Preparation method of flexible infrared detection film for uncooled infrared detector
High crystalline VO2 powder was prepared by hydrothermal synthesis, mixed with conductive carbon black and PTFE, and a flexible infrared detection film was made using the roller pressing process, which solved the problem of low TCR of existing infrared detector materials, and achieved the preparation of high response rate and flexible devices.
Patent Information
- Application Number
- CN202510425239.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-07
- Publication Date
- 2025-06-27
AI Technical Summary
The existing non-cooled infrared detector materials based on thermal detection type have low resistance temperature variation coefficient (TCR), which cannot meet the needs of infrared detection devices with higher response rates, and cannot achieve the preparation of flexible devices.
Vanadium dioxide (VO2) powder with good crystallinity was prepared by hydrothermal synthesis, and it was evenly mixed with conductive carbon black and polytetrafluoroethylene (PTFE) polymer binder, and a flexible infrared detection film was made by the roll pressure process.
The prepared flexible infrared detection film has a high resistance temperature change coefficient (TCR) of no less than 2.96% at room temperature, and has a high response rate, detection rate and detection range. It is suitable for applications of flexible devices such as smart wearable devices.
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Figure CN120209374A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of flexible infrared sensitive thin film materials, and particularly relates to a preparation method of flexible infrared sensitive thin film materials for uncooled infrared detectors. Background Art
[0002] A photodetector converts the received light wave into a physical quantity that is convenient to measure. According to different working principles, photodetectors can be divided into thermal detectors and photon detectors. The content of the present invention is based on infrared detection thin film materials of the thermal detection type.
[0003] Under the irradiation of infrared light, an infrared detection material absorbs photon energy and is converted into heat energy, causing a change in the local temperature of the material. This change in the material temperature causes a change in its resistance, thereby causing a change in the electrical signal in the detection circuit. Generally speaking, the rate of change of the resistance of an infrared detection material with temperature is the temperature coefficient of resistance change (TCR coefficient). The higher the temperature coefficient of resistance change, the stronger the response of the material's resistance to temperature, and thus the more sensitive the detection of infrared signals. Currently, for uncooled infrared detectors based on the thermal detection type, the mainstream infrared detection materials are multivalent vanadium oxides (VOX) and polysilicon (α-Si). The device process flow is to prepare a micron-scale suspended support structure on a rigid substrate by releasing a sacrificial layer, thereby realizing the detection of infrared signals. However, the temperature coefficient of resistance change (TCR) of these mature infrared detection materials is often only between 2% and 3%, which cannot meet the preparation of infrared detection devices with higher response rates, nor can it realize the preparation of flexible devices for various intelligent wearable devices.
[0004] The B-phase vanadium dioxide (VO2) material in vanadium oxides has a significant resistance-temperature effect during the temperature change process, thus showing a high temperature coefficient of resistance change (TCR) and signal-to-noise ratio, and thus is expected to be used in ultra-high-performance infrared detection devices. However, for a long time, the problem of too high film preparation temperature has prevented it from being truly used in the preparation of actual devices. Therefore, it is very necessary to develop a feasible B-phase vanadium dioxide (VO2) thin film preparation technology for device preparation. Summary of the Invention
[0005] In order to solve the problem that for current uncooled infrared detectors based on the thermal detection type, such as the mainstream infrared detection materials multivalent vanadium oxides (VOX) and polysilicon (α-Si), the temperature coefficient of resistance change is often only between 2% and 3%, which cannot meet the preparation of infrared detection devices with higher response rates, nor can it realize the preparation of flexible devices for various intelligent wearable devices, the present invention provides a preparation method of a flexible infrared detection thin film for an uncooled infrared detector.
[0006] The preparation operation steps of the flexible infrared detection film for a non-cooled infrared detector are as follows: (1) Dry grind the B-phase powder accounting for 80% - 87.5% of the total mass of the flexible infrared detection film until the powder particles are less than 100 mesh, and add conductive carbon black (super-p) accounting for 2.5% - 10% of the total mass of the flexible infrared detection film, and mix evenly to obtain a mixed powder substance; Or dry grind the B-phase powder accounting for 90% of the total mass of the flexible infrared detection film until the powder particles are less than 100 mesh to obtain a single powder substance; The B-phase powder is powdered vanadium dioxide (VO2); (2) Drop into the mixed powder substance the PTFE emulsion with a mass concentration of 60% accounting for 16.7% of the total mass of the flexible infrared detection film. At the same time, drop in isopropanol with a mass more than 500 times that of the PTFE emulsion for uniformly dispersing the emulsion, and mix evenly to obtain a mixture; (3) Let the mixture stand still to basically volatilize the isopropanol, and place it on aluminum foil paper to obtain a putty-like substance; (4) In a roll press, repeatedly roll and form the putty-like substance and the aluminum foil paper together to obtain a film-like substance; (5) Bake and dry the film-like substance, cool it to room temperature, and peel off the aluminum foil paper on the film-like substance to obtain a self-supporting flexible infrared detection film; The thickness of the flexible infrared detection film is 20μm - 100μm; the room temperature TCR of the flexible infrared detection film is not less than 2.96%; for the unsupported infrared detection device made of the flexible infrared detection film, the detection rate of infrared light with a wavelength of 1550nm under vacuum is not less than 5.0×10 7 Jones, and the responsivity is not less than 0.1 A / W.
[0007] The further technical solution is as follows: In step (1), the powder particles of the vanadium dioxide are rod-shaped particles with a length of 0.5 - 2μm.
[0008] In step (1), the particle size of the conductive carbon black (super-p) is spherical particles with a diameter of 50 - 200nm.
[0009] In step (3), the standing time is 10 - 15 minutes.
[0010] In step (4), before each rolling, drop one or more drops of isopropanol on both the front and back of the object to be pressed.
[0011] In step (5), the baking conditions are: temperature 70°C, time 20 min, and pressure lower than 1.0 Pa.
[0012] The thickness of the flexible infrared detection film is 20μm to 100μm.
[0013] The beneficial technical effects of the present invention are embodied in the following aspects: 1. The present invention prepares vanadium dioxide (VO2) (B-phase) powder with good crystallinity by a hydrothermal synthesis method. The vanadium dioxide (VO2) (B-phase) powder can be prepared into a thin film material for a non-cooled infrared detector through various processing techniques. At the same time, due to good crystallinity, the synthesized vanadium dioxide (VO2) (B-phase) powder has a high temperature coefficient of resistance (TCR).
[0014] 2. After the synthesized vanadium dioxide (VO2) (B-phase) powder is uniformly mixed with a preferred proportion of conductive carbon black (super-p) and a preferred proportion of polytetrafluoroethylene (PTFE) polymer binder, a flexible infrared detection film can be efficiently made by a roll pressing process. The film has a temperature coefficient of resistance change (TCR) of more than 2.9% at room temperature, and a 1 / f noise lower than 3.5×10 -19 A 2 / Hz, where the TCR value is much higher than 2.4% of the currently marketized infrared detection sensing layer film. The fabricated non-cooled infrared detector has extremely high responsivity, detectivity, and detection range.
[0015] 3. The preferred proportion of polytetrafluoroethylene (PTFE) polymer binder, as a high-temperature resistant material, forms an internal network structure during the film preparation process, endowing the film with excellent flexibility properties and expanding the application scenarios of the film, such as curved surface infrared detection arrays, etc. At the same time, the polytetrafluoroethylene (PTFE) binder still maintains the bonding effect at high temperatures, thus endowing the flexible infrared detection film with the ability to work at high temperatures.
[0016] 4. Preparing the flexible infrared detection film by a roll pressing process enables the designed flexible infrared detection film to have the ability of large-scale production. The roll pressing process is a part of the roll-to-roll process. This production process is highly efficient and low-cost, greatly reducing the cost of preparing the flexible infrared detection film and facilitating its popularization and application.
[0017] 5. By introducing a preferred mass fraction of highly conductive carbon black (super-p) into the flexible infrared detection film material, the resistance of the flexible infrared detection film is reduced, and at the same time, the detectivity is improved.
[0018] 6. The flexible infrared detection film prepared by the present invention has the ability of self-support, making it easier to form an overhead structure when used to fabricate a non-cooled infrared detector, reducing the heat exchange with the outside world, more efficiently responding to light and heat, and effectively improving the responsivity and detectivity. Brief Description of the Drawings
[0019] Figure 1 This is a physical diagram of the flexible infrared detection film for a non-cooled infrared detector according to the present invention.
[0020] Figure 2 This is a schematic structural diagram of the device constructed according to the present invention.
[0021] Figure 3 This is the graph of resistance - temperature test of the present invention.
[0022] Figure 4 This is the graph of the test results of the temperature coefficient of resistance.
[0023] Figure 5 This is the test effect diagram of the photocurrent of the device constructed according to the present invention.
[0024] Figure 6 This is the test effect diagram of the noise of the device constructed according to the present invention.
[0025] Figure 7 This is the test effect diagram of the detectivity of the device constructed according to the present invention.
[0026] Figure 8 This is the test effect diagram of the photocurrent of the device constructed according to the present invention.
[0027] Figure 9 This is the test effect diagram of the photocurrent of the device constructed according to the present invention.
[0028] Figure 10 This is the test effect diagram of the bending of the device constructed according to the present invention.
[0029] Figure 11 This is the test effect diagram of the performance stability during the bending test of the device constructed according to the present invention. Detailed Description of the Invention Example 1
[0030] The specific operating steps for the preparation of the flexible infrared detection film for a non-cooled infrared detector are as follows: (1) Grind 48 mg (80% of the total mass of the flexible infrared detection film) of powdered vanadium dioxide (VO2) in the B phase by dry grinding until the particle size is less than 100 mesh, and add 6 mg (10% of the total mass of the flexible infrared detection film) of conductive carbon black (super-p) and mix evenly to obtain a mixed powder substance.
[0031] The powder particles of the vanadium dioxide are rod-shaped particles with a length of 0.3 - 2 μm. The particle size of the conductive carbon black (super-p) is spherical particles with a diameter of 50 - 200 nm.
[0032] (2) In the mixed powder material, 16.7 mg of polytetrafluoroethylene (PTFE) emulsion with a mass concentration of 60% was dropped in, and 15 ml of isopropyl alcohol was added to uniformly disperse the emulsion (the solid component after volatilization accounted for 10% of the total mass of the flexible infrared detection film), and then stirred and mixed evenly to obtain a mixture.
[0033] (3) The mixture was left standing for 10 min to allow the isopropyl alcohol to basically volatilize, and then placed on aluminum foil paper to obtain a putty-like substance.
[0034] (4) In a roller press, the putty-like substance and the aluminum foil paper were repeatedly rolled and formed together to obtain a film-like substance. Before each rolling, more than one drop of isopropyl alcohol was dropped on both the front and back of the object to be pressed.
[0035] (5) The film-like substance was baked and dried in a constant-temperature oven. The baking conditions were: temperature 70 °C, time 20 min, and pressure 10 Pa. After taking it out and cooling to room temperature, the aluminum foil paper on the film-like substance was peeled off to obtain a self-supporting flexible infrared detection film with a thickness of 21 μm, as shown in Figure 1 . The flexible infrared detection film has self-supporting performance, that is, it can stably maintain the film form without breaking without relying on a substrate.
[0036] See Figure 2 , the film was made into a device for optoelectronic testing. First, the prepared flexible infrared detection film was cut into a size of 5 mm in length and 0.5 mm in width, and a gold counter electrode layer with a thickness of 80 nm was plated on the surface. The channel width between the counter electrodes was 50 μm. Subsequently, conductive copper foils were placed at both ends of the film as a conductive overhead layer and a metal conductive layer. Finally, the device was loaded on a flexible PI substrate for testing.
[0037] See Figure 3 , through temperature-resistance testing, the resistance-temperature curve of the flexible infrared detection film prepared in Example 1 is as shown by the orange curve in Figure 3 . Its resistance at a temperature of 20 °C is 3.5 k ohms, and its resistance at 90 °C is 0.51 k ohms.
[0038] See Figure 4 , through the result processing and calculation of the measured resistance-temperature curve, the room-temperature TCR value of the flexible infrared detection film in Example 1 was obtained as 2.96%.
[0039] See Figure 5 , through the 1550 nm laser photocurrent test with a power density of 954 mw / cm 2 , the photocurrent response of the flexible infrared detection film in Example 1 under a 1V bias voltage was measured to be 1620 µA, as shown by the dark blue curve in Figure 5 .
[0040] SeeFigure 6 By testing its 1 / f noise at a 1 V bias in an atmospheric environment, the noise current of the flexible infrared detection thin film of Example 1 was measured to be 6.04 × 10 -9 A·Hz⁻ 1 / 2 , as Figure 6 shown by the dark blue line in
[0041] See Figure 7 , by calculating the photocurrent magnitude, 1 / f noise, and optical power density, the detectivity of the flexible infrared detection thin film of Example 1 for a laser with a power density of 954 mw / cm 2 and a wavelength of 1550 nm was obtained as 0.856×10 8 Jones. Example 2
[0042] The specific operating steps for preparing the flexible infrared detection thin film for a non-cooled infrared detector are as follows: (1) Grind 49.5 mg (accounting for 82.5% of the total mass of the flexible infrared detection thin film) of vanadium dioxide in phase B (VO2) to a particle size of less than 100 mesh, and add 4.5 mg (accounting for 7.5% of the total mass of the flexible infrared detection thin film) of conductive carbon black (super-p) and mix evenly to obtain a mixed powder substance; Steps (2)-(5) are the same as those in Example 1.
[0043] See Figure 2 , fabricate the film into a device for optoelectronic testing. First, cut the fabricated flexible infrared detection thin film into a size of 5 mm in length and 0.5 mm in width, and deposit an 80-nm-thick gold counter electrode layer on the surface. The channel width between the counter electrodes is 50 μm. Subsequently, place conductive copper foils at both ends of the film as a conductive overhead layer and a metal conductive layer, and finally load the device on a flexible PI substrate for testing.
[0044] See Figure 3 , through temperature-resistance testing, the resistance-temperature curve of the flexible infrared detection thin film prepared in Example 2 is as Figure 3 shown by the magenta curve in
[0045] See Figure 4 , by processing and calculating the results of the measured resistance-temperature curve, the room-temperature TCR value of the flexible infrared detection thin film of Example 2 was obtained as 3.56%.
[0046] See Figure 5 , with a power density of 954 mw / cm 2For the 1550 nm laser photocurrent test, the photocurrent response of the flexible infrared detection film of Example 2 was measured to be 1251 µA under a 1V bias voltage, as shown in Figure 5 the orange curve in
[0047] See Figure 6 , by testing its 1 / f noise under a 1 V bias voltage in an atmospheric environment, the noise current of the flexible infrared detection film of Example 2 was measured to be 6.03 × 10 -9 A·Hz⁻ 1 / 2 , as shown in Figure 6 the magenta line in
[0048] See Figure 7 , by calculating the photocurrent magnitude, 1 / f noise, and optical power density, the detectivity of the flexible infrared detection film of Example 2 for a laser with a power density of 954 mw / cm 2 and a wavelength of 1550 nm was obtained as 1.46×10 8 Jones. Example 3
[0049] The specific operating steps for preparing the flexible infrared detection film for a non-cooled infrared detector are as follows: (1) After dry-grinding 51 mg (85% of the total mass of the flexible infrared detection film) of vanadium dioxide powder in phase B to a particle size less than 100 mesh, it was uniformly mixed with 3 mg (5% of the total mass of the flexible infrared detection film) of conductive carbon black (super-p) to obtain a mixed powder material.
[0050] Steps (2)-(5) are the same as those in Example 1.
[0051] See Figure 2 , the film was made into a device for optoelectronic testing. First, the prepared flexible infrared detection film was cut into a size of 5 mm in length and 0.5 mm in width, and a gold counter electrode layer with a thickness of 80 nm was deposited on the surface. The channel width between the counter electrodes was 50 μm. Subsequently, conductive copper foils were placed at both ends of the film as a conductive overhead layer and a metal conductive layer. Finally, the device was loaded on a flexible PI substrate for testing.
[0052] See Figure 3 , through the temperature-resistance test, the resistance-temperature curve of the flexible infrared detection film prepared in Example 3 is as shown in Figure 3 the yellow-green curve in
[0053] See Figure 4, by processing and calculating the results of the measured resistance-temperature curve, the room-temperature TCR value of the flexible infrared detection film of Example 3 is obtained as 4.24%.
[0054] See Figure 5 , through the 1550 nm laser photocurrent test with a power density of 954 mw / cm 2 , the photocurrent response of the flexible infrared detection film of Example 3 under a 1V bias voltage is measured to be 960 µA, as shown by the magenta curve in Figure 5 .
[0055] See Figure 6 , through the 1 / f noise test of it under a 1 V bias voltage in an atmospheric atmosphere, the noise current of the flexible infrared detection film of Example 3 is measured to be 2.84 × 10⁻ 10 A·Hz⁻ 1 / 2 , as shown by the magenta line in Figure 6 .
[0056] See Figure 7 , by calculating the photocurrent magnitude, 1 / f noise, and optical power density, the detectivity of the flexible infrared detection film of Example 3 for a laser with a power density of 954 mw / cm 2 and a wavelength of 1550 nm is obtained as 2.11×10 8 Jones. Example 4
[0057] The specific operating steps for preparing the flexible infrared detection film for a non-cooled infrared detector are as follows: (1) After dry-grinding 52.5 mg (accounting for 87.5% of the total mass of the flexible infrared detection film) of vanadium dioxide powder of phase B to a particle size of less than 100 mesh, it is uniformly mixed with 1.5 mg (accounting for 2.5% of the total mass of the flexible infrared detection film) of conductive carbon black (super-p) to obtain a mixed powder substance; Steps (2)-(5) are the same as those in Example 1.
[0058] See Figure 2 , the film is made into a device for optoelectronic testing. First, the prepared flexible infrared detection film is cut into a size of 5 mm in length and 0.5 mm in width, and a 80 nm thick gold counter electrode layer is deposited on the surface. The channel width between the counter electrodes is 50 μm. Subsequently, conductive copper foils are placed at both ends of the film as a conductive overhead layer and a metal conductive layer. Finally, the device is loaded on a flexible PI substrate for testing.
[0059] See Figure 3 , through the temperature-resistance test, the resistance-temperature curve of the flexible infrared detection film prepared in Example 4 is asFigure 3 As shown by the medium purple curve, its resistance is 22.2 kΩ at a temperature of 20 °C and 1.63 kΩ at 90 °C.
[0060] See Figure 4 , and through the result processing and calculation of the measured resistance-temperature curve, the room temperature TCR value of the flexible infrared detection film of this Example 4 is obtained as 4.61%.
[0061] See Figure 5 , through the 1550 nm laser photocurrent test with a power density of 954 mw / cm 2 , the photocurrent response of the flexible infrared detection film of this Example 4 under a 1V bias voltage is measured to be 616 µA, as Figure 5 shown by the yellow-green curve in
[0062] See Figure 6 , through the 1 / f noise test of it under a 1 V bias voltage in an atmospheric atmosphere, the noise current of the flexible infrared detection film of this Example 4 is measured to be 1.52 × 10⁻ 10 A·Hz⁻ 1 / 2 , as Figure 6 shown by the yellow-green line in
[0063] See Figure 7 , through the calculation of the photocurrent magnitude, 1 / f noise, and optical power density, the detectivity of the flexible infrared detection film of this Example 4 for a laser with a power density of 954 mw / cm 2 and a wavelength of 1550 nm is obtained as 1.61×10 8 Jones. Example 5
[0064] The specific operation steps for preparing the flexible infrared detection film for a non-cooled infrared detector are as follows: (1) Dry-grind 54 mg (accounting for 90% of the total mass of the flexible infrared detection film) of B-phase vanadium dioxide powder until the particle size is less than 100 mesh; Steps (2)-(5) are the same as those in Example 1.
[0065] See Figure 2 , make the film into a device for optoelectronic testing. First, cut the made flexible infrared detection film into a size of 5 mm in length and 0.5 mm in width, and deposit an 80 nm thick gold counter electrode layer on the surface. The channel width between the counter electrodes is 50 μm. Then place conductive copper foils at both ends of the film as a conductive overhead layer and a metal conductive layer, and finally load the device on a flexible PI substrate for testing.
[0066] See Figure 3, through temperature-resistance testing, the resistance-temperature curve of the flexible infrared detection film prepared in Example 5 is as Figure 3 shown by the light blue curve in . Its resistance at 20 °C is 30.8 kΩ, and at 90 °C is 2.42 kΩ. Figure 4 See
[0067] . By processing and calculating the results of the measured resistance-temperature curve, the room-temperature TCR value of the flexible infrared detection film in Example 1 is obtained as 4.84%. Figure 5 Figure 5 2 See Figure 5 . Through the 1550 nm laser photocurrent test with a power density of 954 mw / cm
[0068] , the photocurrent response of the flexible infrared detection film in Example 5 under a 1V bias is measured to be 374 µA, as shown by the light blue curve in Figure 6 Figure 6 10 . See 1 / 2 . Through the 1 / f noise test of the flexible infrared detection film in Example 5 under a 1 V bias in an atmospheric environment, the noise current of the film is measured to be 1.16 × 10⁻ 10 A·Hz⁻ 1 / 2
[0069] Figure 7 , as shown by the light blue line in 2 . See 8 . By calculating the photocurrent magnitude, 1 / f noise, and optical power density, the detectivity of the flexible infrared detection film in Example 5 for a laser with a power density of 954 mw / cm Example 6
[0070] Prepare the flexible infrared detection film and the counter electrode channel according to the film preparation process in Example 3.
[0071] See Figure 2 . Make the flexible infrared detection film into a device for optoelectronic testing. First, cut the flexible infrared detection film into a size of 5 mm in length and 0.5 mm in width, and deposit an 80 nm thick gold counter electrode layer on its surface. The channel width between the counter electrodes is 50 μm. Then, place conductive copper foils at both ends of the flexible infrared detection film as the conductive overhead layer and the metal conductive layer. Finally, load the device on the flexible PI substrate for testing.
[0072] See Figure 8, a laser with a power of 954 mw / cm2 and a wavelength of 1550 nm was used for the device that can be used for optoelectronic testing. At the same time, the optoelectronic response was tested under a 1V bias voltage. When the device was in the packaged and unpackaged states, namely in a vacuum below 10 pa and in the atmospheric environment, the photocurrents measured in this Example 6 were 970 μA and 450 μA respectively. The response time of the device in a vacuum was 310 ms, and in the atmospheric pressure was 170 ms (the response time is defined as the time from when the current starts to rise to 90% of the maximum value). Example 7
[0073] Prepare the flexible infrared detection thin film and the counter electrode channel according to the thin film preparation process of Example 3.
[0074] See Figure 2 , make the flexible infrared detection thin film into a device that can be used for optoelectronic testing. First, cut the flexible infrared detection thin film into a size of 5 mm in length and 0.5 mm in width, and deposit a 80 nm thick gold counter electrode layer on the surface. The channel width between the counter electrodes is 50 μm. Subsequently, place conductive copper foils at both ends of the thin film as the conductive overhead layer and the metal conductive layer. Finally, load the device on the flexible PI substrate for testing.
[0075] See Figure 9 , while irradiating with lasers with a power of 954 mw / cm 2 , wavelengths of 405 nm, 650 nm, 880 nm, and 1550 nm respectively, apply a 1 V bias voltage to the device that can be used for optoelectronic testing, and test the relationship between the responsivity and detectivity of the detection device and the detection wavelength in the unpackaged atmospheric environment. The responsivity to 405 nm light is 0.572 A / W, the responsivity to 650 nm light is 0.404 A / W, the responsivity to 880 nm light is 0.465 A / W, and the responsivity to 1550 nm light is 0.478 A / W. The detectivity to 405 nm light is 1.196×10 8 Jones, the detectivity to 650 nm light is 8.46×10 7 Jones, the detectivity to 880 nm light is 9.73×10 7 Jones, the detectivity to 1550 nm light is 1.001×10 8 Jones. Example 8
[0076] Prepare the flexible infrared detection thin film and the counter electrode channel according to the thin film preparation process of Example 3.
[0077] See Figure 2, the thin film is made into a device for optoelectronic testing. First, the fabricated flexible infrared detection thin film is cut into a size of 5 mm in length and 0.5 mm in width, and a gold counter electrode layer with a thickness of 80 nm is plated on the surface. The channel width between the counter electrodes is 50 μm. Subsequently, conductive copper foils are placed at both ends of the thin film as a conductive overhead layer and a metal conductive layer. Finally, the device is loaded on a flexible PI substrate for testing.
[0078] See Figure 10 , the device for optoelectronic testing is placed on a working table applying stress, and the channel is irradiated with a laser with a power of 954 mw / cm 2 and a wavelength of 1550 nm. By bending the device to different angles, the change in the optoelectronic response of the device is monitored. See Figure 11 , and its change rate is less than 1% compared to the normalized responsivity without applying stress, indicating that the device has good flexible application value.
[0079] Those skilled in the art can easily understand that the above embodiments are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A method for preparing a flexible infrared detection film for an uncooled infrared detector, characterized in that: The preparation steps are as follows: (1) Dry-grinding the phase B powder accounting for 80% to 87.5% of the total mass of the flexible infrared detection film until the powder particles are smaller than 100 mesh, adding conductive carbon black (super-p) accounting for 2.5% to 10% of the total mass of the flexible infrared detection film and uniformly mixing to obtain a mixed powder material; Alternatively, the phase B powder accounting for 90% of the total mass of the flexible infrared detection film is dry-ground until the powder particles are smaller than 100 meshes to obtain a single powder substance; The phase B powder is powdered vanadium dioxide (VO2); (2) Into the mixed powder material, a polytetrafluoroethylene (PTFE) emulsion with a mass concentration of 60% accounting for 16.7% of the total mass of the flexible infrared detection film is added dropwise, and at the same time, isopropanol with a mass 500 times greater than the mass of the polytetrafluoroethylene (PTFE) emulsion is added dropwise to uniformly disperse the emulsion, and the mixture is mixed to obtain a mixture; (3) The mixture is allowed to stand to allow the isopropyl alcohol solvent to evaporate substantially, and the mixture is placed on aluminum foil to obtain a plasticine-like substance; (4) In a roller press, the plasticine-like material and the aluminum foil are repeatedly rolled together to form a film-like material; (5) baking the film to dry, cooling to room temperature, and peeling off the aluminum foil on the film to obtain a self-supporting flexible infrared detection film; The thickness of the flexible infrared detection film is 20 μm to 100 μm; The room temperature TCR of the flexible infrared detection film is not less than 2.96%; The unsupported infrared detection device made of flexible infrared detection film has a detection rate of not less than 5.0×10-1 for infrared light with a wavelength of 1550 nm under a vacuum of less than 10 Pa. 7 Jones, the responsivity is not less than 0.1 A / W.
2. The method for preparing a flexible infrared detection film for an uncooled infrared detector according to claim 1, characterized in that: In step (1), the vanadium dioxide powder particles are rod-shaped particles with a length of 0.3 to 2 μm.
3. The method for preparing a flexible infrared detection film for an uncooled infrared detector according to claim 1, characterized in that: In step (1), the conductive carbon black (super-p) is a spherical particle with a particle size of 50 to 200 nm.
4. The method for preparing a flexible infrared detection film for an uncooled infrared detector according to claim 1, characterized in that: In step (3), the standing time is 10 to 15 minutes.
5. The method for preparing a flexible infrared detection film for an uncooled infrared detector according to claim 1, characterized in that: In step (4), before each rolling, one or more drops of isopropyl alcohol are added to the front and back sides of the object being pressed.
6. The method for preparing a flexible infrared detection film for an uncooled infrared detector according to claim 1, characterized in that: In step (5), the baking conditions are: temperature 70°C, time 20 min, and pressure less than 10 Pa.