A two-dimensional near-infrared sensing array based on green light-thermal material and a preparation method and application thereof

Abstract

The application belongs to the field of photoelectric sensors, and specifically discloses a two-dimensional near-infrared sensing array based on green photothermal materials, a preparation method and application thereof.The two-dimensional near-infrared sensing array comprises a polydimethylsiloxane base, an upper electrode layer on the upper surface of the polydimethylsiloxane base, a lower electrode layer on the lower surface of the polydimethylsiloxane base, and an ionic liquid doped with alkali lignin stored in the through hole of the polydimethylsiloxane base.Compared with traditional ionic liquid-based near-infrared sensors, the sensing array prepared by the application has certain flexibility, can identify the near-infrared light intensity of different regions, has long-term stability, is green and environmentally friendly, is low in price, and has a simple structure.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of photoelectric sensors, and particularly relates to a two-dimensional near-infrared sensing array based on green photothermal materials and a preparation method and application thereof. BACKGROUND

[0002] As a new type of liquid electrolyte, ionic liquids have a wide application prospect in the field of electrochemistry and sensors due to their good thermal stability, chemical stability, high ionic conductivity, non-toxicity, biodegradability, moderate viscosity and almost zero vapor pressure. Unlike common electrolyte solutions (mainly salt aqueous solutions), as pure substances, ionic liquids have a variety of cations and anions, and the combination of them can obtain up to 10 18 Considering the excellent fluidity and high temperature sensitivity of the conductivity, ionic liquids have been successfully applied to the development of high-sensitivity temperature sensors (see Adv. Electron. Mater., 2015, 1, 1500029; ACS Sensors, 2017, 2, 449; Adv. Mater., 2015, 27, 4622). In addition, ionic liquids can be doped to obtain specific functional sensors.

[0003] Photothermal conversion materials are a kind of conjugated compounds or polymers with low band gap, which can efficiently convert light energy into heat energy through non-radiative transitions such as intersystem crossing and internal conversion. By means of the photothermal conversion effect and the high thermal sensitivity of the ionic liquid conductivity, the ionic liquid can be compounded with the photothermal conversion material to obtain high-sensitivity detection of specific wavelength light. On this basis, a sensor for detecting the intensity of near-infrared light of a specific wavelength can be prepared. Common photothermal conversion materials, such as polypyrrole (PPy), polyaniline (PAni), polythiophene (PTh), polydopamine (PDA), copper and donor-acceptor (D-A) type conjugated polymers, need to be prepared into nanoparticles to obtain better dispersity and stability in ionic liquids. However, the preparation process of these materials is complex, the raw materials are expensive, and the environmental friendliness is poor. More importantly, the problem of nanoparticle aggregation in ionic liquids will lead to poor long-term stability and extremely limited service life of the device. Therefore, the application range of this kind of near-infrared light sensor is very limited, and it cannot be popularized and commercialized in research institutions such as colleges. SUMMARY

[0004] In view of the problems and deficiencies in the prior art, the purpose of the present application is to provide a two-dimensional near-infrared sensing array based on green photothermal materials and a preparation method and application thereof.

[0005] To achieve the purpose of the application, the technical solutions adopted by the present application are as follows:

[0006] The first part of the present application provides a two-dimensional near-infrared sensing array, comprising: a polydimethylsiloxane substrate, wherein through holes are arranged in an array on the polydimethylsiloxane substrate, an upper electrode layer is sealed and attached to the upper surface of the polydimethylsiloxane substrate, and a lower electrode layer is sealed and attached to the lower surface of the polydimethylsiloxane substrate; an ionic liquid is stored in the through hole cavity; the upper electrode layer and the lower electrode layer are both polydimethylsiloxane films containing silver electrode lines, and the silver electrode lines of the upper electrode layer and the lower electrode layer are both in contact with the ionic liquid.

[0007] According to the two-dimensional near-infrared sensing array described above, further, the ionic liquid is an ionic liquid doped with alkali lignin.

[0008] According to the two-dimensional near-infrared sensing array described above, further, the mass fraction of alkali lignin in the ionic liquid is 0.1%-10%. Preferably, it is 5.0%.

[0009] According to the two-dimensional near-infrared sensing array described above, further, the ionic liquid is any one of 1-octyl-3-methylimidazole acetate ([OMIm][Ac]), 1-butyl-3-methylimidazole acetate ([BMIm][Ac]), and 1-ethyl-3-methylimidazole acetate ([EMIm][Ac]).

[0010] According to the two-dimensional near-infrared sensing array described above, further, the silver electrode lines of the upper electrode layer are vertically staggered with the silver electrode lines of the lower electrode layer.

[0011] According to the two-dimensional near-infrared sensing array described above, further, the thickness of the silver electrode lines is 45-60 nm, and the width is 100 μm.

[0012] According to the two-dimensional near-infrared sensing array described above, further, the length of the silver electrode lines is 0.9 cm.

[0013] The second part of the present application provides a preparation method of the two-dimensional near-infrared sensing array described in the first part, characterized by comprising the following steps:

[0014] (1) punching holes on a polydimethylsiloxane substrate to obtain a polydimethylsiloxane substrate containing array through holes;

[0015] (2) evaporating silver electrode lines on the surface of the polydimethylsiloxane film to obtain an upper electrode layer and a lower electrode layer;

[0016] (3) bonding the upper electrode layer with the upper surface of the polydimethylsiloxane substrate containing arrayed through holes, and bonding the lower electrode layer with the lower surface of the polydimethylsiloxane substrate containing arrayed through holes, to obtain a polydimethylsiloxane two-dimensional array containing cavities; the silver electrode lines of the upper electrode layer are vertically staggered with the silver electrode lines of the lower electrode layer;

[0017] (4) injecting the ion liquid doped with alkali lignin into the cavities, and contacting the ion liquid with the silver electrode lines of the upper electrode layer and the lower electrode layer, to obtain the two-dimensional near-infrared light sensing array.

[0018] According to the preparation method, further, in step (1), the arrayed through holes can be obtained by punching the polydimethylsiloxane substrate using a circular puncher with a diameter of 0.8 cm.

[0019] According to the preparation method, further, in step (2), the thickness and width of the silver electrode lines can be controlled by mask evaporation of silver particles with different masses.

[0020] According to the preparation method, further, in step (3), the bonding temperature is 65-80°C, preferably 65°C, and the bonding time is 8-12 h, preferably 8 h.

[0021] According to the preparation method, further, in step (3), the polydimethylsiloxane film containing silver electrode lines, the upper surface and the lower surface of the polydimethylsiloxane substrate containing arrayed through holes need to be subjected to plasma treatment before bonding. The plasma treatment time can be 2-3 min, preferably 2 min. The plasma treatment atmosphere is limited to oxygen.

[0022] According to the preparation method, further, in step (4), before injecting the composite fluid, two needles are inserted into both sides of a through hole of the polydimethylsiloxane substrate, one needle is connected to a syringe containing the composite fluid, and the other needle is connected to the atmosphere to ensure smooth injection of the composite fluid.

[0023] According to the preparation method, further, in step (4), after injecting the composite fluid, the silver electrode line electrodes are bonded with nano-silver paste, and the nano-silver paste needs to be heated on a hot stage at 60°C for 4 h for solidification after bonding.

[0024] The third part of the present application provides the application of the two-dimensional near-infrared sensing array described in the first part in the preparation of a near-infrared sensor.

[0025] The fourth part of the present application provides the application of the two-dimensional near-infrared sensing array described in the first part in the detection of near-infrared light intensity.

[0026] Compared with the prior art, the application has the following beneficial effects:

[0027] (1) The application uses alkali lignin to replace traditional photo-thermal nanomaterials and composite with ionic liquids as a sensing active layer, and successfully prepares a two-dimensional near-infrared sensing array based on green photo-thermal materials. Compared with traditional ionic liquid-based near-infrared sensors, the application selects a polydimethylsiloxane (PDMS) substrate and a thin film, so that the prepared sensing array has a certain flexibility. By dissolving alkali lignin with photo-thermal conversion capability in ionic liquids, each unit of the prepared sensing array can simultaneously respond to near-infrared light, and also has long-term stability.

[0028] (2) The two-dimensional near-infrared sensing array prepared by the application also has the characteristics of green environmental protection, low price, simple structure and the like. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a physical map of the PDMS substrate containing a 5*5 array of through holes prepared by the application;

[0030] Figure 2 It is a physical map of the PDMS thin film of the evaporated silver electrode array prepared by the application;

[0031] Figure 3 It is a physical map of the device after the PDMS thin film of the evaporated silver electrode array and the PDMS substrate containing a 5*5 array of through holes are combined;

[0032] Figure 4 It is a physical map of the two-dimensional near-infrared sensing array of the ionic liquid filled with doped alkali lignin prepared by the application;

[0033] Figure 5 It is a structural schematic diagram of the two-dimensional near-infrared light sensing array, including a top view and a side view;

[0034] Figure 6 It is a thermal response curve and a thermal imaging photo of the alkali lignin used by the application under different intensity near-infrared light power radiation;

[0035] Figure 7 It is a UV-Vis-NIR absorption spectrum of the ionic liquid doped with 0.1% mass fraction of alkali lignin, wherein the light red area is marked as the range of the near-infrared light I region (780-1000nm);

[0036] Figure 8 It is a long-term stability curve diagram of the two-dimensional near-infrared sensing array prepared by the application 1 for sensing near-infrared light;

[0037] Figure 9The response curve diagram of the two-dimensional near-infrared sensing array prepared in Embodiment 1 of the present application to different radiation powers of near-infrared light, and the fitting curve diagram of the response value and the irradiation power of near-infrared light;

[0038] Figure 10 The response curve diagram of the two-dimensional near-infrared sensing array prepared in the present application containing alkali lignin with different doping amounts;

[0039] Figure 11 The response curve of the near-infrared sensor based on alkali lignin-ion liquid to different regional near-infrared light intensities. DETAILED DESCRIPTION

[0040] The following examples are only used to further illustrate the present application. It should be noted that all the technical and scientific terms used in the present application have the same meaning as those in the technical field to which the present application belongs, unless otherwise specified. The experimental methods not specified in the following examples all use conventional techniques in the technical field, or follow the conditions recommended by the manufacturers; the reagents or instruments not specified by the manufacturers are all conventional products that can be obtained from the market.

[0041] In order to enable those skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application will be described in detail below in combination with specific embodiments.

[0042] Embodiment 1

[0043] A preparation method of a two-dimensional near-infrared sensing array based on green photothermal materials, comprising the following steps:

[0044] (1) 50 mg of alkali lignin was added to 1 g of 1-octyl-3-methylimidazole acetate ([OMIm][Ac]) ionic liquid, and vortexed for 10 min and then ultrasonically treated for 30 min to make the alkali lignin completely dissolved in the ionic liquid, obtaining a uniformly mixed composite fluid, which was prepared for use.

[0045] (2) Sylgard 184 (manufacturer: Dow Corning Corporation, USA) was used as the original material base fluid, and mixed according to a mass ratio of base fluid to crosslinking agent of 10:1, and a polydimethylsiloxane substrate (PDMS substrate) with a thickness of 2 cm was prepared by a mold; a punch with a diameter of 0.8 cm was used to punch the PDMS substrate, obtaining a PDMS substrate containing a 5x5 array of through holes, as shown in Figure 1 The upper and lower spacing and the left and right spacing (center-to-center) of adjacent through holes were both 1.2 cm.

[0046] (3) Prepare two pieces of PDMS film with a thickness of 1 cm, and through a mask plate (DH350E vacuum coating instrument, Hangzhou Dahua Technology Co., Ltd.), evaporate 5 parallel silver electrode lines on the PDMS film, wherein the thickness of the silver electrode line is 45-60 nm, the width is about 100 μm, and the interval between the silver electrode line strips is 1.2 cm, as shown in FIG. 3. Figure 2

[0047] (4) Perform Plasma treatment (model: YZD08-2C, Beijing Zhongke Jiming Technology Co., Ltd., power: 120 W, gas used: oxygen) on the upper and lower surfaces of the PDMS substrate containing a 5x5 array of through holes and the surfaces of the two pieces of PDMS film evaporated with silver electrode arrays for 2 min, after the treatment is completed, along the direction perpendicular to the silver electrode line, attach the two pieces of PDMS film evaporated with silver electrode arrays to the upper and lower surfaces of the PDMS substrate containing a 5x5 array of through holes respectively, and then heat at 65°C for 8 h for bonding to obtain a closed PDMS two-dimensional array containing a cavity, as shown in FIG. 4. Figure 3

[0048] (5) Insert a needle with a diameter of 0.5 mm from each side of the PDMS substrate, and the needle should be in communication with the cavity. Through one of the needles, inject the composite fluid doped with 5.0% by mass alkali lignin prepared in step (1) into the cavity, repeat the above operation until all the cavities are completely filled, as shown in FIG. 5. Figure 4

[0049] (6) Adhere the electrode lead to the exposed silver electrode line with nano-silver paste, and heat on a hot stage at 60° for 4 h to completely cure the nano-silver paste, thereby obtaining a two-dimensional near-infrared light sensing array, which is named [OMIm][Ac]+5.0wt% Lignin, and the physical diagram is shown in FIG. 6, and the structural schematic diagram is shown in FIG. 7. Figure 4 Figure 5

[0050] Example 2

[0051] A two-dimensional near-infrared sensing array [OMIm][Ac]+0.1wt% Lignin based on green photo-thermal material, the preparation method is basically the same as that of example 1, the difference is that in step (1), 1 mg of alkali lignin is added to 1 g of 1-octyl-3-methylimidazole acetate ([OMIm][Ac]) ionic liquid.

[0052] Example 3

[0053] ​​​​​A two-dimensional near-infrared sensing array based on green photo-thermal material, [OMIm][Ac] + 10wt% Lignin, was prepared according to the same procedure as Example 1, except that in step (1), 100 mg of alkali lignin was added to 1 g of 1-octyl-3-methylimidazolium acetate ([OMIm][Ac]) ionic liquid.

[0054] Comparative Example

[0055] The sensing array cavity prepared in this comparative example was filled with ionic liquid without the addition of alkali lignin.

[0056] Performance test

[0057] 1. UV-Vis / NIR absorption spectrum of ionic liquid doped with alkali lignin

[0058] The UV-Vis / NIR absorption test was performed on the composite fluid prepared in step (1) of Example 2 of the present application (doped with ionic liquid with a mass fraction of 0.1%), and the results are shown in Figure 6 From the figure, it can be seen that alkali lignin has a wide absorption in the near-infrared light band (750 nm-1000 nm).

[0059] 2. Thermal response of alkali lignin used in the present application under different intensities of near-infrared light power radiation and thermal imaging

[0060] A near-infrared laser (wavelength 808 nm, Ningbo Yuanming Laser Technology Co., Ltd.) was selected as the near-infrared light source, and the spot area was 0.5 cm 2 The thermal response curve of alkali lignin used in the present application was determined by the following method: alkali lignin powder was pressed into a thin sheet with a diameter of 0.8 cm by a tablet press, and the thin sheet was irradiated by the near-infrared laser for 2 min alternately by turning it on and off, with a spot diameter of 0.8 cm. The radiation power of the near-infrared laser was adjusted from 0.1 W to 1.0 W in increments, and the power of the near-infrared light was 0.1 W, 0.2 W, 0.4 W, 0.6 W, 0.8 W and 1.0 W, respectively. The changes in the temperature of the alkali lignin caused by the near-infrared light were recorded by an infrared camera, and the experimental results are shown in Figure 7 .

[0061] As can be seen from Figure 7 , with the increase of the power of the near-infrared light, the temperature of the alkali lignin increased in the same time, and the temperature reached a stable maximum value in about 40 s, indicating that the alkali lignin has the ability to convert light energy into heat energy.

[0062] 3. Single-point response of the two-dimensional near-infrared light sensing array prepared in the present application to near-infrared light

[0063] A near-infrared laser (wavelength: 808 nm, Ningbo Yuanming Laser Technology Co., Ltd.) was selected as the near-infrared light source, the spot area was 0.5 cm 2 , and the near-infrared light power could be adjusted, and the power adjustment range was set to 0.1 W-1.0 W in the test.

[0064] (1) The radiation power of the near-infrared laser was adjusted to be constant at 0.5 W, and the spot area was 0.5 cm 2 . The electrode lead of the two-dimensional near-infrared sensing array prepared in Example 1 was connected to an electrochemical workstation (model: HI660E, Shanghai Chenhua Instrument Co., Ltd.), and a constant potential scan was performed, the voltage was set to 1.0 V, and the current-time curve was recorded. The change of current with near-infrared light irradiation was observed, the irradiation time of near-infrared light was set to 2 min, and the cooling time was 2 min. Six cycles were continuously performed, and the sensing performance of the device on the 1st, 3rd and 7th days was determined. The calculation of the response value (ΔG / G0) depends on a set formula: ΔG / G0=[1-I / I0]×100%, wherein I represents the real-time current, and I0 represents the initial current at the beginning of the test.

[0065] The experimental results are shown in Figure 8 , and Figure 8 it can be seen that in each of the six cycles on the 1st, 3rd and 7th days, the response value of each cycle is basically the same, that is, under the irradiation of near-infrared light with a radiation power of 0.5 W, the response value on the 1st day is 124.43±2.98%, the response value on the 3rd day is 124.53±4.59%, and the response value on the 7th day is 127.27±3.01%. The response value remains almost unchanged within one week, all around 124%, which indicates that the two-dimensional near-infrared sensing array prepared in the application has long-term stability.

[0066] (2) The electrode lead of the two-dimensional near-infrared sensing array prepared in Example 1 was connected to an electrochemical workstation, and a constant potential scan was performed, the spot area was 0.5 cm 2 , the working voltage was set to 1.0 V, and the current-time curve was recorded. The change of current with near-infrared light irradiation was observed, and the irradiation time of near-infrared light was set to 2 min, and the cooling time was 2 min. Among them, the radiation power of the near-infrared laser was adjusted from 0.1 W to 1.0 W in turn, and the power of the near-infrared light was 0.1 W, 0.2 W, 0.4 W, 0.6 W, 0.8 W and 1.0 W in turn.

[0067] The experimental results are shown in Figure 9 , and the relationship between ΔG / G0 and light power intensity P in the figure is fitted to the following equation:

[0068]

[0069] In the formula, A = 2.292, B = 0.194, and the goodness of fit is 99.97%. From... Figure 9 It can be seen that, between 0.1W and 1.0W, the response value ΔG / G0 of the two-dimensional near-infrared sensing array prepared by the present invention increases with the increase of near-infrared light irradiation power, showing a regular increase.

[0070] (3) The electrode leads of the two-dimensional near-infrared sensor arrays prepared in Examples 1 and 3 of this invention were connected to an electrochemical workstation for constant potential scanning. Simultaneously, a sensor array prepared with an ionic liquid without alkali lignin doping was used as a comparison for simultaneous constant potential scanning. The voltage was set to 1.0V, and the current-time curve was recorded to observe the change in current with near-infrared light irradiation. The near-infrared light irradiation time was set to 2 min, the cooling time to 2 min, and the near-infrared light power to be 0.1W, 0.2W, 0.4W, 0.6W, 0.8W, and 1.0W, respectively. The experimental results are as follows: Figure 10 As shown in the figure, [OMIm][Ac]+0wt%Lignin is the comparative example, [OMIm][Ac]+5.0wt%Lignin corresponds to Example 1, and [OMIm][Ac]+10.0wt%Lignin corresponds to Example 3.

[0071] Depend on Figure 10 It can be seen that, under a certain optical power radiation, the response value ΔG / G0 of the two-dimensional near-infrared transmission array prepared by the present invention increases with the increase of alkali lignin doping amount. That is, under a fixed optical power radiation of 1.0W, as the mass fraction of doped alkali lignin increases from 0.0% to 10.0%, the thermal response value increases from 31.38±1.27% (0%) to 564.55±11.33% (5.0%) and 1668.32±50.26% (10.0%), indicating that the doping amount of alkali lignin affects the response performance of the two-dimensional near-infrared transmission array prepared by the present invention.

[0072] 4. The multi-point simultaneous optical response of the two-dimensional near-infrared optical sensing array prepared by this invention

[0073] A near-infrared laser (wavelength 808nm, Ningbo Yuanming Laser Technology Co., Ltd.) was selected as the near-infrared light source. The spot area of ​​the infrared light can be adjusted, and the near-infrared light power was set to 1.0W in the test.

[0074] The radiation power of the near-infrared laser was adjusted to a constant 1.0W. The electrode leads of the two-dimensional near-infrared transmission array prepared in Example 1 were connected to an electrochemical workstation (model: HI660E, Shanghai Chenhua Instrument Co., Ltd.). A constant potential scan was performed on it, with the voltage set to 1.0V, and the spot area of ​​the near-infrared light was adjusted to 2.25cm². 2The light spot areas on the three sensing units A1B1, A1B2 and A2B1 are different, the current-time curves are recorded, the changes of the current with the near-infrared light are observed, the irradiation time of the near-infrared light is set to 2 min, the cooling time is set to 2 min, and the simultaneous responses of the three sensing units A1B1, A1B2 and A2B1 to the near-infrared light are determined respectively.

[0075] The above experimental results are shown in Figure 11 As can be seen from Figure 11 the different light spot areas on the three sensing units A1B1, A1B2 and A2B1, the response values are also different, which are 64.33%, 23.87% and 8.49% respectively. Similarly, when the light spots with different areas are irradiated on the two units A3B3 and A3B4, different response values are also produced, which indicates that each unit of the two-dimensional near-infrared sensing array prepared in the application can simultaneously produce response to the near-infrared light.

[0076] The above examples are specific embodiments of the application, but the embodiments of the application are not limited by the above examples, and any other combinations, changes, modifications, substitutions, simplifications within the design idea of the application all fall within the protection scope of the application.

Claims

1. A two-dimensional near-infrared sensing array, characterized in that, The polydimethylsiloxane base is provided with through holes arranged in an array on the surface, the upper electrode layer is sealed and attached to the upper surface of the polydimethylsiloxane base, and the lower electrode layer is sealed and attached to the lower surface of the polydimethylsiloxane base; the through hole cavity contains an ionic liquid; the upper electrode layer and the lower electrode layer are both polydimethylsiloxane films containing silver electrode lines, and the silver electrode lines of the upper electrode layer and the lower electrode layer are in contact with the ionic liquid; and the ionic liquid is an ionic liquid doped with alkali lignin.

2. The two-dimensional near infrared sensing array of claim 1, wherein, The mass fraction of alkali lignin in the ionic liquid is 0.1% to 10%.

3. The two-dimensional near infrared sensing array of claim 2, wherein, The ionic liquid is any one of 1-octyl-3-methylimidazole acetate, 1-butyl-3-methylimidazole acetate, and 1-ethyl-3-methylimidazole acetate.

4. The two-dimensional near infrared sensing array of claim 3, wherein, The silver electrode lines of the upper electrode layer and the silver electrode lines of the lower electrode layer are vertically staggered.

5. The method of producing a two-dimensional near infrared sensor array according to any one of claims 1 to 4, characterized in that, The method comprises the following steps: (1) punching holes in the polydimethylsiloxane base to obtain a polydimethylsiloxane base containing an array of through holes; (2) evaporating silver electrode lines on the surface of the polydimethylsiloxane film to obtain an upper electrode layer and a lower electrode layer; (3) bonding the upper electrode layer to the upper surface of the polydimethylsiloxane base containing an array of through holes, and bonding the lower electrode layer to the lower surface of the polydimethylsiloxane base containing an array of through holes to obtain a polydimethylsiloxane two-dimensional array containing cavities; the silver electrode lines of the upper electrode layer and the silver electrode lines of the lower electrode layer are vertically staggered; (4) injecting an ionic liquid doped with alkali lignin into the cavities and allowing the ionic liquid to contact the silver electrode lines of the upper electrode layer and the lower electrode layer to obtain the two-dimensional near-infrared light sensing array.

6. The production method according to claim 5, wherein The bonding temperature in step (3) is 65°C to 80°C, and the bonding time is 8h to 12h.

7. The production method according to claim 6, wherein Before bonding in step (3), the polydimethylsiloxane film containing silver electrode lines, the upper surface and the lower surface of the polydimethylsiloxane base containing an array of through holes need to be treated by plasma.

8. Use of the two-dimensional near-infrared sensing array of any one of claims 1 to 4 in the preparation of a near-infrared sensor.

9. Use of the two-dimensional near-infrared sensing array of any one of claims 1 to 4 in detecting near-infrared light intensity.

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