TWI475921B - White-color organic light-emitting device - Google Patents

Description

White organic light-emitting element

The present invention relates to a white organic light-emitting element, and more particularly to a white light organic light-emitting element having high luminous efficiency.

Organic light-emitting device (OLED) has self-luminous properties, agile response speed, wide viewing range, low power consumption, clear contrast, thin panel thickness, light weight and flexibility The advantages of music and so on, it is very likely to become one of the mainstream display technologies in the future.

In the past, the OLED is disclosed in Japanese Patent Publication No. JP2004059535, which discloses an Anthrancene polymer as an organic light-emitting material for an OLED, and an OLED sandwich structure comprising at least a single layer of onion derivative or a single layer of onion. The mixture of the body derivative and other materials can solve the shortcomings of the prior OLEDs such as low efficiency, insufficient brightness and high voltage.

In addition, for a white OLED, white light is generally emitted by mixing light emitted by a blue light-emitting layer and a yellow-red light-emitting layer. However, the conventional blue light-emitting layer and the yellow-red light-emitting layer are both composed of the same derivative of the same onion body. Depending on the type of onion derivative, white OLEDs each have the following disadvantages: poor half-life, components The luminous efficiency is not high, the driving voltage is high, or the color light is difficult to adjust.

In view of this, the main scope of the present invention is to provide a white organic light-emitting element to solve the above problems.

One aspect of the present invention is to provide a white organic light-emitting element.

According to an embodiment of the invention, the white light organic light emitting device comprises a substrate, an anode layer, a blue light emitting layer, a yellow-red light emitting layer, and a cathode layer. The anode layer is formed on the substrate, the blue light emitting layer is formed on the anode layer, the yellow-red light emitting layer is formed on the blue light emitting layer, and the cathode layer is formed on the yellow-red light emitting layer.

Wherein, the blue light-emitting layer comprises a first host material composed of a first derivative of an onion body, and the yellow-red light-emitting layer comprises a second body composed of a second derivative of the onion body a material wherein the second derivative is different from the first derivative.

The advantages and spirit of the present invention will be further understood from the following detailed description of the invention.

Please refer to Figure 1. 1 is a cross-sectional view of a white organic light-emitting element 1 in accordance with an embodiment of the present invention.

As shown in FIG. 1, the white organic light-emitting element 1 includes a substrate 10, an anode layer 12, a blue light-emitting layer 14, a yellow-red light-emitting layer 16, a cathode layer 18, an insulating layer 20, and a polarized light. Layer 22. In practical applications, the substrate 10 can be made of a light transmissive material, such as glass. The anode layer 12 is formed on the substrate 10, the blue light-emitting layer 14 is formed on the anode layer 12, the yellow-red light-emitting layer 16 is formed on the blue-based light-emitting layer 14, and the cathode layer 18 is formed on the yellow-red light-emitting layer. On layer 16.

According to the present invention, the blue light-emitting layer 14 comprises a first host material composed of a first derivative of an onion body and a blue dye dopant, and the yellow-red light-emitting layer 16 comprises the onion. The second derivative of the body constitutes a second host material and a yellow-red dye dopant. It should be emphasized that the second derivative is different from the first derivative, that is, the blue light-emitting layer 14 and the yellow-red light-emitting layer. Layer 16 consists of the same onion but different derivatives.

In order for the blue light-emitting layer 14 to emit blue light, the bandgap of the blue light dye dopant needs to be smaller than the energy gap of the first host material. Similarly, in order for the yellow-red light-emitting layer 16 to emit yellow-red light, the energy gap of the yellow-red light dye dopant needs to be smaller than the energy gap of the second host material. In a specific embodiment, the first host material and the second host material may each adopt a blue light-emitting material because the blue light-emitting material has a higher energy gap than the materials of other color systems.

Please refer to Figure 2. 2 is a diagram showing the energy level distribution of the first host material of the blue light-emitting layer 14 and the second host material of the yellow-red light-emitting layer 16 in the white organic light-emitting element 1 according to the present invention.

As shown in FIG. 2, the first host material of the blue light-emitting layer 14 has a first highest occupied molecular orbit (HOMO) energy level and a first lowest unoccupied molecular orbit (LUMO). ) Energy level. The second host material of the yellow-red light-emitting layer 16 has a second highest occupied molecular orbital energy level and a second lowest unoccupied molecular orbital energy level. It should be noted that in order to avoid the phenomenon that the white light organic light-emitting element 1 emits light at the interface, the first highest occupied molecular orbital energy level needs to be close to or larger than the second highest occupied molecular orbital energy level, and the first lowest unoccupied molecular orbital energy level needs to be Similar or greater than the second lowest unoccupied molecular orbital energy level.

In order to fully exhibit the advantages of the white organic light-emitting element 1 of the present invention, an experimental example will be listed below for detailed explanation.

In this experimental example, the first host material of the blue light-emitting layer 14 has a first highest occupied molecular orbital energy level of 5.74 eV and a first lowest unoccupied molecular orbital energy level of 2.81 eV, that is, the energy of the first host material. The gap is 2.93 eV. The second host material of the yellow-red light-emitting layer 16 has a second highest occupied molecular orbital energy level of 5.58 eV and a second lowest unoccupied molecular orbital energy level of 2.75 eV. That is, the energy gap of the second host material is 2.83 eV. It is emphasized that the first host material and the second host material are composed of the same onion but different derivatives.

Please refer to Table 1. Table 1 shows the results obtained for the luminous efficacy tests of the white light-emitting organic light-emitting element 1 using the same onion derivative laminated light-emitting layer and the same light-emitting layer (i.e., the disclosed one) of the same onion body. It should be noted that the same onion derivative is the material having the above energy gap of 2.93 eV. In addition, the test results were obtained with a white light brightness of 10,000 nits, where CIE-x and CIE-y represent color coordinate values.

As shown in Table 1, the white organic light-emitting element 1 according to the present invention is significantly improved in brightness and the required driving voltage is much lower than that of the white light-emitting organic light-emitting element using the same onion derivative laminated light-emitting layer. That is, the white organic light-emitting element 1 of the present invention has a high luminous efficiency.

As described above, the blue light-emitting layer and the yellow-red light-emitting layer of the white light organic light-emitting element according to the present invention use the same onion body but different host materials of the different materials, thereby achieving high luminous efficiency. Further, the white light organic light-emitting element according to the present invention can also avoid the phenomenon of interface light emission.

The features and spirit of the present invention will be more apparent from the detailed description of the preferred embodiments. On the contrary, the purpose is to cover all kinds of changes and equivalence of the patents to be applied for in the present invention. Within the scope of the fence. Therefore, the scope of the patented scope of the invention should be construed as broadly construed in the

1‧‧‧White organic light-emitting elements

10‧‧‧Substrate

12‧‧‧ anode layer

14‧‧‧Blue light emitting layer

16‧‧‧Yellow-red light emitting layer

18‧‧‧ cathode layer

20‧‧‧Insulation

22‧‧‧ polarizing layer

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view showing a white organic light-emitting element according to an embodiment of the present invention.

2 is a diagram showing the energy level distribution of the first host material of the blue light-emitting layer and the second host material of the yellow-red light-emitting layer in the white light organic light-emitting element according to the present invention.

1‧‧‧White organic light-emitting elements

10‧‧‧Substrate

12‧‧‧ anode layer

14‧‧‧Blue light emitting layer

16‧‧‧Yellow-red light emitting layer

18‧‧‧ cathode layer

20‧‧‧Insulation

22‧‧‧ polarizing layer

Claims (3)

A white light organic light emitting device comprising: a substrate; an anode layer formed on the substrate; a blue light emitting layer formed on the anode layer and comprising one of the first derivatives of an onion body a host material; a yellow-red light-emitting layer formed on the blue light-emitting layer and comprising a second host material composed of a second derivative of the onion body, wherein the second derivative is different from the a first derivative; and a cathode layer formed on the yellow-red light-emitting layer; wherein the first host material and the second host material are a blue light-emitting material, and the first body of the blue light-emitting layer The material has a first highest occupied molecular orbital energy level, and the second host material of the yellow-red light emitting layer has a second highest occupied molecular orbital energy level, and the first highest occupied molecular orbital energy level is greater than the first The second highest occupied molecular orbital energy level, and the first lowest unoccupied molecular orbital energy level is greater than the second lowest unoccupied molecular orbital energy level. The white light organic light emitting device of claim 1, wherein the blue light emitting layer comprises a blue dye dopant, and the blue dye dopant has an energy gap smaller than a gap of the first host material. . The white light organic light-emitting device of claim 2, wherein the yellow-red light-emitting layer comprises a yellow-red dye dopant, and the energy gap of the yellow-red dye dopant is Less than the energy gap of the second host material.