A low-power thin-film resistor type hydrogen sensor and its preparation method

Abstract

The present invention belongs to the field of sensor technology and relates to a low-power thin-film resistor-type hydrogen sensor and a method for preparing the same. The hydrogen sensor comprises a nanoarray hydrogen sensor, a resistor, and a storage capacitor; the branch where the nanoarray hydrogen sensor is located is connected in parallel with the branch where the storage capacitor is located; the branch where the nanoarray hydrogen sensor is located is provided with a resistor in series; and the branch where the nanoarray hydrogen sensor is located and the branch where the storage capacitor is located are powered by a power supply. The present invention utilizes the nanoarray hydrogen sensor to undergo an electrochemical reaction when excited by hydrogen, turning the nanoarray hydrogen sensor into a conductor, and utilizes the storage capacitor as a power supply to achieve low-power operation of the nanoarray hydrogen sensor. By controlling the operating voltage within a set range, it can ensure that the capacitor can quickly reach a stable state during each charge and discharge process, thereby improving the response speed and efficiency of the entire circuit, and the resistance value obtained by bridge measurement is more accurate and stable.

Description

Technical Field

[0001] The present invention belongs to the technical field of sensors, and in particular relates to a low-power thin film resistor type hydrogen sensor and a preparation method thereof. Background Art

[0002] With the rapid development of sensor detection technology, sensors, as core components for data acquisition, are increasingly being used in various fields. However, the widespread deployment of sensors also raises the issue of energy consumption. In particular, how to effectively conserve energy in field work scenarios has become a hot topic of research.

[0003] Traditional energy-saving technologies primarily achieve energy savings by reducing the power consumption of acquisition chips and other components to a minimum. However, this approach reaches a bottleneck after reaching a certain level, making further energy savings virtually impossible. While these methods did achieve significant energy savings initially, further optimization and efficiency improvements encountered significant bottlenecks. For example, once chip power consumption has already dropped to a very low level, further reductions are very limited; while deep sleep mode saves energy, it also impacts overall system performance. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a low-power thin film resistance type hydrogen sensor and a preparation method thereof.

[0005] In a first aspect, the present invention provides a low-power thin-film resistor hydrogen sensor, comprising a nanoarray hydrogen sensor, a resistor, and a storage capacitor; a branch where the nanoarray hydrogen sensor is located is connected in parallel with a branch where the storage capacitor is located; a resistor is connected in series with the branch where the nanoarray hydrogen sensor is located; and the branch where the nanoarray hydrogen sensor is located and the branch where the storage capacitor is located are powered by a power supply;

[0006] When there is no hydrogen, the nanoarray hydrogen sensor is in an insulating state; when there is hydrogen, the nanoarray hydrogen sensor undergoes an electrochemical reaction and conducts, and the storage capacitor enters a charging state. After charging is completed, the power is turned off, and the storage capacitor enters a discharging state to supply power to the branch where the nanoarray hydrogen sensor is located; after the storage capacitor discharges for a set time, the power is turned on again to allow the storage capacitor to re-enter the charging state.

[0007] In a second aspect, the present invention provides a method for preparing a low-power thin film resistor type hydrogen sensor, comprising:

[0008] A first thin film layer is provided on the base layer, and an insulating layer is provided after exposure and etching according to the circuit of the low-power thin film resistance type hydrogen sensor;

[0009] A second thin film layer is provided on the insulating layer to form electrodes of resistance and capacitance as well as wiring electrodes and wiring of the nano-array hydrogen sensor;

[0010] A polyimide layer is provided on the second film layer, and nano-grooves are formed by processing to provide a substrate template for forming a nano-array palladium nano-film;

[0011] Fabrication of palladium nanofilms using nanogrooves.

[0012] On the basis of the above technical solution, the present invention can also be improved as follows.

[0013] Furthermore, the branch formed by the series connection of the nano-array hydrogen sensor and the resistor is connected in parallel with the storage capacitor.

[0014] Furthermore, the resistance of the resistor is a set ratio of the resistance of the nano-array hydrogen sensor.

[0015] Furthermore, the time constant of the storage capacitor is the product of the sum of the nanoarray hydrogen sensor and the resistor and the capacitance value of the storage capacitor; the power supply is controlled on and off according to the time constant to maintain the voltage of the storage capacitor at a set ratio of the fully charged and discharged voltage.

[0016] Furthermore, the storage capacitor is connected in parallel at both ends of a group of resistors and then connected in series with another resistor to form a first parallel branch; the branch where the nanoarray hydrogen sensor is located is connected in parallel with the first parallel branch at both ends of the power supply.

[0017] Furthermore, the capacitance of the storage capacitor is determined according to the resistance variation range of the nano-array hydrogen sensor.

[0018] Furthermore, the storage capacitor is connected in parallel with the branch where the nano-array hydrogen sensor is located, and the storage capacitor is connected in parallel with the branch where the resistor is located.

[0019] Furthermore, the ratio of the resistor to the resistance of the nanoarray sensor is between 1:10 and 1:1000.

[0020] Furthermore, the insulating layer is glass or a flexible substrate; the second thin film layer is set by depositing a molybdenum or copper film on the insulating layer; the polyimide layer is set by one of spin coating, transfer printing and spraying; the polyimide is physically rubbed or ultraviolet exposed to form nanogrooves.

[0021] The beneficial effects of the present invention are as follows: the nanoarray hydrogen sensor is in a relatively insulating state when there is no hydrogen excitation, and no current is generated in the circuit. When hydrogen is excited, the nanoarray hydrogen sensor undergoes an electrochemical reaction to become a conductor, and a storage capacitor is used as a power supply to achieve low-power operation of the nanoarray hydrogen sensor. By controlling the operating voltage within a set range, it can be ensured that the capacitor can quickly reach a stable state during each charging and discharging process, thereby improving the response speed and efficiency of the entire circuit. Using the storage capacitor as a power supply can alleviate voltage instability caused by power supply fluctuations or ambient temperature changes, thereby making the resistance value measured by the bridge more accurate and stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A circuit schematic diagram of a low-power thin-film resistor type hydrogen sensor according to an optional implementation scheme provided in an embodiment of the present invention;

[0023] Figure 2 A sensor circuit design diagram based on a bridge circuit is provided for an optional implementation of Example 1 of the present invention;

[0024] Figure 3 A sensor circuit design diagram based on a bridge circuit according to an optional implementation scheme provided in Example 1 of the present invention;

[0025] Figure 4 A method for preparing a low-power thin-film resistor type hydrogen sensor provided in Example 2 of the present invention;

[0026] Figure 5 A schematic diagram of the planar structure of a double-layer hydrogen sensor provided in Example 2 of the present invention;

[0027] Figure 6 A diagram showing the stacking of membrane layers of a double-layer hydrogen sensor provided in Example 2 of the present invention;

[0028] Figure 7 A plan view of a single-layer hydrogen sensor provided in Example 2 of the present invention;

[0029] Figure 8 This is a stacking diagram of a single-layer hydrogen sensor provided in Example 2 of the present invention.

[0030] Icon: R1-first resistor; R2-second resistor; R3-third resistor; R4-fourth resistor; R5-fifth resistor; Rs-sth resistor; Rs1-s1st resistor; RX-nanoarray hydrogen sensor; RX1-first nanoarray hydrogen sensor; RX2-second nanoarray hydrogen sensor; C-capacitor; C1-first capacitor; C2-second capacitor; U11-first input port; U12-first output port; U21-second input port; U22-second output port. DETAILED DESCRIPTION

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0032] Example 1

[0033] As an embodiment, to solve the above technical problems, this embodiment provides a low-power thin-film resistance type hydrogen sensor, including a nano-array hydrogen sensor, a resistor and a storage capacitor; the branch where the nano-array hydrogen sensor is located is connected in parallel with the branch where the storage capacitor is located; the branch where the nano-array hydrogen sensor is located is connected in series with a resistor; the branch where the nano-array hydrogen sensor is located and the branch where the storage capacitor is located are powered by a power supply;

[0034] When there is no hydrogen, the nanoarray hydrogen sensor is in an insulating state; when there is hydrogen, the nanoarray hydrogen sensor undergoes an electrochemical reaction and conducts, and the storage capacitor enters a charging state. After charging is completed, the power is turned off, and the storage capacitor enters a discharging state to supply power to the branch where the nanoarray hydrogen sensor is located; after the storage capacitor discharges for a set time, the power is turned on again to allow the storage capacitor to re-enter the charging state.

[0035] The present invention utilizes a nanoarray hydrogen sensor that is relatively insulated when not excited by hydrogen, generating no current. When excited by hydrogen, the nanoarray hydrogen sensor undergoes an electrochemical reaction, becoming a conductor, allowing current to flow through it and allowing the storage capacitor to store charge. When the stored charge in the storage capacitor reaches the power supply voltage, the storage capacitor begins to function as a power source, achieving low power consumption.

[0036] As attached Figure 1 The schematic diagram of the low-power thin-film nanoarray hydrogen sensor is shown. VCC represents the power supply, OUT represents the output terminal of the low-power thin-film resistive hydrogen sensor, GND represents the ground terminal, R1 represents the first resistor, and RX represents the nanoarray hydrogen sensor. Based on constant current source circuit testing, the hydrogen sensor circuit parameters are optimized to achieve a low-power design. When a storage capacitor is connected in parallel with the resistor to be measured, its energy storage property mitigates voltage instabilities caused by power supply fluctuations or ambient temperature changes, making the resistance value measured by the bridge more accurate and stable. Furthermore, because the capacitor can accumulate charge across its terminals, even if the external power supply is temporarily interrupted or the voltage drops, the stored energy allows the circuit to maintain normal operation for a period of time without immediately shutting down, thus achieving energy conservation.

[0037] As an optional implementation, the branch formed by the series connection of the nano-array hydrogen sensor and the resistor is connected in parallel to the storage capacitor.

[0038] The nanoarray hydrogen sensor and resistor are connected in series so that the current flowing through the nanoarray hydrogen sensor and the resistor are exactly the same, forming a precise proportional relationship. For example, if the resistance of the nanoarray hydrogen sensor is 100Ω, the resistance of the resistor should be 1Ω. This proportional relationship effectively reflects the signal changes of the highly sensitive nanoarray hydrogen sensor.

[0039] Optionally, the resistance value of the resistor is a set ratio of the resistance value of the nano-array hydrogen sensor.

[0040] As an optional implementation, the resistance of the resistor is 0.1% to 10% of the resistance of the nano hydrogen sensor (when the nano hydrogen sensor is in a stable state), which can ensure the provision of a stable reference resistance and make the entire circuit more sensitive to changes in hydrogen concentration.

[0041] In actual applications, the selection of capacitors corresponding to storage capacitors needs to take into account multiple factors. If the capacitance value of the capacitor is too small, the power switching frequency will be too high, thereby increasing switching losses and electromagnetic interference, affecting the stability and reliability of the system; on the contrary, if the capacitance value of the capacitor is too large, although the switching frequency can be reduced, the manufacturing process will become more complicated, increasing cost and volume, and it will also introduce more parasitic effects, such as lead inductance and distributed capacitance, which will affect the overall performance of the circuit.

[0042] Optionally, the time constant of the storage capacitor is the product of the sum of the nanoarray hydrogen sensor and the resistor and the capacitance value of the storage capacitor; the power supply is controlled to be turned on and off according to the time constant to maintain the voltage of the storage capacitor at a set ratio of the fully charged and discharged voltage.

[0043] The total resistance of the nanoarray hydrogen sensor RX and the first resistor R1 is R. The time constant of capacitor C is t=R⋅C, where R=RX+R1. Since the resistance of the nanoarray hydrogen sensor RX is much greater than the first resistor R1, the total resistance R is primarily determined by RX. Selecting a capacitor with an appropriate capacitance ensures a moderate time constant t, avoiding excessive switching frequency and complicating the thin film fabrication process. The capacitance value should be selected based on the required response time and stability. To ensure optimal circuit operation, the voltage is controlled between 0.63μV and 0.95μV. This range is based on the charge and discharge characteristics of the capacitor. According to the RC circuit charge and discharge equation, the time and voltage of the capacitor charge and discharge process are related. After the time constant t=R⋅C, the capacitor voltage reaches approximately 63% of its final voltage, or 0.63μV. When the voltage reaches 0.95μV, the capacitor is fully charged or discharged, achieving maximum efficiency and the shortest charge and discharge time. Controlling the operating voltage within the range of 0.63μV to 0.95μV ensures that the capacitor quickly reaches a stable state during each charge and discharge process, thereby improving the response speed and efficiency of the entire circuit. Assuming that the six time points during the capacitor charging time are t1, t2, t3, t4, t5, and t6, and the corresponding voltages are V1, V2, V3, V4, V5, and V6, the relationship between the capacitor charging time and voltage, that is, the voltage corresponding to the time constant, is as follows: when t1 = RC, V1 = 0.63μV; when t2 = 2RC, V2 = 0.86μV; when t3 = 2RC, V3 = 0.86μV; when t4 = 3RC, V4 = 0.95μV; when t5 = 4RC, V5 = 0.98μV; when t6 = 5RC, V6 = 0.99μV. When the highly sensitive nano hydrogen sensor's resistance RX (in a stable state) is 10MΩ, the first resistor R1 can be calculated as 100KΩ using a 100:1 ratio: R = (R1 + RX) = 10.1MΩ. When charging once per second, the equations 1 = 3RC; C = 1 / 3R; C = 1 / (3*10.1MΩ); and C = 33nF. From this, we can calculate that a C = 33nF solution can meet a one-second charge and maintain a voltage between 0.63μV and 0.95μV.

[0044] As an optional embodiment, the storage capacitor is arranged in parallel at both ends of a group of resistors and then connected in series with another resistor to form a first parallel branch; the branch where the nanoarray hydrogen sensor is located is connected in parallel with the first parallel branch at both ends of the power supply.

[0045] Optionally, the capacitance of the storage capacitor is determined according to the resistance variation range of the nano-array hydrogen sensor.

[0046] The capacitance in parallel can be determined by the resistance variation range of the sensor. When used on a sensor with a relatively large resistance variation, a capacitor with a relatively large capacitance should be connected in parallel. Otherwise, a capacitor with a relatively small capacitance should be connected in parallel. This selection of capacitance will allow the sensor detection circuit to achieve energy saving while not consuming a large amount of computing power to calculate the capacitance voltage variation curve. Connect the capacitor C in parallel at both ends of the nanoarray hydrogen sensor RX, and at the same time, the bridge equivalent is obtained as shown in the following figure. Figure 2 In the circuit shown, R1, R2, and Rs represent resistors. R1 is specifically the first resistor, R2 is specifically the second resistor, and Rs is specifically the sth resistor. Based on a bridge circuit, the first resistor R1, the second resistor R2, the nanoarray hydrogen sensor RX, and the sth resistor Rs form a bridge structure. The second resistor R2 and the sth resistor Rs are connected in series, then connected in parallel with the branch connecting the first resistor R1 and the nanoarray hydrogen sensor RX. Capacitor C is connected in parallel across the nanoarray hydrogen sensor RX.

[0047] As an optional embodiment, the storage capacitor is connected in parallel with the branch where the nano-array hydrogen sensor is located, and the storage capacitor is connected in parallel with the branch where the resistor is located. Figure 3 As shown, in a bridge circuit, the first resistor R1, the second resistor R2, the nanoarray hydrogen sensor RX, and the sth resistor Rs form the four arms of the bridge structure. The second resistor R2 is connected in series with the sth resistor Rs, and the nanoarray hydrogen sensor RX is connected in series with the first resistor R1. The second resistor R2 and the sth resistor Rs are connected in series, and then connected in parallel with the series branch of the first resistor R1 and the nanoarray hydrogen sensor RX, as well as the branch containing capacitor C. This results in a low-power nanoarray hydrogen sensor bridge circuit.

[0048] Optionally, the ratio of the resistor to the resistance of the nanoarray sensor is between 1:10 and 1:1000.

[0049] Such a proportional design makes the voltage drop on the nanoarray hydrogen sensor much greater than the resistance, thereby effectively reflecting the signal changes of the highly sensitive nano-hydrogen sensor.

[0050] Example 2

[0051] Based on the same principle as the method shown in Example 1 of the present invention, as shown in the attached Figure 4 As shown, an embodiment of the present invention further provides a method for preparing a low-power thin film resistor type hydrogen sensor, comprising:

[0052] A first thin film layer is provided on the base layer, and an insulating layer is provided after exposure and etching according to the circuit of the low-power thin film resistance type hydrogen sensor;

[0053] A second thin film layer is provided on the insulating layer to form electrodes of resistance and capacitance as well as wiring electrodes and wiring of the nano-array hydrogen sensor;

[0054] A polyimide layer is provided on the second film layer, and nano-grooves are formed by processing to provide a substrate template for forming a nano-array palladium nano-film;

[0055] Fabrication of palladium nanofilms using nanogrooves.

[0056] The present invention realizes a high-precision resistor manufacturing process through thin film technology, which can ensure that the resistance value of the resistor maintains extremely high stability and precision during the production process, making the entire circuit more sensitive to changes in hydrogen concentration.

[0057] Optionally, the insulating layer is glass or a flexible substrate; the second thin film layer is set by depositing a molybdenum or copper film on the insulating layer; the polyimide layer is set by one of spin coating, transfer printing and spraying; the polyimide is physically rubbed or ultraviolet exposed to form nanogrooves.

[0058] Specifically, when preparing a double-layer hydrogen sensor, as shown in the following Figure 5 As shown in FIG, when the first thin film layer is provided on the base layer, a molybdenum or copper thin film is first formed on the glass substrate or flexible substrate with a thickness in the range of 100 to 1000 nanometers. Figure 6 The circuit diagram shown in the design is exposed and etched. R3 is the third resistor, RX1 is the first nano-array hydrogen sensor, and C1 is the first capacitor. A first input port U11 is provided on one side of the first capacitor C1, and a first output port U12 is provided on the other side. Then a 200-1000 nanometer insulating layer is made. The insulating layer can be silicon nitride or silicon dioxide, and is exposed and etched according to the circuit diagram. Then a molybdenum or copper film is made consistent with the requirements of the first film layer to form the electrodes of the resistor and capacitor and the wiring electrodes and wiring of the hydrogen sensor. Then a polyimide layer is made with a thickness of 10-200 nanometers. It can be spin-coated, transferred, or sprayed, and nano-grooves are formed by physical friction or ultraviolet light exposure to provide a substrate template for the formation of the nano-array palladium film. Finally, a 3-30 nanometer palladium film is made according to the nano-groove characteristics of the substrate material.

[0059] Specifically, when preparing a single-layer hydrogen sensor, as shown in FIG. Figure 7 As shown, first, a molybdenum or copper film is deposited on a glass or flexible substrate to obtain a first thin film layer with a thickness of 100 to 1000 nanometers, in order to form the following Figure 8The fourth resistor R4, the fifth resistor R5, the second nano-array hydrogen sensor RX2, the s1st resistor Rs1, and the electrodes of the second capacitor C2 are shown. The second capacitor C2 is provided with a second input port U21 on one side and a second output port U22 on the other side. Then, an insulating layer of silicon nitride or silicon dioxide is formed with a thickness of 200 to 1000 nanometers to provide an insulating substrate for the substrate of the second nano-array hydrogen sensor RX2. Then, a polyimide substrate with a thickness of 10 to 200 nanometers is made. Then, the polyimide is physically rubbed or ultraviolet exposed to form nano-grooves, providing a substrate template for forming the array palladium film. Finally, a 3 to 30 nanometer thin film is produced.

[0060] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A low-power thin film resistor type hydrogen sensor, characterized in that: The invention comprises a nano-array hydrogen sensor, a resistor and a storage capacitor; the branch where the nano-array hydrogen sensor is located is connected in parallel with the branch where the storage capacitor is located; the branch where the nano-array hydrogen sensor is located is connected in series with a resistor; the branch where the nano-array hydrogen sensor is located and the branch where the storage capacitor is located are powered by a power supply; When there is no hydrogen, the nanoarray hydrogen sensor is in an insulating state; when there is hydrogen, the nanoarray hydrogen sensor undergoes an electrochemical reaction and turns on, and the storage capacitor enters a charging state. After charging is complete, the power is turned off, and the storage capacitor enters a discharging state to supply power to the branch where the nanoarray hydrogen sensor is located; after the storage capacitor discharges for a set time, the power is turned back on to allow the storage capacitor to re-enter the charging state; the time constant of the storage capacitor is the product of the sum of the nanoarray hydrogen sensor and the resistor and the capacitance value of the storage capacitor; the power is controlled to be turned on and off according to the time constant, and the resistance value of the resistor is 0.1% to 10% of the resistance value of the nanoarray hydrogen sensor, so that the voltage of the storage capacitor is maintained at a set ratio of the fully charged and discharged voltage, so that the voltage of the storage capacitor is controlled to operate between 0.63μV and 0.95μV.

2. A low-power thin film resistance type hydrogen sensor according to claim 1, characterized in that: The branch formed by connecting the nano-array hydrogen sensor and the resistor in series is connected in parallel with the storage capacitor.

3. A low-power thin film resistance type hydrogen sensor according to claim 1, characterized in that: The storage capacitor is connected in parallel at both ends of a group of resistors and then in series with another resistor to form a first parallel branch. The branch where the nano-array hydrogen sensor is located is connected in parallel with the first parallel branch at both ends of the power supply.

4. A low-power thin film resistance type hydrogen sensor according to claim 3, characterized in that: The capacitance of the storage capacitor is determined according to the resistance variation range of the nano-array hydrogen sensor.

5. A low-power thin film resistance type hydrogen sensor according to claim 1, characterized in that: The storage capacitor is connected in parallel with the branch where the nano-array hydrogen sensor is located, and the storage capacitor is connected in parallel with the branch where the resistor is located.

6. A method for preparing a low-power thin-film resistor type hydrogen sensor based on the low-power thin-film resistor type hydrogen sensor according to claim 1, characterized in that: include: A first thin film layer is provided on the base layer, and an insulating layer is provided after exposure and etching according to the circuit of the low-power thin film resistance type hydrogen sensor; A second thin film layer is provided on the insulating layer to form electrodes of resistance and capacitance as well as wiring electrodes and wiring of the nano-array hydrogen sensor; A polyimide layer is provided on the second film layer, and nano-grooves are formed by processing to provide a substrate template for forming a nano-array palladium nano-film; Fabrication of palladium nanofilms using nanogrooves.

7. The method for preparing a low-power thin film resistor type hydrogen sensor according to claim 6, characterized in that: The insulating layer is a glass or flexible substrate; the second thin film layer is formed by depositing a molybdenum or copper film on the insulating layer; the polyimide layer is formed by spin coating, transfer printing and spraying; and the polyimide is physically rubbed or ultraviolet exposed to form nanogrooves.

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