Flexible photodetectors, optical integrated sensing-communication systems and their applications

Abstract

This application relates to the field of optoelectronic technology and discloses a flexible photodetector, an optical integrated sensing-communication system, and its applications. The flexible photodetector includes, from bottom to top, a flexible transparent substrate, a transparent electrode, an electron transport layer / hole transport layer, a photosensitive active layer, a hole transport layer / electron transport layer, and a top electrode. The photosensitive active layer includes an electron donor material and a composite electron acceptor material. The electron donor material is PCE-10 or P3HT. The composite electron acceptor material includes a main electron acceptor material and a reinforcing component. The main electron acceptor material is BTPSV-4F, and the reinforcing component is BTPSV-4Cl. The flexible photodetector of this application has a wide spectral detection capability of 300–1100 nm, covering a wide range of application scenarios; it has a high specific detectivity exceeding 10^13 Jones, enabling the detection of very weak light signals; and it possesses high response speed, high stability, and high reliability, achieving high-speed data transmission while sensing.

Description

Technical Field

[0001] This application relates to the field of optoelectronic technology, specifically to flexible photodetectors, optical integrated sensing-communication systems and applications. Background Technology

[0002] Integrated Communication and Sensing (ISAC) technology combines sensing and communication functions on a single platform. It fully shares the temporal and spatial resources of wireless communication and sensing, enabling the coexistence, mutual assistance, and shared benefits of both technologies. With the booming development of wearable electronics, the demand for devices with integrated communication and sensing capabilities has increased significantly.

[0003] Existing radio frequency (RF) integrated sensing and communication (ISAC) systems utilize RF signals for data transmission and sensing within specific frequency ranges (e.g., frequency range 1: 450–6000 MHz; frequency range 2: 24250–52600 MHz). However, they face several key challenges:

[0004] 1. Spectrum scarcity: With the proliferation of wireless devices, available spectrum resources are becoming increasingly scarce, limiting data transmission speed and system capacity.

[0005] 2. High power consumption: Traditional RF ISAC systems consume a lot of power during data transmission and sensing, which is particularly problematic in mobile and remote applications.

[0006] 3. Limited sensing capabilities: RF technology has limitations in sensing accuracy and range, especially in non-invasive vital sign monitoring.

[0007] The above-mentioned shortcomings limit the application of existing integrated sensing and communication (ISAC) systems in wearable devices.

[0008] Currently, high-performance near-infrared photodetectors with flexible characteristics possess advantages such as tunable spectrum and bandgap, solution-processability, and lightweight flexibility. They can detect human health signals and the surrounding environment through non-invasive detection methods, and have enormous applications in wearable devices, flexible robots, and implantable devices. Flexible near-infrared photodetectors are composed of organic semiconductor materials. By designing and fabricating organic semiconductor materials with specific spectral absorption, and constructing and optimizing devices, highly sensitive detection of light in any wavelength band can be achieved.

[0009] Therefore, developing a sensing-communication integrated system based on a flexible near-infrared photodetector to increase its spectral range and sensing capabilities, making it suitable for wearable electronics in non-invasive vital sign monitoring, is an effective strategy. Summary of the Invention

[0010] This application provides a flexible photodetector, an optical integrated sensing-communication system and its application, aiming to solve the problems of narrow spectrum range, poor sensing capability and high power consumption of existing integrated sensing-communication systems.

[0011] To achieve the above objectives, the present application adopts the following technical solution.

[0012] A first aspect of this application provides a flexible photodetector, comprising, from bottom to top, a flexible transparent substrate, a transparent electrode, an electron transport layer / hole transport layer, a photosensitive active layer, a hole transport layer / electron transport layer, and a top electrode; wherein the photosensitive active layer comprises an electron donor material and a composite electron acceptor material.

[0013] The electron donor material is PCE-10 or P3HT; the composite electron acceptor material includes a main electron acceptor material and a reinforcing component, wherein the main electron acceptor material is BTPSV-4F and the reinforcing component is BTPSV-4Cl.

[0014] In some embodiments, the mass ratio of the electron donor material to the electron acceptor material is (1:0.1) to (1:100); the amount of the reinforcing component accounts for 5 to 80 wt% of the mass of the composite electron acceptor material.

[0015] In some embodiments, the mass ratio of the electron donor material to the electron acceptor material is 1:1.5, and the amount of the reinforcing component accounts for 30 wt% of the mass of the composite electron acceptor material.

[0016] In some embodiments, the photosensitive active layer further includes additives;

[0017] The additive is at least one of 1,8-diiodooctane, chloronaphthalene, or nitrobenzene, and the mass of the additive is 0.01 to 50 wt% of the total mass of the electron donor and electron acceptor materials.

[0018] In some embodiments, the flexible transparent substrate is an inorganic flexible transparent material or an organic flexible transparent material;

[0019] The transparent electrode is a metal oxide, a metal thin film, an organic conductive material, or a conductive nanomaterial.

[0020] The electron transport layer is an N-type semiconductor with a low work function;

[0021] The hole transport layer is a high-power organic or inorganic semiconductor;

[0022] The top electrode is a metal thin film, a conductive polymer thin film, or a metal oxide conductive thin film.

[0023] In some embodiments, the flexible transparent substrate is glass or PET, the transparent electrode is ITO, the electron transport layer is zinc oxide, the hole transport layer is molybdenum oxide, and the top electrode is an Ag thin film.

[0024] A second aspect of this application provides the application of the aforementioned flexible photodetector in an optically integrated sensing-communication system.

[0025] A third aspect of this application provides an optical integrated sensing-communication system, including the aforementioned flexible photodetector, wherein each of its top electrodes includes a sensing electrode and a communication electrode that do not contact each other; wherein the thickness of the sensing electrode is (0.01 to 0.5) times the thickness of the communication electrode, and the area of ​​the sensing electrode is (5 to 100) times the area of ​​the communication electrode.

[0026] In some embodiments, the thickness of the sensing electrode is 0.06 times the thickness of the communication electrode; and the area of ​​the sensing electrode is 7.5 times the area of ​​the communication electrode.

[0027] The fourth aspect of this application is the application of the aforementioned optical integrated sensing-communication integrated system in wearable devices.

[0028] Compared with the prior art, the beneficial effects of this application are as follows:

[0029] The flexible photodetector of this application reduces the trapped states and energy disorder of the active layer by controlling the thin film morphology of the active layer, thereby improving the charge mobility and overall performance. It has a wide spectrum detection capability of 300-1100 nm, which can cover a wide range of application scenarios. It has a high specific detectivity of more than 10^13 Jones, which can detect very weak light signals and is suitable for low-light or long-distance sensing applications.

[0030] The flexible photodetector of this application has high response speed, high stability and reliability. In self-powered mode, the -3dB cutoff frequency exceeds 1MHz (λ=1050nm), which can meet the requirements of high-speed data transmission and communication. After repeated mechanical bending and long-term operation, it shows extremely low performance degradation (<0.1%), and has excellent mechanical stability and long-term operational reliability.

[0031] This application presents an optical integrated sensing-communication system that enables high-speed data transmission while sensing, providing a highly efficient, sensitive, and fast-response optoelectronic detection and sensing-communication integrated solution. It is self-powered, capable of operating under ambient light, sunlight, and NIR illumination conditions without an external power source, significantly reducing system energy consumption and exhibiting excellent adaptability. It can be attached to skin or other irregular surfaces, making it suitable for wearable devices and portable systems. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 A schematic diagram of a flexible photodetector with a reverse structure;

[0034] Figure 2 A schematic diagram of a flexible photodetector with a forward-facing structure;

[0035] Figure 3 This is a schematic diagram of an optical integrated sensing-communication system.

[0036] Figure 4 The spectrum-responsivity curve of a flexible photodetector with a reverse structure;

[0037] Figure 5 Dark current density test diagram for a flexible photodetector with an inverted structure;

[0038] Figure 6 Spectral-specific detectivity test plot for a flexible photodetector with an inverted structure;

[0039] Figure 7 The response speed test diagram of the flexible photodetector with a reverse structure;

[0040] Figure 8 Cutoff frequency test diagram for a flexible photodetector with a reverse structure;

[0041] Figure 9 This is a spectral-response curve of an optically integrated sensing-communication system. Detailed Implementation

[0042] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0043] In the following description of this embodiment, the terms "including", "comprising", "having", and "containing" are all open-ended terms, meaning that they include but are not limited to.

[0044] In the following description of this embodiment, the term "and / or" is used to describe the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, B existing alone, and A and B existing simultaneously. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0045] In the following description of this embodiment, the term "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0046] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0047] Those skilled in the art should understand that, in the following description of the embodiments of this application, the sequence of numbers does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0048] Those skilled in the art will understand that the numerical ranges in the embodiments of this application should be understood as each intermediate value between the upper and lower limits of the specifically disclosed range. Each smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this application. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0049] Unless otherwise stated, the technical / scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. While this application describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this application. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0050] Firstly, this application provides a flexible photodetector, which has a reverse structure or a forward structure, as shown in the schematic diagrams below. Figure 1 and Figure 2 As shown.

[0051] like Figure 1 As shown, the flexible photodetector with a reverse structure includes, from bottom to top, a flexible transparent substrate, a transparent electrode, an electron transport layer, a photosensitive active layer, a hole transport layer, and a top electrode.

[0052] like Figure 2 As shown, the flexible photodetector with a forward structure includes, from bottom to top, a flexible transparent substrate, a transparent electrode, a hole transport layer, a photosensitive active layer, an electron transport layer, and a top electrode.

[0053] The photosensitive active layer comprises an electron donor material and a composite electron acceptor material; the electron donor material is a polymer or small molecule with a high HOMO energy level, such as PCE-10 or P3HT; the composite electron acceptor material comprises various narrow bandgap organic small molecules. This application reduces trapped states and energy disorder in the active layer by controlling the film morphology of the photosensitive active layer, thereby improving charge mobility and overall performance.

[0054] In the embodiments of this application, the electron donor material is preferably PCE-10; the composite electron acceptor material includes a main electron acceptor material and a reinforcing component, wherein the main electron acceptor material is BTPSV-4F; and the reinforcing component is BTPSV-4Cl. The mass ratio of the electron donor material to the electron acceptor material is (1:0.1) to (1:100), preferably 1:1.5; the amount of the reinforcing component accounts for 5 to 80 wt% of the mass of the composite electron acceptor material, preferably 30 wt%. Within this ratio range, a flexible photodetector with high response speed, high stability, and high reliability can be fabricated.

[0055] The structure of the photosensitive active layer is a hybrid thin film obtained by blending electron donor and electron acceptor materials, or a bilayer / multilayer structure prepared layer by layer of electron donor and electron acceptor materials. Preferably, the photosensitive active layer in this application is a blended thin film, prepared by spin coating, blade coating, printing, or spraying, with a thickness ranging from 1 nm to 500 nm. In an embodiment of this application, the photosensitive active layer is prepared by spin coating, with a thickness of 130 nm. After obtaining the photosensitive active layer, it needs to undergo post-processing, such as heat annealing, vacuum treatment, and solvent annealing. Heat annealing is preferably used for the photosensitive active layer, with an annealing temperature of 25°C to 180°C and an annealing time of 1 min to 40 min. In an embodiment of this application, the preferred annealing temperature is 120°C and the annealing time is 20 min.

[0056] As a preferred embodiment, the photosensitive active layer further comprises an additive. The additive may be 1,8-diiodooctane, chloronaphthalene, or nitrobenzene, preferably chloronaphthalene; the mass of the additive is 0.01% to 50 wt% of the total mass of the electron donor and electron acceptor materials, preferably 5%.

[0057] The flexible transparent substrate can be made of inorganic flexible transparent materials, such as glass or quartz; or it can be made of organic flexible transparent materials, such as polyethylene terephthalate (PET), polyimide (PI), polydimethylsiloxane (PDMS), linear triblock copolymer (SEBS), polymethyl methacrylate (PMMA), polyethylene naphthalate (PEN), etc. In the embodiments of this application, glass or PET is preferred as the flexible transparent substrate.

[0058] The transparent electrode can be made of metal oxides, metal thin films, organic conductive materials, or conductive nanomaterials; such as at least one of indium tin oxide (ITO), graphene thin films, silver nanowire thin films, silver nanoparticle meshes, carbon nanotube thin films, MXene, and poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate; preferably, the transparent electrode material is ITO. The transparent electrode of this application can be prepared by methods such as vapor deposition, printing, physical etching, and chemical etching, preferably by physical etching.

[0059] The electron transport layer is selected from N-type semiconductors with low work function, which can be organic or inorganic semiconductors. Specifically, the electron transport layer can be zinc oxide, tin dioxide, lithium fluoride, cesium fluoride, calcium fluoride, potassium fluoride, cesium carbonate, N,N'-bis[3-(dimethylamino)propyl]perylene-3,4,9,10-tetracarboxylic acid diimide (PDIN), PDINO, or poly(9,9-bis(3'-(N,N-dimethyl)-N-ethylaminopropyl-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)) dibromide (PFN-Br). Zinc oxide is preferred as the electron transport layer.

[0060] The hole transport layer is a high-work-function organic or inorganic semiconductor, such as molybdenum oxide, nickel oxide, poly(3,4-ethylenedioxythiophene) / polystyrene sulfonate (PSS:PEDOT), etc., with molybdenum oxide being the preferred hole transport layer.

[0061] The top electrode is a metal thin film, a conductive polymer thin film, or a metal oxide conductive thin film, including but not limited to gold, silver, aluminum, PSS:PEDOT, indium tin oxide (ITO), silver nanowire thin films, and silver nanomesh; the thickness of the top electrode is preferably 1–300 nm, and it can be prepared by vapor deposition, blade coating, screen printing, or printing. In this application, Ag is preferably used as the top electrode material, and vacuum vapor deposition is preferred.

[0062] The flexible photodetector fabricated in this application possesses a broad spectral detection capability of 300–1100 nm, covering a wide range of application scenarios. It exhibits a high specific detectivity exceeding 10^13 Jones, enabling the detection of very weak light signals, making it suitable for low-light or long-distance sensing applications. Furthermore, it demonstrates high response speed, high stability, and high reliability, with a -3dB cutoff frequency exceeding 1MHz (λ = 1050nm) in self-powered mode, meeting the requirements of high-speed data transmission and communication. After repeated mechanical bending and prolonged operation, it exhibits extremely low performance degradation (<0.1%), demonstrating excellent mechanical stability and long-term operational reliability. The flexible photodetector fabricated in this application is suitable for optically integrated sensing-communication systems.

[0063] This application also provides an optical integrated sensing-communication system, the structure of which is as follows: Figure 3 As shown, it includes the aforementioned flexible photodetector, wherein the top electrode of the flexible photodetector includes a sensing electrode and a communication electrode that do not contact each other. The passage between the transparent electrode and the sensing electrode forms a sensor device, while the passage between the transparent electrode and the communication electrode forms a communication device. This application integrates the sensor device and the communication device on the same flexible transparent substrate, thereby obtaining an optically integrated sensing-communication system. In this application, the sensing electrode and the communication electrode can also be etched on the transparent electrode, with the passage between the sensing electrode of the transparent electrode and the sensing electrode of the top electrode forming the sensor device, and the passage between the communication electrode of the transparent electrode and the communication electrode of the top electrode forming the communication device.

[0064] The sensing electrode has a small thickness and a large area to facilitate signal collection; while the communication electrode has a large thickness and a small area to facilitate rapid communication. Preferably, the thickness of the sensing electrode is (0.01 to 0.5) times the thickness of the communication electrode, and the area of ​​the sensing electrode is (5 to 100) times the area of ​​the communication electrode. Particularly preferred is that the thickness of the sensing electrode is 0.06 times the thickness of the communication electrode, and the area of ​​the sensing electrode is 7.5 times the area of ​​the communication electrode.

[0065] The optical integrated sensing-communication system of this application is self-powered and can operate under ambient light, sunlight and NIR illumination conditions without external power supply, which greatly reduces the system's energy consumption and has good adaptability; it can be attached to the skin or other irregular surfaces and is suitable for wearable devices and portable systems.

[0066] The present application will be further illustrated by the following examples.

[0067] Example 1

[0068] This embodiment provides a flexible photodetector with a reverse structure, comprising a flexible transparent substrate, a transparent electrode, an electron transport layer, a photosensitive active layer, a hole transport layer, and a top electrode; wherein the transparent substrate is glass, the transparent electrode is ITO, the electron transport layer is zinc oxide, the photosensitive active layer material is a blend of PCE-10, BTPSV-4F, and BTPSV-4Cl, the hole transport layer is MoOx, and the top electrode is silver. Its fabrication method includes:

[0069] S1. The glass substrate coated with the ITO conductive layer was cleaned sequentially with acetone, deionized water and isopropanol, and then dried with nitrogen. The glass substrate was then treated with ultraviolet ozone for 15 minutes to improve its surface hydrophilicity.

[0070] S2. Dissolve 100 mg of zinc acetate in 10 mL of 2-methoxyethanol and add 100 μg of ethanolamine to obtain a zinc oxide precursor solution; spin-coat the zinc oxide precursor solution onto the ITO surface at 2000 rpm for 40 s; then transfer the glass substrate to air and anneal at 200 °C for 1 h to obtain an electron transport layer;

[0071] S3, spin-coat PFN-Br on the surface of the electron transport layer at a speed of 3000 rpm for 50 s;

[0072] S4, a mixture of PCE-10, BTPSV-4F, and BTPSV-4Cl was dissolved in chloroform at a mass ratio of 1:1.5, and 5% CN was added to the solvent to obtain an active solution with a concentration of 20 mg / mL, wherein BTPSV-4Cl accounted for 30% of the total mass of the mixture. The active solution was spin-coated onto the surface of the PFN-Br interface layer at a spin speed of 1000 rpm and a spin time of 1 min. Subsequently, it was thermally annealed at 120 °C for 20 min using a constant temperature hot stage to obtain a photosensitive active layer with a thickness of 130 nm.

[0073] S5. MoOx is vacuum-deposited on the surface of the photosensitive active layer at a pressure of 10-4 Pa to obtain a hole transport layer with a thickness of 5 nm.

[0074] S6. Vacuum evaporation of Ag is performed on the surface of the hole transport layer at a pressure of 10⁻⁴ Pa to obtain a top electrode with a thickness of 150 nm.

[0075] Example 2

[0076] This embodiment provides a flexible photodetector with a forward structure, comprising a flexible transparent substrate, a transparent electrode, a hole transport layer, a photosensitive active layer, an electron transport layer, and a top electrode; wherein the transparent substrate is glass, the transparent electrode is ITO, the hole transport layer is PSS:PEDOT, the photosensitive active layer material is a blend of PCE-10, BTPSV-4F, and BTPSV-4Cl, the electron transport layer is PDINN, and the top electrode is silver. Its fabrication method includes:

[0077] S1. The glass substrate coated with the ITO conductive layer was cleaned sequentially with acetone, deionized water and isopropanol, and then dried with nitrogen. The glass substrate was then treated with ultraviolet ozone for 15 minutes to improve its surface hydrophilicity.

[0078] S2. The PSS:PEDOT solution was spin-coated onto the ITO surface at a speed of 2000 rpm for 40 s; then the glass substrate was moved into the air and annealed at 160 °C for 1 h to obtain the hole transport layer.

[0079] S3, a mixture of PCE-10, BTPSV-4F, and BTPSV-4Cl was dissolved in chloroform at a mass ratio of 1:1.5, and 5% CN was added to the solvent to obtain an active solution with a concentration of 20 mg / mL, wherein BTPSV-4Cl accounted for 30% of the total mass of the mixture. Subsequently, it was thermally annealed at 120 °C for 20 min using a constant temperature hot stage to obtain a photosensitive active layer with a thickness of 130 nm.

[0080] S4. Dissolve 2 mg of PDINN in 10 mL of methanol to prepare a PDINN solution; spin-coat the PDINN solution onto the surface of the photosensitive active layer at a spin speed of 2000 rpm and a spin time of 1 min to obtain an electron transport layer.

[0081] S5. Ag is vacuum-deposited on the surface of the electron transport layer at a pressure of 10⁻⁴ Pa to obtain a top electrode with a thickness of 150 nm.

[0082] Example 3

[0083] This embodiment provides an integrated optical sensing-communication system, including a flexible transparent substrate, a transparent electrode, an electron transport layer, a photosensitive active layer, a hole transport layer, and a top electrode. The transparent electrode and the top electrode each include unconnected sensing and communication electrodes. The transparent substrate is PET, the transparent electrode is ITO, the electron transport layer is zinc oxide, the photosensitive active layer material is a blend of PCE-10, BTPSV-4F, and BTPSV-4Cl, the hole transport layer is MoOx, and the top electrode is silver. Its preparation method includes:

[0084] S1, prepared size 1.7×1.7cm 2 The PET substrate with an ITO conductive layer was used to remove part of the ITO conductive layer on the PET substrate using laser etching technology, dividing the ITO into two regions: sensing electrode and communication electrode. The PET / ITO substrate was then cleaned with ethanol solvent.

[0085] S2. A 30 mg / mL ZnO nanoparticle methanol solution was spin-coated onto a clean ITO surface at a spin speed of 4000 rpm for 20 s, and then annealed at 150 °C for 20 min to obtain an electron transport layer.

[0086] S3, spin-coat PFN-Br on the surface of the electron transport layer at a speed of 3000 rpm for 50 s;

[0087] S4, a mixture of PCE-10, BTPSV-4F, and BTPSV-4Cl was dissolved in chloroform at a mass ratio of 1:1.5, and 5% CN was added to the solvent to obtain an active solution with a concentration of 20 mg / mL, wherein BTPSV-4Cl accounted for 30% of the total mass of the mixture. The active solution was spin-coated onto the surface of the PFN-Br interface layer at a spin speed of 1000 rpm and a spin time of 1 min. Subsequently, it was thermally annealed at 120 °C for 20 min using a constant temperature hot stage to obtain a photosensitive active layer with a thickness of 130 nm.

[0088] S5. MoOx is vacuum-deposited on the surface of the photosensitive active layer at a pressure of 4 Pa ​​to obtain a hole transport layer with a thickness of 5 nm.

[0089] S6. A photomask is placed over the hole transport layer, and sensing and communication electrodes are deposited by vapor deposition to obtain an optically integrated sensing-communication system. The sensing electrodes have a thickness of 6 nm and an effective area of ​​0.1688 cm². 2 The communication electrode has a thickness of 100 nm and an effective area of ​​0.0225 cm². 2 .

[0090] The performance of the flexible photodetector with the reverse structure prepared in Example 1 was tested, as follows:

[0091] 1. Spectral response testing: The test wavelength range is 300–1100 nm, and the test bias voltage is 0V. The resulting spectrum-response curve of the device is shown below. Figure 4 As shown. From Figure 4 It can be seen that the flexible photodetector with the reverse structure exhibits a responsivity of up to 0.48 A / W in the near-infrared region at 0V; at the same time, the responsivity at 1000nm still exceeds 0.2 A / W, which can meet the requirements of near-infrared testing.

[0092] 2. Dark current density test: The test temperature is 25℃, the test bias range is -1V to 1V, the sampling interval is 10mV, and the scanning method is reverse scanning. The resulting dark current density test graph of the device is shown below. Figure 5 As shown. From Figure 5 It can be seen that the reverse-structure flexible photodetector has a dark current density as low as 0.17 nA / cm2 at 0V, and still has a dark current density as low as nanoamperes at -1V, indicating that the organic photodetector has achieved effective suppression of dark current.

[0093] 3. Based on the data obtained from spectral response testing and dark current density testing, the specific detectivity of the flexible photodetector with a reverse structure in the 300–1100 nm range is calculated when the bias voltage is 0V. The resulting spectral-specific detectivity test pattern is shown below. Figure 6 As shown, at 0V, the specific detectivity exceeds 10^13 Jones in both the visible and near-infrared regions, indicating that the photoelectric performance of this organic photodetector is significantly improved across the entire response band.

[0094] 4. Response speed test: The test temperature was 25℃, the test laser was 940nm, and the test bias voltage was 0V. The resulting device response speed test graph is shown below. Figure 7 As shown, the flexible photodetector with a reverse structure exhibits nanosecond-level response and recovery times in its response time curve under 940nm near-infrared light at 0V, demonstrating extremely fast response speed.

[0095] 5. Cutoff frequency test: The test temperature was 25℃, the test laser was 1050nm, and the test bias voltage was 0V. The cutoff frequency test result is shown in the figure below. Figure 8 As shown, the flexible photodetector with a reverse structure exhibits a cutoff frequency exceeding 1 MHz in the 1050 nm near-infrared light cutoff frequency diagram at 0 V.

[0096] The spectral response of the optical integrated sensing-communication system prepared in Example 3 was tested in the wavelength range of 300–1100 nm with a bias voltage of 0 V. The resulting spectrum-response curve is shown below. Figure 9 As shown. By Figure 9 It can be seen that at 0V, the sensor and communication devices included in the optical integrated sensing-communication system have a responsivity of more than 0.2A / W in the near-infrared region, and the responsivity at 1000nm still exceeds 0.1A / W, which can meet the near-infrared testing requirements.

[0097] Although this application has been described in detail in this specification with general descriptions and specific embodiments, some modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, such modifications or improvements made without departing from the spirit of this application are all within the scope of protection claimed in this application.

Claims

1. A flexible photodetector, characterized in that, The device comprises, from bottom to top, a flexible transparent substrate, a transparent electrode, an electron transport layer / hole transport layer, a photosensitive active layer, a hole transport layer / electron transport layer, and a top electrode; the photosensitive active layer comprises an electron donor material and a composite electron acceptor material. The electron donor material is PCE-10 or P3HT; the composite electron acceptor material includes a main electron acceptor material and a reinforcing component, wherein the main electron acceptor material is BTPSV-4F and the reinforcing component is BTPSV-4Cl.

2. The flexible photodetector according to claim 1, characterized in that, The mass ratio of the electron donor material to the electron acceptor material is (1:0.1) to (1:100); the amount of the reinforcing component accounts for 5% to 80% of the mass of the composite electron acceptor material.

3. The flexible photodetector according to claim 2, characterized in that, The mass ratio of the electron donor material to the electron acceptor material is 1:1.5, and the amount of the reinforcing component accounts for 30% of the mass of the composite electron acceptor material.

4. The flexible photodetector according to claim 1, characterized in that, The photosensitive active layer also includes additives; The additive is at least one of 1,8-diiodooctane, chloronaphthalene, or nitrobenzene, and the mass of the additive is 0.01 to 50 wt% of the total mass of the electron donor and electron acceptor materials.

5. The flexible photodetector according to claim 1, characterized in that, The flexible transparent substrate is an inorganic flexible transparent material or an organic flexible transparent material; The transparent electrode is a metal oxide, a metal thin film, an organic conductive material, or a conductive nanomaterial. The electron transport layer is an N-type semiconductor with a low work function; The hole transport layer is a high-power organic or inorganic semiconductor; The top electrode is a metal thin film, a conductive polymer thin film, or a metal oxide conductive thin film.

6. The flexible photodetector according to claim 5, characterized in that, The flexible transparent substrate is glass or PET, the transparent electrode is ITO, the electron transport layer is zinc oxide, the hole transport layer is molybdenum oxide, and the top electrode is an Ag thin film.

7. The application of the flexible photodetector according to any one of claims 1-6 in an optically integrated sensing-communication system.

8. An optically integrated sensing-communication system, comprising the flexible photodetector according to any one of claims 1-6, characterized in that, Its top electrode includes a sensing electrode and a communication electrode that do not contact each other; wherein the thickness of the sensing electrode is (0.01 to 0.5) times the thickness of the communication electrode, and the area of ​​the sensing electrode is (5 to 100) times the area of ​​the communication electrode.

9. The optical integrated sensing-communication integrated system according to claim 8, characterized in that, The thickness of the sensing electrode is 0.06 times the thickness of the communication electrode; the area of ​​the sensing electrode is 7.5 times the area of ​​the communication electrode.

10. The application of the optical integrated sensing-communication system as described in claim 8 or 9 in wearable devices.

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