Loose nanocluster microcolumn and preparation method thereof, array electrode and preparation method and application thereof

Abstract

The invention belongs to the technical field of electrochemistry, and particularly relates to a loose nanocluster microcolumn and a preparation method thereof, an array electrode and a preparation method and application thereof. Compared with a preparation method in the prior art, the temperature-induced self-assembly-based aerosol jet micro-column 3D printing method provided by the invention has the advantages that loose nanocluster micro-columns prepared by the temperature-induced self-assembly-based aerosol jet micro-column 3D printing method have the multi-scale characteristic from a nanometer scale to a micrometer scale; the multi-scale characteristic brings excellent surface area improvement, compared with a smooth and compact nanoparticle microcolumn, the surface area is improved by 50%, and the microcolumn structure also has the characteristics that the nanoscale characteristic is adjustable, the length-diameter ratio is up to 17 times, and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemistry, and particularly relates to a loose nanocluster microcolumn, a preparation method thereof, an array electrode, a preparation method thereof and an application thereof. Background Art

[0002] Existing micron-scale columnar structures are mostly prepared by means such as mechanical processing, photolithography processing, stereolithography 3D printing, direct writing 3D printing, etc. However, mechanical processing and direct writing 3D printing have low processing accuracy and it is difficult to prepare high-precision and complex microcolumn structures; photolithography processing and stereolithography 3D printing are only applicable to silicon-based semiconductor materials and photosensitive resin materials, and the processable materials are limited. In addition, when preparing a conductive microcolumn structure by the above two processing methods, it is also necessary to sputter a conductive layer on the surface, resulting in a complex preparation process. In addition, the microcolumns prepared based on the above process methods are mostly single-scale structures, which limits the further improvement of their surface area.

[0003] Therefore, there is a need to provide a new method for preparing micron-scale columnar structures, which can further simplify the preparation process, and the microcolumn size is controllable and the surface area is larger. Summary of the Invention

[0004] The purpose of the present invention is to provide a loose nanocluster microcolumn, a preparation method thereof, an array electrode, a preparation method thereof and an application thereof.

[0005] In order to achieve the above purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a preparation method of a loose nanocluster microcolumn, comprising the following steps:

[0007] After atomizing the printing ink, the aerosol droplets formed after preheating form clusters; the average particle size of the clusters is not less than 245 nm;

[0008] Using a protective gas as a carrier gas, spraying the clusters on the surface of a substrate by aerosol jet printing to obtain the loose nanocluster microcolumn; the temperature of the substrate is not less than the evaporation temperature of the solvent in the printing ink.

[0009] Preferably, the particle size of the aerosol droplets is normally distributed in the range of 1-10 μm.

[0010] Preferably, the printing ink comprises nanoparticles, a surfactant and a solvent;

[0011] The nanoparticles include one or more of silver nanoparticles, gold nanoparticles, copper nanoparticles, carbon nanotubes and graphene;

[0012] The particle size of the nanoparticles is 2-50 nm;

[0013] The mass concentration of the nanoparticles in the printing ink is 5-30%.

[0014] Preferably, the surfactant includes polyvinylpyrrolidone; the mass of the surfactant is 5-10% of the mass of the nanoparticles;

[0015] The solvent includes deionized water and ethylene glycol, and the mass ratio of the deionized water to the ethylene glycol is 6:1-60:1.

[0016] Preferably, the conditions for aerosol jet printing include: the distance between the print head and the substrate is 1-5 mm, the printing speed is 0.1-1 mm / s, and the inner diameter of the print head is 150-600 μm; the flow rate of the delivery gas flow at the nozzle is 30 sccm, and the flow rate of the focusing gas flow is 15 sccm. The types of the delivery gas flow and the focusing gas flow are the same as the type of the carrier gas.

[0017] The present invention also provides a loose nanocluster microcolumn prepared by the preparation method described in the above technical solution. The aspect ratio of the loose nanocluster microcolumn is 3-17; the height of the loose nanocluster microcolumn is 200 μm-1 mm.

[0018] The present invention also provides a preparation method for an array electrode, including the following steps:

[0019] After atomizing the printing ink, the generated aerosol droplets are preheated to form clusters; the average particle size of the clusters is not less than 245 nm;

[0020] Using a protective gas as the carrier gas, the clusters are subjected to aerosol jet printing on the surface of the substrate to obtain a loose nanocluster microcolumn in an array structure; the temperature of the substrate is not less than the evaporation temperature of the solvent in the printing ink;

[0021] Sintering the loose nanocluster microcolumn in the array structure to obtain the array electrode.

[0022] Preferably, the sintering temperature is 300 °C and the heat preservation time is 1 h.

[0023] The present invention also provides an array electrode prepared by the preparation method described in the above technical solution.

[0024] The present invention also provides an application of the array electrode described in the above technical solution as a gate electrode in an organic electrochemical transistor.

[0025] The present invention provides a method for preparing loose nanocluster microcolumns, comprising the following steps: after atomizing printing ink, the generated aerosol droplets are preheated to form clusters; the average particle size of the clusters is not less than 245 nm; using a protective gas as a carrier gas, the clusters are subjected to aerosol jet printing on the surface of a substrate to obtain the loose nanocluster microcolumns; the temperature of the substrate is not less than the evaporation temperature of the solvent in the printing ink.

[0026] Compared with the preparation methods in the prior art, the present invention provides an aerosol jet microcolumn 3D printing method based on temperature-induced self-assembly. The loose nanocluster microcolumns prepared by this temperature-induced self-assembly aerosol printing method have multi-scale characteristics from the nanoscale to the microscale. This multi-scale characteristic brings excellent surface area improvement. Compared with smooth and dense nanoparticle microcolumns, the surface area is increased by 50%. Moreover, the microcolumn structure also has adjustable nanoscale characteristics and a length-to-diameter ratio of up to 17 times. Description of the Drawings

[0027] Figure 1 Schematic diagram of aerosol jet printing in the present invention;

[0028] Figure 2 SEM image of the loose nanocluster microcolumns obtained in Example 1;

[0029] Figure 3 SEM image of the smooth and dense nanoparticle microcolumns obtained in Comparative Example 1;

[0030] Figure 4 SEM image of the dense nanocluster microcolumns obtained in Comparative Example 2;

[0031] Figure 5 Schematic diagram of the structure of an organic electrochemical transistor sensor based on a microcolumn array gate electrode in Test Example 2;

[0032] Figure 6 Test results of the diffusion ability of different electrode types in Test Example 2;

[0033] Figure 7 SEM images of the smooth and dense nanoparticle microcolumns obtained in Comparative Example 1 and the loose nanocluster microcolumns obtained in Example 1 after loading reduced graphene oxide;

[0034] Figure 8 Simulation diagrams of the surface electric field distribution of three types of electrodes: the smooth and dense nanoparticle microcolumns obtained in Comparative Example 1, the dense nanocluster microcolumns obtained in Comparative Example 2, and the loose nanocluster microcolumns obtained in Example 1;

[0035] Figure 9 Comparative test of the amplification ability of transistors with the electrodes obtained in Examples 4 to 6 and Comparative Examples 3 and 5 as gate electrodes;

[0036] Figure 10 It is a test result graph of the response behavior of organic electrochemical transistors with array electrodes obtained based on Example 4, planar electrodes of Comparative Example 3, and different concentrations of dopamine. Detailed implementation manners

[0037] The present invention provides a method for preparing loose nanocluster microcolumns, comprising the following steps:

[0038] After atomizing the printing ink, the generated aerosol droplets are preheated to form clusters; the average particle size of the clusters is not less than 245 nm;

[0039] Using a protective gas as a carrier gas, spraying the clusters on the surface of a substrate by aerosol jet printing to obtain the loose nanocluster microcolumns; the temperature of the substrate is not less than the evaporation temperature of the solvent in the printing ink.

[0040] In the present invention, after atomizing the printing ink, the generated aerosol droplets are preheated to form clusters.

[0041] In the present invention, the printing ink preferably comprises nanoparticles, a surfactant, and a solvent; the nanoparticles preferably comprise one or more of silver nanoparticles, gold nanoparticles, copper nanoparticles, carbon nanotubes, and graphene; the particle size of the nanoparticles is preferably 2 - 50 nm; the mass concentration of the nanoparticles in the printing ink is preferably 5 - 30%, specifically it can be 5%, 10%, 15%, 20%, 25%, 30%. In the present invention, the surfactant preferably comprises polyvinylpyrrolidone; the mass of the surfactant is preferably 5 - 10% of the mass of the nanoparticles; the solvent preferably comprises deionized water and ethylene glycol, and the mass ratio of the deionized water to the ethylene glycol is preferably 6:1 - 60:1, more preferably 16:1.

[0042] Before atomization, the present invention also preferably comprises ultrasonic dispersion of the printing ink, and the time of the ultrasonic dispersion is preferably 30 min. Ultrasonic dispersion can ensure the uniform dispersion of the nanoparticles.

[0043] In the present invention, the power of the atomization is preferably 20 W. The present invention has no special limitation on the atomization process, and those well-known to those skilled in the art can be adopted. In the present invention, the particle size of the aerosol droplets preferably follows a normal distribution in the range of 1 - 10 μm.

[0044] The present invention does not have special limitations on the preheating temperature, as long as it can cause the aerosol droplets to form clusters. In the present invention, the average particle size of the clusters is not less than 245 nm, and more preferably 530 nm. In the present invention, when the particle size of the nanoparticles is a fixed value, the diameter of the clusters is preferably positively correlated with the mass concentration of the nanoparticles in the printing ink, that is, the diameter of the clusters increases with the increase of the mass concentration of the nanoparticles; for example, when the particle size of the nanoparticles is 30 - 50 nm and the mass concentration of the nanoparticles in the printing ink is 5%, the average particle size of the clusters is 245 nm; when the particle size of the nanoparticles is 30 - 50 nm and the mass concentration of the nanoparticles in the printing ink is 30%, the average particle size of the clusters is 664 nm, and so on.

[0045] After obtaining the clusters, the present invention uses a protective gas as the carrier gas to perform aerosol jet printing of the clusters on the surface of the substrate to obtain the porous nano - cluster micro - columns.

[0046] In the present invention, the protective gas preferably includes nitrogen. In the present invention, the conditions for aerosol jet printing preferably include: the distance between the print head and the substrate is 1 - 5 mm, the printing speed is 0.1 - 1 mm / s, the inner diameter of the print head is 150 - 600 μm; the flow rate of the delivery gas at the nozzle is 30 sccm, the flow rate of the focusing gas is 15 sccm, and the types of the delivery gas and the focusing gas are the same as the type of the carrier gas.

[0047] The present invention does not have special limitations on the type of the substrate, and those well - known to those skilled in the art can be used. In a specific embodiment of the present invention, the substrate preferably includes a ceramic substrate, a metal plate or a PI flexible film, and the material of the metal plate preferably includes aluminum or copper. In the present invention, the temperature of the substrate is not less than the evaporation temperature of the solvent in the printing ink.

[0048] The process flow schematic diagram of the preparation method provided by the present invention is as Figure 1 shown.

[0049] The present invention also provides a porous nano - cluster micro - column prepared by the preparation method described in the above technical solution. The aspect ratio of the porous nano - cluster micro - column is 3 - 17; the height of the porous nano - cluster micro - column is 200 μm - 1 mm.

[0050] In the present invention, when the height of the porous nano - cluster micro - column is 200 μm and the diameter is 60 μm, the surface area of the porous nano - cluster micro - column is preferably 0.1 cm 2 ; when the height of the porous nano - cluster micro - column is 1 mm and the diameter is 60 μm, the surface area of the porous nano - cluster micro - column is preferably 0.5 cm 2 .

[0051] The present invention also provides a method for preparing an array electrode, comprising the following steps:

[0052] After atomizing the printing ink, the generated aerosol droplets are preheated to form clusters; the average particle size of the clusters is not less than 245 nm;

[0053] Using a protective gas as a carrier gas, the clusters are subjected to aerosol jet printing on the surface of a substrate to obtain loose nanocluster microcolumns in an array structure; the temperature of the substrate is not less than the evaporation temperature of the solvent in the printing ink;

[0054] Sintering the loose nanocluster microcolumns in the array structure to obtain the array electrode;

[0055] In the present invention, after atomizing the printing ink, the generated aerosol droplets are preheated to form clusters. In the present invention, the process of forming clusters is preferably the same as the process of forming clusters described in the above technical solution, and will not be elaborated here.

[0056] After obtaining the clusters, in the present invention, using a protective gas as a carrier gas, the clusters are subjected to aerosol jet printing on the surface of a substrate to obtain loose nanocluster microcolumns in an array structure.

[0057] In the present invention, the process conditions for the array printing are preferably the same as the printing process conditions described in the above technical solution, except that individual loose nanocluster microcolumns are subjected to array printing to obtain loose nanocluster microcolumns in an array structure.

[0058] After obtaining the loose nanocluster microcolumns in the array structure, the present invention sinters the loose nanocluster microcolumns in the array structure to obtain the array electrode.

[0059] In the present invention, the sintering temperature is preferably 300 °C, and the heat preservation time is preferably 1 h.

[0060] The present invention also provides an array electrode prepared by the preparation method described in the above technical solution. In the present invention, in the array electrode, the distance between adjacent two electrodes is preferably 200 μm.

[0061] The present invention also provides an application of the array electrode described in the above technical solution as a gate electrode in an organic electrochemical transistor.

[0062] Unless otherwise specified, the materials and equipment used in the present invention are all commercially available products in the art.

[0063] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0064] Example 1

[0065] In this embodiment, the printing ink is nano-silver ink, where the particle size of nano-silver is 30 - 50 nm, and the mass concentration of nano-silver is 15%; the surfactant is polyvinylpyrrolidone, with a mass of 5% of the mass of nano-silver; the solvent is deionized water and ethylene glycol, and the mass ratio of deionized water to ethylene glycol is 16:1;

[0066] After ultrasonic dispersing the printing ink for 30 min, 2 mL of the ultrasonicated printing ink is placed in an ultrasonic nebulizer, and the power of ultrasonic nebulization is set to 20 W for ultrasonic nebulization to obtain aerosol droplets, and the particle size of the aerosol droplets is normally distributed in the range of 1 - 10 μm;

[0067] After preheating the obtained aerosol droplets at 40°C, clusters with an average particle size of 530 nm are formed;

[0068] Using nitrogen as the carrier gas, the formed clusters are introduced into an aerosol jet device for printing on the surface of the substrate. The printing conditions include: the distance between the print head and the substrate is 3 mm, the printing speed is 1 mm / s, the inner diameter of the print head is 150 μm; the flow rate of the transport gas at the nozzle is 30 sccm, and the flow rate of the focusing gas is 15 sccm. Both the transport gas and the focusing gas are nitrogen; the temperature of the substrate is 160°C; the number of printing layers is 40, and loose nano-cluster micro-columns are obtained. The height of the loose nano-cluster micro-columns is 450 μm, the diameter is 60 μm, and the surface area is 0.23 cm 2 。

[0069] Example 2

[0070] In this embodiment, the printing ink is nano-silver ink, where the particle size of nano-silver is 30 - 50 nm, and the mass concentration of nano-silver is 30%; the surfactant is polyvinylpyrrolidone, with a mass of 5% of the mass of nano-silver; the solvent is deionized water and ethylene glycol, and the mass ratio of deionized water to ethylene glycol is 6:1;

[0071] After ultrasonic dispersing the printing ink for 30 min, 2 mL of the ultrasonicated printing ink is placed in an ultrasonic nebulizer, and the power of ultrasonic nebulization is set to 20 W for ultrasonic nebulization to obtain aerosol droplets, and the particle size of the aerosol droplets is normally distributed in the range of 1 - 10 μm;

[0072] After preheating the obtained aerosol droplets at 40 °C, clusters with an average particle size of 664 nm are formed;

[0073] Using nitrogen as the carrier gas, the formed clusters are introduced into an aerosol jetting device and printed on the surface of the substrate. The printing conditions include: the distance between the print head and the substrate is 3 mm, the printing speed is 1 mm / s, and the inner diameter of the print head is 150 μm; the flow rate of the delivery gas at the nozzle is 30 sccm, and the flow rate of the focusing gas is 15 sccm. Both the delivery gas and the focusing gas are nitrogen; the temperature of the substrate is 160 °C; the number of printed layers is 40, and a loose nano-cluster micro-column is obtained. The height of the loose nano-cluster micro-column is 450 μm, the diameter is 60 μm, and the surface area is 0.20 cm 2 .

[0074] Example 3

[0075] In this example, the printing ink is nano-silver ink, where the particle size of nano-silver is 30 - 50 nm, and the mass concentration of nano-silver is 5%; the surfactant is polyvinylpyrrolidone, with a mass of 5% of the mass of nano-silver; the solvent is deionized water and ethylene glycol, and the mass ratio of deionized water to ethylene glycol is 56:1;

[0076] After ultrasonic dispersing the printing ink for 30 min, 2 mL of the ultrasonicated printing ink is placed in an ultrasonic nebulizer, and the power of ultrasonic nebulization is set to 20 W for ultrasonic nebulization to obtain aerosol droplets. The particle size of the aerosol droplets shows a normal distribution in the range of 1 - 10 μm;

[0077] After preheating the obtained aerosol droplets at 40 °C, clusters with an average particle size of 245 nm are formed;

[0078] Using nitrogen as the carrier gas, the formed clusters are introduced into an aerosol jetting device and printed on the surface of the substrate. The printing conditions include: the distance between the print head and the substrate is 3 mm, the printing speed is 1 mm / s, and the inner diameter of the print head is 150 μm; the flow rate of the delivery gas at the nozzle is 30 sccm, and the flow rate of the focusing gas is 15 sccm. Both the delivery gas and the focusing gas are nitrogen; the temperature of the substrate is 160 °C; the number of printed layers is 40, and a loose nano-cluster micro-column is obtained. The height of the loose nano-cluster micro-column is 450 μm, the diameter is 60 μm, and the surface area is 0.19 cm 2 .

[0079] Example 4

[0080] Clusters are prepared in the same manner as in Example 1;

[0081] Using nitrogen as the carrier gas, the formed clusters are introduced into an aerosol jet device for array printing on the surface of a substrate. The printing conditions include: the distance between the print head and the substrate is 3 mm, the printing speed is 1 mm / s, and the inner diameter of the print head is 150 μm; the flow rate of the delivery gas at the nozzle is 30 sccm, and the flow rate of the focusing gas is 15 sccm. Both the delivery gas and the focusing gas are nitrogen; the temperature of the substrate is 160 °C; the number of printing layers is 40, resulting in loose nanocluster microcolumns with an array structure. The height of a single loose nanocluster microcolumn is 450 μm, the diameter is 60 μm, and the surface area is 0.23 cm 2 ;

[0082] The obtained loose nanocluster microcolumns with an array structure are sintered at 300 °C for 1 h to obtain the array electrodes. The distance between adjacent two electrodes is 200 μm, and the array distribution is 10*10.

[0083] Example 5

[0084] Prepare the clusters in the same way as in Example 2;

[0085] Using nitrogen as the carrier gas, the formed clusters are introduced into an aerosol jet device for array printing on the surface of a substrate. The printing conditions include: the distance between the print head and the substrate is 3 mm, the printing speed is 1 mm / s, and the inner diameter of the print head is 150 μm; the flow rate of the delivery gas at the nozzle is 30 sccm, and the flow rate of the focusing gas is 15 sccm. Both the delivery gas and the focusing gas are nitrogen; the temperature of the substrate is 160 °C; the number of printing layers is 40, resulting in loose nanocluster microcolumns with an array structure. The height of a single loose nanocluster microcolumn is 450 μm, the diameter is 60 μm, and the surface area is 0.20 cm 2 ;

[0086] The obtained loose nanocluster microcolumns with an array structure are sintered at 300 °C for 1 h to obtain the array electrodes. The distance between adjacent two electrodes is 200 μm, and the array distribution is 10*10.

[0087] Example 6

[0088] Prepare the clusters in the same way as in Example 3;

[0089] Using nitrogen as the carrier gas, the formed clusters are introduced into an aerosol jetting device for array printing on the surface of a substrate. The printing conditions include: the distance between the print head and the substrate is 3 mm, the printing speed is 1 mm / s, and the inner diameter of the print head is 150 μm; the flow rate of the conveying gas flow at the nozzle is 30 sccm, and the flow rate of the focusing gas flow is 15 sccm. Both the conveying gas flow and the focusing gas flow are nitrogen; the temperature of the substrate is 160 °C; the number of printing layers is 40, obtaining loose nanocluster microcolumns in an array structure. The height of a single loose nanocluster microcolumn is 450 μm, the diameter is 60 μm, and the surface area is 0.19 cm 2 ;

[0090] The obtained loose nanocluster microcolumns in an array structure are sintered at 300 °C for 1 h to obtain the array electrodes. Among them, the distance between adjacent two electrodes is 200 μm, and the array distribution is 10 * 10.

[0091] Comparative Example 1

[0092] Aerosol droplets are obtained in the manner of Example 1;

[0093] If the obtained aerosol droplets are not preheated or the preheating temperature is lower than 40 °C, no nanoclusters will be formed, and they will still remain in the droplet form;

[0094] Using nitrogen as the carrier gas, the aerosol droplets are introduced into an aerosol jetting device for printing on the surface of a substrate. The printing conditions include: the distance between the print head and the substrate is 3 mm, the printing speed is 1 mm / s, and the inner diameter of the print head is 150 μm; the flow rate of the conveying gas flow at the nozzle is 30 sccm, and the flow rate of the focusing gas flow is 15 sccm. Both the conveying gas flow and the focusing gas flow are nitrogen; the temperature of the substrate is 160 °C; the number of printing layers is 40, obtaining smooth and dense microcolumns. The height of the smooth and dense microcolumns is 250 μm, the diameter is 60 μm, and the surface area is 0.08 cm 2 。

[0095] Comparative Example 2

[0096] Clusters are prepared in the manner of Example 1;

[0097] Using nitrogen as the carrier gas, the formed clusters are introduced into an aerosol jetting device and printed on the surface of a substrate. The printing conditions include: the distance between the print head and the substrate is 3 mm, the printing speed is 1 mm / s, and the inner diameter of the print head is 150 μm; the flow rate of the delivery gas flow at the nozzle is 30 sccm, and the flow rate of the focusing gas flow is 15 sccm. Both the delivery gas flow and the focusing gas flow are nitrogen; the temperature of the substrate is 100 °C; the number of printed layers is 40 layers, obtaining dense nanocluster microcolumns. The height of the dense nanocluster microcolumns is 300 μm, the diameter is 60 μm, and the surface area is 0.11 cm 2 。

[0098] Comparative Example 3

[0099] Aerosol droplets are obtained in the manner of Example 1;

[0100] If the obtained aerosol droplets are not preheated or the preheating temperature is lower than 40 °C, no nanoclusters will be formed and they will still remain in the droplet form;

[0101] Using nitrogen as the carrier gas, the aerosol droplets are introduced into an aerosol jetting device and printed in an array on the surface of a substrate. The printing conditions include: the distance between the print head and the substrate is 3 mm, the printing speed is 1 mm / s, and the inner diameter of the print head is 150 μm; the flow rate of the delivery gas flow at the nozzle is 30 sccm, and the flow rate of the focusing gas flow is 15 sccm. Both the delivery gas flow and the focusing gas flow are nitrogen; the temperature of the substrate is 160 °C; the number of printed layers is 40 layers, obtaining smooth and dense microcolumns in an array structure. The height of a single smooth and dense microcolumn is 250 μm, the diameter is 60 μm, and the surface area is 0.08 cm 2 。

[0102] The obtained smooth and dense cluster microcolumns in an array structure are sintered at 300 °C for 1 h to obtain the array electrodes, where the distance between adjacent two electrodes is 200 μm and the array distribution is 10 * 10.

[0103] Comparative Example 4

[0104] Clusters are prepared in the manner of Example 1;

[0105] Using nitrogen as the carrier gas, the formed clusters are introduced into an aerosol jetting device for array printing on the surface of a substrate. The printing conditions include: the distance between the print head and the substrate is 3 mm, the printing speed is 1 mm / s, the inner diameter of the print head is 150 μm; the flow rate of the delivery gas at the nozzle is 30 sccm, the flow rate of the focusing gas is 15 sccm, and both the delivery gas and the focusing gas are nitrogen; the temperature of the substrate is 100 °C; the number of printing layers is 40 layers, resulting in dense nanocluster microcolumns with an array structure. The height of a single dense nanocluster microcolumn is 300 μm, the diameter is 60 μm, and the surface area is 0.11 cm 2 。

[0106] The obtained dense cluster microcolumns with an array structure are sintered at 300 °C for 1 h to obtain the array electrodes. The distance between adjacent two electrodes is 200 μm, and the array distribution is 10*10.

[0107] Comparative Example 5

[0108] In this comparative example, the printing ink is nano silver ink, where the particle size of nano silver is 30 - 50 nm, and the mass concentration of nano silver is 5%; the surfactant is polyvinylpyrrolidone, with a mass of 5% of the mass of nano silver; the solvent is deionized water and ethylene glycol, and the mass ratio of deionized water to ethylene glycol is 6:1;

[0109] After ultrasonic dispersing the printing ink for 30 min, 2 mL of the ultrasonicated printing ink is placed in an ultrasonic nebulizer, and the power of ultrasonic nebulization is set to 20 W for ultrasonic nebulization to obtain aerosol droplets. The particle size of the aerosol droplets is normally distributed in the range of 1 - 10 μm;

[0110] Using nitrogen as the carrier gas, the aerosol droplets are introduced into an aerosol jetting device for printing on the surface of a substrate. The printing conditions include: the distance between the print head and the substrate is 3 mm, the printing speed is 1 mm / s, the inner diameter of the print head is 150 μm; the flow rate of the delivery gas at the nozzle is 30 sccm, the flow rate of the focusing gas is 15 sccm, and both the delivery gas and the focusing gas are nitrogen; the temperature of the substrate is 90 °C; printing is performed along a square trajectory with a length of 2 mm. The obtained planar printing material is sintered at 300 °C for 1 h to obtain the planar electrode; the thickness of the planar electrode is 5 μm, and the surface area is 0.04 cm 2 。

[0111] Performance Test

[0112] Test Example 1

[0113] Figure 2 SEM image of the loose nanocluster microcolumns obtained in Example 1, Figure 3SEM image of the smooth and dense nanoparticle microcolumns obtained in Comparative Example 1, Figure 4 SEM image of the dense nanocluster microcolumns obtained in Comparative Example 2;

[0114] It can be seen that the surface of the loose nanocluster microcolumns is composed of a large number of nanocluster structures, indicating that nanoclusters are formed under the action of preheating and a relatively high bottom plate temperature, and the nanoclusters can achieve instantaneous pinning on the bottom plate to form a loose and porous structure. The smooth and dense nanoparticle microcolumns are composed of the initial nanoparticles with a size of 30 - 50 nm because no nanocluster structure is formed in the preheater during printing. Although the surface of the dense nanocluster microcolumns is also nanoclusters, due to the relatively low bottom plate temperature during the printing process, the residual solvent on the surface of the nanoclusters fails to volatilize in time, and thus is compressed with each other under the action of the surface tension and gravity of the residual solvent, forming a dense nanocluster structure.

[0115] Compared with the smooth and dense nanoparticle microcolumns and the dense nanocluster microcolumns, the loose nanocluster microcolumns have a rougher surface morphology and a higher surface area.

[0116] Test Example 2

[0117] Prepare an organic electrochemical transistor dopamine sensor based on multi-scale microcolumns using the electrodes obtained in Examples 4 - 6 and Comparative Examples 3 - 5. The schematic structural diagram of the sensor is as Figure 5 shown, where the array is used as the gate electrode. Compared with the smooth and dense microcolumn gate electrode and the dense nanocluster microcolumn gate electrode, the loose nanocluster microcolumn gate electrode exhibits higher dopamine mass transfer ability, dopamine catalytic ability, and transistor amplification ability.

[0118] (1) Figure 6 Table 1 shows the test results of the diffusion ability of different electrode types. Figure 6 Among them, the planar electrode represents Comparative Example 5, the smooth and dense nanoparticle column represents Comparative Example 3, the dense nanocluster column represents Comparative Example 4, the 530 nm loose cluster column represents Example 4, the 664 nm loose cluster column represents Example 5, and the 245 nm loose cluster column represents Example 6;

[0119] Table 1 Test results of the diffusion ability of different electrode types

[0120]

[0121] It can be seen that due to the high surface area of the porous nanocluster microcolumns, the collision probability of dopamine with the electrode surface increases, resulting in a larger dopamine concentration gradient on the electrode surface, thereby enhancing the mass transfer ability of dopamine. By measuring and comparing the diffusion abilities of different electrode types (the strength of the electrode mass transfer ability is reflected by the redox current), the porous nanocluster microcolumn electrode composed of nanoclusters with a diameter of 530 nm exhibits the most excellent mass transfer ability. Further calculation through the redox current shows that the mass transfer ability of the porous nanocluster microcolumn composed of nanoclusters with a diameter of 530 nm is 5.6 times that of the smooth and dense nanoparticle microcolumn electrode.

[0122] (2) The smooth and dense nanoparticle microcolumns obtained in Comparative Example 1 and the porous nanocluster microcolumns obtained in Example 1 were loaded with reduced graphene oxide. The specific process was as follows: The printing ink was an aqueous solution of reduced graphene oxide with a mass fraction of reduced graphene oxide of 1 mg / mL. The above aqueous solution of reduced graphene oxide was ultrasonically dispersed for 30 min, and 2 mL of the ultrasonically treated printing ink was placed in an ultrasonic nebulizer. The power of ultrasonic atomization was set to 18 W for ultrasonic atomization. A print head with an inner diameter of 400 μm was selected, the distance between the print head and the substrate was 3 mm, and the printing speed was 5 mm / s; the flow rate of the conveying gas flow at the nozzle was 40 sccm, and the flow rate of the focusing gas flow was 60 sccm. Both the conveying gas flow and the focusing gas flow were nitrogen; the temperature of the substrate was 80 °C; on the obtained array electrode substrate, printing was performed according to a square trajectory with a length of 2 mm.

[0123] Figure 7 SEM images of the smooth and dense nanoparticle microcolumns obtained in Comparative Example 1 and the porous nanocluster microcolumns obtained in Example 1 after loading reduced graphene oxide; Since reduced graphene oxide has excellent catalytic ability for dopamine, it can be concluded from Figure 7 that the excellent surface area of the porous nanocluster microcolumns endows them with stronger graphene loading ability compared to the smooth and dense microcolumns, which also means more excellent dopamine catalytic ability.

[0124] (3) Figure 8 Simulation diagrams of the surface electric field distribution of three types of electrodes: the smooth and dense nanoparticle microcolumns obtained in Comparative Example 1, the dense nanocluster microcolumns obtained in Comparative Example 2, and the porous nanocluster microcolumns obtained in Example 1; The obtained test results of the electric field strength are shown in Table 2;

[0125] Table 2 Electric field strength at the tip of the microcolumns obtained in the examples and comparative examples

[0126]

[0127] Dopamine undergoes electrooxidation under the action of an external voltage. Due to the tip discharge effect, the nanocluster structure on the surface of the loose nanocluster microcolumn generates a local electric field enhancement at the tip of the nanocluster. The simulation results show that the electric field intensity at the tip of the nanocluster is 3.2 times that of the smooth and dense nanoparticle microcolumn surface, as shown in Table 2. Therefore, in summary, the higher reduction-oxidation graphene loading capacity of the loose nanocluster microcolumn and the local electric field enhancement at the tip of the cluster contribute to the excellent dopamine catalytic ability of the loose nanocluster microcolumn.

[0128] (4) Figure 9 The amplification ability comparison test of the transistors with the electrodes obtained in Examples 4-6, Comparative Example 3, and 5 as the gate electrodes; the specific test results are shown in Table 3;

[0129] Table 3 Test results of the amplification ability of the electrodes obtained in the examples and comparative examples

[0130]

[0131] For the organic electrochemical transistor with the loose nanocluster microcolumn as the gate electrode, due to the high surface area characteristics of the loose nanocluster microcolumn, compared with the other two types of electrodes, it has a higher transistor amplification ability. The transconductance of its transistor is 1.4 times that of the smooth and dense nanoparticle microcolumn, and the on-off ratio is 2.6 times that of it, showing excellent self-amplification ability.

[0132] Figure 10 It is a test result graph of the response behavior of the organic electrochemical transistors based on the array electrode obtained in Example 4 and Comparative Example 3 and the planar electrode of Comparative Example 5 to different concentrations of dopamine. It can be seen that by using the above advantages, the dopamine quantitative test is carried out on the dopamine sensor of the organic electrochemical transistor based on the multi-scale microcolumn. The experimental results show that the organic electrochemical transistor based on the loose nanocluster microcolumn exhibits an ultra-low detection limit of as low as 1 fM, exceeding the planar electrode and the smooth and dense nanoparticle microcolumn electrode by more than six orders of magnitude.

[0133] Although the above embodiments have made a detailed description of the present invention, they are only a part of the embodiments of the present invention, rather than all embodiments. Other embodiments can also be obtained according to this embodiment without creative efforts, and these embodiments all belong to the protection scope of the present invention.

Claims

1. A method for preparing loose nanocluster microcolumns, characterized in that: The following steps are involved: After the printing ink is atomized, the generated aerosol droplets are preheated to form clusters; the average particle size of the clusters is not less than 245nm; The clusters are aerosol-jet printed on the surface of a substrate using protective gas as carrier gas to obtain the loose nano cluster microcolumns; the temperature of the substrate is not less than the evaporation temperature of the solvent in the printing ink.

2. The preparation method according to claim 1, characterized in that: The particle size of the aerosol droplets is normally distributed within the range of 1 to 10 μm.

3. The preparation method according to claim 1, characterized in that: The printing ink comprises nanoparticles, a surfactant and a solvent; The nanoparticles include one or more of nanosilver particles, nanogold particles, nanocopper particles, carbon nanotubes and graphene; The particle size of the nanoparticles is 2 to 50 nm; The mass concentration of the nanoparticles in the printing ink is 5-30%.

4. The preparation method according to claim 3, characterized in that: The surfactant comprises polyvinyl pyrrolidone; the mass of the surfactant is 5-10% of the mass of the nanoparticles; The solvent includes deionized water and ethylene glycol, and the mass ratio of the deionized water to the ethylene glycol is 6:1 to 60:

1.

5. The preparation method according to claim 1, characterized in that: The conditions for aerosol jet printing include: a distance between the print head and the substrate of 1 to 5 mm, a printing speed of 0.1 to 1 mm / s, an inner diameter of the print head of 150 to 600 μm; a flow rate of the conveying gas flow at the nozzle of 30 sccm, a flow rate of the focusing gas flow of 15 sccm, and the types of the conveying gas flow and the focusing gas flow are the same as the type of the carrier gas.

6. The loose nanocluster microcolumn prepared by the preparation method according to any one of claims 1 to 5, characterized in that: The aspect ratio of the loose nanocluster microcolumn is 3 to 17; the height of the loose nanocluster microcolumn is 200 μm to 1 mm.

7. A method for preparing an array electrode, characterized in that: The following steps are involved: After the printing ink is atomized, the generated aerosol droplets are preheated to form clusters; the average particle size of the clusters is not less than 245nm; Using protective gas as carrier gas, the clusters are aerosol-jetted on the surface of a substrate for array printing to obtain loose nano cluster microcolumns in an array structure; the temperature of the substrate is not less than the evaporation temperature of the solvent in the printing ink; The loose nanocluster microcolumns in an array structure are sintered to obtain the array electrode.

8. The preparation method according to claim 7, characterized in that: The sintering temperature is 300° C. and the holding time is 1 hour.

9. The array electrode prepared by the preparation method according to claim 7 or 8.

10. Use of the array electrode according to claim 9 as a gate electrode in an organic electrochemical transistor.

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