AgBiS2 / Ag2S bulk heterojunction dynamic-static dual-mode photoelectric sensor device and preparation method thereof

Abstract

The application provides an AgBiS2 / Ag2S bulk heterojunction dynamic and static dual-mode photoelectric sensor device and a preparation method thereof, the material is green and environmentally friendly, the process is simple and low-temperature, the intrinsic difference of carrier generation, transport and recombination kinetics of two component materials in the AgBiS2 / Ag2S bulk heterojunction under different wavelengths is utilized, the transient light response mode of the 320-1122 nm wave band is realized for static imaging, the relaxation light response mode of the 1342 nm and above wave band is realized for dynamic sensing, the device working mode is determined by the incident light wavelength; that is to say, the dynamic and static dual-mode is realized based on the intrinsic characteristics of the material, an external switching circuit is not needed, the problem that the prior art depends on external circuit switching or complex structure design is fundamentally solved, and the system complexity and power consumption are significantly reduced.

Description

Technical Field

[0001] This invention belongs to the field of optoelectronic sensing technology, and particularly relates to an AgBiS2 / Ag2S bulk heterojunction dynamic and static dual-mode optoelectronic sensor and its preparation method. Background Technology

[0002] As a core component of next-generation machine vision, dual-mode photoelectric sensors enable the collaborative perception of both static and dynamic scene information, playing an irreplaceable role in cutting-edge fields such as autonomous driving, embodied intelligence, industrial inspection, and human-machine interaction. In autonomous driving, they need to accurately identify traffic signs and lane lines while simultaneously capturing the trajectories of pedestrians or moving vehicles in real time. In embodied intelligence systems, they must perceive the layout of static objects in the environment while tracking the motion of target objects. In industrial automation, they need to simultaneously record the static layout of production lines and monitor the rapid movements of robotic arms. Furthermore, dual-mode sensing technology also demonstrates significant application value in security monitoring, intelligent transportation, and medical imaging diagnosis, serving as a key technological path to achieving highly robust visual perception in complex environments.

[0003] However, most existing optoelectronic sensors are single-function devices, making it difficult to simultaneously achieve dual-mode functionality of static imaging and dynamic sensing within the same device architecture. Currently, mainstream technologies for achieving dual-mode dynamic and static sensing often rely on external control strategies or complex multi-structure integration. On the one hand, researchers have attempted to achieve dual-function switching through circuit switching. For example, the University of Science and Technology of China developed an InGaN nanowire / hydrogel heterojunction dual-function visual sensor, which achieves dynamic and static fusion sensing by switching between photosynaptic and photodetector modes through open / closed-circuit switching. However, this device relies on III-V epitaxial processes, resulting in high fabrication costs, and faces process compatibility challenges with monolithic integration with silicon-based readout circuits, making it difficult to meet the application requirements of low-cost, large-scale array integration. On the other hand, the academic community is also exploring multi-functional integration through complex device structures. For example, the Institute of Metal Research, Chinese Academy of Sciences, proposed a charge-coupled phototransistor, employing a dual photocapacitor gate structure and utilizing the dielectric layer electron shielding / tunneling effect to achieve static image acquisition and dynamic event detection with a single transistor. The measured dynamic range is 120 dB, the response is 15 μs, and the power consumption is one-thousandth that of traditional transistors. However, relying on precise gate stacking structure design, devices currently built based on two-dimensional materials or carbon nanotubes still need improvement in terms of stability and large-area uniformity. The complex device structure places stringent requirements on process precision, increasing the difficulty and cost of fabrication. In recent years, although two-dimensional materials have shown potential in optoelectronic devices, their atomic-level thickness leads to limited light absorption efficiency, and challenges in large-area uniform fabrication and compatibility with CMOS processes have not been fully resolved. In addition, wavelength-selective dual-mode detection has become a research hotspot. Some studies have achieved broadband and narrowband dual-mode responses based on GaAs / MoS2 / rare-earth-doped upconversion heterojunctions, but these rely on rare-earth materials and epitaxial processes. Other studies have built wavelength-switching bipolar detectors based on heterostructures such as CdSe / Bi2Te3 to achieve opposite photocurrent polarities for encrypted communication, but this relies on the precise design of dual built-in electric fields and involves the toxic element cadmium. Meanwhile, although perovskite materials have excellent performance in the field of optoelectronic detection, the toxicity of lead-based perovskites and the environmental instability of halogen perovskites have long constrained their practical application and industrialization.

[0004] The existing technology has the following main drawbacks:

[0005] 1. Existing dynamic and static dual-mode sensing technology based on external circuit control uses InGaN nanowires / hydrogels and other material systems, which have high manufacturing costs, are difficult to integrate with silicon-based readout circuits on a single chip, and require additional control circuits, increasing system complexity and power consumption.

[0006] 2. Existing dynamic and static dual-mode integration technology based on complex device structures adopts architectures such as charge-coupled phototransistors, relies on precision gate stacking and two-dimensional materials for construction, the stability and uniformity of materials need to be improved, the process requirements are stringent, integration is not easy, and the manufacturing cost is high.

[0007] 3. Existing wavelength-selective dual-mode detection technologies employ materials such as GaAs / MoS2 / rare-earth-doped upconversion heterojunctions, FTO / CdSe / Bi2Te3, and perovskites. These technologies rely on rare-earth doping, epitaxial processes, or precise bandgap design. Furthermore, some of these systems involve complex processes, poor stability, and the use of toxic elements, which contradicts China's RoHS regulations regarding limits on hazardous substances such as lead and cadmium (cadmium ≤ 0.01%, lead ≤ 0.1%). Consequently, these technologies struggle to meet the environmental access requirements and large-scale application needs of green electronic products.

[0008] Therefore, selecting suitable intrinsic functional semiconductor materials and developing a novel optoelectronic sensor that can achieve wavelength-selective dynamic and static dual-mode sensing without external switching based on the intrinsic properties of the materials has important theoretical significance and broad application prospects. Summary of the Invention

[0009] To address the aforementioned issues, this invention provides an AgBiS2 / Ag2S bulk heterojunction dynamic-static dual-mode optoelectronic sensor and its fabrication method. The material is green and environmentally friendly, and the process is simple and low-temperature. It can achieve large-area array integration and dynamic-static fusion imaging applications, and can also achieve wavelength decoupled dynamic-static dual-mode imaging in the ultraviolet to near-infrared bands.

[0010] An AgBiS2 / Ag2S bulk heterojunction dynamic and static dual-mode photoelectric sensor device, from bottom to top, consists of a substrate (1), a thin film transistor array (2), a photosensitive material layer (3), a hole transport layer (4), a top electrode layer (5), and an encapsulation layer (6); wherein, the photosensitive material layer (3) is composed of AgBiS2 / Ag2S material; The light signal is transmitted sequentially from the substrate (1) and the thin film transistor array (2) to the photosensitive material layer (3). When the light signal is in the static imaging band, the AgBiS2 in the photosensitive material layer (3) mainly generates photogenerated carriers under the irradiation of the light signal. At this time, the imaging on the TFT photoelectric sensor chip composed of multiple photoelectric sensors prepared on the TFT backplane is a static imaging that disappears instantaneously as the light signal disappears. When the light signal is in the dynamic imaging band, its energy is too low to excite AgBiS2 to generate a response. Ag2S will undergo defect ionization under illumination, and this ionized state needs a period of time to recover to the ground state, which increases the carrier recombination time and thus produces photoconductive relaxation. At this time, the imaging on the TFT photoelectric sensor chip disappears slowly as the light signal disappears, thus being able to record the motion trajectory of moving objects and having dynamic sensing characteristics.

[0011] Furthermore, the static imaging band is the 320nm-1122nm band; the dynamic imaging band is the 1342nm and above band.

[0012] Furthermore, the hole transport layer (4) is composed of PTAA [poly(4-phenyl)(2,4,6-trimethylphenyl)amine].

[0013] Furthermore, the top electrode layer (5) is composed of a MoO3 layer and an Au electrode layer deposited sequentially.

[0014] Furthermore, the encapsulation layer (6) is composed of a Parylene layer and a UV electronic adhesive layer.

[0015] Furthermore, the thin-film transistor array (2) is equipped with a back-end array reading system, which is used to read the current signal collected on the TFT photoelectric sensor chip and finally transmit the current signal wirelessly to form an image on the terminal APP.

[0016] A method for fabricating a dual-mode (dynamic and static) photoelectric sensor device using an AgBiS2 / Ag2S bulk heterojunction includes the following steps: S1: Provides transparent thin-film transistor chips; S2: Cleaning thin-film transistor chips; S3: Place the thin-film transistor chip in a thermal evaporation coating machine to deposit silver; S4: Place the thin-film transistor chip with silver material into a plasma cleaner to bombard and oxidize it into silver oxide, thus obtaining a silver oxide seed layer; S5: Spin-coat the AgBiS2 / Ag2S precursor solution onto the silver oxide seed layer; S6: Place the chip spin-coated with AgBiS2 / Ag2S precursor solution in a glove box and heat it; S7: Spin-coat the PTAA solution onto the thin-film transistor chip containing AgBiS2 / Ag2S material; S8: Place the thin-film transistor chip coated with PTAA layer into a thermal evaporation coating machine to evaporate MoO3 layer and Au electrode layer to form top electrode layer; S9: Place the thin-film transistor chip with the top electrode layer into a Parylene coating machine to coat it with Parylene film for encapsulation; S10: Apply UV electronic adhesive to the surface of the thin-film transistor chip encapsulated with Parylene film and cure it with a UV flashlight.

[0017] Further, the preparation method of the AgBiS2 / Ag2S material precursor solution in step S5 is as follows: weigh AgCl, BiCl3, and thiourea and dissolve them in N,N-dimethylformamide solution, so that the molar ratio of AgCl to BiCl3 is 6:4~9:1, and stir to mix them evenly.

[0018] Furthermore, during the chip fabrication process, steps S5 and S6, namely the spin-coating-heating process, need to be repeated 1 to 5 times to form a uniform and dense AgBiS2 / Ag2S material before proceeding to step S7.

[0019] Beneficial effects: 1. This invention provides a dual-mode photoelectric sensor device with AgBiS2 / Ag2S bulk heterojunction. Utilizing the intrinsic differences in carrier generation, transport, and recombination dynamics between the two components of the AgBiS2 / Ag2S bulk heterojunction at different wavelengths, it achieves spontaneous switching between a transient optical response mode in the 320-1122 nm band for static imaging and a relaxation optical response mode in the 1342 nm and above band for dynamic sensing. The device's operating mode is autonomously determined by the incident light wavelength. In other words, this invention achieves dual-mode operation based on the intrinsic properties of the materials, eliminating the need for external switching circuits. This fundamentally solves the problem of existing technologies relying on external circuit switching or complex structural designs, significantly reducing system complexity and power consumption.

[0020] 2. This invention provides an AgBiS2 / Ag2S bulk heterojunction dynamic and static dual-mode photoelectric sensor. The photosensitive material layer is made of environmentally friendly AgBiS2 / Ag2S material, which does not contain toxic elements such as lead and cadmium. It is prepared by a low-temperature solution method, which meets environmental protection requirements. At the same time, the photoelectric sensor does not require complex epitaxial processes during its preparation and can be directly integrated on the TFT backplane, overcoming the disadvantages of high preparation cost and difficulty in integration with readout circuits in the prior art.

[0021] 3. This invention provides a method for fabricating a dynamic-static dual-mode photoelectric sensor device based on the low-temperature solution processability of AgBiS2 / Ag2S materials. The device array can be directly fabricated on a 64×64 array TFT backplane to form a TFT photoelectric sensor chip. The imaging system built on this basis can carry out dynamic-static fusion imaging simulation and dynamic-static fusion imaging control application verification, meet the needs of practical applications, and overcome the limitations of the existing technology in terms of small array size and difficulty in practical application. Attached Figure Description

[0022] Figure 1 This is a simplified structural diagram of the AgBiS2 / Ag2S bulk heterojunction dynamic-static dual-mode photoelectric sensor in an embodiment of the present invention.

[0023] Figure 2A The EPR (electron paramagnetic resonance) characterization of AgBiS2 / Ag2S materials at 520 nm is shown in the embodiments of the present invention.

[0024] Figure 2B EPR characterization of AgBiS2 / Ag2S material at 1450 nm in this embodiment of the invention.

[0025] Figure 2C The single-point device prepared by AgBiS2 / Ag2S material before array integration in this embodiment of the invention has a structure of ITO / photosensitive material (AgBiS2 / Ag2S material) / PTAA / MoO3 / Au. The basic phenomenon of the It curve was tested under illumination of 520 nm and 1550 nm.

[0026] Figure 3 The illustration shows the HRTEM characterization (inset) and SIMS test results of the AgBiS2 / Ag2S material in the embodiments of the present invention.

[0027] Figure 4 The above figures show the photocurrent over time curves of the first pixel in the AgBiS2 / Ag2S bulk heterojunction dynamic-static dual-mode optoelectronic sensor array before integration at wavelengths of 405 nm, 520 nm, 635 nm, 808 nm, 1060 nm, 1122 nm, 1342 nm, 1450 nm, and 1550 nm.

[0028] Figure 5 This refers to the linear dynamic range of the previous pixel under 520 nm or 1060 nm wavelength laser illumination in the AgBiS2 / Ag2S bulk heterojunction dynamic and static dual-mode optoelectronic sensor array integration embodiment of the present invention.

[0029] Figure 6 The attenuation time of the previous pixel in the AgBiS2 / Ag2S bulk heterojunction dynamic-static dual-mode optoelectronic sensor array integration in this embodiment of the invention is shown as a function of wavelength under laser irradiation at 405 nm, 520 nm, 635 nm, 808 nm, 1060 nm, 1342 nm, 1450 nm and 1550 nm.

[0030] Figure 7 This invention relates to the relaxation variation of photocurrent of a single pixel under 1550 nm laser irradiation at different optical power densities before the integration of the AgBiS2 / Ag2S bulk heterojunction dynamic-static dual-mode optoelectronic sensor array in this embodiment.

[0031] Figure 8 This invention relates to the relaxation variation of photocurrent of a pixel in the AgBiS2 / Ag2S bulk heterojunction dynamic-static dual-mode optoelectronic sensor array before it is integrated, under illumination by a 1550 nm laser with the same optical power density for different durations.

[0032] Figure 9 This is an image of a car projected by a projector and collected by the TFT photoelectric sensor chip in an embodiment of the present invention.

[0033] Figure 10A This is the It curve of a single pixel on a 64×64 pixel TFT photoelectric sensor chip under white light illumination in an embodiment of the present invention.

[0034] Figure 10B This is the It curve of a single pixel on a 64×64 pixel TFT photoelectric sensor chip in an embodiment of the present invention, acquired under 1450 nm laser illumination.

[0035] Figure 11A This is a moving digital image of a 64×64 pixel TFT photoelectric sensor chip under white light illumination in an embodiment of the present invention.

[0036] Figure 11B This is a moving digital 3D image presented by a 64×64 pixel TFT photoelectric sensor chip under 1450 nm laser illumination in an embodiment of the present invention. Detailed Implementation

[0037] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0038] The main technical problems addressed by this invention are as follows: 1. Based on the intrinsic properties of the material, a dual-mode system (dynamic and static) is achieved without the need for an external switching circuit.

[0039] This invention utilizes the intrinsic differences in the photogenerated carrier generation, transport, and recombination dynamics of the two components in an AgBiS2 / Ag2S bulk heterojunction at different wavelengths to achieve spontaneous switching of the transient optical response mode in the 320-1122 nm band for static imaging and the relaxation optical response mode in the 1342 nm and above band for dynamic sensing. The device's operating mode is autonomously determined by the incident light wavelength. This design fundamentally solves the problem of existing technologies relying on external circuit switching or complex structural designs, significantly reducing system complexity and power consumption.

[0040] 2. The materials are green and environmentally friendly, the process is simple and low-temperature, and it can be integrated into a single piece.

[0041] This invention uses environmentally friendly AgBiS2 / Ag2S materials, which are free of toxic elements such as lead and cadmium, and is prepared using a low-temperature solution method, meeting environmental protection requirements. The device fabrication process eliminates the need for complex epitaxial processes, allowing for direct array integration on the TFT (thin-film transistor) backplane, overcoming the drawbacks of existing technologies such as high fabrication costs and difficulty in integrating with readout circuits.

[0042] 3. It can realize large-area array integration and dynamic-static fusion imaging applications.

[0043] This invention leverages the low-temperature solution processability of AgBiS2 / Ag2S materials to directly fabricate device arrays on a 64×64 TFT backplane, forming TFT optoelectronic sensor chips. The imaging system built upon this system can perform motion-static fusion imaging simulation and motion-static fusion imaging control application verification, meeting practical application requirements and overcoming the limitations of existing technologies such as small array size and difficulty in practical application.

[0044] To achieve the above objectives, the present invention provides an AgBiS2 / Ag2S bulk heterojunction dynamic-static dual-mode photoelectric sensor, such as... Figure 1 As shown, from bottom to top, the layers are: substrate (1), thin film transistor array (2), photosensitive material layer (3), hole transport layer (4), top electrode layer (5), and encapsulation layer (6); wherein, the photosensitive material layer (3) is composed of AgBiS2 / Ag2S material; The light signal is transmitted sequentially from the substrate (1) and the thin film transistor array (2) to the photosensitive material layer (3). When the light signal is in the static imaging band, the AgBiS2 in the photosensitive material layer (3) mainly generates photogenerated carriers under the irradiation of the light signal. At this time, the imaging on the TFT photoelectric sensor chip composed of multiple photoelectric sensors prepared on the TFT backplane is a static imaging that disappears instantaneously as the light signal disappears. When the light signal is in the dynamic imaging band, its energy is too low to excite AgBiS2 to generate a response. Ag2S will undergo defect ionization under illumination, and this ionized state needs a period of time to recover to the ground state, which increases the carrier recombination time and thus produces photoconductive relaxation. At this time, the imaging on the TFT photoelectric sensor chip disappears slowly as the light signal disappears, thus being able to record the motion trajectory of moving objects and having dynamic sensing characteristics.

[0045] It should be noted that the functions of each layer of the photoelectric sensor device provided by this invention are as follows: The thin-film transistor array (2) includes a TFT switch array and an ITO pixel electrode array located above it. Each ITO pixel electrode is electrically connected to the corresponding TFT drain. Each region of the photosensitive material layer (3) generates photogenerated carriers under the irradiation of the light signal. The photogenerated carriers include photogenerated electrons and photogenerated holes. The photogenerated electrons in each region move to their respective ITO pixel electrodes, and the photogenerated holes move to the hole transport layer (4) and are further transported to the top electrode layer (5). Each ITO pixel electrode collects a different number of photogenerated electrons, which, together with the photogenerated holes collected synchronously by the top electrode layer (5), form a photocurrent loop of the corresponding size. The photocurrent formed is read out by the thin-film transistor array (2), which can reflect the light signal intensity of different regions and realize the imaging function of the TFT photoelectric sensor chip.

[0046] Meanwhile, the thin-film transistor array (2) is equipped with a back-end array reading system, which is used to read the current signal collected on the TFT photoelectric sensor chip through the circuit contained in the TFT backplane, and finally transmit the current signal wirelessly to form an image on the terminal APP.

[0047] Furthermore, the materials used in each layer of the photoelectric sensor device provided by the present invention are described below: The substrate (1) is made of ordinary glass; the thin-film transistor array (2) formed on the substrate (1) consists of a TFT switch array, a readout circuit, and an ITO (indium tin oxide) glass pixel electrode array located above the TFT switch array. The ITO pixel electrode array serves as the bottom electrode layer, and each ITO pixel electrode is electrically connected to the corresponding TFT drain. The substrate (1) and the thin-film transistor array (2) together form the TFT backplane; the photosensitive material layer (3) formed on the thin-film transistor array is made of AgBiS2 / Ag2S material and is grown in thin film on the ITO pixel electrode area of ​​the TFT backplane by a silver seed layer induction method. This layer mainly determines the function of the dynamic and static dual-mode photoelectric sensor; the photosensitive material layer is formed on the photosensitive material layer. The hole transport layer (4) is composed of PTAA [poly(4-phenyl)(2,4,6-trimethylphenyl)amine]; the top electrode layer (5) formed on the hole transport layer and the common electrode region on the TFT backplane is composed of a MoO3 layer and an Au electrode layer deposited sequentially, wherein the role of MoO3 is interface modification and surface passivation; the encapsulation layer (6) covering the top electrode layer is composed of a Parylene layer and a UV electronic adhesive layer, which is used to protect the surface of the photoelectric sensor; the TFT photoelectric sensor chip uses a transparent glass substrate, ITO as the electrode, and a thin film transistor array for image readout, with an array size of 12×12 to 64×64, and each pixel size of 1 mm × 1 mm to 200 μm × 200 μm.

[0048] It should be noted that the readout integrated circuit is not limited to 64×64 array TFT chips, but can also be other larger array TFT or CMOS readout integrated circuit chips, which will not be elaborated in this invention.

[0049] Furthermore, the present invention also provides a method for fabricating a dual-mode dynamic-static photoelectric sensor device of AgBiS2 / Ag2S bulk heterojunction, the method comprising the following steps: S1: Provides transparent thin-film transistor chips; S2: Cleaning thin-film transistor chips; S3: Place the thin-film transistor chip in a thermal evaporation coating machine to deposit silver; S4: Place the thin-film transistor chip containing silver material into a plasma cleaner to bombard and oxidize it into silver oxide; S5: Spin-coat the AgBiS2 / Ag2S precursor solution onto the silver oxide seed layer; S6: Place the chip coated with AgBiS2 / Ag2S precursor solution in a glove box and heat it.

[0050] S7: Spin-coat the PTAA solution onto the thin-film transistor chip containing AgBiS2 / Ag2S material; S8: Place the thin-film transistor chip coated with PTAA into a thermal evaporation coating machine to deposit the MoO3 layer and Au electrode layer.

[0051] S9: Place the thin-film transistor chip with the top electrode layer into a Parylene coating machine to deposit a Parylene thin film for encapsulation.

[0052] S10: Apply UV electronic adhesive to the surface of the thin-film transistor chip encapsulated with Parylene film and cure it with a UV flashlight.

[0053] Further, step S2, cleaning the thin-film transistor chip, includes: ultrasonically cleaning the thin-film transistor chip with ethanol for 5-15 minutes.

[0054] Furthermore, in step S3, the thickness of the evaporated silver material is 5~30 nm. The purpose of this step is to arrange a silver seed layer on the thin-film transistor chip so as to facilitate the subsequent close growth of the AgBiS2 / Ag2S photosensitive material into a thin film.

[0055] Further, in step S4, the chip is placed in a plasma cleaner. The oxidation parameters are: bombarding the chip with the evaporated silver material at an oxygen flow rate of 85-99 sccm for 1-5 minutes to oxidize the evaporated silver material into silver oxide.

[0056] Further, the preparation method of the AgBiS2 / Ag2S material precursor solution in step S5 is as follows: weigh AgCl, BiCl3, and thiourea and dissolve them in N,N-dimethylformamide solution, so that the molar ratio of AgCl to BiCl3 is 6:4~9:1, and stir to mix them evenly.

[0057] Further, in step S5, the chip is placed in a spin coater and rotated at a speed of not less than 2000 revolutions per minute for 10 to 60 seconds, during which 50 to 100 microliters of a homogenized precursor solution are added dropwise.

[0058] Furthermore, in step S6, the chip is placed on a hot plate at 150-200 degrees Celsius and heated for 3-10 minutes.

[0059] Furthermore, during the chip fabrication process, steps S5 and S6 (i.e., spin coating-heating) need to be repeated 1 to 5 times to form a uniform and dense AgBiS2 / Ag2S material.

[0060] Furthermore, the AgBiS2 / Ag2S thin film preparation method mentioned in this step is achieved by using a silver seed layer stimulation method, that is, using a silver seed layer will increase the density of AgBiS2 / Ag2S thin film growth.

[0061] Furthermore, the method for preparing the PTAA solution in step S7 is as follows: weigh PTAA and dissolve it in toluene to make its mass concentration 2 mg / mL-10 mg / mL.

[0062] Furthermore, the spin coating process in step S7 is as follows: place the chip in a spin coater, add 200-400 microliters of PTAA solution, and spin at a speed of not less than 2000 revolutions per minute for 20-60 seconds.

[0063] Furthermore, in step S8, the thickness of the deposited MoO3 material layer is 5-15 nm, and the thickness of the deposited Au material layer is 30-100 nm. The purpose of this step is to prepare the top electrode.

[0064] Furthermore, in step S9, the Parylene film thickness is 2-5 micrometers.

[0065] Furthermore, in step S10, the UV adhesive is cured by irradiation with a UV flashlight for 5-15 minutes.

[0066] The following example uses actual data to verify the basic principle and performance of an AgBiS2 / Ag2S bulk heterojunction dynamic-static dual-mode optoelectronic sensor device prepared by the method described above according to embodiments of the present invention.

[0067] First, the role of AgBiS2 / Ag2S materials in devices was investigated.

[0068] like Figure 2A As shown, the single electron concentration in the AgBiS2 / Ag2S material at 520 nm is equal in the dark, after 10 min of 520 nm illumination, and after the 520 nm light source is turned off, indicating that the single electron concentration does not change with illumination. This suggests that charge carriers in the material are rapidly generated and recombine.

[0069] like Figure 2B As shown, the single electron concentration in the AgBiS2 / Ag2S material increases after 10 min of 1450 nm illumination and gradually decreases after the 1450 nm light source is turned off, but remains higher than the single electron concentration in the initial dark state. This illustrates the slow generation and recombination process of charge carriers in the material.

[0070] like Figure 2CAs shown, the basic phenomenon of the It curve was tested on a single-point device before array integration using AgBiS2 / Ag2S material. The structure is ITO / photosensitive material (AgBiS2 / Ag2S material) / PTAA / MoO3 / Au. The results show that it exhibits transient photoresponse at 520 nm, which is consistent with the trend of single electron concentration in AgBiS2 / Ag2S material at 520 nm. At 1550 nm, it exhibits relaxation photoresponse, which is consistent with the trend of single electron concentration in AgBiS2 / Ag2S material at 1450 nm. This indicates that the intrinsic difference in carrier generation, transport and recombination dynamics of the two components of AgBiS2 / Ag2S material at different wavelengths is the basic reason for the device to produce this dual-band phenomenon, and is also the basic reason for the device to perform static imaging and dynamic sensing.

[0071] like Figure 3 As shown, the AgBiS2 / Ag2S material was characterized by HRTEM (high-resolution transmission electron microscopy) (inset) and SIMS (secondary ion mass spectrometry). The results show that the distribution of AgBiS2 and Ag2S materials in the AgBiS2 / Ag2S material is relatively uniform, forming a bulk heterojunction structure.

[0072] Next, basic optoelectronic performance tests were performed on a single pixel of the AgBiS2 / Ag2S bulk heterojunction dynamic and static dual-mode AgBiS2-based optoelectronic sensor before array integration.

[0073] like Figure 4 As shown, when the bias voltage is 0 V, the photoelectric sensor is illuminated with lasers of wavelengths of 405 nm, 520 nm, 635 nm, 808 nm, 1060 nm, 1122 nm, 1342 nm, 1450 nm and 1550 nm. The device has a response across the entire wavelength range and the response is relatively stable, showing the application potential of the device in broadband imaging.

[0074] like Figure 5 As shown, when the bias voltage is 0 V, the linear dynamic range (LDR) of the photoelectric sensor reaches 138 dB when illuminated by a laser with a wavelength of 520 nm and different optical power densities; when the photoelectric sensor is illuminated by a laser with a wavelength of 1060 nm and different optical power densities, the linear dynamic range of the device can still reach 130 dB. This indicates that the device has a wide measurement range and can maintain accurate response over a wide intensity range from extremely weak light (such as micro-light signals) to extremely strong light (such as lasers). It ensures both detection sensitivity and is not prone to saturation, thus exhibiting strong adaptability.

[0075] like Figure 6As shown, when the bias voltage is 0 V, the photoelectric sensor is illuminated with lasers at wavelengths of 405 nm, 520 nm, 635 nm, 808 nm, 1060 nm, 1342 nm, 1450 nm, and 1550 nm. The decay time of the device increases with increasing wavelength, with a more significant change in decay time at 1342 nm and beyond, exhibiting a clear infrared-specific response behavior. This result indicates that the photoelectric sensor of the present invention possesses a longer response retention effect in the infrared band, which can be used to realize a memory-like storage function for infrared input signals, thereby meeting the requirements of photoelectric sensor devices for dynamic imaging.

[0076] like Figure 7 As shown, when the bias voltage is 0 V, the device is irradiated with 1550 nm lasers of different optical power densities. Experimental results show that as the irradiation power increases, the relaxation process of the device's photoresponse gradually slows down. This phenomenon indicates that the memory effect of the photoelectric sensor of this invention under infrared excitation increases with increasing optical power, exhibiting a significant light intensity-dependent modulation capability, demonstrating that the dynamic imaging mode of this photoelectric sensor is tunable.

[0077] like Figure 8 As shown, when the bias voltage is 0 V, a 1550 nm laser with the same optical power density is applied to the photoelectric sensor of the present invention for irradiation times of 0 seconds, 1 second, 3 seconds, 6 seconds, 8 seconds, and 10 seconds, respectively. After the laser is removed, the retention time of its photocurrent is measured. The experimental results show that the relaxation time of the device photocurrent increases significantly with the increase of irradiation time. This phenomenon indicates that the memory effect of the photoelectric sensor of the present invention under infrared excitation is enhanced with the extension of illumination time, exhibiting obvious illumination time-dependent control capability, further verifying the adjustability and adaptability of its dynamic imaging mode.

[0078] Then, the dynamic and static dual-mode imaging capability of the 64×64 array TFT optoelectronic sensor chip after the AgBiS2 / Ag2S bulk heterojunction dynamic and static dual-mode AgBiS2-based optoelectronic sensor array was tested.

[0079] like Figure 9 The image shown is of a car projected onto a projector and captured by the photoelectric sensor chip under white light illumination. The image is clearly visible, verifying the visible light imaging capability of the TFT photoelectric sensor chip.

[0080] like Figure 10A The image shows the It curve of a single pixel on a TFT photoelectric sensor chip under white light illumination. This curve exhibits a fast response. Figure 10BThe image shows the It curve of a single pixel on the photoelectric sensor chip under 1450 nm light illumination. The falling edge of the curve exhibits a relaxation effect, consistent with the It curve phenomenon of a single pixel before array integration.

[0081] Figure 11A When a moving digit 3 is illuminated with white light, it can be seen that the 64×64 array TFT photoelectric sensor chip can only display the final position of the moving digit 3. Figure 11B An image of a moving digit 3 illuminated by a 1450 nm laser shows that a 64×64 array TFT photoelectric sensor chip can display the starting and ending positions of the moving digit 3.

[0082] In summary, this invention provides an AgBiS2 / Ag2S bulk heterojunction dynamic-static dual-mode photoelectric sensor and its fabrication method. This allows for large-scale monolithic heterojunction integration onto readout circuit chips such as thin-film transistor arrays to obtain TFT photoelectric sensor chips. Furthermore, the TFT photoelectric sensor chip is fabricated using a low-temperature solution-based method for AgBiS2 / Ag2S materials, resulting in low processing difficulty. Therefore, it enables the fabrication and application of large-area pixel photoelectric sensors, capable of revealing detailed features and movement directions of images through dynamic-static fusion imaging.

[0083] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A dual-mode photoelectric sensor device with dynamic and static modes, characterized in that, From bottom to top, the layers are: substrate (1), thin film transistor array (2), photosensitive material layer (3), hole transport layer (4), top electrode layer (5), and encapsulation layer (6); wherein, the photosensitive material layer (3) is composed of AgBiS2 / Ag2S material; The light signal is transmitted sequentially from the substrate (1) and the thin film transistor array (2) to the photosensitive material layer (3). When the light signal is in the static imaging band, the AgBiS2 in the photosensitive material layer (3) mainly generates photogenerated carriers under the irradiation of the light signal. At this time, the imaging on the TFT photoelectric sensor chip composed of multiple photoelectric sensors prepared on the TFT backplane is a static imaging that disappears instantaneously as the light signal disappears. When the light signal is in the dynamic imaging band, its energy is too low to excite AgBiS2 to generate a response. Ag2S will undergo defect ionization under illumination, and this ionized state needs a period of time to recover to the ground state, which increases the carrier recombination time and thus produces photoconductive relaxation. At this time, the imaging on the TFT photoelectric sensor chip disappears slowly as the light signal disappears, thus being able to record the motion trajectory of moving objects and having dynamic sensing characteristics.

2. The AgBiS2 / Ag2S bulk heterojunction dynamic-static dual-mode photoelectric sensor as described in claim 1, characterized in that, The static imaging band is the 320nm-1122nm band; the dynamic imaging band is the 1342nm and above band.

3. The AgBiS2 / Ag2S bulk heterojunction dynamic-static dual-mode photoelectric sensor as described in claim 1, characterized in that, The hole transport layer (4) is composed of PTAA [poly(4-phenyl)(2,4,6-trimethylphenyl)amine].

4. The AgBiS2 / Ag2S bulk heterojunction dynamic-static dual-mode photoelectric sensor as described in claim 1, characterized in that, The top electrode layer (5) is composed of a MoO3 layer and an Au electrode layer deposited sequentially.

5. The AgBiS2 / Ag2S bulk heterojunction dynamic-static dual-mode photoelectric sensor as described in claim 1, characterized in that, The encapsulation layer (6) consists of a Parylene layer and a UV electronic adhesive layer.

6. The AgBiS2 / Ag2S bulk heterojunction dynamic-static dual-mode photoelectric sensor as described in claim 1, characterized in that, The thin-film transistor array (2) is equipped with a back-end array reading system, which is used to read the current signal collected on the TFT photoelectric sensor chip and finally transmit the current signal wirelessly to form an image on the terminal APP.

7. A method for fabricating a dual-mode (dynamic and static) photoelectric sensor device using an AgBiS2 / Ag2S bulk heterojunction, characterized in that, Includes the following steps: S1: Provides transparent thin-film transistor chips; S2: Cleaning thin-film transistor chips; S3: Place the thin-film transistor chip in a thermal evaporation coating machine to deposit silver; S4: Place the thin-film transistor chip with silver material into a plasma cleaner to bombard and oxidize it into silver oxide, thus obtaining a silver oxide seed layer; S5: Spin-coat the AgBiS2 / Ag2S precursor solution onto the silver oxide seed layer; S6: Place the chip spin-coated with AgBiS2 / Ag2S precursor solution in a glove box and heat it; S7: Spin-coat the PTAA solution onto the thin-film transistor chip containing AgBiS2 / Ag2S material; S8: Place the thin-film transistor chip coated with PTAA layer into a thermal evaporation coating machine to evaporate MoO3 layer and Au electrode layer to form top electrode layer; S9: Place the thin-film transistor chip with the top electrode layer into a Parylene coating machine to coat it with Parylene film for encapsulation; S10: Apply UV electronic adhesive to the surface of the thin-film transistor chip encapsulated with Parylene film and cure it with a UV flashlight.

8. The method for fabricating an AgBiS2 / Ag2S bulk heterojunction dynamic-static dual-mode photoelectric sensor as described in claim 7, characterized in that, The method for preparing the AgBiS2 / Ag2S material precursor solution in step S5 is as follows: weigh AgCl, BiCl3, and thiourea and dissolve them in N,N-dimethylformamide solution, so that the molar ratio of AgCl to BiCl3 is 6:4~9:1, and stir to mix them evenly.

9. The method for fabricating an AgBiS2 / Ag2S bulk heterojunction dynamic-static dual-mode photoelectric sensor as described in claim 7, characterized in that, During chip fabrication, steps S5 and S6, i.e., spin coating-heating process, need to be repeated 1 to 5 times to form a uniform and dense AgBiS2 / Ag2S material before proceeding to step S7.

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