CN108598288A - A kind of composite multifunction OLED electrodes and preparation method thereof - Google Patents

Abstract

The invention discloses a composite multifunctional OLED electrode and a preparation method thereof. The composite multifunctional OLED electrode includes a flexible substrate and a metal nanowire-photoelectric polymer mixed layer grown on the flexible substrate, and a metal nanowire-photoelectric polymer mixed layer. The layer includes metal nanowires and optoelectronic polymer materials, and a layer of optoelectronic polymer materials is spin-coated on the metal nanowires, so that the optoelectronic polymer materials are filled in the gaps of the metal nanowires. The invention uses pressure to embed metal nanowires into soft and viscous optoelectronic polymer materials to form a composite multifunctional OLED electrode with smooth interface, good transparent conductive properties and hole/electron injection capabilities, which solves the problems of traditional methods. It is difficult to balance the transparency and conductivity of metal nanowires, and the non-vacuum preparation method can greatly reduce the current manufacturing cost of OLED electrodes.

Description

A composite multifunctional OLED electrode and its preparation method

technical field

The invention relates to the technical field of transparent conductive electrodes, in particular to a composite multifunctional OLED electrode based on metal nanowires and optoelectronic polymer materials and a preparation method thereof.

Background technique

Metals are widely prepared as electrodes for organic electronic and optoelectronic devices due to their extremely high electrical conductivity, but bulk or thin-film metals are usually opaque, which limits the use of metals as transparent conductive electrodes. In order to solve the problem of opacity of the metal thin film, the researchers found that the metal grid structure and the metal nanowire grid can solve the above problem. Metal grids are usually in the form of two-dimensional grids or hexagonal grids, deposited by thermal evaporation, patterned by photolithography or printed. Since the voids in the metal network are almost 100% transparent, the transmittance of the metal grid flexible transparent conductive electrode can be easily tuned by changing the metal coverage (ie, the line width of the metal nanonet). Theoretically, a metal grid with perfect conditions of optimized line width has a higher transmittance than ITO with the same sheet resistance. For example, theoretically nanopatterned silver film electrodes can achieve 90% optical transmittance and 0.8 Ω/nm sheet resistance, and practically prepared metal grid electrodes can usually achieve about 80% optical transmittance.

Metal nanowire grids have the significant advantage of direct deposition from liquid dispersions by solution methods, in addition to those possessed by metal grids. So far, the most widely used metallic nanowires are silver nanowires (AgNWs), which can be uniformly dispersed in ethanol solvents to form high-quality solutions, benefiting from the inherent metallic nature and high aspect ratio of AgNWs, the growth Ultrathin random nanowire grids on plastic substrates exhibit high mechanical flexibility, high electrical conductivity, and transparency. However, both metal nanowire grids and metal grids have an application problem, that is, the metal grid (micron scale) protruding from the substrate is relatively thicker than the ultra-thin organic layer (nanoscale), which easily leads to short circuits in the device. , making this flexible transparent conductive electrode unsuitable for direct application in practical organic optoelectronic devices.

At present, in this field, there are many effective techniques for using metal nanowires to prepare flexible transparent electrodes, such as embedding silver nanowires into flexible substrates to reduce their surface roughness, or spin-coating conductive polymer materials on the surface of silver nanowires. PEDOT:PSS (PEDOT:PSS is an aqueous solution of a polymer, which is composed of two substances, PEDOT and PSS. PEDOT is a polymer of EDOT (3,4-ethylenedioxythiophene monomer), and PSS is polyphenylene Ethylene sulfonate) to fill the unevenness of the silver nanowire film surface to avoid short circuit, or sacrifice part of its flexibility to combine silver nanowires with ITO to obtain ideal conductivity. Films made of nanowires are flattened to reduce surface roughness. Although the above-mentioned method has certain achievements, there are still many disadvantages: 1. The existing technology has the disadvantage of being difficult to balance light transmission and conductivity: if the concentration of silver nanowires in the silver nanowire solution is increased, the resistance of the prepared film is small , but the light transmittance is poor; if the concentration of silver nanowires is reduced, the light transmittance will increase while the conductivity of the film will decrease accordingly. 2. The existing technology to solve the unevenness of the silver nanowire film surface is not perfect. For example, directly embedding silver nanowires into insulating polymer materials will improve the flatness of the film surface, but it will also limit its conductivity; Or directly spin-coat the conductive polymer PEDOT:PSS on the surface of silver nanowires. Although the surface roughness of the nanowire film can be reduced to a certain extent, the surface of PEDOT:PSS is still uneven, which is not conducive to the subsequent preparation of devices. 3. The cost of the prior art is higher.

Contents of the invention

The purpose of the present invention is to propose a composite multi-functional OLED electrode based on metal nanowires and optoelectronic polymer materials and its preparation method. Metal nanowires are embedded in soft and viscous optoelectronic polymer materials by pressure to form composite multifunctional electrodes. OLED electrode, the composite multifunctional OLED electrode not only has smooth interface, good transparent conductive properties and hole/electron injection ability, but also can realize single-electrode light emission or OLED (Chinese name is organic electroluminescent diode, hereinafter referred to as OLED) color conversion. The invention solves the problem that the light transmittance and electrical conductivity of the metal nanowire prepared by the traditional method are difficult to be balanced, and adopts the method of non-vacuum preparation, which can greatly reduce the manufacturing cost of the current OLED electrode.

To achieve the above object, the present invention provides the following scheme:

A composite multifunctional OLED electrode, the composite multifunctional OLED electrode includes a flexible substrate and a metal nanowire-photoelectric polymer hybrid layer grown on the flexible substrate;

The metal nanowire-photoelectric polymer hybrid layer includes a metal nanowire and a photoelectric polymer material; a layer of the photoelectric polymer material is spin-coated on the metal nanowire, so that the photoelectric polymer material is filled in the in the gaps between the metal nanowires.

Optionally, the metal nanowires are silver nanowires.

Optionally, the silver nanowires are silver nanowires with a particle diameter of 80 nm and a length of 5 μm.

Optionally, the optoelectronic polymer material is poly 2-(2-ethylhexyloxy)-5-methoxyphenylene vinylene solution.

Optionally, the flexible substrate is a PEI flexible substrate or a PI flexible substrate.

The present invention also provides a preparation method of a composite multifunctional OLED electrode, the preparation method comprising:

A metal nanowire solution is covered on the flexible substrate by a solution method to form a metal nanowire layer; the metal nanowire solution is formed by dispersing the metal nanowire in an ethanol solution;

Spin-coat a layer of optoelectronic polymer material on the metal nanowire layer, and fill the optoelectronic polymer material into the gap of the metal nanowire by heating and pressing to form a metal nanowire-optoelectronic polymer hybrid layers to make composite multifunctional OLED electrodes.

Optionally, the thickness of the metal nanowire layer is 150-250 nm.

Optionally, the thickness of the metal nanowire-photoelectric polymer hybrid layer is 150-250 nm.

Optionally, in the heating and pressing method, the heating temperature is 100 degrees, and the pressurizing pressure is above 0.6Mpa.

Optionally, the solution method is a spin coating method, a spray coating method or a printing method, and the heating and pressing method is a nanoimprint method or an air pressure method.

According to the specific embodiments provided by the invention, the invention discloses the following technical effects:

The invention provides a composite multifunctional OLED electrode and a preparation method thereof. The composite multifunctional OLED electrode includes a flexible substrate and a metal nanowire-photoelectric polymer hybrid layer grown on the flexible substrate, and a metal nanowire-photoelectric polymer hybrid layer. The layer includes metal nanowires and optoelectronic polymer materials, and a layer of optoelectronic polymer materials is spin-coated on the metal nanowires, so that the optoelectronic polymer materials are filled in the gaps of the metal nanowires. The invention uses pressure to embed metal nanowires into soft and viscous optoelectronic polymer materials to form a composite multifunctional OLED electrode with smooth interface, good transparent conductive properties and hole/electron injection capabilities, which solves the problems of traditional methods. It is difficult to balance the transparency and conductivity of metal nanowires, and the non-vacuum preparation method can greatly reduce the current manufacturing cost of OLED electrodes.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

Fig. 1 is the structural schematic diagram of composite multifunctional OLED electrode of the embodiment of the present invention;

2 is a schematic flow diagram of a method for preparing a composite multifunctional OLED electrode according to an embodiment of the present invention;

Fig. 3 is a schematic diagram of the preparation process of the composite electrode based on the silver nanowire electrode and the photoelectric polymer material MEH-PPV according to the embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The purpose of the present invention is to propose a composite multifunctional OLED electrode based on metal nanowires and optoelectronic polymer materials and its preparation method. The composite multifunctional OLED electrode not only has good transparent and conductive characteristics and hole/electron injection capabilities , can also realize luminescence and OLED color conversion, which solves the problem that the light transmission and conductivity of silver nanowires prepared by traditional methods are difficult to balance, and the non-vacuum preparation method can greatly reduce the current manufacturing cost of OLED electrodes.

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

Embodiment one

Fig. 1 is the structural schematic diagram of composite multifunctional OLED electrode of the embodiment of the present invention,

As shown in Figure 1, the composite multifunctional OLED electrode provided by the embodiment of the present invention includes a flexible substrate 1 and a metal nanowire-photoelectric polymer hybrid layer 2 grown on the flexible substrate; The mixed layer includes a metal nanowire 21 and an optoelectronic polymer material 22; a layer of the optoelectronic polymer material 22 is spin-coated on the metal nanowire 21, so that the optoelectronic polymer material 22 is filled in the metal nanowire 21 gaps.

Preferably, the metal nanowires 21 are silver nanowires with a diameter of 80 nm and a length of 5 μm. The optoelectronic polymer material 22 is poly 2-(2-ethylhexyloxy)-5-methoxyphenyl acetylene solution, referred to as MEH-PPV solution in English, and the optoelectronic polymer material 22 has the functions of injecting holes, emitting light Etc. The flexible substrate 1 is a PEI flexible substrate or a PI flexible substrate.

Fig. 2 is a schematic flow chart of a method for preparing a composite multifunctional OLED electrode according to an embodiment of the present invention. As shown in Fig. 2 , a method for preparing a composite multifunctional OLED electrode provided by an embodiment of the present invention includes:

Step 101: Cover a layer of metal nanowire solution on the flexible substrate by a solution method to form a metal nanowire layer; the metal nanowire solution is formed by dispersing metal nanowires in an ethanol solution.

Step 102: Spin-coat a layer of optoelectronic polymer material on the metal nanowire layer, and use heating and pressure to fill the optoelectronic polymer material into the gaps of the metal nanowires to form metal nanowires-optoelectronics The polymer mixed layer is made into a composite multifunctional OLED electrode.

Wherein, the thickness of the metal nanowire layer is 150-250 nm.

The thickness of the metal nanowire-photoelectric polymer mixed layer is 150-250nm.

In the heating and pressing method, the heating temperature is 100 degrees, and the pressing air pressure is above 0.6Mpa.

The solution method includes spin coating method, spray coating method, printing method, etc., and the heating and pressing method includes nanoimprinting method, air pressure method, etc.

Embodiment three:

Figure 3 is a schematic diagram of the preparation process of a composite electrode based on silver nanowire electrodes and optoelectronic polymer materials MEH-PPV according to an embodiment of the present invention. The preparation method of the composite electrode of MEH-PPV includes:

First, silver nanowires with a particle diameter of 80 nm and a length of 50 μm are dispersed in an ethanol solution to form a silver nanowire solution, and the mass fraction of the ethanol solution is 1 wt%.

Secondly, the silver nanowire solution was spin-coated on the flexible PET substrate, and the average film thickness was controlled at about 200nm, followed by annealing at 100°C for 20 minutes.

Furthermore, the MEH-PPV solution is spin-coated on the silver nanowire film, the solvent is toluene, the film thickness is controlled at about 200m, and the photoelectric polymer material MEH-PPV solution is filled into the gap of the silver nanowire by heating and pressing. In order to make a composite electrode with flexibility, transparency, good conductivity and small roughness, and ensure the flatness of the interface.

The invention combines the advantages of luminescent polymer materials and metal nanowires to prepare multifunctional composite electrodes capable of luminescence or color conversion. Compared with the prior art, the present invention has the following advantages:

1. The multifunctional composite electrode prepared by the present invention not only realizes the functions of flexibility, transparency, and conductivity, but also has very low interface roughness, and has good compatibility with the upper film.

2. The multifunctional composite light-emitting electrode prepared by the present invention can realize the light emission of the electrode, can modulate the light emission spectrum of the device at a relatively low cost, and is easy to realize large-scale production.

In this paper, specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; meanwhile, for those of ordinary skill in the art, according to the present invention Thoughts, there will be changes in specific implementation methods and application ranges. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims (10)

1. A composite multifunctional OLED electrode, characterized in that, the composite multifunctional OLED electrode includes a flexible substrate and a metal nanowire-photoelectric polymer hybrid layer grown on the flexible substrate; The metal nanowire-photoelectric polymer hybrid layer includes a metal nanowire and a photoelectric polymer material; a layer of the photoelectric polymer material is spin-coated on the metal nanowire, so that the photoelectric polymer material is filled in the in the gaps between the metal nanowires. 2. The composite multifunctional OLED electrode according to claim 1, wherein the metal nanowires are silver nanowires. 3. The composite multifunctional OLED electrode according to claim 2, wherein the silver nanowires are silver nanowires with a particle diameter of 80 nm and a length of 5 μm. 4 . The composite multifunctional OLED electrode according to claim 1 , wherein the optoelectronic polymer material is poly 2-(2-ethylhexyloxy)-5-methoxyphenylacetylene solution. 5. The composite multifunctional OLED electrode according to claim 1, wherein the flexible substrate is a PEI flexible substrate or a PI flexible substrate. 6. A preparation method for a composite multifunctional OLED electrode, characterized in that the preparation method comprises: A metal nanowire solution is covered on the flexible substrate by a solution method to form a metal nanowire layer; the metal nanowire solution is formed by dispersing the metal nanowire in an ethanol solution; Spin-coat a layer of optoelectronic polymer material on the metal nanowire layer, and fill the optoelectronic polymer material into the gap of the metal nanowire by heating and pressing to form a metal nanowire-optoelectronic polymer hybrid layers to make composite multifunctional OLED electrodes. 7 . The method for preparing composite multifunctional OLED electrodes according to claim 6 , wherein the thickness of the metal nanowire layer is 150-250 nm. 8 . The method for preparing composite multifunctional OLED electrodes according to claim 6 , wherein the thickness of the metal nanowire-photoelectric polymer hybrid layer is 150-250 nm. 9. The preparation method of composite multifunctional OLED electrode according to claim 6, characterized in that, in the heating and pressing method, the heating temperature is 100 degrees, and the pressing pressure is above 0.6Mpa. 10. The preparation method of the composite multifunctional OLED electrode according to claim 6, wherein the solution method is a spin coating method, a spray coating method or a printing method, and the heating and pressing method is a nanoimprint method or an air pressure method. Law.