KR100955882B1 - Polymer light-emitting diode including water soluble polymer layer containing anion and method for preparing the same - Google Patents

Abstract

The present invention relates to a polymer organic electroluminescent device and a method of manufacturing the same, more specifically, a first electrode; Second electrode; And a light emitting layer interposed between the first electrode and the second electrode, the polymer organic electroluminescent device comprising an anion-containing water-soluble polymer layer formed by a wet coating on the light emitting layer. An element and a method of manufacturing the same.

According to the present invention, it is possible to manufacture a laminated structure by a wet coating by laminating a light emitting layer solvent and an insoluble anion-containing water-soluble polymer layer as a secondary thin film material on the light emitting layer to prevent mixing between the thin film layer, and further, the top of the light emitting layer The anion-containing water-soluble polymer layer of blocks the fast-moving holes injected from the anode and simultaneously increases the electric field between the anode and the anion-containing water-soluble polymer layer by pushing out the electrons injected from the cathode with an electrostatic repulsive force. The present invention can provide a polymer organic electroluminescent device having an effect of improving electron mobility and a method of manufacturing the same.

Polymer organic electroluminescent device, water-soluble polymer layer containing anion

Description

Polymer organic electroluminescent device comprising an anion-containing water-soluble polymer layer and a method for manufacturing the same {Polymer light-emitting diode including water soluble polymer layer containing anion and method for preparing the same}

The present invention relates to a polymer organic electroluminescent device and a method of manufacturing the same, and more particularly, by forming a solvent for the light emitting layer and an insoluble anion-containing water-soluble polymer layer as a secondary thin film material on the light emitting layer to prevent mixing between the thin film layers. It is possible to manufacture a laminated structure by coating, and furthermore, the anion-containing water-soluble polymer layer on the top of the light emitting layer blocks holes having fast mobility injected from the anode and simultaneously pushes the electrons injected from the cathode with an electrostatic repulsive force to By increasing the electric field between the anion-containing water-soluble polymer layer relatively, as a result, the present invention relates to a polymer organic electroluminescent device having an effect of improving the electron mobility and a method of manufacturing the same.

An organic electroluminescent device (organic EL device or OLED) is an active light emitting display device that utilizes a phenomenon in which light is generated when electrons and holes are combined in an organic film when a current flows through a thin film of fluorescent or phosphorescent organic compound. It is possible to make the parts simple and the manufacturing process is simple, and it has the advantages of securing a wide viewing angle of high quality. In addition, the video can be fully implemented, high color purity can be realized, and low power consumption and low voltage driving are possible, which makes it suitable for portable electronic devices.

The internal quantum efficiency of such an organic electroluminescent device is approaching 100% due to the development of phosphorescent materials and the introduction of a new multi-layer structure. The former is properly balanced, leading to improved device stability and characteristics.

Meanwhile, organic EL devices may be classified into low molecular organic EL devices (OLED) using low molecular materials and high molecular organic EL devices (PLED) using high molecular materials in terms of characteristics and manufacturing process of organic film materials. In the process, PLED can mainly be applied to processes such as coating and printing, whereas low-molecular OLED has to use vacuum deposition.

In the PLED, a new stack structure has been studied, and this structure is proposed to improve device stability and efficiency, but it is not easy to manufacture a stack structure compared to a low molecular OLED. The reason is that in the case of PLED, a thin film is formed by a wet process. In this case, a first thin film layer such as a light emitting layer is laminated on a substrate, and then a solution of a second thin film layer material such as an electron injection layer is applied on the first thin film layer. This is because the primary thin film layer is dissolved or finely swelled by the solvent for the second thin film layer. Therefore, when manufacturing a PLED lamination device, selection of the solvent used for the primary thin film layer and the secondary thin film layer is important. However, unless the buffer layer constituent material between the thin film layers is an insoluble material having cross-linkage, most of these problems occur, so that the basic stability of the PLED is lowered.

Therefore, it is a new method for improving device stability, luminous efficiency, and luminance, which are fundamentally prevented from mixing between the primary thin film layer and the secondary thin film layer or dissolution of the primary thin film layer by the solvent for forming the secondary thin film layer. Introduction of the laminated structure will be possible.

Therefore, the first object of the present invention, the anion-containing water-soluble polymer layer on the top of the light emitting layer to prevent the hole having a fast mobility injected from the anode and at the same time push the electrons injected from the cathode with an electrostatic repulsive force positive and negative By increasing the electric field between the containing water-soluble polymer layer relatively, to provide a polymer organic electroluminescent device having an effect that can improve the electron mobility as a result.

In addition, a second object of the present invention is to prepare a laminated structure by wet coating by laminating a solvent for the light emitting layer and an insoluble anion-containing water-soluble polymer layer as a secondary thin film material on the light emitting layer to prevent mixing between the thin film layers. It is to provide a method for producing a polymer organic electroluminescent device possible.

In order to achieve the first object of the present invention,

A first electrode;

Second electrode; And

A polymer organic electroluminescent device comprising a light emitting layer interposed between the first electrode and the second electrode,

It provides a polymer organic electroluminescent device comprising an anion-containing water-soluble polymer layer formed by a wet coating on the light emitting layer.

According to one embodiment of the present invention, the water-soluble polymer layer may include a water-soluble polyurethane resin.

According to another embodiment of the present invention, the water-soluble polyurethane resin may be polyurethane-polyurea, polyurethane-polyacrylate or mixtures thereof.

According to another embodiment of the present invention, the thickness of the anion-containing water-soluble polymer layer may be 1 nm to 10 nm.

According to a further embodiment, the anion is ^{F -, Cl -, Br -} , I -, OH -, CN -, NO 3 -, HCO 3 -, MnO 4 -, SO 4 2 -, Cr 2 O ₇ ^{2 -} may be one or more anions selected from the group consisting of ^- and PO ₄ ^3.

According to another embodiment of the present invention, the polymer used as the light emitting layer may be a blue, red or green light emitting material.

According to another embodiment of the present invention, the polymer organic electroluminescent device further comprises at least one layer selected from the group consisting of a hole injection layer, a hole transport layer, an electron transport layer and an electron injection layer between the first electrode and the second electrode. can do.

According to another embodiment of the present invention, the laminated structure of the polymer organic electroluminescent device,

First electrode / hole injection layer / light emitting layer / anion-containing water-soluble polymer layer / second electrode,

First electrode / hole injection layer / light emitting layer / anion-containing water-soluble polymer layer / electron injection layer / second electrode ,

First electrode / hole injection layer / hole transport layer / light emitting layer / anion-containing water-soluble polymer layer / second electrode,

First electrode / hole injection layer / hole transport layer / light emitting layer / anion-containing water-soluble polymer layer / electron injection layer / second electrode, or

It may be a first electrode / hole injection layer / hole transport layer / light emitting layer / anion-containing water-soluble polymer layer / electron transport layer / electron injection layer / second electrode.

In order to achieve the second object of the present invention,

Forming a first electrode on the substrate;

Forming a light emitting layer on the anode;

Forming an anion-containing water-soluble polymer layer by wet coating on the light emitting layer;

It provides a method for producing a polymer organic electroluminescent device comprising an anion-containing water-soluble polymer layer comprising the step of forming a second electrode on the anion-containing water-soluble polymer layer.

According to one embodiment of the invention, the wet coating solution for forming the anion-containing water-soluble polymer layer may be prepared by dissolving the water-soluble polymer in distilled water containing anion.

According to another embodiment of the present invention, the water-soluble polymer may be a water-soluble polyurethane resin.

According to another embodiment of the present invention, the concentration of the water-soluble polymer in the anion-containing water-soluble polymer solution may be 0.4% by weight to 2% by weight.

According to another embodiment of the present invention, the anion-containing distilled water may be prepared by performing a column chromatography process on a solution of an ion compound containing a cation and an anion to obtain a solution containing only an anion.

According to another embodiment of the present invention, the anion concentration in distilled water containing the anion may be 0.1ppm to 30ppm.

According to a further embodiment, the anion is ^{F -, Cl -, Br -} , I -, OH -, CN -, NO 3 -, HCO 3 -, MnO 4 -, SO 4 2 -, Cr 2 O ₇ ^{2 -} may be one or more anions selected from the group consisting of ^- and PO ₄ ^3.

According to another embodiment of the present invention, the thickness of the anion-containing water-soluble polymer layer may be 1 nm to 10 nm.

According to another embodiment of the present invention, the method may further include forming one or more layers selected from the group consisting of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer between the first electrode and the second electrode. .

Hereinafter, the present invention will be described in more detail.

The polymer organic electroluminescent device according to the present invention comprises: a first electrode; Second electrode; And a light emitting layer interposed between the first electrode and the second electrode, the polymer organic electroluminescent device comprising an anion-containing water-soluble polymer layer formed by a wet coating on the light emitting layer.

In the polymer organic electroluminescent device according to the present invention, the anion-containing water-soluble polymer layer prevents mixing between the light emitting layer and the secondary thin film layer on the top of the light emitting layer, and serves to balance charge in the light emitting layer.

That is, since the anion-containing water-soluble polymer layer is formed by wet coating a solution made by dissolving a water-soluble polymer in a specific anion-containing solution on a light emitting layer that is organic solvent, the light emitting layer is melted or swelled finely by the anion-containing water-soluble polymer solution. Since no problem occurs, the stability and efficiency of the light emitting device may be further improved. Furthermore, after the anion-containing water-soluble polymer layer is cured to form a solid thin film, even if another anion-containing water-soluble polymer layer is formed on the solid thin film, the mixing phenomenon between the thin film layers does not occur. An electroluminescent element can be manufactured.

In addition, in the conventional organic light emitting device EL device, the hole injected from the anode has a faster mobility than the electron injected from the cathode, the polymer organic electroluminescent device according to the present invention is water-soluble in the anion-containing water-soluble polymer layer The polymer component blocks the hole flow from the anode, thereby allowing the hole to stay in the light emitting layer for a long time. In addition, the polymer organic electroluminescent device according to the present invention includes an anion in the water-soluble polymer layer, while the water-soluble polymer component plays a role of blocking the hole flow from the anode, the anion component is electrons and electrostatics from the cathode It generates a miracle repulsive force. Due to the repulsive force generated at this time, the electric field between the positive electrode and the anion-containing water-soluble polymer layer is relatively increased, and as a result, the electron mobility is improved. This is a mixture of a metal-insulator-semiconductor (MIS) structure and a p-type-insulator-n-type (PIN) structure, thereby maximizing the efficiency of the organic EL device.

In the polymer organic electroluminescent device according to the present invention, due to the introduction of an anion-containing water-soluble polymer layer, the blocking of hole flow and the electrostatic repulsion of electrons occur at the same time, thereby increasing the number of times that holes and electrons recombine within the light emitting layer for a unit time. The luminous efficiency and luminance of the overall polymer organic electroluminescent device is improved.

Particularly, in the polymer organic electroluminescent device according to the present invention, a thin film layer for blocking hole flow and a thin film layer for electrostatically pushing electrons are not provided as separate layers, but a single thin film layer may simultaneously perform the above two functions. There is a big feature in that it is made to be. That is, due to the adoption of such a multi-functional single thin film layer, the overall stack structure of the device can be more simplified, and various types of stack structures can be introduced.

In addition, in order to further enhance the effect of increasing the electric field between the anode and the water-soluble polymer layer by generating an electrostatic repulsion of electrons, a simple ionic compound layer is not introduced into the device stack structure, but only anion components are separated from the ionic compound. Then, it was introduced into the water-soluble polymer layer. As a result, the polymer organic electroluminescent device according to the present invention simply comprises a water-soluble polymer layer, only an ionic compound layer, or a current structure, luminance compared to the device structure comprising a water-soluble polymer layer and an ionic compound layer as separate layers, respectively. It has the effect that a characteristic and luminous efficiency improve further.

Preferably, the water-soluble polymer includes a water-soluble polyurethane resin, and the water-soluble polyurethane resin may be a polyurethane-polyurea, a polyurethane-polyacrylate, or a mixture thereof.

Generally, polyurethane resins can be synthesized using isocyanate and polyester type polyols or polyether type polyols as intermediates, and water-soluble polyurethane resins can be synthesized using triethylenetetraamine as a polyurethane prepolymer having an isocyanate end group. Polyurethane-polyurethanes are prepared in the form of polyurethane-polyureas by reaction with polyvalent amines such as (TETA), or by reacting polyurethane prepolymers having isocyanate end groups with monomers such as ethylene glycol dimethacrylate (EGDMA) or the like. It may be prepared in the form of acrylate.

A schematic synthesis method of the polyurethane-polyurea resin and the polyurethane-polyacrylate resin is as follows.

Synthesis Example  1.Polyurethane Polyurea

Synthesis Example  2. Polyurethane Polyacrylate

In the polymer organic electroluminescent device according to the present invention, the thickness of the anion-containing water-soluble polymer layer is preferably 1 to 10 nm. If the thickness of the anion-containing water-soluble polymer layer is less than 1 nm, there is a problem that the hole flow blocking and electron repulsion effect is weak and the luminous efficiency is reduced. In addition, when the thickness of the anion-containing water-soluble polymer layer exceeds 10 nm, there is a problem that the electrons do not reach the light emitting layer efficiently, the light emission efficiency is reduced.

On the other hand, the anion of the water-soluble polymer layer is one, and would also mubang long as it can push the electrons injected from the negative electrode electrostatically, but are not limited to, F ^-, Cl ^-, Br ^-, I ^-, OH ^{-, _{CN -, NO 3 -, HCO}} 3 -, MnO 4 -, SO 4 2 -, Cr 2 O 7 2 - is preferably one or more anion selected from the group consisting of ^- and PO ₄ ^3.

The material constituting the light emitting layer of the polymer organic electroluminescent device according to the present invention is not particularly limited and may include not only blue, red, or green light emitting materials, but also light emitting materials of all colors throughout the visible light region.

The polymer organic electroluminescent device according to the present invention may further include at least one layer selected from the group consisting of a hole injection layer, a hole transport layer, an electron transport layer and an electron injection layer between the first electrode and the second electrode. The hole injection layer, the hole transport layer, the electron transport layer and the electron injection layer serves to increase the probability of the light emitting bond in the light emitting polymer by efficiently transferring holes or electrons to the light emitting polymer, a material commonly used in the art Can be used.

More specifically, various embodiments of the polymer organic electroluminescent device according to the present invention may refer to FIGS. 1A to 1E.

The device of Figure 1a has a structure consisting of a first electrode / hole injection layer / light emitting layer / anion-containing water-soluble polymer layer / second electrode, the device of Figure 1b is a first electrode / hole injection layer / light emitting layer / anion-containing water-soluble polymer layer It has a structure consisting of an electron injection layer and a second electrode. In addition, the device of Figure 1c has a structure of the first electrode / hole injection layer / hole transport layer / light emitting layer / anion-containing water-soluble polymer layer / second electrode, the device of Figure 1d is a first electrode / hole injection layer / hole transport layer / The light emitting layer / anion-containing water-soluble polymer layer / electron injection layer / second electrode has a structure of the first electrode / hole injection layer / hole transport layer / light emitting layer / anion-containing water-soluble polymer layer / electron transport layer / electron injection layer / Has a structure of a second electrode.

On the other hand, the present invention provides a method for producing a polymer organic electroluminescent device, which includes forming a first electrode on a substrate; Forming a light emitting layer on the anode; Forming an anion-containing water-soluble polymer layer by wet coating on the light emitting layer; And forming a second electrode on the anion-containing water-soluble polymer layer.

In the method for manufacturing a polymer organic electroluminescent device according to the present invention, first, the first electrode material is coated on a substrate, and as the substrate, a substrate used in a conventional organic electroluminescent device is used, having transparency and surface smoothness. In consideration of ease of handling and waterproofness, a glass substrate or a plastic substrate can be used in various ways. As the first electrode, an indium tin oxide (ITO) glass substrate which is most widely used in organic electroluminescent devices may be used, and tin oxide (SnO ₂ ), zinc oxide (ZnO), and the like which are transparent and have excellent conductivity may be used. , Highly conductive metals such as lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium- Various modifications are possible, such as silver (Mg-Ag), calcium (Ca) -aluminum (Al), aluminum (Al) -ITO, or the like, which may be produced as a reflective electrode.

Subsequently, a hole injection layer and / or a hole transport layer may be selectively formed on the first electrode by a wet coating method such as spin coating or ink jet printing, and the light emitting layer may be formed by wet coating such as spin coating or ink jet printing. Can be.

At this time, the thickness of the hole injection layer and the hole transport layer is preferably 20 to 50nm, when the thickness of the hole injection layer and the hole transport layer is out of the above range is not preferable because the hole injection and hole transport characteristics are poor. It is preferable that the thickness of the light emitting layer is 50 to 120 nm. However, when the thickness of the light emitting layer is less than 50 nm, the light emission efficiency is lowered.

Next, an anion-containing water-soluble polymer layer is formed on the light emitting layer by a wet coating method. At this time, the production of the anion-containing water-soluble polymer layer is made by dissolving a water-soluble polymer such as a water-soluble polyurethane resin in distilled water containing anion, and then wet coating the upper portion of the light emitting layer.

In this case, the water-soluble polymer may be a water-soluble polyurethane resin such as polyurethane-polyurea, polyurethane-polyacrylate or a mixture thereof as described above, the concentration of the water-soluble polymer in the anion-containing water-soluble polymer solution is 0.4% by weight to It is preferable that it is 2 weight%. When the concentration of the water-soluble polymer is less than 0.4% by weight, the thickness of the water-soluble polymer layer is thin, so that the blocking effect of the hole flow is weak. Therefore, there is a problem in that the luminous efficiency is reduced. It is not preferable because there is a problem that the luminous efficiency decreases because the hole and electrons are imbalanced due to thickening.

The solution for preparing the anion-containing water-soluble polymer layer may be prepared by separating only anions from a solution in which cations and anions are mixed using a method such as column chromatography. Column chromatography is a process of separating a substance between a solid phase and a liquid phase. The adsorption force between a substance to be separated and a column is due to an attraction force between molecules such as electrostatic attraction, complexation, or hydrogen bonding. In the present invention, since the purpose is to selectively separate only anions from the mixed ionic compound solution with cations and anions, the column is filled with a cation exchange resin and the ionic compound solution is injected from the top of the column. The ionic compound solution injected into the column causes the cation and anion components in the ionic compound solution to flow down inside the column at different rates by the selective adsorption force of the cation exchange resin used in the solid phase. When the process is completed, the anion in the ionic compound solution is adsorbed on the column, and only the anion remains selectively in the solution passing through the column, and after confirming the presence and concentration of the anion in the resulting solution, the solution for wet coating It can be used as.

The anion concentration in the distilled water containing the anion is preferably from 0.1ppm to 30ppm, which has a problem that the effect of electron mobility to transfer the electrons injected from the negative electrode when the anion concentration is less than 0.1ppm, is rarely appeared, 30ppm If it exceeds, the repulsive force with electrons injected from the cathode becomes too strong as the negative ions increase, so the adverse effect of electron mobility to transfer electrons occurs, which reduces the luminous efficiency because electrons and holes are not properly balanced in the light emitting layer. This is because there is a problem that is not preferable.

On the other hand, the anion, as described above, ^{F -, Cl -, Br -} , I -, OH -, CN -, NO 3 -, HCO 3 -, MnO 4 -, SO 4 2 -, Cr 2 O 7 2 ^- and PO ₄ ^{3 -} may be one or more anions selected from the group consisting of the thickness of the anion-containing water-soluble polymer layer is preferably 1 nm to 10 nm.

Subsequently, an electron transport layer and / or an electron injection layer are optionally formed on the anion-containing water-soluble polymer layer by a wet coating method such as spin coating or inkjet printing, wherein the thicknesses of the electron transport layer and the electron injection layer are 20 nm to 40 nm, respectively. And 0.8 nm to 1 nm. When the thickness of the electron transport layer and the electron injection layer is less than the above range, it is difficult to realize sufficient electron transport characteristics and electron injection characteristics, and when the thickness exceeds the above range, the driving voltage is similarly increased, which is not preferable.

Finally, by forming a second electrode on the electron transport layer and / or the electron injection layer by vacuum deposition or sputtering, a polymer organic electroluminescent device according to the present invention can be manufactured, wherein the second electrode is formed. As the metal, lithium (Li), magnesium (Mg), calcium (Ca), aluminum (Al), Al: Li, Ba: Li, Ca: Li, etc., which have a small work function, are used.

The polymer organic electroluminescent device including the anion-containing water-soluble polymer layer according to the present invention may be provided in various types of flat panel display devices, for example, passive matrix organic light emitting display devices and active matrix organic light emitting display devices.

According to the present invention, it is possible to manufacture a laminated structure by a wet coating by laminating a light emitting layer solvent and an insoluble anion-containing water-soluble polymer layer as a secondary thin film material on the light emitting layer to prevent mixing between the thin film layer, and further, the top of the light emitting layer The anion-containing water-soluble polymer layer of blocks the fast-moving holes injected from the anode and simultaneously increases the electric field between the anode and the anion-containing water-soluble polymer layer by pushing out the electrons injected from the cathode with an electrostatic repulsive force. The present invention can provide a polymer organic electroluminescent device having an effect of improving electron mobility and a method of manufacturing the same.

Hereinafter, examples and comparative examples according to the present invention will be specifically illustrated, but this is to aid the understanding of the present invention, and the scope of the present invention is not limited to the following examples.

Preparation of Anion-Containing Water-Soluble Polymer Solution

F ^- ion was used as an anion for forming an anion-containing water-soluble polymer layer by wet coating, and an anion-containing water-soluble polymer solution was prepared by the following method.

The anionic aqueous solution is dissolved by dissolving 0.002 g of CsF in 200 ml of distilled water at a temperature of 25 ° C., and then selectively adsorbing Cs ⁺ ions to the anion exchange resin (ALDRICH Amberlite IRA-410CL resin) in the column using column chromatography. Prepared by separating only F ^- ions from a mixture of, Cs ⁺ and F ^- ions. The presence of F ⁻ ions in the prepared anionic aqueous solution and the concentration thereof were confirmed using an ICP (Inductively Coupled Plasma) Perkinelmer Optima 2100 instrument.

Anionic water-soluble polymer solution was prepared by dissolving 0.035 g of a water-soluble polyurethane-polyurea resin in 25 ml of F ^- ion aqueous solution prepared as described above at 25 ° C.

Anion-containing water soluble Polymer layer  Thickness determination

In order to determine the optimal thickness of the anion-containing water-soluble polymer layer, data on the optimum thickness of the water-soluble polymer layer was referred to.

The water-soluble polymer layer was formed by spin coating a water-soluble polymer solution on the light emitting layer, and the thickness thereof was measured by α-step. The thickness of the water-soluble polymer layer formed while gradually decreasing the concentration of the water-soluble polymer in a state in which the rotation speed and the rotation time of the spin coating was constant. Using concentrations and thicknesses corresponding to thicknesses of 10 nm or more, graphs were made by linear equations to determine concentrations for thicknesses less than 10 nm based on the least-squares method. The thickness graph by the least square method is shown in FIG. 2.

The polymer organic electroluminescent device of ITO / PEDOT: PSS / PFO / water-soluble polymer layer / LiF / Al structure was fabricated by varying the thickness of the water-soluble polymer layer (marked as 'polymer layer thickness' in the drawing), and each of the manufactured devices The current and the brightness of were compared, and the results are shown in FIGS. 3 and 4.

As shown in FIGS. 3 and 4, the polymer organic electroluminescent device according to the present invention showed excellent results in terms of current and luminance, as compared with the conventional polymer organic electroluminescent device that does not include a water-soluble polymer layer.

In particular, at the thickness of 4 nm corresponding to the case where the concentration of the polyurethane used to form the water-soluble polymer layer was 6.4 mg / cc, the current and brightness showed the maximum results.

Example  1 to 5. Anion-containing water soluble according to the present invention Polymer layer  Polymer organic containing Electric field  Manufacture of light emitting device

Anion-containing water-soluble polymer layer containing anions at different concentrations on top of the light emitting layer (Example 1: 0.1 ppm, Example 2: 1 ppm, Example 3: 10 ppm, Example 4: 25 ppm, Example 5: 30 ppm), and then the polymer organic electroluminescent device was manufactured using the same.

An ITO glass substrate was used as the device anode, and a PEDOT: PSS was formed on the ITO substrate as a hole injection layer and a hole transport layer to smooth the surface of the ITO and assist the injection and flow of holes. In addition, as a light emitting layer, a thin film having a thickness of 30 nm consisting of PFO + @ -NPD was formed on the layer of PEDOT: PSS by a known method.

The prepared anion-containing water-soluble polymer layer on the light emitting layer was formed to a thickness of 2 nm by a spin coating method, and a LiF layer (0.8 nm) as an electron injection layer and an Al metal (120 nm) layer as a cathode were formed on the substrate. ^The polymer organic electroluminescent device according to the present invention was prepared by vacuum deposition at a rate of 0.1 to 1 dl / sec under a vacuum condition of ^-6 torr.

Comparative example  1. Polymer organic according to the prior art Electric field  Manufacture of light emitting device

A polymer organic electroluminescent device according to the prior art was manufactured by the same method as Examples 1 to 5, except that the anion-containing water-soluble polymer layer was not laminated on the light emitting layer.

Comparative example  2. Water soluble Only polymer layer  Polymer organic containing Electric field  Manufacture of light emitting device

By the same method as in Examples 1 to 5, except that a thin film of 4 nm was formed by spin coating using a polyurethane thin film layer as a water-soluble polymer layer containing no anion instead of an anion-containing water-soluble polymer layer. A polymer organic electroluminescent device according to the technology was prepared.

Evaluation example : Example  1 to 5 and Comparative example  Polymer organic according to 1 to 2 Electric field  Evaluation of current, brightness and luminous efficiency of light emitting device

Voltages were applied to the polymer organic electroluminescent elements prepared in Examples 1 to 5 and Comparative Examples 1 to 2 to evaluate current characteristics (I-V), luminance (L-V), and luminous efficiency (E-V), respectively.

The fabricated device uses the KEITHLEY 2400 and KEITHLEY 195A devices to convert the current according to the applied voltage and the light from the device into current into a database of brightness and efficiency by a program called Test Point. lost. The I-V, L-V, and E-V characteristics of the fabricated device were measured and the results are shown in FIGS. 5 to 7.

From the graphs shown in FIGS. 5 to 7, it can be seen that the polymer organic electroluminescent devices according to Examples 1 to 5 and Comparative Examples 1 to 2 show current characteristics, luminance characteristics, and luminous efficiency characteristics of typical light emitting devices. have. 5 to 7, the device in which the anion-containing water-soluble polymer layer is laminated compared to the conventional conventional device of Comparative Example 1 shows more excellent current, brightness and luminous efficiency characteristics, and further, the anion-containing water-soluble polymer layer is laminated. In this case, it can be seen that the current, luminance, and luminous efficiency characteristics are more excellent than when only the water-soluble polymer layer is laminated (Comparative Example 2).

Particularly, from the graph showing the luminance characteristics of FIG. 6, in the case of a device in which only a water-soluble polymer layer is laminated based on an applied voltage of 10 V (Comparative Example 2), the luminance is 4439 cd / m ^2, but an anion-containing water-soluble polymer layer is laminated. In the case of the device according to the present invention (Example 2), it can be seen that the luminance is 5294 d / m ² . In addition, the device according to Example 2 exhibits similar brightness characteristics as the devices according to Comparative Examples 1 and 2 up to an applied voltage of about 5V, but at a higher applied voltage, the device exhibits a sharp brightness enhancement effect. The negative ions generate electrons and electrostatic repulsive force from the negative electrode, and the repulsive force increases the electric field between the positive electrode and the water-soluble polymer, and consequently improves the mobility of the electrons.

On the other hand, as shown in the luminous efficiency characteristics of Figure 7, the device according to Example 2 at the applied voltage of about 7V the luminous efficiency is 1.0cd / A, the device according to Comparative Example 1 is luminous efficiency 0.52cd / A It can be seen from the fact that the luminous efficiency also increased significantly by lamination of the anion-containing water-soluble polymer layer. In addition, when the anion-containing water-soluble polymer layer is laminated as in the present invention (1.0cd / A), only the water-soluble polymer layer is laminated, that is, the luminous efficiency compared to the device (0.9cd / A) according to Comparative Example 2 It can be seen that this is even better.

1A to 1E are cross-sectional views schematically showing the structure of the polymer organic electroluminescent device according to the present invention.

Figure 2 is a graph showing the result of measuring the thickness of the anion-containing water-soluble polymer layer according to the concentration of the anion-containing water-soluble polymer in the manufacturing process of the polymer organic electroluminescent device of the present invention.

3 is a graph showing a measured current value of the polymer organic electroluminescent device with respect to the thickness of the water-soluble polymer layer in the polymer organic electroluminescent device according to the present invention.

4 is a graph showing the luminance measurement value of the polymer organic electroluminescent device with respect to the thickness of the water-soluble polymer layer in the polymer organic electroluminescent device according to the present invention.

5 is a graph showing the results of measuring the current characteristics according to the applied voltage of the polymer organic electroluminescent device according to Examples 1 to 5 and Comparative Examples 1 to 2.

6 is a graph illustrating results of measuring luminance characteristics according to an applied voltage of the polymer organic electroluminescent devices according to Examples 1 to 5 and Comparative Examples 1 to 2. FIG.

7 is a graph showing the results of measuring the luminous efficiency according to the applied voltage of the polymer organic electroluminescent device according to Examples 1 to 5 and Comparative Examples 1 to 2.

Claims (17)

A first electrode; Second electrode; And A polymer organic electroluminescent device comprising a light emitting layer interposed between the first electrode and the second electrode, A polymer organic electroluminescent device comprising an anion-containing water-soluble polymer layer formed by a wet coating on the light emitting layer. The polymer organic electroluminescent device according to claim 1, wherein the water-soluble polymer layer comprises a water-soluble polyurethane resin. The polymer organic electroluminescent device according to claim 2, wherein the water-soluble polyurethane resin is polyurethane-polyurea, polyurethane-polyacrylate or a mixture thereof. The polymer organic electroluminescent device according to claim 1, wherein the anion-containing water-soluble polymer layer has a thickness of 1 nm to 10 nm. The method of claim 1, wherein the anion is ^{F -, Cl -, Br -} , I -, OH -, CN -, NO 3 -, HCO 3 -, MnO 4 -, SO 4 2 -, Cr 2 O 7 2 - And PO ₄ ^{3 −} , wherein the polymer organic electroluminescent device is one or more anions selected from the group consisting of. The polymer organic electroluminescent device according to claim 1, wherein the polymer used as the light emitting layer is a blue, red or green light emitting material. The method of claim 1, wherein the polymer organic electroluminescent device further comprises one or more layers selected from the group consisting of a hole injection layer, a hole transport layer, an electron transport layer and an electron injection layer between the first electrode and the second electrode. Polymer organic electroluminescent device. According to claim 1, The laminated structure of the polymer organic electroluminescent device, First electrode / hole injection layer / light emitting layer / anion-containing water-soluble polymer layer / second electrode, First electrode / hole injection layer / light emitting layer / anion-containing water-soluble polymer layer / electron injection layer / second electrode , First electrode / hole injection layer / hole transport layer / light emitting layer / anion-containing water-soluble polymer layer / second electrode, First electrode / hole injection layer / hole transport layer / light emitting layer / anion-containing water-soluble polymer layer / electron injection layer / second electrode, or A polymer organic electroluminescent device, comprising: a first electrode / hole injection layer / hole transport layer / light emitting layer / anion-containing water-soluble polymer layer / electron transport layer / electron injection layer / second electrode. Forming a first electrode on the substrate; Forming a light emitting layer on the first electrode; Forming an anion-containing water-soluble polymer layer by wet coating on the light emitting layer; Method of manufacturing a polymer organic electroluminescent device comprising an anion-containing water-soluble polymer layer comprising the step of forming a second electrode on the anion-containing water-soluble polymer layer. 10. The polymer organic electroluminescent device of claim 9, wherein the wet coating solution for forming the anion-containing water-soluble polymer layer is prepared by dissolving the water-soluble polymer in distilled water containing the anion. Manufacturing method. The method of manufacturing a polymer organic electroluminescent device comprising the anion-containing water-soluble polymer layer according to claim 10, wherein the water-soluble polymer is a water-soluble polyurethane resin. The method of claim 10, wherein the concentration of the water-soluble polymer in the anion-containing water-soluble polymer solution is 0.4% by weight to 2% by weight. The method of claim 10, wherein the anion-containing distilled water is prepared by performing a column chromatography process on a solution of an ion compound containing a cation and an anion to obtain a solution containing only an anion. Method for producing a polymer organic electroluminescent device comprising a polymer layer. The method of manufacturing a polymer organic electroluminescent device comprising the anion-containing water-soluble polymer layer according to claim 10, wherein the anion concentration in the distilled water containing the anion is 0.1 ppm to 30 ppm. 10. The method of claim 9, wherein the anion is ^{F -, Cl -, Br -} , I -, OH -, CN -, NO 3 -, HCO 3 -, MnO 4 -, SO 4 2 -, Cr 2 O 7 2 - And PO ₄ ^{3 −} , wherein the at least one anion is selected from the group consisting of an anion-containing water-soluble polymer layer. 10. The method of claim 9, wherein the thickness of the anion-containing water-soluble polymer layer is 1 nm to 10 nm. The method of claim 9, further comprising forming at least one layer selected from the group consisting of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer between the first electrode and the second electrode. Method for producing a polymer organic electroluminescent device comprising a water-soluble polymer layer containing.

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