CN106409636B - One kind is based on patterned ZnO negative electrodes of inkjet printing and preparation method thereof - Google Patents

Abstract

The invention discloses a patterned ZnO cathode based on inkjet printing and a preparation method thereof. The ZnO cathode comprises a cathode substrate, a patterned ZnO seed layer and a patterned ZnO cathode from bottom to top. The ZnO seed layer was introduced by inkjet printing, and the patterned ZnO cathode was grown by electrochemical deposition or hydrothermal method. Compared with the existing technology, the inkjet printing method prepares the patterned ZnO seed layer, which greatly reduces the complexity and difficulty of the process. It is not only easy to produce but also uses less materials, and the manufacturing cost is low. The required graphics can be flexibly designed through computer programming. , very suitable for large-scale production and future industrial production, and has broad market application prospects.

Description

A ZnO cathode based on inkjet printing patterning and its preparation method

technical field

The invention relates to the field of vacuum electronic devices, in particular to a patterned ZnO cathode based on inkjet printing and a preparation method thereof.

Background technique

After more than a hundred years of development, vacuum electronic devices have made great contributions to modern science and technology, especially national defense science and technology. Since the 1960s, the semiconductor industry and integrated circuit technology have developed rapidly, and solid-state power electronic devices have continued to develop, making vacuum devices lose their dominant position. However, the new semiconductors represented by GaN devices are still immature, and there are still many deficiencies in energy efficiency, maximum power, operating frequency, and reliability. At present, it is not possible to completely overcome the disadvantages of solid-state devices. Vacuum electronic devices will still be widely used and developed in cutting-edge scientific and technological fields such as national defense and aerospace.

As a new type of flat panel display device, field emission display (FED) of vacuum electronic device relies on the electrons emitted by vacuum field emission to bombard the phosphor on the anode panel to emit light. It has the excellent brightness, response speed and viewing angle of CRT. characteristics, and has the advantages of flat panel display in size, power consumption and working voltage, etc., and has extremely broad application prospects. The field emission cold cathode array is the core part of FED, and carbon nanotubes have been considered as excellent field emitters since their discovery. However, the use of carbon nanotubes as emitters requires a very high vacuum inside the device. Oxygen remaining in the high-temperature environment will oxidize the emission tip, and during the packaging process, the higher temperature causes the carbon nanotubes on the cathode surface to be lost. The distribution in a good display device is not uniform enough, which will affect the uniformity and stability of the device to a large extent. Compared with carbon nanotubes, zinc oxide (ZnO) nanomaterials have the advantages of simple growth, uniform structure, and oxidation resistance, and their field emission properties have attracted the attention of experts.

The size, shape, spacing, and arrangement of ZnO nanoarrays are regulated by patterning technology, which not only achieves the superposition of the properties of ZnO nanostructure monomers, but also brings many unique properties to ZnO nanoarrays, which can be extremely The performance of the ZnO nano-array device is greatly improved, so the zinc oxide patterned cathode has very important application significance. Traditional semiconductor patterning generally adopts photolithography method. In patent CN201410322876, the photoresist is spin-coated on the substrate, exposed and developed using a mask to obtain a patterned photoresist, and then a zinc oxide film is obtained by magnetron sputtering. The substrate is ultrasonically peeled off in an acetone organic solvent to obtain a patterned ZnO film. However, in the photolithography process, the precision of the mask plate is not high, the etching time is not easy to control, and it is easy to cause poor precision of the etching pattern, and the magnetron sputtering equipment is expensive and the cost is high. Patent CN201410260626 first prepares the ZnO seed layer film by sol-gel method, and prepares a patterned TiO ₂ shielding layer on the surface of the ZnO seed layer film by micro-contact embossing, and then selectively grows it by hydrothermal method to prepare a periodic Microstructured ZnO nanowire arrays. However, it is necessary to control the amount and distribution of reagents on the mold, and the process is relatively complicated. Therefore, finding a method for preparing a patterned cathode that can simplify the process and have low cost will be beneficial to the preparation of printed display devices.

Contents of the invention

The object of the present invention is to provide a ZnO cathode based on inkjet printing patterning and a preparation method thereof. A patterned ZnO cathode can be prepared in a large area by the method, and the cost is low and the preparation process is simple.

To achieve the above object, the present invention adopts the following technical solutions:

A patterned ZnO cathode based on inkjet printing, comprising a cathode substrate, a patterned ZnO seed layer and a patterned ZnO cathode from bottom to top.

The patterned ZnO seed layer is prepared by inkjet printing, using ZnO ink suitable for inkjet printing.

The ZnO ink suitable for inkjet printing adopts any one of ZnO sol solution, ZnO quantum dot solution and Zn2 ⁺ -containing organic solution.

In the described organic solution containing Zn ²⁺ , the solute is Zn(NO ₃ ) ₂ or Zn(Ac) ₂ , and the organic solvent is ethanol, propanol, ethylene glycol, isopropanol, ethanolamine, ethylene glycolamine, One or more mixtures of ethylene glycol methyl ether, butyl acetate and ethylene glycol ether; the Zn ²⁺ concentration in the Zn ²⁺ -containing organic solution is 0.001-0.5 mol/L.

In the sol solution of ZnO, the solute is Zn(NO ₃ ) ₂ or Zn(Ac) ₂ , and the solvent is methanol, ethanol, propanol, ethylene glycol, isopropanol, ethanolamine, ethylene glycol amine, ethylene glycol One or more mixtures of alcohol methyl ether and deionized water, the concentration is 0.01-2mol/L.

The pattern of the patterned ZnO seed layer is flexibly controlled by changing the parameters of inkjet printing or computer programming. After inkjet printing, the patterned ZnO seed layer is dried and solidified at a temperature of 90° C. for 5- 10min; the thickness of the ZnO seed layer after curing is 5-500nm.

The patterned ZnO cathode is a ZnO cathode array, and the height of the cathode material is 1-50 μm.

The preparation method of the patterned ZnO cathode based on inkjet printing as described above comprises the following steps:

(1) Scribing and cleaning the cathode substrate substrate;

(2) After performing plasma treatment on the cathode substrate for 5 minutes, inkjet print the ZnO seed layer of the required pattern;

(3) Drying the ZnO seed layer in step (2), followed by sintering, the sintering temperature is 250-400°C, and the sintering time is 1-2 hours, to obtain a patterned ZnO seed layer;

(4) Grow a patterned ZnO cathode on the patterned ZnO seed layer by electrochemical method or hydrothermal method;

(5) Sintering the ZnO cathode in step (4), the sintering temperature is 250-400° C., and the sintering time is 1-2 hours.

The beneficial effect of the present invention is that: the ink-jet printing-based patterned ZnO cathode mentioned in the present invention and its preparation method can flexibly control the pattern only through computer programming. This method can not only effectively simplify the manufacturing process of the patterned cathode, but also is suitable for large-area preparation of devices, requires less material, reduces manufacturing costs, simple process, and improves production efficiency. It can be applied to cold cathodes and field emission displays of vacuum electronic devices. Devices and field emission light sources, etc.

Description of drawings

Figure 1 is a schematic structural view of a ZnO cathode based on inkjet printing patterning in Example 1 of the present invention;

Marks in the figure: 11—cathode substrate; 121—patterned ZnO seed layer; 122—patterned ZnO cathode;

Fig. 2 is a kind of preparation flow chart of the ZnO cathode based on inkjet printing patterning in embodiment 1 of the present invention;

3 is a scanning electron microscope image of a patterned ZnO cathode based on inkjet printing in Example 1 of the present invention;

4 is a field emission current density-electric field intensity curve of a ZnO cathode based on inkjet printing patterning in Example 1 of the present invention.

detailed description

In order to make the above features and advantages of the present invention more comprehensible, the present invention will be further described in detail in conjunction with the accompanying drawings.

Embodiment 1: As shown in Figure 1, a ZnO cathode based on inkjet printing patterning includes a cathode substrate 11, a patterned ZnO seed layer 121 and a patterned ZnO cathode 122 from bottom to top; its preparation method specifically includes the following step:

(1) Preparation of zinc oxide ink (sol solution of ZnO)

Weigh 2.2g of zinc acetate with an electronic balance, put it into 30ml of ethanol solution, stir with a constant temperature magnetic stirrer until dissolved, then add 0.3833ml of ethylene glycol amine, stir with a magnetic stirrer for one hour and keep the temperature at 60 ℃, aging for 50 hours, forming a uniform and transparent sol, and obtaining a ZnO sol solution;

(2) Preparation of the cathode substrate 11: scribing and cleaning the cathode substrate 11 (ITO glass substrate 11);

(3) Preparation of patterned ZnO seed layer 121: subject the ZnO sol solution obtained in step (1) to constant temperature magnetic stirring and ultrasonication for 45 minutes, and conduct plasma treatment on the cathode substrate 11 in step (2) for 5 minutes, and print Prepare a patterned ZnO seed layer 121 on the surface of the ITO glass substrate 11, then heat it at 90°C for 5 minutes, and finally heat-treat it in a muffle furnace at 260°C for 2 hours to obtain a patterned ZnO seed layer 121;

(4) Preparation of patterned ZnO cathode 122:

Using the electrochemical deposition method, put 0.2677g of zinc nitrate into 300ml of deionized water and stir in a water bath. A two-electrode system is used. The anode is connected to a stainless steel sheet, and the cathode is connected to ITO glass. The distance between the two electrodes is 3cm. The current density of cm ² was deposited on the ITO glass substrate 11 with patterned ZnO seed layer 121, and the deposition time was 90 min; after the electrochemical deposition, the sample was repeatedly rinsed with deionized water, and then annealed at 260 ° C for 2 h, so that Obtain patterned ZnO cathode 122;

Or use the hydrothermal method, weigh 0.2231g zinc nitrate and 0.1051g hexamethylenetetramine into 30ml deionized water, put the patterned ZnO seed layer 121 obtained in step (3) into it, and grow it at 90°C After 6 hours, rinse repeatedly with deionized water and anneal at 260° C. for 2 hours to obtain a patterned zinc oxide cathode 122 .

After heat treatment at 260° C. in step (3), the zinc oxide gel forms a zinc oxide film. After heat treatment in step (4), the adhesion between the patterned zinc oxide cathode 122 and the ITO glass substrate 11 is strengthened. The preparation process of a patterned ZnO cathode based on inkjet printing is shown in FIG. 2 , and the scanning electron microscope photo is shown in FIG. 3 .

The field emission characteristics of a patterned ZnO cathode based on inkjet printing of the present invention were tested in a field emission test system. The measured field emission current density − electric field strength (J−E) is shown in Fig. 4.

Example 2:

(1) Preparation of zinc oxide ink (organic solution containing Zn ²⁺ )

Weigh 0.367g of zinc acetate with an electronic balance, add it to 5ml of ethylene glycol methyl ether solution, stir with a constant temperature magnetic stirrer until dissolved, then add 0.2395ml of ethanolamine, stir with a magnetic stirrer for 2 hours and keep the temperature at 60 ℃ to obtain zinc oxide ink;

(2) Preparation of the cathode substrate: scribing and cleaning the cathode substrate (ITO glass substrate);

(3) Preparation of the patterned seed layer: The zinc oxide precursor sol ink obtained in step (1) was subjected to constant temperature magnetic stirring and ultrasonication for 45 minutes, and the cathode substrate in step (2) was subjected to plasma treatment for 5 minutes. A patterned seed layer was prepared on the surface of the glass substrate, and then kept at 90°C for 10 minutes, and finally heat-treated in a muffle furnace at 350°C for 1 hour to obtain a patterned ZnO seed layer;

(4) Preparation of patterned ZnO cathode:

Using the electrochemical deposition method, put 0.2677g of zinc nitrate into 300ml of deionized water and stir in a water bath. A two-electrode system is used. The anode is connected to a stainless steel sheet, and the cathode is connected to ITO glass. The distance between the two electrodes is 3cm. A current density of cm ² was deposited on an ITO glass substrate 11 with a patterned seed layer, and the deposition time was 90 minutes; after the electrochemical deposition, the sample was repeatedly rinsed with deionized water, and then annealed at 350°C for 1 hour to obtain a pattern Fe ZnO cathode;

Or use the hydrothermal method, weigh 0.2231g zinc nitrate and 0.1051g hexamethylenetetramine into 30ml deionized water, put the patterned ZnO seed layer obtained in step (3), and grow at 90°C for 6 Hours, after the end, rinse repeatedly with deionized water, and anneal at 400°C for 1 hour to obtain a patterned zinc oxide cathode.

Example 3

(1) Preparation of zinc oxide ink (ZnO quantum dot solution)

Weigh 0.0549g of ZnAc ₂ •2H ₂ O into 15ml of ethanol, stir with a magnetic stirrer for 1 hour and keep the temperature at 60°C. Then weigh 0.021g LiOH•H ₂ O and add it into 10ml ethanol, and sonicate for 20min. The prepared LiOH solution was injected dropwise into the vigorously stirred ZnO precursor solution, and the stirring was continued for several hours to prepare the ZnO quantum dot ink.

(2) Preparation of the cathode substrate: scribing and cleaning the cathode substrate (ITO glass substrate);

(3) Preparation of the patterned seed layer: The zinc oxide precursor sol ink obtained in step (1) was subjected to constant temperature magnetic stirring and ultrasonication for 45 minutes, and the cathode substrate in step (2) was subjected to plasma treatment for 5 minutes. A patterned seed layer was prepared on the surface of the glass substrate, then kept at 90°C for 8 minutes, and finally heat-treated in a muffle furnace at 350°C for 1.5 hours to obtain a patterned ZnO seed layer;

(4) Preparation of patterned cathode:

Using the electrochemical deposition method, put 0.2677g of zinc nitrate into 300ml of deionized water and stir in a water bath. A two-electrode system is used. The anode is connected to a stainless steel sheet, and the cathode is connected to ITO glass. The distance between the two electrodes is 3cm. The current density of cm ² was deposited on the ITO glass substrate 11 with a patterned seed layer, and the deposition time was 90 min; after the electrochemical deposition, the sample was repeatedly rinsed with deionized water, and then annealed at 350 ° C for 1.5 h, thus obtaining Patterned zinc oxide cathode;

Or use the hydrothermal method, weigh 0.2231g zinc nitrate and 0.1051g hexamethylenetetramine into 30ml deionized water, put the patterned ZnO seed layer obtained in step (3), and grow at 90°C for 6 Hours, after the end, rinse repeatedly with deionized water, and anneal at 350°C for 1.5h to obtain a patterned zinc oxide cathode.

The invention proposes a patterned ZnO cathode based on inkjet printing. Introduced by inkjet printing seed layer, the patterned cathode is grown by electrochemical deposition or hydrothermal method. Compared with the existing technology, the inkjet printing method prepares the patterned seed layer, which greatly reduces the complexity and difficulty of the process. It is not only easy to produce but also uses less materials, and the manufacturing cost is low. The required graphics can be flexibly designed through computer programming. It is very suitable for large-area production and future industrial production, and has broad market application prospects.

The present invention is not limited to the above-mentioned specific embodiments, and anyone can obtain other forms of preparation methods based on inkjet printing patterned arrays under the enlightenment of the present invention. All equivalent changes and modifications made according to the patent scope of the present invention shall be included in the protection scope of the present invention.

Claims (6)

1. A kind of 1. preparation method based on the patterned ZnO negative electrodes of inkjet printing, it is characterised in that：The ZnO negative electrodes from lower and Above include cathode base, graphical ZnO Seed Layer and graphical ZnO negative electrode, its preparation method to comprise the following steps：

   （1）Cathode base substrate carries out scribing and cleaning；

   （2）After plasma treatment 5min being carried out to cathode base substrate, the ZnO Seed Layers of figure needed for inkjet printing；

   （3）To step（2）ZnO Seed Layers dried, then sintering, sintering temperature be 250-400 DEG C, sintering time 1- 2 hours, obtain graphical ZnO Seed Layer；

   （4）Graphical ZnO negative electrode is grown in graphical ZnO Seed Layer using electrochemical process or hydro-thermal method；Described is graphical ZnO negative electrodes are ZnO cathode arrays, and the height of cathode material is 1-50 μm；

   （5）To step（4）ZnO negative electrodes be sintered, sintering temperature be 250-400 DEG C, sintering time is 1-2 hour.
2. 2. the preparation method according to claim 1 based on the patterned ZnO negative electrodes of inkjet printing, it is characterised in that：It is described Graphical ZnO Seed Layer prepared by the method for inkjet printing, using the ZnO inks suitable for inkjet printing.
3. 3. the preparation method according to claim 2 based on the patterned ZnO negative electrodes of inkjet printing, it is characterised in that：It is described The ZnO inks suitable for inkjet printing using ZnO sol solutionses, ZnO quantum dot solution and containing Zn²⁺Organic solution in appoint It is a kind of.
4. 4. the preparation method according to claim 3 based on the patterned ZnO negative electrodes of inkjet printing, it is characterised in that：Institute That states contains Zn²⁺Organic solution in, solute is Zn (NO₃)₂Or Zn (Ac)₂, organic solvent is ethanol, propyl alcohol, ethylene glycol, isopropyl One or more of mixed liquors in alcohol, monoethanolamine, ethylene glycol amine, ethylene glycol monomethyl ether, butyl acetate and ethylene glycol ethyl ether；It is described to contain Zn²⁺Organic solution in Zn²⁺Concentration is 0.001-0.5 mol/L.
5. 5. the preparation method according to claim 3 based on the patterned ZnO negative electrodes of inkjet printing, it is characterised in that：Institute In the ZnO stated sol solutionses, solute is Zn (NO₃)₂Or Zn (Ac)₂, solvent be methanol, ethanol, propyl alcohol, ethylene glycol, isopropanol, One or more of mixed liquors in monoethanolamine, ethylene glycol amine, ethylene glycol monomethyl ether and deionized water, concentration 0.01-2mol/L.
6. 6. the preparation method according to claim 1 based on the patterned ZnO negative electrodes of inkjet printing, it is characterised in that：It is described The figure of graphical ZnO Seed Layer flexibly controlled by the parameter or computer programming for changing inkjet printing, ink-jet is beaten Patterned ZnO Seed Layers carry out baking and curing after print, and drying temperature is 90 DEG C, time 5-10min；ZnO seeds after solidification Thickness degree is 5-500nm.