Near-infrared flexible polarized photoelectric detector and preparation method thereof

Abstract

The invention discloses a near-infrared flexible polarized photoelectric detector and a preparation method thereof. The photoelectric detector comprises an Sb2Se3 micron wire, a PET flexible substrate, a metal Ag electrode, a silver wire and polydimethylsiloxane (a PDMS mixture). According to the preparation method, an effective metal-semiconductor-metal (M-S-M) structure is constructed by combining the Sb2Se3 micron wire and the Ag electrode, curing packaging is carried out by adopting a PDMS mixture, the incident light transmittance is improved, meanwhile, the response speed of a device can be greatly improved through ohmic contact formed by the micron wire and the Ag electrode, and the power loss of the device is remarkably reduced. Compared with the prior art, the detector provided by the invention still keeps a stable and high extinction ratio under mechanical bending deformation, and realizes sensitive polarization, quick response and stable performance of a near-infrared band at the same time.

Description

Technical Field

[0001] The present invention relates to a flexible optoelectronic device and a preparation method thereof, and particularly relates to a near-infrared flexible polarization photodetector and a preparation method thereof. Background Art

[0002] In recent years, with the rapid development of the third-generation semiconductor technology, photodetectors have very important application values in the fields of optical communication, remote sensing, polarization imaging, and military detection. Polarization detection can fuse the spatial spectrum and polarization information of the target, improve the information volume of the detected target, and realize the recognition and detection capabilities of the target in complex environments. With the rapid development of integrated circuits, polarization photodetectors need to meet the characteristics of miniaturization, low power consumption, high performance, and suitability for complex environments. Therefore, selecting appropriate semiconductor materials to construct appropriate structures to achieve stable performance, low cost, and suitability for complex bending conditions of detection devices is the key problem faced by current near-infrared polarization photodetectors.

[0003] However, at present, most polarization photodetectors are integrated on rigid substrates, generally with large volumes, complex preparation technologies, and high power consumption. At the same time, due to the relatively hard structure of rigid detectors, they are extremely prone to damage and failure due to external impact or bending. In addition, such detectors cannot be bent and deformed, so their applications in some dynamic environments (such as those that require flexible adaptation to different working states) will be limited. Summary of the Invention

[0004] Object of the Invention: To solve the above problems, the present invention provides a near-infrared flexible polarization photodetector and a preparation method thereof. An effective MSM structure is constructed by a single Sb2Se3 micron wire and an Ag electrode, and a PDMS mixture is used for curing and encapsulation. By using the excellent flexibility, shock absorption, and anti-impact properties of PDMS after curing, the polarization photodetector can be bent and deformed to a certain extent. At the same time, PDMS can absorb a certain amount of mechanical vibration and impact, protecting the device from mechanical damage. In addition, PDMS has good optical transparency and is almost completely transparent to the near-infrared band, without causing obvious influence on the transmission of optical signals, ensuring that the detector is polarization-sensitive, has a fast response, and stable performance in the near-infrared band.

[0005] Technical solution: To achieve the above object, the technical solution adopted by the near-infrared flexible polarization photodetector of the present invention is specifically as follows: The near-infrared flexible polarization photodetector includes Sb2Se3 microwires, metal Ag electrodes, silver wires, a PET flexible substrate, and a PDMS (polydimethylsiloxane) mixture; both ends of the Sb2Se3 microwires are metal Ag electrodes; one end of the silver wire is connected to the metal Ag electrode, and the other end extends outside the PET; the MSM (metal-semiconductor-metal) structure device composed of Ag-Sb2Se3-Ag is located in the center of the PET substrate, and the direction is parallel to the long side of the PET substrate; the PDMS (polydimethylsiloxane) mixture uniformly wraps the MSM detection device composed of Ag-Sb2Se3-Ag.

[0006] Further, the length of the Sb2Se3 microwires is 0.5 - 0.8 cm, and the diameter is 18 - 29 μm.

[0007] Further, the thickness of the PET is 0.05 mm, and the specification is 2.0 - 3.0 cm × 0.5 cm.

[0008] Further, the diameter of the silver wire is 0.05 mm, the length is 2 - 3 cm, and the purity is 99.99%.

[0009] Further, the thickness of the cured PDMS mixture is 0.4 - 0.5 mm, and the size is equivalent to that of the PET flexible substrate, which is 2.0 - 3.0 cm × 0.5 cm.

[0010] The technical solution adopted by the preparation method of the near-infrared flexible polarization photodetector of the present invention is specifically as follows: (1) Prepare a PET substrate with corresponding dimensions and clean it; (2) Select Sb2Se3 microwires with high crystal quality, smooth surface, and uniform size and transfer them to the clean PET; (3) Uniformly apply a layer of conductive Ag electrodes at both ends of the Sb2Se3 microwires so that they can wrap both ends of the microwires to form a stable electrode structure; (4) Select a suitable silver wire, connect one end to the Ag electrode, and extend the other end outside the PET; (5) Uniformly apply the prepared PDMS mixture on the PET, and then place it in an oven for curing to obtain a near-infrared flexible polarization photodetector based on Sb2Se3 microwires.

[0011] Further, for the substrate cleaning in step 1): Put the PET flexible substrate into a clean beaker, add ethanol to submerge it, put it into an ultrasonic cleaner for cleaning for 15 minutes. After the cleaning is completed, put the PET substrate into deionized water for ultrasonic cleaning for 15 minutes to remove impurities. Then use nitrogen to blow off the moisture on the surface of the substrate, and finally put it into a drying oven for drying.

[0012] Further, in step 2), the Sb2Se3 microwires are located in the middle of the PET substrate, and the long axis direction thereof is parallel to the long side of the PET substrate.

[0013] Further, in step 3), the distance between the Ag electrodes at both ends of the Sb2Se3 microwires is 0.4 - 0.5 cm.

[0014] Further, for the preparation of the PDMS mixture in step 5): Weigh the base polymer (polydimethylsiloxane with vinyl end groups) and the curing agent (hydrosiloxane and platinum catalyst) and mix them in a ratio of 10:1 (by weight), then stir well. Place the mixture in an ultrasonic oscillator for 15 min to remove the bubbles in the mixture, thereby obtaining a transparent viscous PDMS mixture.

[0015] Further, in step 5), the oven temperature is set to 60 °C, and the curing time is set to 120 - 150 min.

[0016] Beneficial effects: Compared with the prior art, the present invention has the following remarkable effects: Through the effective MSM structure constructed by a single Sb2Se3 microwire and Ag electrodes, and using a transparent PDMS mixture to cure and encapsulate the entire device, the flexibility, bendability, and impact resistance of the device are greatly improved, enabling the device to be usable in a complex bending environment. Moreover, the device can still maintain a high extinction ratio in the mechanically bent state, achieving polarization sensitivity, fast response, and stability in the near-infrared band. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of the device of the present invention.

[0018] Figure 2 It is the microstructure of the Sb2Se3 microwires in the device of the present invention.

[0019] Figure 3 It is the I-V characteristic curve of the device of the present invention under different bending curvatures.

[0020] Figure 4 It is the I-T curve of the device of the present invention under different bending curvatures.

[0021] Figure 5 It is the extinction ratio curve of the device of the present invention under different bending curvatures. DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention discloses a near-infrared flexible polarization photodetector and its preparation method. Please refer to Figure 1As shown in the figure, the near-infrared flexible polarization photodetector provided by the present invention will be further described in detail below: The near-infrared flexible polarization photodetector includes Sb2Se3 micro-wires 1, metal Ag electrodes 2, silver wires 3, PET 4, and PDMS (polydimethylsiloxane) mixture 5; the length of the Sb2Se3 micro-wires is 0.5 - 0.8 cm, and the diameter is 18 - 29 μm; both ends of the Sb2Se3 micro-wires 1 are metal Ag electrodes 2; one end of the silver wire 3 is connected to the metal Ag electrode 2, and the other end extends outside the PET 4; the diameter of the silver wire 3 is 0.05 mm, the length is 2 - 3 cm, and the purity is 99.99%; the thickness of the PET 4 is 0.05 mm, and the specification is 2.0 - 3.0 cm × 0.5 cm; the MSM structure device composed of Ag-Sb2Se3-Ag is located in the center of the PET 4, and the direction is parallel to the long side of the PET 4; the PDMS (polydimethylsiloxane) mixture 5 uniformly wraps the MSM detection device composed of Ag-Sb2Se3-Ag; the thickness of the PDMS mixture 5 after curing is 0.4 - 0.5 mm, and the size is equivalent to that of the PET 4 flexible substrate, which is 2.0 - 3.0 cm × 0.5 cm.

[0023] The preparation method provided by the present invention will be further described in detail below:

[0024] The first step: First, cut the PET flexible substrate 4 into a size of 2.0 - 3.0 cm × 0.5 cm with scissors, and smooth the edges; then place the cut PET flexible substrate 4 into a beaker, add anhydrous ethanol to submerge it, clean it with an ultrasonic cleaner for 15 minutes, after the cleaning is over, put the PET substrate 4 into deionized water and ultrasonically clean it for 15 minutes to remove impurities, then use nitrogen to blow off the moisture on the surface of the substrate 4, and finally put it into a drying oven to dry, so as to ensure that the substrate 4 is flat and clean.

[0025] The second step: Select the Sb2Se3 micro-wires 1 with high crystallization quality, smooth surface and uniform size from the prepared Sb2Se3 micro-wires 1 and transfer them to the cleaned and dried PET flexible substrate 4. During the transfer process, ensure that its long axis direction is parallel to the long side of the PET flexible substrate 4 and is in the center position of the flexible substrate 4.

[0026] The third step: Apply a layer of conductive Ag electrode 2 evenly on both ends of the Sb2Se3 micro-wires 1. During the operation, the coating thickness should be appropriate and the distribution should be uniform, so that it can fully wrap both ends of the micro-wires to form a stable MSM structure;

[0027] The fourth step: Cut the silver wire 3 into a length of 2 - 3 cm, connect one end of the silver wire 3 to the metal Ag electrode 2 coated on the end of the Sb2Se3 micro-wires 1, ensure tight contact and good electrical conductivity. The other end extends to the external area of the PET flexible substrate for reliable connection with the test equipment.

[0028] Step 5: Preparation of PDMS mixture 5: Weigh the base polymer (vinyl-terminated polydimethylsiloxane) and the curing agent (hydrosiloxane and platinum catalyst) according to a mass ratio of 10:1. Put the two into a clean centrifuge tube, and then stir them thoroughly until evenly mixed. After the stirring is completed, transfer the mixture to an ultrasonic oscillator and process it for 15 minutes to remove the bubbles therein, obtaining a transparent viscous PDMS mixture 5.

[0029] Step 6: Evenly apply the prepared PDMS mixture 5 on the MSM device prepared in the third step. Use a scraper to evenly apply it so that the PDMS mixture completely covers the device, ensuring that there are no air bubbles remaining in the PDMS mixture 5 during the application process. The application range of the PDMS mixture 5 is consistent with the size of the PET flexible substrate.

[0030] Step 7: Carefully transfer the device coated with PDMS mixture 5 to an oven for curing. The oven temperature is set at 60 °C, and the curing time is set at 120 - 150 minutes.

[0031] Step 8: Test the near-infrared flexible polarization photodetector prepared in the seventh step. Bend the device at different curvatures, and respectively collect the I-T and I-V data under different curvatures under the irradiation of a 900-nm near-infrared light source, and plot the I-V characteristic curve, the I-T curve, and the extinction ratio curve under 900-nm near-infrared polarized light. As Figure 3 、 4 、5 shown, they are respectively the I-V characteristic curve, the I-T curve, and the extinction ratio curve of the near-infrared flexible polarization photodetector of Sb2Se3 microwires under bending curvatures of 57.7 mm, 28.7 mm, 21.7 mm, 15.8 mm, 18.7 mm, and 18.1 mm. As the bending curvature gradually decreases, although the photocurrent shows an obvious downward trend, the extinction ratio of the system always remains in the range of 4.8 to 5 and is not affected by the change of external bending stress. In summary, this device not only can maintain a high extinction ratio under mechanical bending conditions, but also has polarization sensitivity in the near-infrared band, fast response ability, and excellent stability.

Claims

1. A near-infrared flexible polarization photodetector, characterized in that, It includes Sb2Se3 microwires (1), metal Ag electrodes (2), silver wires (3), a PET flexible substrate (4), and a PDMS (polydimethylsiloxane) mixture (5); both ends of the Sb2Se3 microwires (1) are wrapped by conductive Ag paste to form metal Ag electrodes (2), constituting a metal-semiconductor-metal (MSM) structure; one end of the silver wire (3) is connected to the metal Ag electrode (2), and the other end extends outside the PET flexible substrate (4); the MSM structure is located in the center of the PET flexible substrate (4), and the long axis direction of the Sb2Se3 microwires (1) is parallel to the long side of the PET flexible substrate (4); the PDMS mixture (5) uniformly wraps the MSM structure device to form a cured encapsulation layer.

2. The near-infrared flexible polarization photodetector according to claim 1, wherein The length of the Sb2Se3 microwires (1) is 0.5 - 0.8 cm, and the diameter is 18 - 29 μm.

3. The near-infrared flexible polarization photodetector according to claim 1, wherein The thickness of the PET flexible substrate (4) is 0.05 mm, and the specification is 2.0 - 3.0 cm × 0.5 cm.

4. The near-infrared flexible polarization photodetector according to claim 1, characterized in that, The diameter of the silver wire (3) is 0.05 mm, the length is 2 - 3 cm, and the purity is 99.99%.

5. The near-infrared flexible polarization photodetector according to claim 1, characterized in that, The thickness of the cured PDMS mixture (5) is 0.4 - 0.5 mm, and the size matches that of the PET flexible substrate (4).

6. A method for preparing a near-infrared flexible polarization photodetector according to any one of claims 1 to 5, characterized in that, It includes the following steps: 1) Prepare the PET flexible substrate (4) and clean it. 2) Transfer the Sb2Se3 microwires (1) onto the cleaned PET flexible substrate (4), ensuring that the long axis direction is parallel to the long side of the PET flexible substrate (4). 3) Uniformly apply conductive Ag paste at both ends of the Sb2Se3 microwires (1) so that it can wrap both ends of the Sb2Se3 microwires (1) to form metal Ag electrodes (2). 4) Connect one end of the silver wire (3) to the metal Ag electrode (2), and the other end extends outside the PET flexible substrate (4). 5) Uniformly apply the PDMS mixture (5) on the PET flexible substrate (4), and complete the encapsulation after curing.

7. The preparation method of the near-infrared flexible polarization photodetector according to claim 6, characterized in that, In step 1), the substrate cleaning steps include: placing the PET flexible substrate (4) in ethanol and deionized water in turn for ultrasonic cleaning for 15 minutes each, and drying it with nitrogen and then drying it in an oven.

8. The preparation method of the near-infrared flexible polarization photodetector according to claim 6, characterized in that, In step 3), the distance between the metal Ag electrodes (2) at both ends of the Sb2Se3 microwires (1) is 0.4 - 0.5 cm.

9. The preparation method of the near-infrared flexible polarization photodetector according to claim 6, wherein, In step 5), the preparation steps of the PDMS mixture (5) include: mixing the base polymer and the curing agent in a weight ratio of 10:1, fully stirring, and performing ultrasonic treatment for 15 min to remove bubbles in the mixture.

10. The preparation method of the near-infrared flexible polarization photodetector according to claim 6, characterized in that, In step 5), the curing conditions are that the oven temperature is set at 60 °C, and the curing time is set at 120 - 150 min.

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