CN110459341B

CN110459341B - Semitransparent electrode based on metal nano composite structure

Info

Publication number: CN110459341B
Application number: CN201910618624.2A
Authority: CN
Inventors: 邓玲玲; 周文棋; 李珏; 李易年
Original assignee: Nanjing University of Posts and Telecommunications
Current assignee: Nanjing University of Posts and Telecommunications
Priority date: 2019-07-10
Filing date: 2019-07-10
Publication date: 2021-04-06
Anticipated expiration: 2039-07-10
Also published as: CN110459341A

Abstract

The invention provides a semitransparent electrode based on a metal nano composite structure in the technical field of photoelectron, wherein the semitransparent electrode is composed of metal nano wires and metal nano particles, the metal nano particles are added into a randomly arranged metal nano wire network, the metal nano particles are added into the metal nano wire network electrode, and the electric field near the electrode is enhanced by utilizing the plasma resonance of the metal nano particles and the resonance coupling effect between the metal nano particles and the metal nano wires, so that the charge injection efficiency of the electrode is enhanced.

Description

Semitransparent electrode based on metal nano composite structure

Technical Field

The invention relates to an electrode, in particular to a semitransparent electrode, and belongs to the technical field of photoelectrons.

Background

With the rapid development of a new generation of flexible electronic devices, the traditional electrode material Indium Tin Oxide (ITO) has the disadvantages of brittleness, complex preparation process, high price and the like, and increasingly shows limitations. Therefore, new flexible conductive materials, such as carbon nanotubes, graphene, and metal nanowires, have been produced. Among them, the nano-size effect and the inherent characteristics of high conductivity, high aspect ratio and good flexibility of silver nanowires (AgNWs) are recognized as the most promising ITO substitute material. To date, metal nanowires obtained by bar coating, spray coating, and the like generally exhibit a randomly distributed network, and a significant portion of the metal nanowires do not contribute to charge transport, while transparency is also reduced. In order to increase the conductivity by increasing the density of the metal nanowire network, the transmittance is decreased. Therefore, the performance of the metal nanowire flexible electrode is improved, and the problems of both conductivity and light transmittance are considered.

When light is incident on the metal nanoparticles, if the frequency of incident photons is matched with the overall vibration frequency of the metal nanoparticles or metal island conduction electrons, the nanoparticles or metal islands can generate strong absorption effect on the photons, and a Localized Surface Plasmon Resonance (LSPR) phenomenon can occur. Research shows that the local surface plasmon resonance of the metal nano particles with sharp shapes is stronger, and a stronger resonance electric field can be generated.

According to the invention, the metal nanoparticles are added into the metal nanowire network electrode, and the electric field intensity of the translucent electrode is enhanced by utilizing the local surface plasma resonance characteristic of the metal nanoparticles and the coupling electric field excited by the interaction of the nanowires and the nanoparticles, so that the injection efficiency of electrode carriers is enhanced, and the charge transmission capability of the electrode is improved.

Disclosure of Invention

The invention aims to provide a semitransparent electrode based on a metal nano composite structure, so that charges have high transmission efficiency.

The purpose of the invention is realized as follows: a semitransparent electrode based on a metal nano composite structure is composed of metal nanowires and metal nanoparticles, wherein the metal nanoparticles are added into a randomly arranged metal nanowire network.

As a further limitation of the invention, the length of the metal nanowire is 1-50 μm, the diameter of the metal nanowire is 30-70nm, and the particle size of the metal nanoparticle is within the range of +/-20 nm of the diameter of the metal nanowire.

As a further limitation of the present invention, the duty ratio of the metal nanowires in the metal nanowire network is 20% to 30%, and the coverage of the metal nanoparticles is 0.2% to 0.6%.

As a further limitation of the present invention, the metal nanoparticles have relatively sharp shapes such as edges, corners, and the like.

As a further limitation of the present invention, the metal nanoparticles and the metal nanowires are spaced apart by a distance in a range of 5-10 nm.

As a further definition of the present invention, the metal nanoparticles are wrapped with a transparent insulating material to adjust a distance between the metal nanoparticles and the metal nanowires.

The transparent insulating material is silicon dioxide or sodium polystyrene sulfonate.

Compared with the prior art, the invention adopting the technical scheme has the following technical effects:

1. according to the invention, metal nano particles are added into the metal nano wire network electrode, and the electric field near the electrode is enhanced by utilizing the plasma resonance of the metal nano particles and the resonance coupling effect between the metal nano particles and the metal nano wires, so that the charge injection efficiency of the electrode is enhanced;

2. the particle size of the metal nano particles is within the range of +/-20 nm of the diameter of the metal nano wires, so that the electric field near the electrode can be effectively enhanced, but the surface roughness of the electrode cannot be obviously increased;

3. the method of wrapping the insulating transparent medium material by the nano particles can effectively adjust the distance between the metal nano wires and the metal nano particles in the electrode, so that the coupling resonance effect is better, the metal nano particles are not oxidized and agglomerated, and the design target is better realized;

4. the use of the angular nanoparticles enables the resonance electric field to be stronger, is more favorable for improving the electric field near the electrode and improves the charge injection capability of the electrode;

5. the coverage rate of the metal nano particles is carefully designed and calculated, the influence on the integral transmittance of the electrode is small, and the electrode can be used as a transparent electrode.

Drawings

Fig. 1 shows the structure of the present invention.

Fig. 2 shows the change of the electrode transmittance with the duty ratio according to the first embodiment.

FIG. 3 shows the transmittance of the electrode according to the particle size in example two.

FIG. 4 is a graph showing the variation of the electric field intensity of the electrode according to the particle size in the second embodiment.

Fig. 5 shows the transmittance of the electrode according to the third embodiment of the present invention as a function of the distance between the silver nanowires and the silver nanowires.

FIG. 6 shows the variation of the electric field strength of the electrode according to the cubic spacing between the silver nanowires and the silver nanowires in the third embodiment.

FIG. 7 shows the transmittance and extinction of the electrodes of the fourth example as a function of the nanocube coverage of silver.

FIG. 8 shows the variation of the electric field strength of the electrode with the nanoparticle material in example V.

FIG. 9 shows the variation of the electric field strength of the electrode with the shape of the nanoparticles in example V.

Detailed Description

The technical scheme of the invention is further explained in detail by combining the attached drawings:

example 1:

silver nanowires with the length of 1 mu m and the diameter of 30nm form a silver nanowire electrode network, and the duty ratio of the nanowires in the electrode network is changed; FIG. 2 is a graph showing the change of the transmittance of the silver nanowire electrode network along with the duty ratio in the 400-480nm band; it can be seen that the transmittance of the silver nanowire electrode network increases with the decrease of the duty ratio, and when the duty ratio is less than 30%, the electrode transmittance can be basically ensured to be more than 80%. The duty cycle is selected to be in the range of 20% -30% because the duty cycle is not too small.

Example 2:

adding silver nanocubes into a silver nanowire electrode network with a duty ratio of 22%, wherein the length of each silver nanowire is 1.2 mu m, the diameter of each silver nanowire is 50nm, the distance between each silver nanowire and each silver nanocube is 5nm, and the coverage rate of each silver nanocube in the electrode is 0.55%. FIG. 3 shows the variation of the transmittance of silver electrode in the wavelength band of 400-480nm by changing the cubic particle size of silver nanoparticles, and it can be seen that the transmittance of electrode is still over 80% after nanoparticles are added. As can be seen from fig. 4, the electric field of the silver electrode is enhanced after the addition of the nanocube. The nano cube with the particle size smaller than the diameter of the nanowire has a weak effect on electric field enhancement; the nano cube with the grain diameter of 50nm and 60nm has good effect of enhancing the electric field of the silver electrode, and when the grain diameter is increased, the effect of enhancing the electric field of the electrode by the nano cube is weakened; the electric field enhancement effect is comprehensively considered, the grain size of the selected nano cube is within the range of +/-20 nm of the diameter of the silver nanowire, and the electric field enhancement effect on the silver electrode can be achieved on the premise of ensuring high transmittance.

Example 3:

the duty ratio is 22%, the length of the silver nanowire is 1.2 mu m, the diameter of the silver nanowire is 50nm, a 60nm nano cube is added, and the coverage rate of the silver nano cube in the electrode is 0.4%. FIG. 5 shows the variation of the transmittance of the silver electrode in the wavelength band of 400-480nm by changing the distance between the silver nanocube and the nanowire, and it can be seen that the transmittance of the silver electrode is maintained above 80% after the distance is changed. As can be seen from fig. 6, the electric field of the silver electrode is enhanced after the addition of the nanocube. When the distance is within 10nm, the electric field intensity of the silver electrode is increased along with the increase of the distance; when the distance is larger than 10nm, the effect of enhancing the electric field of the nano cubic counter electrode is not changed greatly; comprehensively considering, when the distance between the nano wire and the nano cube is 5-10nm, the enhancement effect on the electric field of the silver electrode is better.

Example 4:

the silver nanowire electrode network with the duty ratio of 22% has the silver nanowire length of 1.2 mu m and the diameter of 50nm, the 50nm nano cube is added, and the distance between the nano cube and the nanowire is 6 nm. FIG. 7 shows the change of the coverage (number) of the nano-cubic, the transmittance of the silver electrode and the extinction ratio in the 400-480nm band. As can be seen from fig. 7, the transmittance of the silver electrode decreases with increasing nanocube coverage, and the extinction increases with increasing nanocube coverage. When the particle coverage is less than 0.6%, the transmittance of the electrode is 80% or more, the extinction ratio increases, and the electric field increases.

Example 5:

the method comprises the steps of (1) a silver nanowire electrode network with the duty ratio of 30%, wherein the length of a silver nanowire is 50 mu m, the diameter of the silver nanowire is 70nm, 50nm metal nanoparticles are added, and the distance between the nanoparticles and the nanowires is 5 nm. Changing the material and shape of the nano particles, and observing the change condition of the field intensity near the electrode; wherein, FIG. 8 is the variation of the electric field intensity with the material added with the nano-particles, and FIG. 9 is the variation of the electric field intensity with the shape of the added nano-particles; it can be seen that the gold material and other sharp-shaped nanoparticles all have an enhancement effect on the electric field near the electrode.

In conclusion, a nanowire electrode network with the duty ratio of 20% -30% is formed by using metal nanowires with the length of 1-50 [ mu ] m and the diameter of 30-70nm, metal nanoparticles with sharp shapes and the particle size within the range of +/-20 nm of the diameter of the metal nanowires are added into the nanowire electrode network, the distance between the nanowires and the nanoparticles is 5-10nm, and therefore the transmittance of the formed semitransparent electrode with the metal nanocomposite structure can be kept above 80%, and the electric field near the electrode is enhanced, so that the charge injection efficiency of the electrode is enhanced.

The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can understand that the modifications or substitutions within the technical scope of the present invention are included in the scope of the present invention, and therefore, the scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A semi-transparent electrode based on a metal nano composite structure is characterized in that: the semitransparent electrode is composed of metal nanowires and metal nanoparticles, the metal nanoparticles are added into a randomly arranged metal nanowire network, the length of each metal nanowire is 1-50 mu m, the diameter of each metal nanowire is 30-70nm, the particle size of each metal nanoparticle is within the range of +/-20 nm of the diameter of each metal nanowire, a certain distance is reserved between each metal nanoparticle and each metal nanowire, the distance ranges from 5nm to 10nm, the metal nanoparticles are cubic, and the electric field intensity of the semitransparent electrode is enhanced by utilizing the local surface plasmon resonance characteristic of the metal nanoparticles and the coupling electric field excited by interaction of the nanowires and the nanoparticles.

2. The metal nanocomposite structure-based translucent electrode according to claim 1, wherein: the duty ratio of the metal nanowires in the metal nanowire network is 20% -30%, and the coverage rate of the metal nanoparticles is 0.2% -0.6%.

3. The metal nanocomposite structure-based translucent electrode according to claim 1, wherein: the metal nano particles are wrapped with a transparent insulating material so as to adjust the distance between the metal nano particles and the metal nano wires.

4. The metal nanocomposite structure-based translucent electrode according to claim 3, wherein: the transparent insulating material is silicon dioxide or sodium polystyrene sulfonate.