JP2013179107A - Organic light-emitting diode and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer organic LED which can be multilayered by a coating method.SOLUTION: In an organic light-emitting diode 1a, respective thin films, i.e., a hole injection layer 13, a hole transport layer 14, a light-emitting layer 15, and a cathode 16, are laminated on a substrate 11 having an anode 12 formed on an upper surface thereof. The light-emitting layer 15 is an organic-inorganic hybrid thin film in which TFB as a light-emitting polymer is dispersed in SiObeing an inorganic substance.

Description

  The present invention relates to a multilayer organic light emitting diode in which a plurality of thin films are laminated on a transparent substrate, and a method for manufacturing the same.

  An organic light emitting diode (hereinafter referred to as “organic LED”) is an LED (Light Emitting Diode) that utilizes light emission of organic EL (Electroluminescence). A display using this does not require a backlight like a liquid crystal display and can emit light with small energy. Furthermore, it has advantages such as a high response speed, a wide viewing angle, a thin shape, and low cost, and is therefore regarded as a promising next-generation display to replace liquid crystal displays and plasma displays.

  By the way, the organic LEDs currently commercialized are mainly low molecular weight organic LEDs using a vacuum deposition method in a film forming process. This is because it is possible to easily incorporate a laminated structure, achieve functional separation in each layer, and achieve high efficiency and long life. On the other hand, the film formation process by the vacuum evaporation method requires a high vacuum and has a demerit that it is difficult to increase the area because of its large size dependency.

  In recent years, polymer organic LEDs having higher productivity than low molecular organic LEDs have attracted attention and are actively studied (for example, see Patent Document 1). A polymer organic LED can be applied with an existing printing technique and can be formed by a coating method. Therefore, compared with a low molecular weight organic LED, there is a merit that a high vacuum is not required, a film forming apparatus is inexpensive, a film forming time is short, and an area can be increased.

JP 2011-129387A

  While the polymer organic LED has the above-mentioned merits, it is inferior to the low molecular organic LED in efficiency and lifetime. The cause is that when the coating method is adopted, when the upper layer is applied, the lower layer is dissolved by the solvent, and the original characteristics cannot be exhibited.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a polymer organic LED that can be multilayered by a coating method and a method for manufacturing the same.

  In order to achieve the above-described object, the organic LED according to the present invention is an organic LED in which thin films of a hole injection layer, a hole transport layer, a light emitting layer, and a cathode are laminated on a substrate having an anode formed on an upper surface. In the light emitting diode, the light emitting layer is a thin film in which a light emitting polymer is dispersed in an inorganic substance.

Here, the inorganic substance is preferably SiO ₂ . The light emitting polymer is preferably Poly (9,9-dioctyl-fluorene-co-N-4-butylphenyl-diphenylamine) (TFB).

  A thin film of an electron transport layer may be further formed between the light emitting layer and the cathode. Similarly, a thin film of an electron transport layer and an electron injection layer may be further formed between the light emitting layer and the cathode.

  The organic light emitting diode manufacturing method according to the present invention includes an organic light emitting diode in which at least a hole injection layer, a hole transport layer, a light emitting layer, and a cathode are stacked in this order on a substrate having an anode formed on an upper surface. The thin film of the light emitting layer is coated with a solution in which PHPS and a phosphor polymer are dissolved in a solvent on the thin film of the hole transport layer, heat-treated under high humidity, and then dried. It is characterized by forming.

  In the organic LED according to the present invention, since the light emitting layer is insoluble in an organic solvent, there is no fear of characteristic deterioration due to confusion with respect to the organic layers provided above and below, and the degree of freedom in device design is increased. In addition, the gas barrier property of the light emitting layer can protect the LED element from oxygen and moisture in the atmosphere.

It is a figure which shows the basic element structure of organic LED concerning embodiment of this invention. It is a figure which shows the other element structure of the organic LED. It is a figure which shows the further another element structure of the organic LED. It is a figure which shows the structure of the measurement system which measures EL spectrum of organic LED. It is a graph which shows the measurement result of EL spectrum of this organic LED (sample A) of an Example. It is a graph which shows the measurement result of EL spectrum of this organic LED (sample D) of an Example. It is a graph which shows the measurement result of EL spectrum of such organic LED (sample B) of an example. It is a graph which shows the measurement result of EL spectrum of such organic LED (sample C) of an example. It is a graph which shows the measurement result of EL spectrum of such organic LED (sample E) of an example. It is a graph which shows the measurement result of EL spectrum of such organic LED (sample F) of an example. It is a graph which shows the measurement result of EL spectrum of such organic LED (sample G) of an example.

  Hereinafter, an organic LED according to an embodiment of the present invention will be described with reference to the drawings.

<Element structure of organic LED>
FIG. 1 shows a basic element structure of an organic LED according to this embodiment. The organic LED 1a is formed by laminating a hole injection layer 13, a hole transport layer 14, a light emitting layer 15 and a cathode 16 in this order on a transparent substrate 11 having an anode 12 formed on the upper surface. When a voltage is applied between the anode 12 and the cathode 16, light emission in the visible light region can be observed from the transparent substrate 11 side.

  Although there is no difference in the thickness of each layer in the figure, the thickness of the anode 12, the hole injection layer 13, the hole transport layer 14, the light emitting layer 15 and the cathode 16 is actually about several tens to 100 nm. On the other hand, the thickness of the transparent substrate 11 is about 2 mm, and there is a difference of about 4 digits in thickness.

  First, the light emitting layer 15 will be described. The light-emitting layer 15 is a hybrid thin film in which a light-emitting polymer that is an organic polymer material is dispersed in an inorganic material, and is formed using a sol-gel method as described later. As described above, the conventional organic LED in which the light emitting layer is composed only of the light emitting polymer has a problem that the lower layer is dissolved by the upper layer solvent when each layer is formed by a coating method. On the other hand, by dispersing the light emitting polymer in the inorganic substance, the light emitting layer becomes insoluble in the organic solvent, and it is not necessary to consider the solubility of the lower layer, so that lamination by a coating method is possible.

  Furthermore, the conventional organic LED has a defect that the light emitting layer deteriorates due to the influence of oxygen, moisture, etc. in the atmosphere. In the present invention, deterioration is prevented by protecting the light emitting layer from oxygen, moisture, etc. in the atmosphere by utilizing the gas barrier property of the inorganic substance.

In the present embodiment, the light-emitting layer 15 is made of SiO ₂ that is an inorganic substance, Poly (9,9-dioctyl-fluorene-co-N-4-butylphenyl-) represented by the following formula (Formula 1) that is a light-emitting polymer. Diphenylamine) (TFB) is used. Since SiO ₂ is insoluble in an organic solvent, if the light emitting layer 15 is composed of a thin film of SiO ₂ containing a light emitting polymer, there is no fear of deterioration due to mixing in the upper and lower organic layers, and the degree of freedom in device design increases.

  As the light emitting polymer contained in the light emitting layer 15, various polymer materials having conductivity can be used. In addition to the above TFB, Poly (9,9-n-dihexy1-2,7-fluorene-alt-9- phenyl-3,6-carbazole) (PF-Cz).

  In the organic LED 1a of FIG. 1, a hole injection layer 13 and a hole transport layer 14 are provided between the light emitting layer 15 and the anode 12 in order to relax the hole injection barrier from the anode 12 to the light emitting layer 15. ing. Holes are injected from the anode 12 by the hole injection layer 13, and the holes are efficiently guided to the light emitting layer 15 by the hole transport layer 14.

  A typical material for the hole injection layer 13 is poly (3,4-ethylenedioxythiophene) -polystyrenesulfonic acid (PEDOT-PSS). A typical material for the hole transport layer 14 is Poly (4-butylphenyl-diphenyl-amine) (Poly-TPD). Poly-TPD is insoluble in xylene, an organic solvent, and a good amorphous film can be obtained.

  The electrode material of the organic LED 1a must be capable of injecting sufficient electrons and holes to efficiently emit light. For this reason, the cathode 16 on the electron injection side has a low work function, and the anode 12 has a low work function so that the barrier between the electron energy order (HOMO, LUMO) for receiving carriers of organic molecules and polymers is as small as possible. Use one with a large work function. In order to extract light, at least one of the electrodes needs to be transparent.

  Based on the above, ITO (Indium-Tin-Oxide), which is a general transparent electrode material, is used as the material of the anode 12. On the other hand, as the material of the cathode 16, it is effective to use a metal having a small work function such as an alkali metal or an alkaline earth metal. Examples of the material of the cathode 16 include alloys such as magnesium-silver (MG-Ag), magnesium-indium (Mg-In), and lithium-aluminum (Li-Al), and aluminum itself.

  FIG. 2 shows another element structure of the organic LED. In the organic LED 1b of FIG. 2, an electron transport layer 17 is added between the light emitting layer 15 and the cathode 16 in the structure of FIG. The electron transport layer 17 efficiently transports electrons injected from the cathode 16 to the light emitting layer.

  Typical material for the electron transport layer 17 is 2,9-dimethyl, 4,7-diphenyl, 1,10-phenanthroline (BCP), or a mixed material of BCP and Poly (methyl methacrylare) (PMMA). Is mentioned. Since BCP has a deep HOMO level, it functions as an electron transport layer and a hole blocking layer when a voltage is applied. By dispersing PMMA, which is a binder polymer, in this BCP, it is used as a composite material with amorphous properties.

  FIG. 3 shows still another element structure of the organic LED. In the organic LED 1c of FIG. 3, an electron injection layer 18 is further added between the electron transport layer 17 and the cathode 16 in the structure of FIG. The electron injection layer 18 is provided for the purpose of reducing the energy barrier in electron injection using the tunnel effect.

A typical material for the electron injection layer 18 is Cs ₂ CO ₃ . Cs ₂ CO ₃ can be formed by vapor deposition, but since it can be dissolved in alcohols with a small amount, a thin film can be formed by spin coating. The underlying BCP thin film is insoluble in alcohols, so it has good compatibility in stacking. By making the Cs ₂ CO ₃ thin film extremely thin, the tunneling effect can be used to reduce the energy barrier in electron injection.

<Method for forming each layer of organic LED>
Next, a method of forming each layer of the organic LEDs 1a to 1c (hereinafter collectively referred to as “organic LED 1”) will be described. First, a method for forming the light emitting layer (hybrid thin film) 15 will be described.

  In the present embodiment, the light emitting layer 15 is formed using a sol-gel method. In general, the sol-gel method undergoes hydrolysis and condensation reactions from a starting material solution containing a metal element to change the shape from solution to sol and from sol to gel, and to completely remove the remaining liquid at about 600 ° C. Used in the synthesis of glass and ceramics.

  This synthesis method can be synthesized at a lower temperature than the melting method and sintering method, and depending on the material, it can be synthesized at a low temperature of about room temperature to 150 ° C. Therefore, it is suitable for the synthesis of a hybrid material of an organic substance that is weak against heat and a metal oxide that is an inorganic substance.

As a starting material for dispersing the light emitting polymer in SiO ₂ that is an inorganic material, there can be mentioned Perhydropolysilazane (PHPS) or an alkoxysilane-based material. In this embodiment, PHPS is used. PHPS is dispersed in an organic solvent xylene solution to form a sol-gel precursor, and TFB is injected into the sol-gel precursor as a light-emitting polymer.

PHPS is an inorganic polymer that repeatedly has NH, Si-H, and Si-N bonds as shown in the following chemical formula (Chemical Formula 2). Excellent solubility. When PHPS is heat-treated under high humidity, a dense SiO ₂ thin film can be obtained by repeating hydrolysis and condensation reactions.

Specifically, a solution in which PHPS and TFB are dispersed in xylene is sufficiently stirred by ultrasonic vibration or the like, and then applied onto the thin film of the hole transport layer 14 by a spin coater. Thereafter, heat treatment is performed under high humidity. Finally, the formed thin film is rinsed with a xylene solvent and then dried. In this way, a hybrid thin film in which TFB is dispersed in SiO ₂ is obtained.

As a result of IR absorption spectrum measurement, the conversion conditions of PHPS to SiO ₂ were optimized, and it was found that the conversion to SiO ₂ was best when heat-treated at a temperature of 50 ° C and a humidity of 90% RH for 3 hours. Also, TFB is best in SiO ₂ by applying a 3.5 wt% solution mixed with TFB at a ratio of 30 wt% to PHPS and applying heat treatment under the above conditions. A hybrid thin film that was dispersed and showed insolubility could be obtained.

The ratio of TFB dispersed in the hybrid thin film varies depending on the mixing ratio of TFB. TFB was best dispersed in the hybrid film when it was 30 wt%. If the concentration is lower than this concentration, the TFB will be too small compared to SiO ₂ and the emission will be weak. On the other hand, when the concentration is higher than this concentration, the amount of TFB remaining on the surface of the formed hybrid thin film increases and is difficult to be dispersed in SiO ₂ .

  Among the layers constituting the organic LED 1, the hole injection layer 13, the hole transport layer 14, the electron transport layer 17 and the electron injection layer 18 including the light emitting layer 15 described above are formed by a spin coating method. The cathode 15 is formed by vapor deposition of a metal such as aluminum.

  The spin coating method is suitable for forming an organic material. A thin film can be formed by dropping a solution in which an organic material is dissolved on a smooth surface and rotating the surface. For example, when forming the hole injection layer 13, a transparent substrate (generally a glass substrate) 11 having a transparent electrode ITO film 12 formed on the surface is prepared, and an organic layer is previously formed on the surface of the transparent substrate 11. Add a solution of PEDOT-PSS dissolved in a solvent dropwise, apply using a spin coater, and dry.

  The film thickness and surface state of each layer formed by the spin coating method vary depending on the concentration of the solution, the amount of the solution dripped, and the rotation speed of the spin coater. The coating may be performed multiple times to form a layer.

<Production of sample>
Table 1 shows the sample names of samples manufactured by the method of the present invention, the presence or absence of rinsing, the element structure, and the material of each layer. The “presence / absence of rinsing” in the headings in Table 1 indicates whether or not the hybrid thin film was rinsed with xylene as a solvent after the hybrid thin film (light emitting layer 15) was formed by the sol-gel method. Further, “element structure” indicates whether the element structure of the LED is any of the element structures 1a to 1c shown in FIGS. 1 to 3, and “material of each layer” indicates a material used for each layer of the LED.

  The manufacturing conditions of samples A and D in Table 1 will be described. PEDOT-PSS is applied to a film thickness of about 40 nm by a spin coater on the cleaned transparent substrate 11 in which the ITO film as the anode 12 is formed in a stripe shape and a masking tape is attached to the end. After film formation of PEDOT-PSS, heat and dry with a heater at 200 ° C for 10 minutes.

  Next, a solution in which Poly-TPD is dispersed at a rate of 1 wt% in chlorobenzene, an organic solvent, is dropped onto the PEDOT-PSS thin film, and a thin film with a thickness of about 30 nm is formed by spin coating. Then, heat with a heater at 80 ° C for 10 minutes to dry.

  The hybrid thin film used for the light emitting layer 14 is formed by forming a poly-TPD film, and then applying a solution containing the sol-gel precursor solution tresmile and TFB on the poly-TPD film by spin coating. The mixing ratio of TFB is 30 wt% with respect to PHPS, and the solution concentration is 3.5 wt%. After coating, heat treatment is performed for 3 hours at a temperature of 50 ° C and humidity of 90% RH in a small environmental tester to form a hybrid thin film in which TFB is dispersed in SiO2.

  Thereafter, the sample A is not rinsed, and the sample D is removed by rinsing TFB remaining on the surface of the hybrid thin film with xylene. Specifically, after wiping with Kimwipe moistened with xylene, it is dried with a heater at 80 ° C for 10 minutes.

  After the formation of each layer, aluminum (Al) is vapor-deposited on the hybrid thin film as the cathode 15. Specifically, a mask with holes in stripes is placed on the device so as to intersect with the ITO film, and about 100 nm by a small vacuum deposition device (VPC-260F, ULVAC) through the mask pattern. Evaporate thick Al. Finally, the organic film chlorobenzene is used to etch the thin film where there was the masking tape to expose the ITO film (anode 12).

  Next, manufacturing conditions for Samples B and E will be described. In the preparation of Samples A and D described above, after forming a hybrid thin film as the light emitting layer 14, an electron transport material BCP dissolved in chlorobenzene at 1 wt% is applied onto the film by a 30 nm spin coating method. The element that was not rinsed after the formation of the hybrid thin film was Sample B, and the element that was rinsed with xylene was Sample E.

  Next, the manufacturing conditions of samples C and F will be described. The manufacturing conditions for samples C and F are basically the same as the manufacturing conditions for samples B and E described above. The difference is that BCP alone is used in the samples B and E as the electron transport layer 17, whereas PMMA, which is a binder polymer, is added to BCP in the samples C and F.

Next, manufacturing conditions for the sample G will be described. Sample G is prepared by dissolving 1 mg / 1 ml of Cs ₂ CO ₃ , which is an electron injection material, in 2-ethoxyethanol on a thin film of BCP and PMMA which is the electron transport layer 17 formed in Sample F described above. The electron injection layer 18 is formed by applying by spin coating.

<Measurement of EL spectrum>
FIG. 4 shows the configuration of a measurement system that measures the EL spectrum of each sample. The measurement of the EL spectrum of the organic LED 1 is performed as follows. That is, a voltage is applied from the source meter 2 between the anode 12 and the cathode 16 of the organic LED 1, and the light emission at that time is collected by the integrating sphere unit 3, passed through the optical fiber 4, and input to the multichannel spectrometer 5. The multi-channel spectroscope 5 measures the light intensity for each wavelength, analyzes the measured value with software installed in a PC (personal computer) 6, and displays the result as a graph on the display.

  In this embodiment, Keithley 2400 as the source meter 2, Hamamatsu Photonics A10094 as the integrating sphere unit 3, Hamamatsu Photonics PMA-12 C10027-02 as the multichannel spectrometer 5, and Hamamatsu Photonics U6039-06 as the luminous efficiency measurement software Were used respectively.

  Before explaining the measurement results, the light emission mechanism of the organic LED will be briefly explained. Light is emitted when electrons and holes injected into the light-emitting polymer by voltage application recombine. An excited singlet is formed when the spins of the injected electrons and holes are opposite, and an excited triplet is formed when the spins are the same.

In the behavior of the excited singlet (assuming there is a state ¹ X and ¹ Y different from it), ¹ X and the ground state X ₀ can associate with each other to form an excited state dimer. is there. The resulting dimer is called an excimer (excited dimer). Similarly, when the dimer formation is made of molecular species ¹ X and Y ₀ different from each other, the dimer is called an exciplex (excited complex).

  Luminescence is obtained when the excimer and exciplex are returned from the excited state to the ground state. In general, the former is called excimer emission and the latter is called exciplex emission. Since an excimer has an energy level different from that of a monomer, the obtained emission spectrum is known to exhibit lower energy emission unlike the monomer. The same applies to exciplex light emission.

<Measurement results and discussion>
The spin coating of the hybrid thin film, which is the light emitting layer of each sample, was performed under four conditions with the spin coater rotating speeds of 1000 rpm, 2000 rpm, 4000 rpm, and 7000 rpm, and a rotation time of 30 sec.

  5 to 11 show EL spectra of samples A to G. FIG. In each graph, the line type of the graph differs depending on the rotation speed of the spin coater. As the number of revolutions increases, the thickness of the formed film decreases, and the spectrum changes accordingly. Tables 2 to 8 show the light emission characteristics of Samples A to G. Each table shows the spin coater rotation speed, applied voltage, luminance, and external quantum efficiency.

  FIG. 5 shows the EL spectrum of sample A, and FIG. 6 shows the EL spectrum of sample D. Table 2 shows the light emission characteristics of Sample A, and Table 3 shows the light emission characteristics of Sample D.

  Both samples have an emission peak around 420 nm. However, in Sample D rinsed with xylene, an organic solvent, an emission peak was also observed at around 600 nm. Since there is no organic substance with an emission peak around 600 nm, this emission is thought to originate from the emission of TFB. In other words, this luminescence seems to be due to the TFB excited dimer (excimer).

Since this luminescence was not observed in the sample A from which the remaining organic substances were not removed, it was found that there is a high possibility that a dimer is present in TFB dispersed in SiO ₂ . This may be because dimers are formed in the TFB when the thin film becomes denser as the sol-gel reaction progresses.

  Further, comparing the light emission characteristics of Table 2 and Table 3, it can be seen that there is no TFB remaining on the surface of the hybrid thin film of Sample D. This is because the voltage at which light emission occurs in the same sample structure with or without rinsing with xylene is reduced.

  FIG. 7 shows the EL spectrum of sample B, FIG. 8 shows sample C, FIG. 9 shows sample E, and FIG. Table 4 shows the emission characteristics of Sample B, Table 5 shows Sample C, Table 6 shows Sample E, and Table 7 shows Sample F.

  7 and 8, both EL spectra have a light emission peak near 620 nm in addition to the light emission peak near 420 nm of TFB. This other peak has energy approximately equal to the width of the HOMO level of TFB and the LUMO level of BCP. Therefore, this luminescence around 620 nm seems to be an exciplex luminescence phenomenon.

  In addition, since sample B and sample C are not rinsed with xylene, it is highly possible that the TFB remaining on the thin film surface was dissolved with chlorobenzene, an organic solvent of BCP, and had a gradation structure when the hybrid thin film was formed. . Therefore, the interface between the TFB molecule and the BCP molecule is increased more than when the layers are simply stacked, and it is considered that an environment that easily causes an exciplex phenomenon has been created.

  7 and 8 show that sample C has a higher TFB emission intensity. Considering the exciplex phenomenon, and considering this result, sample C has binder, PMMA, and when it has a gradation structure, the interface between TFB molecule and BCP molecule is less than sample B, and the exciplex is suppressed. I think it was possible. As a result, when Table 4 and Table 5 are compared, it can be understood that Sample C has a higher external quantum efficiency overall. Incidentally, Exciplex basically deteriorates the light emission characteristics of the device.

  Next, in FIGS. 9 and 10, both the samples E and F have light emission in the vicinity of 620 nm by the exciplex in addition to the light emission of TFB, similarly to the samples B and C. Considering the results of samples A and D, excimer emission between TFB molecules may also be included. For samples E and F, there is no possibility of a gradation structure due to TFB and BCP remaining on the surface of the thin film, so the EL spectrum contains a large amount of TFB emission.

  However, in both samples, the emission intensity near 620 nm increases as the rotational speed increases. This is thought to be due to the fact that the light emission site is at the interface between the hybrid thin film and the BCP thin film. This is because the holes injected from the ITO film easily pass through the hybrid thin film due to the thin film thickness, and the hole blocking function of BCP worked. As a result, it is considered that the carrier density at the interface has increased and the occurrence probability of the exciplex emission phenomenon has increased. This can also be explained from the large decrease in external quantum efficiency at 7000 rpm in Tables 6 and 7.

  From these results, it was found that even when the electron transport layer was laminated on the hybrid thin film, the same effect as that obtained by laminating the low molecular weight organic LEDs was obtained. As a result, it is possible to adjust the light emitting area by effectively stacking in consideration of the energy band of the organic material and changing the rotation speed, and feasibility of a highly efficient multi-layer device by coating method Was confirmed.

  FIG. 11 shows the EL spectrum of Sample G. Table 8 shows the light emission characteristics of Sample G.

Sample G is compared with sample F under the same conditions except that a thin film of Cs ₂ CO ₃ (electron injection layer 18) is stacked. As shown in FIG. 11, even when the rotational speed is 4000 rpm, the TFB emission is stronger than the exciplex emission. In comparison, the spectrum of sample F in FIG. 10 is dominated by the exciplex emission from 4000 rpm.

This is presumably because Cs ₂ CO ₃ functions as an electron injection layer. In other words, it is shown that electrons are efficiently injected from Al (cathode 16), and a light emitting area can be formed in the hybrid thin film. Therefore, compared with the sample F, although there are conditions where the external quantum efficiency is low, the overall value is high.

  As described above, an organic LED having a three-layer, four-layer, and five-layer element structure was successfully manufactured by a coating method. In the organic LEDs having these three structures, it was possible to observe light emission by excimer or exciplex in all elements. As a result, it was found that the EL emission area can be controlled by the element structure and the number of revolutions by analyzing the difference in structure and the influence of the film thickness by the number of revolutions.

  From the above results, by using a hybrid thin film of an inorganic material and an organic polymer material for the light emitting layer, even in a polymer organic LED, it depends on the design and film thickness of an efficient energy band like a low molecular organic LED. The light emitting area was adjusted, and it was found that there is a possibility of high efficiency and long life.

1a, 1b, 1c Organic LED
2 Source meter 3 Integrating sphere unit 4 Optical fiber 5 Multichannel spectrometer 5 PC
DESCRIPTION OF SYMBOLS 11 Transparent substrate 12 Anode 13 Hole injection layer 14 Hole transport layer 15 Light emitting layer 16 Cathode 17 Electron transport layer 18 Electron injection layer

Claims (7)

An organic light emitting diode in which a thin film of a hole injection layer, a hole transport layer, a light emitting layer and a cathode is laminated on a substrate having an anode formed on the upper surface,
The organic light emitting diode, wherein the light emitting layer is a thin film in which a light emitting polymer is dispersed in an inorganic substance. Wherein the inorganic material is SiO _2, the organic light emitting diode according to claim 1.   3. The organic light emitting diode according to claim 1, wherein the light emitting polymer is Poly (9,9-dioctyl-fluorene-co-N-4-butylphenyl-diphenylamine) (TFB). 4.   The organic light emitting diode according to any one of claims 1 to 3, wherein a thin film of an electron transport layer is further formed between the light emitting layer and the cathode.   4. The organic light emitting diode according to claim 1, wherein a thin film of an electron transport layer and an electron injection layer is further formed between the light emitting layer and the cathode. A method for producing an organic light emitting diode comprising laminating at least a hole injection layer, a hole transport layer, a light emitting layer, and a cathode in this order on a substrate having an anode formed on an upper surface,
A thin film of the light-emitting layer is formed by applying a solution obtained by dissolving PHPS and a phosphor polymer in a solvent on the thin film of the hole transport layer, heat-treating under high humidity, and drying. A method for manufacturing an organic light emitting diode.   The method according to claim 6, wherein the light emitting polymer is Poly (9,9-dioctyl-fluorene-co-N-4-butylphenyl-diphenylamine) (TFB).

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