Efficient moisture-driven array self-powered sensing system

Abstract

The invention discloses an efficient moisture-driven array self-powered sensing system, and relates to the technical field of energy collection technology and humidity sensitive materials, the array self-powered sensing system comprises a moisture generator array and / or a humidity sensor, humidity sensitive materials of the humidity generator array and the humidity sensor are composite materials composed of carbon quantum dots, graphene oxide and molybdenum trioxide; wherein the mass ratio of the carbon quantum dots to the graphene oxide to the molybdenum trioxide is (0.5-2): (0.5-2): 1. According to the invention, through dual-carbon modification of molybdenum trioxide by carbon quantum dots and graphene oxide and combination of the synergistic effect of the carbon quantum dots, the graphene oxide and the molybdenum trioxide, the response sensitivity, the conductivity and the humidity application range of the humidity sensitive material are remarkably improved, and meanwhile, the energy output performance of a moisture generator is enhanced; the humidity generator array and the humidity sensor realize multi-parameter autonomous monitoring through circuit integration. The intelligent robot multi-mode sensing system has important application value in the fields of intelligent robot multi-mode sensing, ocean and agriculture autonomous monitoring and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy collection and humidity sensitive material, and particularly relates to a high-efficiency humidity-driven arrayed self-powered sensing system. BACKGROUND

[0002] In smart agriculture, plant humidity monitoring is the key to ensuring the healthy growth of plants. Real-time monitoring of plant humidity dynamics not only helps to avoid water waste and soil salinization caused by excessive irrigation, but also prevents crop yield reduction caused by insufficient humidity, which is of great significance to the sustainable development of agriculture. Traditional plant humidity monitoring equipment relies on external power sources such as wired power supply or disposable battery power supply, which has many limitations such as complex deployment, difficult maintenance and insecurity. In addition, some traditional humidity sensors also have slow response speed, narrow detection range and cannot be effectively attached to leaves, which cannot meet the high timeliness and high accuracy requirements of humidity data in smart agriculture, and restricts their application in actual agricultural scenarios.

[0003] Self-powered sensing technology has attracted great attention. New energy technologies such as thermoelectric, triboelectric and piezoelectric can convert small amounts of energy in the surrounding environment into electrical signals for energy supply and information detection, forming self-powered intelligent devices with dual functions of energy collection and sensing. However, although these technologies can convert wind energy and raindrop energy in the agricultural environment into electrical energy, the generation of electrical signals is limited to specific environmental and mechanical vibration conditions, which cannot meet the continuous and stable sensing needs.

[0004] Humidity generators use the ubiquitous and inexhaustible atmospheric water resources to provide a solution for sustainable energy acquisition. Atmospheric water has natural stability and universality in plant growth environments. Whether it is a high-humidity environment formed by irrigation in a greenhouse, dew condensation at night in an open planting area, or water vapor evaporated from the soil surface, it can provide continuous energy input for the humidity generator. Using the humidity generator to realize in-situ non-destructive real-time continuous detection of plant water information has unique advantages and broad application prospects.

[0005] In summary, the current humidity sensors have low humidity detection sensitivity, and the humidity generators have low humidity energy conversion. Therefore, how to provide a high-efficiency humidity-driven arrayed self-powered sensing system with high sensitivity detection and high-efficiency energy conversion is a technical problem that needs to be solved in the field. SUMMARY

[0006] To solve the above problems, the present application provides a high-efficiency humidity-driven arrayed self-powered sensing system.

[0007] To achieve the above purpose, the present application adopts the following technical solutions: The application discloses a high-efficiency humidity-driven array self-powered sensing system, comprising a humidity generator array and / or a humidity sensor; wherein the humidity-sensitive material of the humidity generator array and the humidity sensor is double-carbon modified molybdenum trioxide. The humidity-sensitive material is a composite material composed of carbon quantum dots, graphene oxide and molybdenum trioxide.

[0008] Preferably, the mass ratio of the carbon quantum dots, graphene oxide and molybdenum trioxide is 0.5-2:0.5-2:1.

[0009] Preferably, the mass ratio of the carbon quantum dots, graphene oxide and molybdenum trioxide is 1:0.5:1.

[0010] Preferably, the preparation method of the humidity-sensitive material comprises the following steps: (1) preparing carbon quantum dots: after orange peel is cleaned and dried, the orange peel powder is ground, the orange peel powder and deionized water are mixed, and then the mixture is subjected to hydrothermal reaction at 200-220 DEG C for 12-24 hours; after the reaction is completed, the carbon quantum dots are obtained by filtration; (2) preparing graphene oxide: graphite sheets are dispersed in an acid solution, KMnO4 is added under ice bath, then the mixture is subjected to 30-45 DEG C oil bath, 70-85 DEG C oil bath treatment, finally deionized water and H2O2 are added to perform ultrasonic treatment, centrifugal washing and drying until the mixture is neutral, and then the graphene oxide is obtained; (3) preparing molybdenum trioxide: a molybdenum phosphate hydrate solution and an acetic acid-chitosan solution are mixed, then the mixture is subjected to hydrothermal reaction at 180-200 DEG C for 20-24 hours; after the reaction is completed, the precipitate is washed and dried, then the precipitate is calcined at 500-600 DEG C for 2-3 hours, and then the orthogonal alpha-molybdenum trioxide flower-like microspheres are obtained after cooling; (4) the carbon quantum dots, the graphene oxide and the molybdenum trioxide are prepared into the humidity-sensitive material by electrostatic self-assembly method.

[0011] Preferably, in the step (1), the mass-volume ratio of the orange peel powder and the deionized water is 0.3-1g:25-50mL. The filtration is performed by using filter paper and 0.1-0.22 mu m ultrafiltration membrane in sequence.

[0012] Preferably, in the step (1), the drying is performed at 80 DEG C for 48 hours.

[0013] Preferably, in the step (2), the acid solution is a mixture of H2SO4, H3PO4 and HNO3 with a volume ratio of 60-80:10-30:1-20. The mass-volume ratio of the graphite sheets, the acid solution, KMnO4, deionized water and H2O2 is 1-20g:100-150mL:4-6g:100-120mL:10-15mL.

[0014] Preferably, the concentration of the molybdenum phosphate hydrate solution in step (3) is 0.1-0.5 g / mL; The mass ratio of acetic acid and chitosan in the acetic acid-chitosan solution is 4-8 mL:0.1-0.2 g; The mass-volume ratio of the molybdenum phosphate hydrate and acetic acid is 0.1-0.5 g:4-8 mL; The cooling rate of the cooling and heating is 1-2 ℃ / min.

[0015] Preferably, the humidity sensor comprises a flexible interdigital electrode and a humidity-sensitive material assembled on the flexible interdigital electrode.

[0016] Preferably, the flexible interdigital electrode is prepared by laser etching of a PET-ITO flexible conductive film, and the laser power is 5-10 W.

[0017] Preferably, the PET-ITO film is cleaned with ethanol and deionized water alternately for 3 times before etching and dried at 60-80 ℃ for 12-24 h.

[0018] Preferably, a (PDDA / PSS)2preliminary layer is provided between the flexible interdigital electrode and the sensitive material.

[0019] Preferably, the preliminary layer is formed by alternately immersing the flexible interdigital electrode in PDDA solution and PSS solution for 10 min each, repeating 2 times and then drying.

[0020] Preferably, the concentration of the PDDA solution is 20-38 wt%; The concentration of the PSS solution is 18-30 wt%.

[0021] Preferably, the humidity sensor is constructed by electrostatic self-assembly technology to assemble the humidity-sensitive material on the flexible interdigital electrode.

[0022] Preferably, the common substrate of the humidity generator array is a flexible conductive film, and the vertical and horizontal interlaced non-conductive areas and conductive areas are formed by laser etching, and each of the conductive areas serves as a bottom electrode to assemble the humidity-sensitive material and an aluminum mesh to obtain a humidity generator unit.

[0023] Preferably, the flexible electrode is a PET-ITO flexible electrode.

[0024] Preferably, the aluminum mesh is 20 mesh.

[0025] Preferably, the humidity generator units are connected by copper wires.

[0026] Preferably, the humidity generator array and the humidity sensor are integrated through a circuit board and an alarm is given according to different humidity conditions.

[0027] Preferably, the high-efficiency humidity-driven arrayed self-powered sensing system has important application value in the fields of intelligent robot multi-modal perception, autonomous monitoring of oceans and agriculture, etc.

[0028] Compared with the prior art, the present application has the following beneficial effects: (1) In the present application, the humidity sensor, the humidity generator array and the self-powered sensing system are prepared based on double-carbon modified molybdenum trioxide, combined with flexible electrode design and arrayed integration, and have the advantages of flexibility, integrability, response sensitivity and stability, realizing high-sensitivity humidity detection and high-efficiency humidity energy conversion, and can be widely applied to environmental humidity monitoring, intelligent agriculture and other scenes; (2) The humidity-sensitive material in the present application is double-carbon modified by carbon quantum dots and graphene oxide on molybdenum trioxide, combined with the synergistic effect of the three, which significantly improves the response sensitivity, conductivity and humidity adaptation range of the humidity-sensitive material, and enhances the energy output performance of the humidity generator; (3) The humidity generator prepared in the present application utilizes humidity power generation, and has stable output performance. The arrayed design further improves the energy collection efficiency. The PET-ITO flexible electrode and self-assembly technology are adopted, and the device has good flexibility and mechanical stability, and is suitable for curved surface application. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. The drawings in the description are only embodiments of the present application.

[0030] Figure 1 A humidity generator array structure schematic diagram is provided for the embodiments of the present application. Figure 2 A preparation method flowchart of the carbon quantum dot / graphene oxide / molybdenum trioxide humidity sensor is provided for the embodiments of the present application. Figure 3 Morphology characterization maps of carbon quantum dots, graphene oxide and molybdenum trioxide in the embodiments of the present application are provided. Among them, (a) is the SEM result of alpha-molybdenum trioxide; (b) is the SEM result of graphene oxide; (c) is the high-resolution TEM and lattice fringe analysis result of carbon quantum dots; (d) is the SEM result of carbon quantum dot, graphene oxide and molybdenum trioxide composite material; (e) is the EDS spectrum result of carbon quantum dot, graphene oxide and molybdenum trioxide composite material. Figure 4The graph shows the humidity sensing performance test results of different proportions of carbon quantum dots, graphene oxide, and molybdenum trioxide in the embodiments of the present invention. Among them, (a) shows the change of resistance signal of single carbon quantum dots, graphene oxide, molybdenum trioxide and carbon quantum dot / graphene oxide / molybdenum trioxide composites in the humidity range of 0%RH-97%RH; (b) shows the response characteristics of carbon quantum dots, graphene oxide and molybdenum trioxide composites with different proportions at 43%RH. Figure 5 The image shows the sensing performance test results of the carbon quantum dot / graphene oxide / molybdenum trioxide humidity sensor in this embodiment of the invention. Among them, (a) is the response recovery time result of the carbon quantum dot / graphene oxide / molybdenum trioxide humidity sensor when rapidly switching from 11% RH to 97% RH; (b) is the dynamic resistance response result of the humidity sensor; (c) is the response gradient curve of the humidity sensor; (d) is the response fitting curve of the carbon quantum dot / graphene oxide / molybdenum trioxide humidity sensor in the range of 11-97% RH; (e) is the response change result during the humidity rise / fall cycle; and (f) is the repeatability test result of the carbon quantum dot / graphene oxide / molybdenum trioxide humidity sensor. Figure 6 This is a structural and performance test diagram of the wet generator according to an embodiment of the present invention; Among them, (a) shows the structure of the wet generator; (b) shows the response recovery comparison of the single carbon quantum dot, graphene oxide, molybdenum trioxide wet generator and the carbon quantum dot / graphene oxide / molybdenum trioxide wet generator; (c) shows the dynamic voltage change of the wet generator under different relative humidity values ​​(from 0 to 97% RH); and (d) shows the polarity test results of the wet generator. Figure 7 This is a structural and performance test diagram of the moisture-generating array according to an embodiment of the present invention; Wherein, (a) is the structure of the wet gas power generation array; (b) is the output voltage of different numbers of wet gas generators; Figure 8 This is an application effect diagram of the humidity sensor and humidifier generator according to an embodiment of the present invention; Among them, (a) is the result of a carbon quantum dot / graphene oxide / molybdenum trioxide humidity sensor used for plant humidity detection; (b) is a device that uses skin moisture to generate electricity.

[0031] Figure 9 An array-based self-powered sensing system driven by high efficiency moisture; Among them, (a) is a self-powered sensing system when dry; (b) is a self-powered sensing system when moderate humidity; and (c) is a self-powered sensing system when high humidity. Detailed Implementation

[0032] Embodiments of the present application are described below, examples of which are shown in the accompanying drawings, the embodiments described with reference to the drawings are exemplary and are intended to explain the present application, and are not understood as limiting the present application.

[0033] Example 1 The present application provides a preparation method of a humidity sensitive material based on double carbon modified molybdenum trioxide, which specifically comprises the following steps: (1) Preparation of carbon quantum dots: Fresh orange peel was washed and dried in a drying oven at 80°C for 48h, and then ground into powder for use. 0.3g of orange peel powder was taken and mixed with 50mL of deionized water in a high-pressure reaction kettle, heated at 220°C for 12h, and then naturally cooled. The solution was filtered with filter paper and then filtered with a 0.22μm ultrafiltration membrane to obtain a yellow carbon quantum dot solution. The solution was diluted 10 times with deionized water and stored at -4°C under low temperature; (2) Preparation of graphene oxide by improved Hummers method: 1g of graphite flakes was uniformly dispersed in 100mL of an acid mixture of H2SO4, H3PO4 and HNO3 (volume ratio 70:20:10, wherein the concentration of H2SO4 was 98%, the concentration of H3PO4 was 85%, and the concentration of HNO3 was 68%), and 6g of KMnO4 was slowly added under stirring at 0°C in an ice bath. Then the mixed solution was stirred at 45°C in an oil bath for 2h, and the beaker was placed back in the ice bath, and 100mL of deionized water was slowly added. The beaker was placed in an 85°C oil bath for 1h, and finally 120mL of deionized water and 15mL of H2O2 (30%) were added to the mixed solution, and ultrasonic oscillation treatment was carried out for 1h. The obtained suspension was filtered and centrifuged at 5000rpm for 30min, and washed with deionized water and hydrochloric acid solution until neutral. The obtained precipitate was ultrasonically oscillated for 1h, and finally dried in a 80°C drying oven for 12h to obtain graphene oxide; (3) Preparation of orthorhombic α-molybdenum trioxide: 0.1 g of molybdenum phosphate hydrate was dissolved in 10 mL of deionized water, stirred until completely dissolved to form solution A, 4 mL of acetic acid was added to 6 mL of deionized water and mixed uniformly, then 0.1 g of chitosan (MW = 30000) was added, and stirred until completely mixed to form solution B; solution A and solution B were mixed and stirred uniformly, poured into a high-pressure reaction kettle with a capacity of 50 mL, reacted at a high temperature of 180℃ for 24 h, after the reaction was completed and cooled to room temperature, centrifuged, and the precipitate was washed with deionized water and anhydrous ethanol for 3 times respectively, and the washed precipitate was dried at 60℃ for 12 h to obtain a precursor powder; the precursor powder was loaded into a crucible and calcined in a muffle furnace at 500℃ for 2 h, the heating rate and cooling rate were 1℃ / min, and finally α-molybdenum trioxide flower-like microspheres were obtained; The prepared carbon quantum dots, graphene oxide and molybdenum trioxide materials were characterized, and the results are shown in Figure 3 The SEM analysis of the prepared carbon quantum dots, graphene oxide and molybdenum trioxide materials is shown in Figure 3 (a) and (b) of FIG. 1, the molybdenum trioxide microspheres are composed of irregular nanoparticles, and the graphene oxide is accompanied by wrinkles and folding areas due to the rich oxygen-containing functional groups and structural defects; the HRTEM image of the carbon quantum dots is shown in Figure 3 (c) of FIG. 1, the average size of the carbon quantum dots is 5.45 nm, and the interplanar spacing of the crystal is 0.21 nm, corresponding to the (100) crystal plane of graphite; Figure 3 (d) and (e) of FIG. 1 are SEM and EDS mapping of the carbon quantum dots, graphene oxide and molybdenum trioxide composite material, and it can be seen that each material is uniformly dispersed.

[0034] Example 2 As shown in Figure 2 , the present application provides a preparation of a carbon quantum dot / graphene oxide / molybdenum trioxide humidity sensor, comprising the following steps: (1-1) The carbon quantum dots, graphene oxide and molybdenum trioxide materials prepared in Example 1 are used as prepared; (1-2) Preparation of flexible and transparent interdigital electrode: the ITO on the PET-ITO flexible conductive film is patterned by laser etching to prepare the electrode of the humidity sensor, and the PET-ITO flexible conductive film is cleaned with ethanol and deionized water alternately for three times, and dried in a 60℃ drying box for 12 h, and the electrode for etching patterning is formed by instantaneous decomposition of the ITO film with laser (5W) energy, and the required interdigital electrode pattern is reserved; (1-3) The flexible interdigitated electrode prepared in step (1-2) is cleaned and dried alternately with ethanol and deionized water. The dried interdigitated electrode is immersed in a 38wt% polydiallyldimethylammonium chloride (PDDA) solution and left to stand for 10 min. A uniform positive charge layer is formed on the electrode surface by electrostatic adsorption. After cleaning and drying with deionized water, the electrode is placed in a 30wt% poly(4-styrene sulfonic acid) (PSS) solution and left to stand for 10 min. A negative charge layer is formed on the PDDA layer by electrostatic interaction. After washing and drying, the above steps are repeated to obtain the pre-lead layer film (PDDA / PSS)2. The purpose of this step is to make the humidity-sensitive film firmly and stably connected to the electrode and prevent the humidity-sensitive film from falling off. The dried electrode is placed in a mixed solution of carbon quantum dots / graphene oxide / molybdenum trioxide in different proportions for 20 min, and repeated three times to make the carbon quantum dot / graphene oxide / molybdenum trioxide film adhere to the electrode surface. After drying, a carbon quantum dot / graphene oxide / molybdenum trioxide humidity sensor is obtained. Humidity sensor performance test The sensing performance of a carbon quantum dot / graphene oxide / molybdenum trioxide sensor and the power generation performance of a wet generator were investigated by controlling humidity at room temperature (25℃) using different saturated salt solutions. The results are as follows: To optimize sensor performance and determine the optimal material ratio, the response characteristics of composite materials containing different proportions of carbon quantum dots, graphene oxide, and molybdenum trioxide at 43% RH were tested. Figure 4 As shown in (b), the sensor response reaches its maximum value when the mass ratio of the three materials is 1:0.5:1, further confirming the synergistic enhancement effect among the three. Therefore, this optimal ratio was used in subsequent experiments. When the humidity environment rapidly changes from 11% RH to 97% RH, as shown in (b), the sensor response reaches its maximum value. Figure 5 As shown in (a), the resistance of the carbon quantum dot / graphene oxide / molybdenum trioxide sensor decreased from 13.8 MΩ to 0.6 MΩ, a reduction of two orders of magnitude, and its response / recovery time was as short as 0.8 s / 1.4 s, demonstrating excellent fast response capability. The dynamic resistance response and response gradient curves of the carbon quantum dot / graphene oxide / molybdenum trioxide humidity sensor at different relative humidity levels (0-97%RH) are shown below. Figure 5 As shown in (b) and (c) in the figure, this further demonstrates the excellent sensitivity and responsiveness over a wide humidity range; Figure 5 Figure (d) shows the response fitting curve of the carbon quantum dot / graphene oxide / molybdenum trioxide humidity sensor in the range of 11-97%RH, exhibiting a good linear relationship (R0). 2 =0.972); To examine the reversibility of the sensor, its resistance change during humidity rise / fall cycles was measured, and the hysteresis characteristics of the humidity sensor were calculated accordingly. Figure 5 As shown in (e), the carbon quantum dot / graphene oxide / molybdenum trioxide humidity sensor exhibits minimal hysteresis between 0-97% RH, with the maximum hysteresis value occurring at 75% RH, at only 3.55%, indicating that this humidity sensor has excellent reliability. Figure 5 (f) shows the repeatability test results of the carbon quantum dot / graphene oxide / molybdenum trioxide humidity sensor after switching between three cycles of 33% RH, 52% RH, 85% RH and 11% RH. No obvious response change was observed, which proves that the sensor has excellent stability and repeatability. like Figure 4 As shown in (a), the resistance signals of single carbon quantum dots, graphene oxide, molybdenum trioxide (with the same amount of each component added and the same total amount of all three components), and carbon quantum dot / graphene oxide / molybdenum trioxide composites change within a humidity range of 0%RH-97%RH. The carbon quantum dot sensor exhibits a high resistance (≥200MΩ) over a wider humidity range, and notably, its resistance even exceeds its range (overload) at low humidity (0-23%RH). In contrast, while the graphene oxide sensor can operate across the entire humidity range, its electrical resistance... The resistance change is small (kΩ level), while the molybdenum trioxide sensor only shows a large change in the 23-75%RH range. The change is relatively weak in high and low humidity, which is difficult to meet the signal strength requirements of humidity sensors. The carbon quantum dot / graphene oxide / molybdenum trioxide composite material shows a significant synergistic effect, achieving stable detection in the 0-97%RH humidity detection range. It also shows a more moderate resistance change trend in a wide humidity range, indicating that the introduction of carbon quantum dots and graphene oxide effectively modulates the conductivity of molybdenum trioxide and improves the response sensitivity.

[0035] Example 3 This invention provides a method for preparing a wet generator, specifically including the following steps: The wet generator unit consists of a pair of asymmetric electrodes and a composite material of molybdenum trioxide and carbon quantum dots / graphene oxide / molybdenum trioxide, such as... Figure 6 As shown in (a), the bottom electrode is made of PET-ITO, and the top electrode is an aluminum mesh (20 mesh) to facilitate the passage of water molecules. The carbon quantum dot / graphene oxide / molybdenum trioxide composite material serves as the framework to achieve water absorption and ion migration. The material ratio is 1:0.5:1. Molybdenum trioxide and carbon quantum dot / graphene oxide / molybdenum trioxide are attached to the ITO surface through electrostatic self-assembly. For ease of comparison, a single carbon quantum dot, graphene oxide, and molybdenum trioxide wet generator (with the same amount of each component added and the same total amount of all three components) was constructed using the same method, and relevant performance tests were conducted, such as... Figure 6 As shown in (b), the carbon quantum dot / graphene oxide / molybdenum trioxide wet generator has higher output and faster response / recovery in the face of alternating humidity. This is because the carbon quantum dot / graphene oxide / molybdenum trioxide composite material constructs a more efficient and interconnected moisture and ion transport network, reduces internal resistance, and thus converts chemical energy (adsorption energy) into electrical energy more efficiently. Figure 6 Figure (c) shows the dynamic voltage changes under different relative humidity values ​​(from 0 to 97% RH), demonstrating a significant step voltage response; additionally, as Figure 6 As shown in (d), the output voltage of the wet gas generator reverses the positive and negative signals when the electrodes are reversed, which is consistent with the characteristics of a galvanic cell.

[0036] Example 4 This invention provides a method for fabricating a wet gas generator array, the structure of which is as follows: Figure 1 Specifically, it includes the following steps: To further improve output, a wet gas generator array was designed, such as... Figure 7 As shown in (a), crisscrossing non-conductive regions and nine identical square conductive regions are formed on a PET-ITO flexible conductive film by laser etching. Nine moisture generators are assembled using the PET-ITO conductive regions as bottom electrodes to form a moisture generator array. The array's moisture generator units are connected by copper wires. Under 52% RH conditions, as the number of series-connected moisture generators increases, the voltage output of the moisture generator array increases almost linearly, such as... Figure 7 As shown in (b), when the number of power generation units is increased to 9, the output voltage reaches 3.2V.

[0037] Application examples The carbon quantum dot / graphene oxide / molybdenum trioxide humidity sensor prepared in Example 2 was applied to plant humidity monitoring: To investigate the water status of plants, flexible carbon quantum dot / graphene oxide / molybdenum trioxide humidity sensors were attached to the epidermis of plant leaves and the soil surface, respectively, and continuous monitoring was conducted for 10 days. Prior to formal monitoring, the plants were subjected to a 3-day water deprivation treatment, followed by intermittent watering. A correlation model of plant water status was established based on the detected humidity responses. The response values ​​of the carbon quantum dot / graphene oxide / molybdenum trioxide humidity sensors over time are shown in the figure below. Figure 8As shown in (a) of FIG. 1, the first watering time of the plant is taken as the monitoring starting point, on the first day after the first watering, the response value of the soil humidity sensor reaches 80%, and the response value of the plant leaf humidity sensor is lower than that of the soil but gradually increases, indicating that the soil surface water is sufficient, and the plant starts to absorb water. At this time, the leaf transpiration is strong, and the released water vapor is more; on the second day to the fourth day after the watering treatment, the response values of the soil and plant leaf humidity sensors decrease, indicating that the soil surface water decreases, the plant leaf transpiration gradually weakens, and the water vapor release amount decreases accordingly. On the fourth day, the second watering is performed on the plant, and within one day thereafter, the response values of the two humidity sensors increase, indicating that the transpiration of the plant returns to normal after watering, and the water vapor is released; The carbon quantum dot / graphene oxide / molybdenum trioxide humidity generator prepared in Example 3 is applied to skin humidity generation In order to verify the practical application value of the carbon quantum dot / graphene oxide / molybdenum trioxide humidity generator, based on the principle that the water distribution near the human skin is determined by the distance, the humidity generator can generate electricity by means of the skin humidity, and the non-contact response is as shown in (b) of FIG. 1. Figure 8 As shown in (b) of FIG. 1, when the distance between the finger and the humidity generator is reduced to 5 mm, the output voltage reaches 310 mV.

[0038] The carbon quantum dot / graphene oxide / molybdenum trioxide humidity generator array prepared in Example 3 is combined with the carbon quantum dot / graphene oxide / molybdenum trioxide humidity sensor prepared in Example 2 through a circuit board to form a self-powered humidity sensing system, as shown in (a)-(c) of FIG. 2. Figure 9 As shown in (a)-(c) of FIG. 2, the first red indicator light of the self-powered sensing system is on when it is dry, the second green indicator light of the self-powered sensing system is on when the humidity is moderate, and the third red indicator light of the self-powered sensing system is on when the humidity is high.

[0039] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A high-efficiency moisture-driven arrayed self-powered sensing system, characterized in that, It includes a humidity generator array and / or a humidity sensor; wherein the humidity-sensitive material of the humidity generator array and the humidity sensor is molybdenum trioxide modified with carbon bismuth. The humidity-sensitive material is a composite material composed of carbon quantum dots, graphene oxide, and molybdenum trioxide.

2. The high-efficiency moisture-driven arrayed self-powered sensing system according to claim 1, characterized in that, The mass ratio of the carbon quantum dots, graphene oxide, and molybdenum trioxide is 0.5-2:0.5-2:

1.

3. The high-efficiency moisture-driven arrayed self-powered sensing system according to claim 1, characterized in that, The method for preparing the humidity-sensitive material includes the following steps: (1) Preparation of carbon quantum dots: After washing and drying orange peel, grind it into powder. Mix the orange peel powder with deionized water and carry out a hydrothermal reaction at 200-220℃ for 12-24h. After the reaction is completed, filter to obtain carbon quantum dots. (2) Preparation of graphene oxide: Graphite sheets are dispersed in acid solution, KMnO4 is added under ice bath, and then treated in oil bath at 30-45℃ and 70-85℃ in sequence. Finally, deionized water and H2O2 are added for ultrasonication, centrifugation, washing until neutral and drying to obtain graphene oxide. (3) Preparation of molybdenum trioxide: After mixing molybdenum phosphate hydrate solution with acetic acid-chitosan solution, the mixture is subjected to hydrothermal reaction at 180-200℃ for 20-24h. After the reaction is completed, the precipitate is washed and dried, calcined at 500-600℃ for 2-3h, and then cooled to obtain orthogonal α-molybdenum trioxide flower-shaped microspheres. (4) The carbon quantum dots, the graphene oxide and the molybdenum trioxide are used to prepare a humidity-sensitive material by electrostatic self-assembly.

4. The high-efficiency moisture-driven arrayed self-powered sensing system according to claim 3, characterized in that, The mass-to-volume ratio of orange peel powder and deionized water in step (1) is 0.3-1g:25-50mL; The filtration process employs filter paper and a 0.1-0.22μm ultrafiltration membrane sequentially.

5. The high-efficiency moisture-driven arrayed self-powered sensing system according to claim 3, characterized in that, The acid solution mentioned in step (2) is a mixture of H2SO4, H3PO4 and HNO3 in a volume ratio of 60-80:10-30:1-20; The mass-to-volume ratio of the graphite sheet, acid solution, KMnO4, deionized water, and H2O2 is 1-20g:100-150mL:4-6g:100-120mL:10-15mL; The concentration of the molybdenum phosphate hydrate solution mentioned in step (3) is 0.1-0.5 g / mL; The mass ratio of acetic acid to chitosan in the acetic acid-chitosan solution is 4-8 mL: 0.1-0.2 g; The mass-to-volume ratio of the molybdenum phosphate hydrate to acetic acid is 0.1-0.5 g: 4-8 mL; The cooling and heating rate is 1-2℃ / min.

6. The high-efficiency moisture-driven arrayed self-powered sensing system according to claim 1, characterized in that, The humidity sensor includes a flexible interdigital electrode and a humidity-sensitive material assembled on the flexible interdigital electrode.

7. A humidity sensor according to claim 1, characterized in that, A (PDDA / PSS)2 lead layer is provided between the flexible interdigitated electrode and the sensitive material.

8. The high-efficiency moisture-driven arrayed self-powered sensing system according to claim 1, characterized in that, The common substrate of the moisture generator array is a flexible conductive film. Non-conductive and conductive areas are formed by laser etching. Each conductive area serves as a bottom electrode. The humidity-sensitive material and aluminum mesh are assembled from bottom to top to obtain the moisture generator unit.

9. The high-efficiency moisture-driven arrayed self-powered sensing system according to claim 8, characterized in that, The wet generator units are connected by copper wires.

10. The high-efficiency moisture-driven arrayed self-powered sensing system according to claim 1, characterized in that, The moisture generator array and the humidity sensor are integrated via a circuit board.

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