Self-driven artificial tactile sensor array and preparation method thereof

Abstract

The invention discloses a self-driven artificial tactile sensor array and a preparation method thereof, the self-driven artificial tactile sensor array comprises a plurality of units arranged in an array, and each unit comprises a friction nanometer generator and a synaptic transistor; the friction nanometer generator comprises a first substrate, a first friction layer and a second friction layer, the first friction layer comprises a first branch part and a second branch part, the first branch part is arranged on the first substrate, the second branch part is arranged on the first branch part, and the second branch part is in a zigzag shape; the synaptic transistor comprises a second substrate, an active region and a gate dielectric layer, the active region is arranged on the second substrate, the gate dielectric layer covers the exposed surface of the active region, and the gate dielectric layer is reused as a second friction layer of the friction nano-generator; and the second branch part of the first friction layer is in contact with and separated from the second friction layer to generate triboelectricity. According to the invention, the self-driven bionic touch function can be realized.

Description

Technical Field

[0001] The present invention belongs to the field of communication technology, and in particular relates to a self-driven artificial tactile sensor array and a preparation method thereof. Background Art

[0002] In recent years, with the rapid development of artificial synaptic devices, researchers have achieved the organic combination of flexible sensors and artificial synaptic devices to simulate the functions of biological neural synapses, and applied them to the field of bionic perception, realizing the conversion of external stimuli (such as light, pressure, smell, etc.) into electrical signals, so that the system can respond similarly to the biological sensory system according to the external environment, and has made a series of attractive research progress in artificial perception systems such as tactile perception systems and visual perception systems. Transistor-based synaptic bionic devices are becoming increasingly prominent due to their good stability, controllable test parameters and clearer operating mechanisms. Among them, double-layer synaptic transistors can migrate and accumulate under the influence of electric field induction, thereby changing the channel conductivity characteristics because the ions in their gate dielectric layer can move freely. The gate electrode in the transistor can be regarded as the presynaptic membrane, the channel layer can be regarded as the postsynaptic membrane, and the channel conductance can be regarded as the synaptic weight. This synapse-like working mode is expected to develop ultra-low energy consumption artificial synaptic devices on this basis.

[0003] In 2012, Wang Zhonglin's team first proposed the friction nanogenerator, which uses the characteristics of friction electrification and charge transfer, and has unique advantages in the field of energy collection and sensing. Combining the friction nanogenerator with the synaptic transistor, the friction potential can not only serve as a power source to drive the synaptic transistor, but also link the spatiotemporal information generated by external mechanical stimulation with the output signal. Active interactive self-driven sensing is used to achieve synaptic plasticity, logical functions and bionic applications in artificial touch, neuromorphic learning, etc. However, in the self-driven tactile sensors that appear today, the friction nanogenerator and the synaptic transistor are two separate parts, and the friction electric signal is simply interconnected with the transistor through wires, which has problems of transmission loss and low transmission efficiency. In addition, the preparation process of the two separate parts is separate, cumbersome and complicated, and has not formed a truly unified whole. There are still certain limitations in device integration.

[0004] Therefore, it is urgent to develop a new type of self-driven artificial tactile sensor array and its preparation method to solve the above technical problems. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a self-driven artificial tactile sensor array and a preparation method thereof. The technical problem to be solved by the present invention is achieved by the following technical solutions:

[0006] In a first aspect, the present invention provides a self-driven artificial tactile sensor array, comprising: a plurality of units arranged in an array, wherein the unit is a whole composed of a friction nanogenerator and a synaptic transistor;

[0007] The friction nanogenerator comprises a first substrate, a first friction layer and a second friction layer, the first friction layer comprises a first branch and a second branch, the first branch is arranged on the first substrate, the second branch is arranged on the first branch, and the second branch is sawtooth-shaped;

[0008] The synaptic transistor includes a second substrate, an active region and a gate dielectric layer, wherein the active region is arranged on the second substrate, the gate dielectric layer covers the exposed surface of the active region, and the gate dielectric layer is reused as a second friction layer of the friction nanogenerator;

[0009] The second branch of the first friction layer contacts and separates from the second friction layer, generating friction electricity.

[0010] In a second aspect, the present invention further provides a method for preparing a self-driven artificial tactile sensor array, comprising:

[0011] A friction layer array is prepared, wherein the friction layer array includes a plurality of friction nanogenerators arranged in an array, wherein the friction nanogenerator includes a first substrate, a first friction layer, and a second friction layer, wherein the first friction layer includes a first branch and a second branch, wherein the first branch is arranged on the first substrate, and the second branch is arranged on the first branch, and the second branch is serrated;

[0012] A synaptic transistor array is prepared, wherein the synaptic transistor array includes a plurality of synaptic transistors arranged in an array, wherein the synaptic transistor includes a second substrate, an active region and a gate dielectric layer, wherein the active region is arranged on the second substrate, the gate dielectric layer covers the exposed surface of the active region, and the gate dielectric layer is reused as a second friction layer of the friction nanogenerator;

[0013] The second branch of the first friction layer contacts and separates from the second friction layer, generating friction electricity.

[0014] Beneficial effects of the present invention:

[0015] The present invention provides a self-driven artificial tactile sensor array and a preparation method thereof, comprising 4×4 independent units composed of a friction layer array and a synaptic transistor array, wherein the independent units comprise a friction nanogenerator and a synaptic transistor, and the self-driven artificial tactile sensor comprises a flexible substrate, an active area formed on the substrate, a source and a drain formed on the active area, wherein the source, the drain and the active area form a whole; the whole is covered with a gate dielectric layer, wherein the material of the gate dielectric layer is ion gel, the gate dielectric layer is reused as the second friction layer of the friction nanogenerator, and a first friction layer constituting the friction nanogenerator is spaced apart from the gate dielectric layer by a certain gap, and the first friction layer is attached to the flexible substrate constituting the friction nanogenerator; the second branch of the first friction layer contacts and separates from the second friction layer, thereby generating friction electricity and affecting the conductive properties of the active area. Structurally, the ion gel serves as the gate dielectric layer of the synaptic transistor, and the gate dielectric layer is reused as the second friction layer of the friction nanogenerator, so that the friction nanogenerator and the synaptic transistor form a highly integrated unified structure. The first friction layer in the friction nanogenerator contacts or separates from the second friction layer to generate a pulse voltage, forming a corresponding induced charge in the active area, changing the conductive properties of the active area, and generating a synaptic current between the source and the drain without external power supply, thereby realizing a self-driven bionic tactile function; in terms of materials, the ion gel serves as the gate dielectric layer of the synaptic transistor, and forms a double electric layer structure at the gate dielectric layer / oxide semiconductor interface, generating a huge capacitance, thereby inducing an extremely high carrier concentration, so that the synaptic transistor can operate at an extremely low voltage.

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of a self-driven artificial tactile sensor array provided by an embodiment of the present invention;

[0018] Figure 2 is a schematic diagram of a unit provided by an embodiment of the present invention;

[0019] Figure 3 (a) is a schematic diagram of a first friction layer provided by an embodiment of the present invention as a negative friction electrode sequence material;

[0020] 3(b) is a schematic diagram of a first friction layer provided by an embodiment of the present invention as a positive friction electrode sequence material;

[0021] Figure 4 is a schematic diagram of an equivalent circuit of a self-driven artificial synaptic transistor provided by an embodiment of the present invention;

[0022] Figure 5 is a schematic diagram of a transfer characteristic curve of an indium oxide transistor provided by an embodiment of the present invention;

[0023] Figure 6 is a transistor I provided in an embodiment of the present invention d A schematic diagram of changes over time. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below with reference to specific embodiments, but the embodiments of the present invention are not limited thereto.

[0025] In the existing technology, Professor Bao Zhennan's research group used distributed carbon nanotube pressure sensors, organic ring oscillators and organic synaptic transistors to prepare a 2×3 array of flexible artificial synaptic sensors. The pressure information is converted into the input voltage signal of the synaptic transistor through the coupling of the piezoresistive sensor and the ring oscillator, realizing the artificial nerve fiber that senses tiny mechanical movements. However, since the piezoresistive sensor used has low sensitivity and requires external power supply; the three components of the system have different device structures and working principles, resulting in different preparation processes and independent functional device structures, it is difficult to prepare highly integrated and sensitive array tactile sensors, which seriously limits its application in human-computer interaction, intelligent perception and other directions.

[0026] Sun Qijun's team combined a piezoelectric nanogenerator with an ion gel-gated graphene transistor to build an artificial tactile sensing device. As a self-powered mechanical sensor, the piezoelectric nanogenerator converts the external strain amplitude and frequency into a specific pulse signal and transmits it to the transistor gate, further regulating the charge carriers of the graphene channel. This piezoelectric artificial sensory neuron can simulate the biological stimulus receptors, transmission neurons and synapses in the human sensory nervous system to achieve the perception, transmission and processing of external stimuli. However, the tactile sensor realized by combining the piezoelectric nanogenerator with a transistor needs to be deformed to a certain extent before the tactile sensor can be activated, and there are specific requirements for the frequency and amplitude of mechanical movement. At the same time, the piezoelectric generator and the transistor are only simply interconnected by wires, which has problems such as transmission loss and low transmission efficiency. Moreover, the preparation processes of the two parts are independent of each other, making it difficult to prepare a highly integrated tactile sensor array.

[0027] In summary, (1) most of the current bionic tactile sensors are capacitive sensors or piezoresistive sensors based on external voltage. Both types of sensors are not sensitive to external mechanical changes and require external voltage drive, which greatly limits their working environment and practicality, and require complex circuit design to match with synaptic transistors to achieve bionic tactile function; (2) As a self-powered mechanical sensing device, the friction nanogenerator can directly convert external mechanical signals into electrical signals without power drive, but its function as a tactile sensor is single, which is a certain gap compared with the bionic tactile sensor. At the same time, in the reported self-driven tactile sensors, the friction nanogenerator and the synaptic transistor are two independent parts, and the friction electric signal is simply interconnected with the transistor through a wire, which has problems such as transmission loss and low transmission efficiency. In addition, the preparation processes of the functional units of the device are independent of each other, and a truly unified whole has not been achieved. There are still certain limitations in device integration.

[0028] In response to the challenges faced by bionic tactile perception, it is urgent to design an artificial tactile sensor array with low power consumption, high sensitivity and easy integration; specifically: based on a flexible substrate, the tactile sensor can fit the surface of the biological body better and achieve conformal integration; the gate dielectric layer of the synaptic transistor is reused as the friction layer of the nanogenerator, and the friction electricity directly acts on the synaptic transistor, and the friction nanogenerator and the synaptic transistor form a highly integrated unified structure; the electrolyte serves as the gate dielectric layer, forming a double electric layer structure with the oxide semiconductor layer, generating a huge capacitance, which can induce an extremely high carrier concentration at the interface, enabling the transistor to work normally at extremely low voltage; the active area and the source and drain electrodes of the synaptic transistor adopt an in-situ growth process method to continuously deposit different materials in the same cavity, effectively improving the uniformity and purity of the material surface, reducing the interface impedance between the electrode and the active area, enhancing the bonding force between the oxide semiconductor and the source and drain electrodes, improving the stability and service life of the device, simplifying the process flow while avoiding problems such as environmental pollution introduced by process separation.

[0029] See also Figure 1 and Figure 2 , Figure 1 is a schematic diagram of a self-driven artificial tactile sensor array provided by an embodiment of the present invention, Figure 2 is a schematic diagram of a unit provided by an embodiment of the present invention. A self-driven artificial tactile sensor array provided by the present invention comprises: a plurality of units 10 arranged in an array, the unit 10 comprises a friction nanogenerator 20 and a synaptic transistor 30;

[0030] The friction nanogenerator 20 includes a first substrate 21, a first friction layer 22, and a second friction layer. The first friction layer 22 includes a first branch 22-1 and a second branch 22-2. The first branch 22-1 is arranged on the first substrate 21, and the second branch 22-2 is arranged on the first branch 22-1. The second branch 22-2 is sawtooth-shaped.

[0031] The synaptic transistor 30 includes a second substrate 31, an active region 32 and a gate dielectric layer 33. The active region 32 is disposed on the second substrate 31. The gate dielectric layer 33 covers the exposed surface of the active region 32. The gate dielectric layer is reused as a second friction layer of the friction nanogenerator.

[0032] The second branch 22-2 of the first friction layer 22 is in contact with and separated from the second friction layer, generating friction electricity. It can be understood that the second branch of the first friction layer is sawtooth-shaped, which can increase the contact area and increase the output voltage of the friction nanogenerator.

[0033] In an optional embodiment of the present invention, the material of the first substrate 21 and the second substrate 31 includes any one of hydrogel (hyaluronic acid-dopamine gel), polyimide (PI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polydimethylsiloxane (PDMS), and polycarbonate (PC).

[0034] It should be noted that both the first substrate and the second substrate are flexible substrates, so that the sensor manufactured in this embodiment can be more easily attached to the surface of an object to achieve conformal integration.

[0035] It should be emphasized that the material of the first substrate 21 and the second substrate 31 is hydrogel, so that the first substrate 21 and the second substrate 31 can be firmly attached to the surface of the object, and conformal integration can be easily achieved. The hydrogel is similar to the extracellular matrix in nature, has excellent biocompatibility, and has high oxygen permeability and moisturizing properties. It can maintain the comfort of the wearing part for a long time and reduce dryness and hypoxia problems.

[0036] In an optional embodiment of the present invention, the material of the first friction layer 22 includes one of nylon, wool, silk, rubber, nitrile, copper foil, aluminum foil, polytetrafluoroethylene, polypropylene, polyethylene, polydimethylsiloxane, and polyimide.

[0037] In an optional embodiment of the present invention, the synaptic transistor 30 further includes an active region, a source and a drain (not shown in the figure), the source and the drain are located on the active region 32, and the source and the drain are spaced apart;

[0038] Among them, the materials of the active region include In 2 O 3, any one of IZO, IGO, and IGZO, with a thickness of the active region of 20 to 30 nm; the source and drain are made of the same material, including any one of aluminum, ITO, Au, Cr-Au, and Ti-Au, with a thickness of 35 to 50 nm, and a channel length of 60 to 200 μm and a width of 800 to 6000 μm between the source and the drain.

[0039] In an optional embodiment of the present invention, the material of the gate dielectric layer 33 includes one or more of an electrolyte solution, an ionic liquid, an ion gel, an ion conductive polymer, or a proton conductive polymer.

[0040] Specifically, the self-driven artificial tactile sensor array provided in this embodiment includes 4×4 independent units 10 composed of a friction layer array 40 and a synaptic transistor array 50, the independent unit 10 includes a friction nanogenerator 20 and a synaptic transistor 30, and the self-driven artificial tactile sensor includes a flexible substrate, an active area 32 formed on the substrate, a source and a drain (not shown in the figure) formed on the active area 32, and the source, the drain and the active area 32 form a whole; the whole is covered with a gate dielectric layer 33, the material of the gate dielectric layer 33 is ion gel, the gate dielectric layer 33 is reused as the second friction layer of the friction nanogenerator, and a certain gap is separated from the gate dielectric layer 33 to form a first friction layer 22 constituting the friction nanogenerator 20, and the first friction layer 22 is attached to the friction nanogenerator. On the flexible substrate of the generator 20; in addition, an elastic medium is arranged around the flexible substrate of the friction nanogenerator 20, and the elastic medium is also arranged on the flexible substrate of the synaptic transistor 30, so that the friction nanogenerator 20 is movably connected with the synaptic transistor 30. It can also be understood that the friction nanogenerator 20 and the synaptic transistor 30 move relative to each other, and the two achieve relative approach movement through the elastic medium, that is, the second branch 22-2 of the first friction layer 22 contacts the second friction layer, and the two achieve relative divergence movement through the elastic medium, that is, the second branch 22-2 of the first friction layer 22 contacts and separates from the second friction layer. In this way, friction electricity is generated, which affects the conductive properties of the active area 32. The material of the elastic medium can be any one of springs, rubber, silicone, and elastic fibers. Among them, the ion gel serves as the gate dielectric layer 33 of the synaptic transistor and the second friction layer of the friction nanogenerator 20, realizing the organic combination of the friction nanogenerator 20 and the synaptic transistor 30. The structure is simple, light and flexible. The first friction layer 22 contacts and separates with the second friction layer to generate a pulse voltage, forming a corresponding induced charge in the active area 32, changing the conductive properties of the active area 32, and realizing a self-driven bionic tactile function without external power supply, that is, a synaptic current between the source and the drain.

[0041] It should be noted that Figure 1 The illustrated embodiment only schematically shows the positional relationship between the friction layer array and the synaptic transistor array, and does not represent the actual size. Figure 2 The illustrated embodiment only schematically shows the positional relationship of the various film layers included in the unit and does not represent the actual size thereof.

[0042] Based on the same inventive concept, Figure 3 As shown, Figure 3 (a) is a schematic diagram of a first friction layer provided in an embodiment of the present invention as a negative friction electrode sequence material, 3 (b) is a schematic diagram of a first friction layer provided in an embodiment of the present invention as a positive friction electrode sequence material, the present invention also provides a method for preparing a self-driven artificial tactile sensor array, which is used to prepare the self-driven artificial tactile sensor array provided in the above embodiment of the present invention. The embodiment of the self-driven artificial tactile sensor array is referred to above and will not be described in detail here; please continue to combine Figure 1 and Figure 2 As shown, the preparation method comprises:

[0043] A friction layer array 40 is prepared, wherein the first friction layer 22 array includes a plurality of friction nanogenerators 20 arranged in an array, the friction nanogenerator 20 includes a first substrate 21, a first friction layer 22, and a second friction layer, the first friction layer 22 includes a first branch 22-1 and a second branch 22-2, the first branch 22-1 is arranged on the first substrate 21, the second branch 22-2 is arranged on the first branch 22-1, and the second branch 22-2 is serrated;

[0044] A synaptic transistor array 50 is prepared, wherein the synaptic transistor array 50 includes a plurality of synaptic transistors 30 arranged in an array, wherein the synaptic transistor 30 includes a second substrate 31, an active region 32, and a gate dielectric layer 33, wherein the active region 32 is disposed on the second substrate 31, and the gate dielectric layer 33 covers the exposed surface of the active region 32, and the gate dielectric layer is reused as a second friction layer of the friction nanogenerator;

[0045] The second branch 22 - 2 of the first friction layer 22 contacts and separates from the second friction layer, thereby generating friction electricity.

[0046] In an optional embodiment of the present invention, the preparation process of the friction nanogenerator 20 includes:

[0047] The surface of the first substrate 21 is ultrasonically cleaned with an organic solvent and deionized water respectively to remove organic pollutants attached to the surface of the first substrate 21, wherein the thickness of the first substrate 21 is 150 μm; the organic solvent may be acetone or isopropanol;

[0048] Polydimethylsiloxane (PDMS) and a curing agent were mixed in a mass ratio of 10:1 and stirred for 20 minutes, and vacuum degassed for 20 minutes to remove bubbles to form a mixture;

[0049] The mixture was spin-coated on a sawtooth groove mold at a speed of 500 rpm for 60 seconds, and after heat curing at 85° C. for 1 hour, the first friction layer 22 with a sawtooth surface microstructure was peeled off, wherein the height of the sawtooth surface microstructure was 5 μm, and the side length of the bottom square was 5 μm, wherein the height of the sawtooth surface microstructure refers to the dimension in a direction perpendicular to the first substrate 21;

[0050] The first friction layer 22 is prepared on the first substrate 21 .

[0051] In an optional embodiment of the present invention, the preparation process of the synaptic transistor 30 includes:

[0052] The surface of the second substrate 31 is ultrasonically cleaned with an organic solvent and deionized water respectively to remove organic pollutants attached to the surface of the second substrate 31, wherein the thickness of the second substrate 31 is 150 μm; wherein the organic solvent may be acetone or isopropanol;

[0053] A 25 nm thick active region 32 is deposited on the surface of the second substrate 31 by using a radio frequency magnetron sputtering system; wherein the material of the active region 32 is indium oxide (In 2 O 3 ), during magnetron sputtering, the RF power is 100 W, the sputtering pressure in the cavity is 0.3 Pa, the sputtering gas is argon, the argon flow rate is 30 sccm, and the deposition rate is 2.5 nm / min;

[0054] A 40 nm thick ITO (Indium tantalum) layer is deposited on the upper surface of the active region 32 by using a radio frequency magnetron sputtering system. 2 O 3 :SnO 2 =90:10wt%), forming a source and a drain respectively; wherein the length of the channel region between the source and the drain is 125μm, the width is 1600μm, during magnetron sputtering, the ignition pressure is 2Pa, the RF power is 50W, the sputtering pressure in the cavity is 0.65Pa, the sputtering gas is argon, the argon flow rate is 20sccm, and the deposition rate is 7nm / min;

[0055] The ionic liquid 1-ethyl-3-methylimidazoline bis(trifluoromethylsulfonyl)imide [(EMI)(TFSA)] is placed in a vacuum drying oven at 70°C and dried for 24 hours. Polyvinylidene fluoride-co-hexafluoropropylene [P(VDF-HFP)], ionic liquid [(EMI)(TFSA)] and acetone are mixed in a mass ratio of 1:4:7, and stirred at 50°C and 500 rpm using a magnetic heating stirrer for about 4 hours to obtain an ion gel precursor solution. The ion gel precursor solution is covered on the active area 32, the source and the drain by screen printing to form a gate dielectric layer, and the gate dielectric layer is reused as the second friction layer of the friction nanogenerator.

[0056] Specifically, in this embodiment, please continue to refer to Figure 3 , a self-driven artificial tactile sensor composed of a friction nanogenerator 20 and a synaptic transistor 30, the ion gel gate dielectric layer 33 is reused as the second friction layer of the friction nanogenerator, and the second friction layer and the first friction layer 22 above form a friction nanogenerator 20. When the first friction layer 22 and the second friction layer are in contact at the interface, due to the different attraction of different materials to electrons, opposite positive and negative charges will be induced on both sides of the interface. Figure 3 As shown in (a), when the first friction layer 22 is a negative friction electrode sequence material, due to the principle of electrostatic induction, the ion gel gate dielectric layer 33 will induce positive charge. When the gap in the friction nanogenerator 20 changes, there is a potential difference between the surface charge of the ion gel and the internal charge, which causes the ions in the electrolyte to migrate. Directed positive ions appear at the interface between the ion gel gate dielectric layer 33 and the semiconductor layer, which is equivalent to In 2 O 3 The semiconductor layer provides a positive gate voltage, causing In 2 O 3 The Fermi level rises. Figure 3 As shown in (b), when the first friction layer 22 is a positive friction electrode sequence material, due to the principle of electrostatic induction, the ion gel gate dielectric layer 33 will induce negative charges, and there is a potential difference between the surface charge of the ion gel and the internal charge, which causes the ions in the electrolyte to migrate, and directional negative ions appear at the interface between the ion gel gate dielectric layer 33 and the semiconductor layer, which is equivalent to In 2 O 3 The semiconductor layer provides a negative gate voltage, causing In 2 O 3 The Fermi level of the transistor decreases. Since the ion gel is used as the gate dielectric layer 33, the ion concentration and distribution therein are controlled by the gate voltage, thereby adjusting the conductive properties of the transistor. This adjustment is similar to the neurotransmitter release and receptor binding process in biological synapses, so it can achieve functions similar to biological synapses.

[0057] In an optional embodiment of the present invention, both the growth of the active region 32 and the deposition of the source and drain on the upper surface of the active region 32 adopt an in-situ growth process, and the deposition of different materials is continuously performed in the same cavity.

[0058] Specifically, in this embodiment, in terms of the preparation method, the active region 32, source and drain electrodes of the synaptic transistor are all prepared by an in-situ growth process. On the one hand, the same measurement and control sputtering process is adopted to continuously deposit different materials in the same chamber, thereby simplifying the process flow while avoiding problems such as environmental pollution introduced by process separation. On the other hand, the in-situ growth process can improve the surface uniformity and purity of the material, reduce the interface impedance between the electrode and the active region, enhance the bonding force between the oxide semiconductor and the source and drain electrodes, and improve the stability and service life of the device.

[0059] The process of preparing the active area, source and drain by in-situ growth process is as follows:

[0060] S1. Start the equipment and load the sample. Start the cold water tank and main power supply. Open the nitrogen inlet valve. Wait until the pressure in the chamber reaches 10 5 Pa, close the air inlet valve and put in the sample.

[0061] S2, start the mechanical pump and molecular pump in sequence, and evacuate the chamber until the pressure reaches 10 -4 Pa.

[0062] S3, growth of indium oxide in the active area; select indium oxide target, preheat RF source, and adjust ignition pressure; set argon flow rate to 30sccm, and adjust gate valve to make the pressure inside the chamber about 2Pa; open target baffle, turn on RF power for ignition, and observe glow discharge inside the cavity; set power to 100W, and adjust gate valve to reduce cavity pressure to 0.3Pa; start sample stage rotation, and pre-sputter indium oxide for 5min to clean target surface and ensure deposition uniformity; after pre-sputtering, open sample baffle and formally sputter indium oxide for 10min to ensure uniformity and thickness of active area film; after sputtering, close sample baffle, stop argon flow, stop sample stage rotation, and turn off RF source.

[0063] S4. Replace the target material and mask in situ; while maintaining the vacuum in the chamber, use the target rotation mechanism to switch from the indium oxide target to the ITO (indium tin oxide) target for the deposition of the source and drain; in the chamber, use the automatic mask switching system to replace the mask used for the active area with the mask for the source and drain to ensure deposition in the correct position.

[0064] S5, in-situ growth of source and drain ITO; preheat the RF source and adjust the starting pressure; set the argon flow rate to 20sccm, adjust the gate valve to make the internal pressure of the chamber 2Pa; open the target baffle and start the RF power supply for starting; set the RF power supply power to 50W, adjust the gate valve to reduce the chamber pressure to 0.65Pa, and start the deposition of source and drain ITO; start the sample stage rotation and pre-sputter ITO for 5min to remove possible oxide layer or contamination on the target surface; after the pre-sputtering, open the sample baffle and formally sputter ITO, the deposition time of the source and drain is 7min to ensure the uniformity of the film and sufficient conductivity; after the sputtering, close the sample baffle, set the argon flow rate to 0, stop the sample stage rotation, and turn off the RF source.

[0065] S6. Close the argon pressure reducing valve and the air inlet valve; open the gate valve and pump air for 5 minutes; after the pumping is completed, close the gate valve, gradually reduce the system pressure, shut down the molecular pump, and after it stops completely, close the front valve and the mechanical pump in turn, and inject protective gas pressure for sampling.

[0066] In an optional embodiment of the present invention, see Figures 4 to 6 , Figure 4 is a schematic diagram of an equivalent circuit of a self-driven artificial synaptic transistor provided by an embodiment of the present invention, Figure 5 is a schematic diagram of a transfer characteristic curve of an indium oxide synaptic transistor provided by an embodiment of the present invention, Figure 6 The indium oxide synaptic transistor I provided in the embodiment of the present invention d A schematic diagram of the change over time, from Figure 5 It can be seen that the curve presents a parabolic shape, where the source-drain voltage is fixed at 0.5V, and the gate voltage is cyclically double-sweeped from -5V to 2V. Due to the charge trapping effect, the transfer curve of the transistor forms a storage window; Figure 6 The transistor I is shown in the process of reciprocating contact and separation between the first friction layer 22 and the ion gel gate dielectric layer 33 on the PET substrate. d The curve of the change over time, where the source-drain voltage V ds =0.5V, by Figure 6 It can be seen that when the contact separation frequency is low, I d As the change over time stabilizes, when the frequency increases, I d As time goes by, it increases steadily. When there is no contact separation, I d Stable without change.

[0067] In summary, the present invention provides a self-driven artificial tactile sensor array and a preparation method thereof, which have the following beneficial effects:

[0068] 1. The friction nanogenerator 20 is cleverly combined with the synaptic transistor 30. The gate dielectric layer directly reuses the nanogenerator friction layer, and the friction nanogenerator and the synaptic transistor form a highly integrated unified structure. The friction nanogenerator 20 is used as a sensor to collect external tactile information. Compared with traditional piezoresistive and capacitive sensors, it has higher sensitivity and is simpler to operate. The friction nanogenerator 20 converts the mechanical signal into an electrical pulse signal and inputs it into the synaptic transistor 30, generating a synaptic current between the source electrode and the drain electrode, thereby preparing a low-power, highly sensitive, integrated artificial bionic tactile sensor.

[0069] 2. The ion gel as the gate dielectric layer 33 forms a double electric layer structure at the interface, generating a huge capacitance, which can induce a very high carrier concentration on the surface of the oxide semiconductor, so that the synaptic transistor can be operated at a very low voltage (V ds =0.1V). At the same time, the ion gel acts as the gate dielectric layer 33 and also as the second friction layer of the friction nanogenerator 20, realizing the real organic combination of the friction nanogenerator 20 and the synaptic transistor 30. By changing the material of the first friction layer 22, the gate voltage is directly generated by friction on the ion gel dielectric layer, and the output characteristics of the transistor are further regulated. It has the advantages of simple structure, easy integration, low power consumption, low delay, etc.

[0070] 3. The ion gel is used as the gate dielectric layer 33, and the ion concentration and distribution therein are controlled by the gate voltage, thereby adjusting the conductive properties of the transistor. This regulatory effect is similar to the neurotransmitter release and receptor binding process in biological synapses, so the function of mimicking biological synapses can be achieved.

[0071] 4. The active area and source and drain electrodes of the synaptic transistor adopt an in-situ growth process method to continuously deposit different materials in the same cavity, effectively improving the uniformity and purity of the material surface, reducing the interface impedance between the electrode and the active area, enhancing the bonding force between the oxide semiconductor and the source and drain electrodes, and improving the stability and service life of the device. While simplifying the process flow, it avoids problems such as environmental pollution introduced by process separation.

[0072] 5. Using hydrogel polymer as a flexible substrate can firmly adhere to the surface of an object and easily achieve conformal integration. The hydrogel is similar to the extracellular matrix in nature and has excellent biocompatibility. It also has high oxygen permeability and moisturizing properties, which can maintain the comfort of the wearing area for a long time and reduce dryness and hypoxia problems.

[0073] 6. The first friction layer 22 has a serrated surface microstructure, which increases the contact area and enhances the output voltage of the friction nanogenerator 20.

[0074] 7. An artificial tactile sensor based on a friction nanogenerator 20, wherein the first friction layer 22 includes materials with a relatively positive friction electrode sequence, such as nylon, wool, silk, rubber, nitrile, copper foil or aluminum foil; and materials with a relatively negative friction electrode sequence, including polytetrafluoroethylene, polypropylene, polyethylene, polydimethylsiloxane or polyimide.

[0075] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant is intended to cover non-exclusive inclusion, so that the article or device including a series of elements includes not only those elements, but also other elements that are not explicitly listed. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the article or device including the elements. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The orientation or position relationship indicated by "up", "down", "left", "right", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0076] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification.

[0077] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A self-driven artificial tactile sensor array, characterized in that: include: A plurality of array-arranged units, each unit comprising a triboelectric nanogenerator and a synaptic transistor; The friction nanogenerator comprises a first substrate, a first friction layer and a second friction layer, the first friction layer comprises a first branch and a second branch, the first branch is arranged on the first substrate, the second branch is arranged on the first branch, and the second branch is sawtooth-shaped; The synaptic transistor comprises a second substrate, an active region and a gate dielectric layer, wherein the active region is arranged on the second substrate, the gate dielectric layer covers the exposed surface of the active region, and the gate dielectric layer is reused as the second friction layer of the friction nanogenerator; The second branch of the first friction layer contacts and separates from the second friction layer, thereby generating friction electricity.

2. The self-driven artificial tactile sensor array according to claim 1, characterized in that: The material of the first substrate and the second substrate includes any one of hydrogel, polyimide, polyethylene naphthalate, polyethylene terephthalate, polydimethylsiloxane, and polycarbonate.

3. The self-driven artificial tactile sensor array according to claim 1, characterized in that: The material of the first friction layer includes any one of nylon, wool, silk, rubber, nitrile, copper foil, aluminum foil, polytetrafluoroethylene, polypropylene, polyethylene, polydimethylsiloxane, and polyimide.

4. The self-driven artificial tactile sensor array according to claim 1, characterized in that: The synaptic transistor further comprises an active region, a source and a drain, wherein the source and the drain are located on the active region and are spaced apart from each other; Among them, the material of the active area includes any one of In2O3, IZO, IGO, and IGZO, and the thickness of the active area is 20 to 30 nm; the material of the source and the drain is the same, including any one of aluminum, ITO, Au, Cr-Au, and Ti-Au, and the thickness of the source and the drain is the same, which is 35 to 50 nm, and the channel length between the source and the drain is 60 to 200 μm, and the width is 800 to 6000 μm.

5. The self-driven artificial tactile sensor array according to claim 1, characterized in that: The material of the gate dielectric layer includes one or more of an electrolyte solution, an ionic liquid, an ionic gel, an ion conductive polymer or a proton conductive polymer.

6. A method for preparing a self-driven artificial tactile sensor array, comprising: Prepare a friction layer array, wherein the friction layer array includes a plurality of friction nanogenerators arranged in an array, wherein the friction nanogenerator includes a first substrate, a first friction layer, and a second friction layer, wherein the first friction layer includes a first branch and a second branch, wherein the first branch is disposed on the first substrate, and the second branch is disposed on the first branch, and the second branch is serrated; Prepare a synaptic transistor array, wherein the synaptic transistor array includes a plurality of synaptic transistors arranged in an array, wherein the synaptic transistor includes a second substrate, an active region and a gate dielectric layer, wherein the active region is disposed on the second substrate, the gate dielectric layer covers the surface exposed by the active region, and the gate dielectric layer is reused as a second friction layer of the friction nanogenerator; The second branch of the first friction layer contacts and separates from the second friction layer, thereby generating friction electricity.

7. The method for preparing a self-driven artificial tactile sensor array according to claim 6, characterized in that: The preparation process of the friction nanogenerator includes: ultrasonically cleaning the surface of the first substrate using an organic solvent and deionized water respectively to remove organic pollutants attached to the surface of the first substrate; The material for forming the first friction layer and the curing agent are mixed and stirred in a preset mass ratio, and vacuum degassed to remove bubbles to form a mixture; The mixture is spin-coated on a mold having a serrated groove at a preset speed, and after heat curing at a preset temperature, peeled off to obtain a first friction layer with a serrated surface microstructure, wherein the height of the serrated surface microstructure is 4 to 6 μm, and the side length of the bottom square is 4 to 6 μm; The first friction layer is prepared on the first substrate.

8. The method for preparing a self-driven artificial tactile sensor array according to claim 6, characterized in that: The preparation process of the synaptic transistor includes: ultrasonically cleaning the surface of the second substrate using an organic solvent and deionized water respectively to remove organic pollutants attached to the surface of the second substrate; A radio frequency magnetron sputtering system is used to deposit a material of a specific shape for forming an active area on the surface of the second substrate; in the magnetron sputtering process, one or more of In2O3, ZnO, and Ga2O3 are selected as sputtering targets, argon is used as an inert carrier gas, the sputtering power is 50 to 100 W, the sputtering pressure is 0.3 to 0.5 Pa, and the deposition rate is 2 to 6 nm / min; A radio frequency magnetron sputtering system is used to deposit a material for forming a source and a drain on the upper surface of the active area; in the magnetron sputtering process, one or more of metal aluminum, ITO, Au, Cr, and Ti are selected as sputtering targets, argon is used as an inert carrier gas, the sputtering power is 50 to 100 W, the sputtering pressure is 0.5 to 0.7 Pa, and the deposition rate is 6 to 8 nm / min; The material for forming the gate dielectric layer is mixed with the corresponding solvent in a preset mass ratio, and stirred using a magnetic heating stirrer to obtain a precursor solution; the precursor solution is covered on the active area, the source electrode and the drain electrode by screen printing, spin coating or dropper transfer to form the gate dielectric layer, and the gate dielectric layer is reused as the second friction layer of the friction nanogenerator.

9. The method for preparing a self-driven artificial tactile sensor array according to claim 6, characterized in that: The active region is grown and the source and drain are deposited on the upper surface of the active region by an in-situ growth process, and different materials are deposited continuously in the same cavity.

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