flexibility and stretchability and the like, and has an application prospect in the fields of wearable sensing and flexible electronics.

Description

Technical Field

[0001] This invention relates to the fields of functional materials and optoelectronic sensing technology, specifically to a novel composite material that combines a triplet-triplet annihilation upconversion luminescence system with an ion-conductive elastomer, and its preparation and application as a self-powered, flexible optoelectronic sensor. Background Technology

[0002] As core devices for converting optical signals into electrical signals, photoelectric sensors play a fundamental role in information sensing, intelligent interaction, and environmental monitoring. With the rapid development of wearable and flexible electronics technologies, photoelectric sensors are gradually evolving from traditional rigid devices towards more flexible, low-power, and adhesive applications to meet the demands of complex curved surfaces, dynamic interfaces, and long-term adhesion. Against this backdrop, material systems capable of stably realizing optical signal detection and electrical signal output on flexible carriers have become an important research direction in this field.

[0003] Existing flexible photodetector technologies are mostly based on inorganic semiconductor thin films, organic semiconductors, or their composite structures. Although related devices have made some progress in terms of photoresponse speed and sensitivity, their implementation usually relies on sophisticated device structure design, vacuum deposition, or multilayer packaging processes, which still have shortcomings in terms of fabrication complexity, interface stability, and long-term compatibility with soft substrates. In addition, these devices often require an external bias voltage or a relatively high operating voltage, limiting their applicability in low-power or self-powered applications.

[0004] On the other hand, low-energy light response technology has gradually attracted attention in recent years, especially in the near-infrared and other low-energy light bands, where it has potential applications in flexible wearables, environmental sensing, and covert optical communication. Triplet-Triplet Annihilation Upconversion (TTA-UC) technology can generate an effective upconversion response under low-energy light excitation conditions, providing a feasible path for expanding the utilization of low-energy light. Currently, this type of technology is mainly applied in the fields of optical signal enhancement or wavelength conversion, and its output is primarily optical signals, usually requiring readout using optical detection systems, which limits its application in compact, flexible electrical signal detection systems.

[0005] In the field of flexible electronics, ionic elastomers are widely used in flexible electrodes, interface layers, and ionic electronic devices due to their combination of flexible polymer network structure and ionic conductivity. These materials exhibit good interfacial adaptability and mechanical compliance, maintaining stable electrical properties under flexible substrates or dynamic interface conditions. However, existing research on ionic elastomers largely focuses on their mechanical, electrochemical, or strain response characteristics, with relatively limited research on their photoelectric conversion or photoresponse electrical signal output under photoexcitation conditions.

[0006] In summary, current flexible photoelectric detection technology still struggles to simultaneously achieve low-energy light response, direct electrical signal readout, and adaptability to flexible devices. On one hand, low-energy light upconversion technology has not been effectively integrated into flexible electrical signal detection systems; on the other hand, the application potential of flexible ion-conducting materials in photoresponse functionality has not been fully explored. Therefore, there is an urgent need to construct a photoelectric detection material system capable of directly coupling photoresponse and electrical signal output under low-energy light excitation conditions, suitable for flexible and wearable applications, to meet the development needs of novel low-power, flexible photoelectric detection and sensing technologies. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a composite material with a simple preparation process, adjustable performance, and good flexibility and ionic conductivity, which can stably generate measurable electrical signal output under specific wavelength light excitation conditions, thereby realizing the conversion of optical signals to electrical signals, and can be used in flexible optoelectronic detection devices.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] This invention provides an ion elastomer photoelectric sensor based on triplet-triplet annihilation upconversion and its preparation method. The sensor includes an electrode and a sensitive layer formed by an ion elastomer solidified on the surface of the electrode. The ion elastomer includes an ion-conductive elastomer matrix and a photosensitizer and a luminescent agent uniformly dispersed in the ion-conductive elastomer matrix.

[0010] The photosensitizer and the luminescent agent constitute a triplet-triplet annihilation upconversion system, which can generate an upconversion response under specific wavelength light excitation conditions, and enable the ionic conductive elastomer to generate a measurable electrical signal output inside itself or at the electrode interface.

[0011] The ion-conductive elastomer matrix is ​​a polymer network that simultaneously possesses elastic deformation capability and ion conductivity at room temperature. It contains migratable ion carriers, thereby providing the basic conditions for the generation and transmission of electrical signals.

[0012] Furthermore, the polymer network is preferably formed from acrylate monomers that can be polymerized by free radicals, and the ion carriers can be selected from alkali metal ions, organic cations, or combinations thereof, to adjust the electrical conductivity and mechanical properties of the ionic elastomer.

[0013] Furthermore, the photosensitizer is a compound with intersystem crossing capability and capable of triplet energy transfer to the luminescent agent, and the luminescent agent is an organic luminescent molecule capable of triplet-triplet annihilation and radiative transition. The types and doping ratios of the photosensitizer and luminescent agent can be selected and adjusted as needed to obtain a stable upconversion response and electrical signal output.

[0014] The present invention also provides a method for preparing the triplet-triplet annihilation upconversion ion elastomer, which includes the following steps:

[0015] S1. Pre-formation of ion-conducting matrix: Polyethylene glycol is mixed with lithium salt electrolyte and heated to melt, forming a uniform ion-conducting phase matrix;

[0016] S2. Preparation of TTA-UC active monomer: The photosensitizer and luminescent agent are dissolved in a volatile organic solvent, mixed and the solvent is removed to obtain a homogeneous blend solid; then acrylate monomers are added to the solid and heated and stirred until completely dissolved to form a monomer solution loaded with TTA-UC active molecules;

[0017] S3. Preparation of the stock solution and photocuring: The ion-conducting matrix obtained in step S1 is mixed with the TTA-UC active monomer solution obtained in step S2, a photoinitiator is added, and the mixture is heated and stirred to form a uniform TTA-UC ion elastomer stock solution; the stock solution is applied to the substrate or electrode surface, and in-situ free radical polymerization is initiated by ultraviolet light irradiation, and the mixture is cured into a film to obtain the triplet-triplet annihilation upconversion ion elastomer.

[0018] The preparation method constructs an ion-conducting phase and an optically active phase of a supported triplet-triplet annihilation upconversion system, respectively. Before polymerization, the ion-conducting phase and the optically active phase are mixed to form a stable homogeneous system. Subsequently, the optically active phase is fixed in the ion-conducting elastomer network by in-situ polymerization, thereby obtaining a structurally uniform and stable triplet-triplet annihilation upconversion ion elastomer.

[0019] This invention further provides the application of the triplet-triplet annihilation upconversion ion elastomer in flexible photoelectric sensors. By solidifying the ion elastomer onto the electrode surface to form a sensitive layer, photoresponse detection is achieved by measuring the electrical signal generated under photoexcitation conditions without external bias or with low bias.

[0020] Compared with existing technologies, this invention combines a triplet-triplet annihilation upconversion system with an ionic conductive elastomer, achieving direct output of electrical signals under low-energy photoexcitation conditions. This reduces the energy consumption of the device and has the potential for self-powered applications. Simultaneously, using an electrical signal for photoresponse readout effectively reduces ambient light interference and improves the signal-to-noise ratio compared to optical signal-based detection methods. Furthermore, thanks to the introduction of the ionic elastomer matrix, the resulting material exhibits excellent flexibility, stretchability, and deformation adaptability, making it suitable for wearable devices and flexible electronics applications. Moreover, the stepwise pre-assembly-in-situ integration polymerization method employed in this invention features mild process conditions and a simple process, facilitating large-area fabrication and the processing of complex-shaped devices. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating the structure and working principle of the TTA-UC ion elastomer photoelectric sensor of the present invention.

[0022] Figure 2 This is a schematic diagram of the molecular structure of the photosensitizer / luminescent agent pair and the energy level of the TTA-UC process in the TTA-UC ionic elastomer photoelectric sensor of the present invention.

[0023] Figure 3 The photocurrent response curves of the single-component TTA-UC ion elastomer photoelectric sensor and the TTA-UC system of the present invention are shown.

[0024] Figure 4 The photocurrent response curves of the TTA-UC ion elastomer photoelectric sensor of the present invention under different excitation light intensities are shown.

[0025] Figure 5 The photoelectric response curves of the TTA-UC ion elastomer photoelectric sensor of the present invention to excitation light of different wavelengths are shown.

[0026] Figure 6 The photoelectric response curve of the TTA-UC ion elastomer photoelectric sensor of the present invention under long-term light excitation is shown.

[0027] Figure 7 This is the photoelectric response curve of the TTA-UC ion elastomer photoelectric sensor of the present invention for glucose detection applications. Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto. Equivalent transformations or substitutions made by those skilled in the art without departing from the technical solution of the present invention should all fall within the scope of protection of the present invention.

[0029] like Figure 1The diagram shown illustrates the structure and working principle of the TTA-UC ion-elastomer photoelectric sensor of the present invention. The structure of the present invention includes: an electrode and a sensitive layer formed by an ion-elastomer solidified on the electrode surface. The ion-elastomer includes an ion-conductive elastomer matrix and a photosensitizer and a luminescent agent uniformly dispersed in the ion-conductive elastomer matrix. The photosensitizer and the luminescent agent constitute a triplet-triplet annihilation upconversion system, which can generate an upconversion response under specific wavelength light excitation conditions, and enable the ion-conductive elastomer to generate a measurable electrical signal output within itself or at the interface with the electrode.

[0030] like Figure 2 The diagram shows the molecular structure of the photosensitizer / luminescent agent pair and the TTA-UC process energy level diagram of the TTA-UC ionic elastomer photoelectric sensor selected in Example 1. The photosensitizer is a compound with intersystem crossing capability and capable of triplet energy transfer to the luminescent agent; the luminescent agent is an organic luminescent molecule capable of triplet-triplet annihilation and radiative transition.

[0031] Example 1: Fabrication of a TTA-UC ionic elastomer photoelectric sensor based on PdOEP photosensitizer / DPA luminescent agent.

[0032] First, weigh 2.2 g of polyethylene glycol-20000 (PEG-20000, used as a polymer matrix precursor and plasticizer) and 1.8 g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, lithium salt electrolyte) into a mortar and grind them thoroughly until they are homogeneous. Then, transfer the mixture to a container and heat it at 80 °C to melt it and form a transparent, viscous homogeneous system, thus obtaining an ion-conducting matrix.

[0033] Then take 75 μL of a concentration of 10 -3 A solution of tetraphenylporphyrin palladium (PdOEP, photosensitizer) at mol / L, and 1.5 mL of a 10 mol / L solution. -2 A solution of 9,10-diphenylanthracene (DPA, luminescent agent) in mol / L (solvent: tetrahydrofuran-THF) was mixed and heated at 80°C, with nitrogen purging or vacuum treatment to remove the solvent, to obtain a solid in which PdOEP and DPA were uniformly blended.

[0034] Add 0.67 g of ethyl acrylate (EA) and 0.67 g of hydroxyethyl acrylate (HEA) to the above solid, and stir and heat at 60°C until the solid is completely dissolved to form a homogeneous and clear triplet-triplet annihilation upconversion active monomer solution.

[0035] The active monomer solution was thoroughly mixed with the aforementioned ion-conducting matrix, and then the photoinitiator 2-hydroxy-2-methylphenylacetone was added at an amount of 3% of the total mass of the monomers in the system. The mixture was stirred and mixed under light-protected conditions to obtain a homogeneous, viscous triplet-triplet annihilation upconversion ion elastomer stock solution.

[0036] The above-mentioned stock solution is coated onto the pre-prepared electrode surface, and photo-initiated polymerization is carried out under ultraviolet light irradiation to solidify and form a flexible ion elastomer sensitive layer, thereby obtaining a flexible photoelectric sensor.

[0037] The performance of the obtained device was tested using a 532 nm continuous laser as the excitation source. Under photoexcitation conditions, the device was able to generate a stable electrical signal output, and the intensity of the electrical signal varied with the intensity of the excitation light, indicating that the ion-elastic material can be used for photoelectric detection.

[0038] according to Figure 3 The test results show that the TTA-UC system has a significantly stronger photoelectric signal response compared to a single luminescent molecule or a single photosensitive molecule, thus confirming that a significant photoelectric response signal can be provided in the TTA-UC process.

[0039] according to Figure 4 The test results show that as the intensity of the excitation light gradually increases, the intensity of the electrical signal response generated by the device under photoexcitation conditions changes accordingly, and there is a good linear correlation between the change in electrical signal and the intensity of the excitation light. This linear relationship is consistent with the second-order dynamic characteristics of the TTA-UC mechanism itself, further verifying its intrinsic photoelectric conversion mechanism.

[0040] according to Figure 5 The test results were obtained by using excitation light of different wavelengths to test the photoelectric response of the TTA-UC ion elastomer photoelectric sensor described in this invention. The results show that a significant photoelectric response signal can only be observed in wavelengths that meet the excitation conditions of the TTA-UC system, thus proving the selective response characteristics of the device to the excitation light wavelength.

[0041] Example 2: Photoelectric detection performance of ionotropic elastomers containing phenylboronic acid for glucose.

[0042] While keeping the triplet-triplet annihilation upconversion system composition, ionic elastomer matrix type, and preparation process unchanged in Example 1, phenylboronic acid was introduced as a functional additive into the ionic conductive elastomer to prepare a triplet-triplet annihilation upconversion ionic elastomer photoelectric sensor that is responsive to changes in the external chemical environment.

[0043] Specifically, in the precursor system of the ion-conductive matrix, phenylboronic acid is added to the polymer precursor mixing system according to a predetermined mass fraction, and it is fully dispersed by stirring and heating. Then, it is cured according to the in-situ polymerization method described in Example 1 to obtain a phenylboronic acid-containing ion elastomer photoelectric sensor with a uniform structure.

[0044] The obtained device was used in a glucose detection experiment. In the experiment, glucose solutions of different concentrations were prepared, and the device was placed under the same environmental conditions to sequentially contact each concentration of glucose solution. Under the same photoexcitation conditions, the electrical signals generated by the device were acquired and recorded in real time.

[0045] like Figure 7 Test results show that as the concentration of glucose in the environment gradually increases, the intensity of the electrical signal response generated by the device under photoexcitation conditions changes accordingly, and within a certain concentration range, there is a good linear correspondence between the change in electrical signal and the glucose concentration.

[0046] Further repeated tests showed that, as Figure 6 The linear response shown exhibits good stability and repeatability.

[0047] Furthermore, through multiple cyclic tests on the same device, it was found that its photoelectric response signal remained stable during multiple changes in glucose concentration, indicating that the triplet-tript annihilation upconversion ion elastomer photoelectric sensor containing phenylboronic acid has good response consistency and operational stability.

[0048] The above experimental results demonstrate that by introducing phenylboronic acid functional components into the ionic elastomer, the triplet-tript annihilation upconversion ionic elastomer of the present invention can not only realize the conversion of optical signals to electrical signals, but also be used for photoelectric detection of changes in glucose concentration, thus expanding its application scenarios in the field of chemical detection.

[0049] The triplet-triplet annihilation upconversion ion elastomer photoelectric sensor prepared by this invention, based on its flexibility, stretchability, and ability to stably generate electrical signal output under specific wavelength light excitation conditions, can be widely used in flexible photoelectric detection and related technical fields.

[0050] For example, in the field of wearable optoelectronic detection, the ion elastomer can be made into a flexible patch or thin film structure for detecting electrical signal response changes in light signals in biological materials, biomimetic tissues, or the environment, which is suitable for flexible sensing and signal acquisition scenarios.

[0051] In the field of robotics and electronic skin, the ionic elastomer can be integrated into a biomimetic sensing system as a flexible photoelectric sensitive unit to realize the sensing of electrical signals of changes in the external light environment, thereby expanding the application capabilities of electronic skin in multimodal sensing.

[0052] In the field of security and anti-counterfeiting, the material's selective electrical signal response to light excitation at specific wavelengths can be utilized to develop new anti-counterfeiting labels or secure communication devices based on electrical signal reading methods, thereby improving the reliability of anti-counterfeiting identification and information transmission.

[0053] Furthermore, in the fields of chemical detection and environmental monitoring, by introducing functional recognition components into ion-emulsifiers, photoelectric response detection of changes in the concentration of specific chemical substances can be achieved, which is applicable to chemical analysis, environmental monitoring and related sensing applications.

[0054] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An ion elastomeric optoelectronic sensor based on triplet-triplet annihilation upconversion, characterized in that, The sensor includes an electrode and a sensitive layer formed by an ion-conducting elastomer solidified on the electrode surface. The ion-conducting elastomer includes an ion-conducting elastomer matrix and a photosensitizer and a luminescent agent uniformly dispersed in the ion-conducting elastomer matrix. The photosensitizer and the luminescent agent constitute a triplet-triplet annihilation upconversion system, which can generate an upconversion response under specific wavelength light excitation conditions, and enable the ion-conducting elastomer to generate a measurable electrical signal output within itself or at the interface with the electrode.

2. The ion elastomeric optoelectronic sensor based on triplet-triplet annihilation upconversion according to claim 1, characterized in that, The ion-conductive elastomer matrix is ​​a polymer network that simultaneously possesses elastic deformation capability and ion conductivity at room temperature. It contains migratable ion carriers, thereby providing the basic conditions for the generation and transmission of electrical signals.

3. The ion elastomeric optoelectronic sensor based on triplet-triplet annihilation upconversion according to claim 2, characterized in that, The polymer network is formed from acrylate monomers that can be polymerized by free radicals, and the ion carriers include alkali metal ions, organic cations, or a combination of alkali metal ions and organic cations.

4. The ion elastomer photoelectric sensor based on triplet-triplet annihilation upconversion according to claim 1, characterized in that, The photosensitizer is a compound with intersystem crossing ability and capable of transferring triplet energy to the luminescent agent; the luminescent agent is an organic luminescent molecule capable of undergoing triplet-triplet annihilation and generating radiative transitions.

5. The ion elastomer photoelectric sensor based on triplet-triplet annihilation upconversion according to claim 4, characterized in that, The photosensitizer is a porphyrin or its metal complex, and the luminescent agent is an anthracene or tetraphenyl derivative.

6. The ion elastomer photoelectric sensor based on triplet-triplet annihilation upconversion according to claim 5, characterized in that, The photosensitizer is tetraphenylporphyrin palladium, and the luminescent agent is 9,10-diphenylanthracene.

7. A method of manufacturing an ion elastomeric photonic sensor based on triplet-triplet annihilation upconversion according to any one of claims 1 to 6, characterized in that, The method is as follows: A stepwise pre-assembly-in-situ integrated polymerization process was used to construct an ion-conducting phase and an optically active phase of a supported triplet-triplet annihilation upconversion system, respectively. Prior to polymerization, the ionicly conductive phase is mixed with the optically active phase to form a stable homogeneous system; Subsequently, the optically active phase was fixed in the ion-conducting elastomer network by in-situ polymerization, thereby obtaining a triplet-triptt annihilation upconversion ion elastomer with uniform structure and stable performance. Under specific wavelength light excitation conditions, the aforementioned ionic elastomer can generate a measurable electrical signal output, thereby realizing the conversion of optical signals into electrical signals.

8. The method of preparation of an ion elastomer optoelectronic sensor based on triplet-triplet annihilation upconversion according to claim 7, characterized in that, The specific steps of the method include: S1. Pre-formation of ion-conducting matrix: Polyethylene glycol is mixed with lithium salt electrolyte and heated to melt, forming a uniform ion-conducting phase matrix; S2. Preparation of TTA-UC active monomer: The photosensitizer and luminescent agent are dissolved in a volatile organic solvent, mixed and the solvent is removed to obtain a homogeneous blend solid; then acrylate monomers are added to the solid and heated and stirred until completely dissolved to form a monomer solution loaded with TTA-UC active molecules; S3. Preparation of the stock solution and photocuring: The ion-conductive matrix obtained in step S1 is mixed with the TTA-UC active monomer solution obtained in step S2, a photoinitiator is added, and the mixture is heated and stirred to form a uniform TTA-UC ion elastomer stock solution; the stock solution is applied to the substrate or electrode surface, and in-situ free radical polymerization is initiated by ultraviolet light irradiation, and the mixture is cured into a film to obtain the TTA-UC ion elastomer.

9. The method of claim 7, wherein the method further comprises: The in-situ polymerization is a free radical polymerization initiated by ultraviolet light.

10. Use of the ion elastomeric photodetector based on triplet-triplet annihilation upconversion according to claim 1 in photodetection, characterized in that, Photoresponse detection is achieved by measuring the electrical signal generated under photoexcitation conditions without external bias or with low bias.

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