CN102201545A - Organic light-emitting device - Google Patents

Abstract

The present invention provides an organic light emitting device, comprising: transparent substrate, positive pole, organic luminescent layer, negative pole and light scattering membrane. Wherein the anode is positioned on the transparent substrate; the organic light-emitting layer is positioned on the anode; the cathode is positioned on the organic light-emitting layer; and the light scattering film is positioned below the transparent substrate and has a thickness of more than 100 mu m, scattering particles are doped in a matrix of the light scattering film, the size of the scattering particles is between 100 and 1000 nanometers, the weight ratio of the scattering particles to the matrix is between 0.05 and 10 percent, and the refractive indexes of the scattering particles and the matrix are different. The light scattering film can reflect incident light for multiple times, and increase the probability of scattering light to different angles, thereby reducing the color difference of Organic Light Emitting Devices (OLED) at different viewing angles.

Description

An organic light emitting device

technical field

The invention relates to an organic light-emitting device, in particular to an organic light-emitting device with little color difference at different viewing angles.

Background technique

The structure of an organic light-emitting device (OLED for short) is based on the principle of electroluminescence. Its typical structure is to make a layer of tens of nanometers thick organic light-emitting material on the ITO glass as the light-emitting layer, and there is a metal electrode with a low work function above the light-emitting layer. When a voltage is applied to the electrodes, the light-emitting layer produces light radiation. Different from inorganic thin-film electroluminescent devices (TFEL), the electroluminescence of organic materials belongs to injection composite luminescence. The energy is transferred to the light-emitting molecules, so that the electrons in the light-emitting molecules are excited to the excited state, and the excited state is an unstable state, and the de-excitation process produces visible light.

Organic light-emitting devices (OLEDs) have the advantages of lightness, thinness, high chroma, high contrast, and can be made on flexible substrates, and can be used as lighting and display applications. However, the organic light-emitting device (OLED) is an optical micro-resonator structure, and the wavelengths of phase matching at different viewing angles are different, which will cause changes in the amount of light output at different wavelengths at different viewing angles, making the organic light-emitting device (OLED) at different viewing angles. Therefore, the color of the organic light-emitting device (OLED) with different viewing angles has a large difference.

In view of this, how to design a new type of organic light-emitting device (OLED) to reduce the color difference of different viewing angles as much as possible is a problem that technicians in the industry need to solve urgently.

Contents of the invention

Aiming at the defect in the prior art that the colors of organic light-emitting devices (OLEDs) have large differences in different viewing angles, the present invention provides a novel organic light-emitting device.

According to the present invention, an organic light-emitting device is provided, including: a transparent substrate, an anode, an organic light-emitting layer, a cathode and a light-scattering film. Wherein, the anode is located on the transparent substrate; the organic light-emitting layer is located on the anode; the cathode is located on the organic light-emitting layer; and the light-scattering film is located below the transparent substrate and has a thickness greater than 100 μm, and the matrix of the light-scattering film is doped with scattering particles with a size of 100 μm. Between ~1000 nanometers and the weight ratio of the matrix is between 0.05% and 10%, the refractive index of the scattering particles is different from that of the matrix.

Preferably, the matrix is made of silicone material.

Preferably, the scattering particles are different from the matrix material and comprise titanium oxide, zirconium oxide or silicon dioxide nanoparticles.

Preferably, the anode is made of indium tin oxide.

Preferably, the cathode is made of at least one of magnesium, aluminum, silver or calcium.

Preferably, the organic light emitting device further includes a hole transport layer located between the anode and the organic light emitting layer.

Preferably, the organic light emitting device further includes an electron transport layer located between the cathode and the organic light emitting layer.

Preferably, the organic light emitting device further includes a hole injection layer located between the anode and the hole transport layer.

Preferably, the transparent substrate can be made of glass.

The organic light-emitting device (OLED) of the present invention can scatter the incident light multiple times to increase the probability of light scattering to different angles, thereby reducing the color difference of the organic light-emitting device (OLED) at different viewing angles.

Description of drawings

Readers will have a clearer understanding of various aspects of the present invention after reading the detailed description of the present invention with reference to the accompanying drawings. in,

Figure 1 shows a schematic cross-sectional view of an organic light-emitting device without a light-scattering film in the prior art;

Figure 2 shows a schematic cross-sectional view of an organic light-emitting device with a thin light-scattering film in the prior art;

Fig. 3 shows a schematic cross-sectional view of an organic light emitting device according to the present invention.

Detailed ways

The specific implementation manners of the present invention will be described in further detail below with reference to the accompanying drawings.

Fig. 1 shows a schematic cross-sectional view of an organic light-emitting device without a light-scattering film in the prior art. Referring to FIG. 1 , the organic light emitting device 10 includes: a transparent substrate 100 , an anode 110 , a hole transport layer 120 , an organic light emitting layer 130 , an electron transport layer 140 and a cathode 150 . Wherein, the anode 110 is located on the transparent substrate 100, the hole transport layer 120 is located on the anode 110, the organic light emitting layer 130 is located on the hole transport layer 120, the electron transport layer 140 is located on the organic light emitting layer 130, and the cathode 150 is located on the electron transport layer 140 above. Under bias conditions, electrons from the cathode 150 recombine with holes from the anode 110 at the organic light emitting layer 130, causing the organic light emitting layer 130 to emit light.

As shown in Figure 1, the light emitted from the organic light-emitting layer 130 passes through the hole transport layer 120, the anode 110, and the transparent substrate 100 in sequence, because the matching wavelengths of various lights are different, so when the light 101 enters the air from the transparent substrate 100 , the refractive index is also different, which will cause many differences in the amount of light emitted by different wavelengths at different viewing angles, so that the light colors of the organic light emitting device 10 at different viewing angles are greatly different.

Fig. 2 shows a schematic cross-sectional view of an organic light-emitting device with a thin light-scattering film in the prior art. Referring to FIG. 2 , the organic light emitting device 20 includes: a transparent substrate 200 , an anode 210 , a hole transport layer 220 , an organic light emitting layer 230 , an electron transport layer 240 , a cathode 250 and a light scattering film 260 . 1, the anode 210 is located on the transparent substrate 200, the hole transport layer 220 is located on the anode 210, the organic light-emitting layer 230 is located on the hole transport layer 220, the electron transport layer 240 is located on the organic light-emitting layer 230, and the cathode 250 is located on the above the electron transport layer 240 . Also under bias conditions, electrons from the cathode 250 recombine with holes from the anode 210 at the organic light emitting layer 230, causing the organic light emitting layer 230 to emit light. The light emitted from the organic light emitting layer 230 passes through the hole transport layer 220 , the anode 210 and the transparent substrate 200 sequentially.

Continuing to refer to Figure 2, in order to improve the defect that the output of light of different wavelengths at different viewing angles is different due to the different matching wavelengths of various lights, which makes the light color of organic light-emitting devices very different at different viewing angles, the transparent substrate A light-scattering film 260 is attached to the bottom of the 200, because the matrix 261 of the light-scattering film 260 is doped with dispersed particles 262, which can scatter the light 201 coming out of the transparent substrate 200, increasing the probability of light 201 scattering to different viewing angles. Slightly improve the above-mentioned defect that the light color of different viewing angles is different, but because the light scattering film 260 is relatively thin, the light 201 from the transparent substrate 200 has a narrow range of viewing angles after being scattered, so the light that exists at different viewing angles The color difference is still large.

Fig. 3 shows a schematic cross-sectional view of an organic light emitting device according to the present invention. Referring to FIG. 3 , the organic light emitting device 30 includes: a transparent substrate 300 , an anode 310 , a hole transport layer 320 , an organic light emitting layer 330 , an electron transport layer 340 , a cathode 350 and a light scattering film 360 . In this embodiment, the transparent substrate 300 is made of glass, the anode 310 is an indium tin oxide layer, and the cathode 350 is made of magnesium-silver alloy.

Similar to FIG. 2, the anode 310 is located on the transparent substrate 300, the hole transport layer 320 is located on the anode 310, the organic light-emitting layer 330 is located on the hole transport layer 320, the electron transport layer 340 is located on the organic light-emitting layer 330, and the cathode 350 is located on the above the electron transport layer 340 . In another embodiment, a hole injection layer may also be disposed between the anode 310 and the hole transport layer 320 . Under bias conditions, electrons from the cathode 350 recombine with holes from the anode 310 at the organic light emitting layer 330, causing the organic light emitting layer 330 to emit light. The light emitted from the organic light emitting layer 330 passes through the hole transport layer 320 , the anode 310 and the transparent substrate 300 in sequence.

Also in order to improve the defect that the output of light of different wavelengths at different viewing angles is very different due to the different matching wavelengths of various lights, which makes the light color of organic light-emitting devices very different at different viewing angles, it is arranged under the transparent substrate 300 There is a light-scattering film 360, the matrix 361 of the light-scattering film 360 is doped with scattering particles 362, the size of the scattering particles 362 is between 100-1000 nanometers, and the weight ratio of the matrix 361 is between 0.05-10%. The material is organosilicon. In this embodiment, the scattering particles 362 are titanium oxide nanoparticles. In other embodiments, the scattering particles 362 may be zirconium oxide or silicon dioxide nanoparticles. The refractive index of the scattering particles 362 is larger or smaller than that of the matrix 361 . The thickness of the light-scattering film 360 is greater than 100 μm, because the light-scattering film 360 is thicker and can scatter the light 301 from the transparent substrate 300 multiple times, so that the probability of the light 301 being scattered to different viewing angles can be increased to improve the performance of the organic light-emitting device in different viewing angles. There is a defect that there is a large difference in the light color of the viewing angle.

The invention has the advantages that: the organic light-emitting device has a thick light-scattering film, which can scatter the light entering the air multiple times, increase the opportunity of light scattering to different angles, and reduce the difference in light color of the organic light-emitting device at different viewing angles.

Hereinbefore, specific embodiments of the present invention have been described with reference to the accompanying drawings. However, those skilled in the art can understand that without departing from the spirit and scope of the present invention, various changes and substitutions can be made to the specific embodiments of the present invention. These changes and replacements all fall within the scope defined by the claims of the present invention.

Claims (9)

1. An organic light-emitting device, comprising:

a transparent substrate;

an anode on the transparent substrate;

an organic light emitting layer on the anode;

a cathode on the organic light emitting layer; and

and a light scattering film which is positioned below the transparent substrate and has a thickness of more than 100 μm, wherein scattering particles are doped in a matrix of the light scattering film, the size of the scattering particles is between 100 and 1000 nanometers, the weight ratio of the scattering particles to the matrix is between 0.05 and 10%, and the refractive index of the scattering particles is different from that of the matrix.

2. The organic light emitting device of claim 1, wherein the host is made of an organosilicon material.

3. The organic light emitting device of claim 1, wherein the scattering particles are different from the host material and comprise titanium oxide, zirconium oxide, or silica nanoparticles.

4. The organic light emitting device of claim 1, wherein the anode is made of indium tin oxide.

5. The organic light emitting device of claim 1, wherein the cathode is made of at least one of magnesium, aluminum, silver, or calcium.

6. The organic light emitting device of claim 1, further comprising a hole transport layer between the anode and the organic light emitting layer.

7. The organic light-emitting device of claim 1, further comprising an electron transport layer between the cathode and the organic light-emitting layer.

8. The organic light-emitting device of claim 6, further comprising a hole injection layer between the anode and the hole transport layer.

9. The organic light-emitting device of claim 1, wherein the transparent substrate is made of glass.

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