CN1953234B - White light organic electroluminescent components and their applications - Google Patents

Abstract

A white organic electroluminescent assembly for an organic electroluminescent display. The organic electroluminescent display comprises a white organic electroluminescent component and a color filter. The white organic electroluminescent device comprises an anode, a cathode, a cover layer and an organic layer. The cover layer is positioned on the cathode, and the organic layer is positioned between the anode and the cathode. The organic layer comprises a blue light emitting layer, and the thickness of the organic layer is X +120N nanometer, wherein X is more than or equal to 85 and less than or equal to 125, and N is 0, 1 or 2. The white organic electroluminescent component is used for emitting white light, the color filter is used for converting the white light into first color light, and the first color light is red light, blue light or green light.

Description

White light organic electroluminescent components and their applications

technical field

The invention relates to a white light organic electroluminescent component, in particular to a white light organic electroluminescent component used for an organic electroluminescent display.

Background technique

At present, the full-color technology widely used in the field of organic electroluminescent components can be roughly divided into three categories: (1) red, green and blue sequential evaporation (RGB side-by-side pattern); (2) light color conversion (color conversion) ; (3) White light organic electroluminescent components plus color filters. Among them, red, green and blue sequential evaporation is suitable for small molecule components in the evaporation process. As for the light-color conversion technology, it needs to go through the light-color conversion layer first.

Although the technology of white light organic electroluminescent components is gradually becoming mature, there are still some technical bottlenecks that need to be overcome urgently. Among them, the complexity of the device is an issue, which requires doping multiple light-emitting dopants in the light-emitting layer, or through incomplete energy transfer from the host to the dopant, so that the host and the dopant emit light simultaneously to form white light.

Therefore, a white light organic electroluminescent component with a larger working range for full-color technology is urgently needed in this field.

Contents of the invention

The object of the present invention is to provide a white light organic electroluminescent component. The white light organic electroluminescence component includes an anode, a cathode, a cover layer and an organic layer. A capping layer is located on the cathode, and an organic layer is located between the anode and the cathode. The organic layer includes a blue light emitting layer, and the thickness of the organic layer is X+120N nanometers, where 85≤X≤125, and N=0, 1 or 2.

Another object of the present invention is to provide an organic electroluminescence display. The organic electroluminescence display includes the white organic electroluminescence components and color filters as mentioned above. Wherein, the white light organic electroluminescent component is used to emit white light, and the color filter is used to convert the white light into a first color light, and the first color light is red light, blue light or green light.

The present invention can obtain a white light emitting organic electroluminescent component only by adjusting the thickness of the light-emitting layer in the white organic electroluminescent component, and has the advantage of increasing the working range of the full-color process.

After referring to the drawings and the implementation methods described later, anyone with ordinary skills in the technical field of the invention can understand other objectives of the invention, as well as the technical means and implementation methods of the invention.

Description of drawings

1 is a schematic cross-sectional view of a first embodiment according to the present invention;

2 is a schematic cross-sectional view of a second embodiment according to the present invention; and

Fig. 3 is an exploded schematic diagram of a second embodiment according to the present invention.

Explanation of main component symbols

1: White light organic electroluminescent components

11: anode

12: Organic layer

121: blue light emitting layer

123: Electron transport layer

125: Hole transport layer

13: Cathode

14a, 14b: Blu-ray

15: Overlay

16: light

17: Electron injection layer

19: Hole injection layer

2: Organic electroluminescence display

21: White light organic electroluminescent components

22: First shade

23: Color filter

24: Second color light

25: Corresponding drive circuit

26: third color light

31: Display panel substrate

311: inner surface

313: outer surface

32: Luminous area

33: Color filter

34: Non-luminous area

35: Drive circuit components

Detailed ways

The first embodiment of the present invention is a white light organic electroluminescence module 1 , as shown in FIG. 1 . The white light organic electroluminescent component 1 includes an anode 11 , a cathode 13 , a cover layer 15 , an electron injection layer 17 , a hole injection layer 19 and an organic layer 12 . The covering layer 15 is located on the cathode 13, the electron injection layer 17, the hole injection layer 19 and the organic layer 12 are all located between the anode 11 and the cathode 13, and the organic layer 12 is located between the electron injection layer 17 and the hole injection layer 19 . The organic layer 12 includes a blue light emitting layer 121 , an electron transport layer 123 between the blue light emitting layer 121 and the cathode 13 , and a hole transport layer 125 between the blue light emitting layer 121 and the anode 11 .

In the white light organic electroluminescent component 1 of the present invention, the anode 11 is located on the substrate, and besides serving as an electrode, it also provides the function of reflecting light. Therefore, the anode 11 is preferably provided by an opaque and reflective material selected from the group consisting of gold, silver, aluminum, aluminum neodymium alloy, molybdenum, and chromium.

In the white organic electroluminescence component 1 , the light from the light emitting layer will be emitted through the cathode 13 as an electrode. Therefore, the cathode 13 needs to have a certain degree of transparency. Therefore, the cathode 13 is preferably provided by a translucent material selected from the group consisting of metals, transparent metal oxides, and combinations thereof. For example, but not limited thereto, the metal may be aluminum, calcium, magnesium, indium, tin, manganese, silver, gold, magnesium alloys, magnesium-tin alloys, magnesium-antimony alloys, magnesium-tellurium alloys, magnesium-silver alloys, magnesium-indium alloys, Aluminum-lithium alloy, etc.; the transparent metal oxide can be indium tin oxide alloy (ITO), indium oxide-zinc oxide alloy (In ₂ O ₃ -ZnO), zinc oxide, etc. Generally speaking, within the available thickness range, it is preferable to use a thinner film layer to provide the cathode 13 . For example, when the cathode 13 is silver and its feasible thickness is 15 nm to 20 nm, preferably 15 nm is used.

The cover layer 15 located on the top of the white organic electroluminescent component 1 is used to increase the transmittance above the light-emitting layer in the component. Preferably, a material with a higher refractive index than the cathode material is used to provide the covering layer 15 so as to guide more light. For example (but not limited thereto), materials selected from the following can be used to provide the covering layer 15: tris-(8-hydroxyquinoline)aluminum (Alq ₃ ), zinc indium oxide (ZTO), tin oxide ( SnOx), indium oxide (InOx), molybdenum oxide (MoOx), tellurium oxide (TeOx), antimony oxide (SbOx), zinc oxide (ZnOx), zinc selenide (ZnSe), and zinc telluride (ZnTe). Preferably, materials selected from the following are used to provide the capping layer 15: tris-(8-quinolinolato)aluminum, tin dioxide (SnO ₂ ), tellurium dioxide (TeO ₂ ), zinc selenide (ZnSe), and Zinc telluride (ZnTe). Wherein, when tin dioxide is selected to provide the covering layer 15, the thickness is preferably 10 nm to 20 nm, more preferably 15 nm.

An electron injection layer (EIL) 17 is located between the cathode 13 and the organic layer 12 to facilitate injection of electrons from the cathode 13 into the organic layer 12 . The electron injection layer 17 can be made of materials selected from the group consisting of alkali metals, alkaline earth metals, and combinations thereof. For example (but not limited thereto), alkali metals can be lithium, sodium, potassium, rubidium, cesium; alkaline earth metals can be magnesium, calcium, strontium, barium. Wherein, when the electron injection layer 17 is calcium, its thickness is preferably 1 nm to 10 nm, more preferably 5 nm. It should be noted that, in the white light organic electroluminescence module 1 of the present invention, the electron injection layer 17 is an optional material layer and is not required. That is, what is shown in FIG. 1 is only one embodiment of the present invention, and in actual application, the electron injection layer 17 does not necessarily exist.

A hole injection layer (HIL) 19 is located between the anode 11 and the organic layer 12 for enhancing hole injection from the anode 11 to the organic layer 12 . For example (but not limited thereto), materials that can be used to provide the hole injection layer 19 include: fluorinated polymers (CF _x ), where X is greater than 0 and less than or equal to 2; copper phthalocyanine (CuPc); and 4,4',4"-tri-(N-(2-naphthyl)-N-phenyl-amino)-triphenylamine (2-TNATA), etc. Like the electron injection layer 17, the hole injection layer 19 is The white light organic electroluminescent component 1 of the present invention is also not necessary, so anyone skilled in the art may omit the hole injection layer 19 according to actual needs.

The organic layer 12 includes a blue light emitting layer 121 , an electron transport layer 123 between the blue light emitting layer 121 and the cathode 13 , and a hole transport layer 125 between the blue light emitting layer 121 and the anode 11 . Wherein, the blue light emitting layer 121 has a first thickness, which ranges from 10 to 50 nanometers according to the selected material. For example, when the blue light-emitting layer 121 is doped with 3% by weight of p-bis[p-N,N-diphenyl-amino-styryl]benzene (p-bis[p-N,N-diphenyl-amino- styryl]benzene, DSA-Ph) 2-(methyl)-9,10-bis-(2-naphthyl)anthracene (2-methyl-9,10-di(2-naphthyl)anthracene, MADN) layer (That is, MADN is used as the base material, and 3% DSA-Ph is used as the dopant), the thickness of the blue light emitting layer 121 can be 30 nanometers. Other materials that can be selected as the substrate of the blue light-emitting layer 121 include (but not limited to): anthracene derivatives, oxadiazolyl derivatives such as 1,3-bis[(4-tert-butylphenyl)- 1,3,4-oxadiazolyl]phenylene (1,3-bis(4-t-butylphenyl-1,3,4-oxadizolyl)phenylene, OXD), 1,2,4-triazole derivatives (TAZ), distyrylbenzene (DSB) or distyrylarylene derivatives (DSA) such as 4,4'-bis(2,2'-diphenylvinyl)-1,1'-bis Benzene (DPVBi), and 1,4-bis[2-(3-N-ethylcarbazolyl)vinyl]benzene (1,4-bis[2-(3-N-ethyl-carbazolyl)vinyl]benzene , BCzVB). Materials that can be used as dopants include (but are not limited to): parylene, (2,5-bis(5-tert-butylphenyl-2-benzoxazolyl)thiophene ( BBOT), and N-arylbenzimidazole (TPBI), etc.

The electron transport layer 123 has a second thickness ranging from 10 to 50 nm, depending on its material. For example, when tris-(8-quinolinolato)aluminum (Alq ₃ ) is used to provide the electron transport layer 123 , its thickness may be 30 nm. Other materials that can be used to provide the electron transport layer 123 include (but not limited to): metal chelated oxinoid compound (also referred to as 8-quinolinol or 8-hydroxyquinol Phenyl (8-hydroxy-quinoline)) and butadiene derivatives, etc.

The hole transport layer 125 has a third thickness ranging from 40 to 50 nm, depending on its material. For example, when using N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (N,N'-di(naphthalene-l-yl)-N,N' -diphenyl-benzidine, NPB) to provide the hole transport layer 125, its thickness can be 45 nanometers. Aromatic tertiary amines can also be used to provide the hole transport layer 125. The aromatic tertiary amines have at least trivalent nitrogen atoms linked to carbon atoms and have at least one aromatic ring. The aromatic tertiary amine can be arylamine such as monoarylamine, diarylamine, triarylamine, and polymericarylamine (polymericarylamine), such as: N, N'-di(naphthalene-1-yl) -N,N'-diphenyl-benzidine (NPB), N,N,N',N'-tetranaphthyl-benzidine (TNB), N,N'-diphenyl-N,N'- Bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (N,N'-diphenyl-N,N-bis(3-methylphenyl)-1,1'- biphenyl-4,4'-diamine, TPD) and 4,4',4"-three (3-methylphenylphenylamino)-triphenylamine (MTDATA), etc. The hole transport layer 125 can also be made of polycyclic aromatic Provided by polycyclic aromatic compound, such as: poly(2-vinyltriphenylamine) (poly(vinyltriphenylamine), PVT) and poly(n-vinylcarbazole) (poly(n□Vinylcarbazole), PVK).

1, blue light 14a and 14b are emitted from the blue light-emitting layer 121, wherein the blue light 14a is emitted upward through the electron transport layer 123, the electron injection layer 17, the cathode 13 and the covering layer 15 in sequence; the blue light 14b is emitted to the Downward emission, through the hole transport layer 125 to the hole injection layer 19, reflected by the anode 11 into light 16, the light 16 then sequentially passes through the hole injection layer 19, the hole transport layer 125, the blue light emitting layer 121, the electron transport layer 123 , the electron injection layer 17 , the cathode 13 and the cover layer 15 to emit. Here, the reflected light 16 will change from blue light to other colors by passing through the micro-cavity formed by the above-mentioned layers.

It has been found that by adjusting the depth of the micro-resonant cavity, that is, adjusting the total thickness of the organic layer 12 to (X+120N) nanometers, where 85≤X≤125, and N≤0 and is an integer, the blue light 14b can be reflected to produce yellow reflection The light 16 , the blue light 14 a and the yellow light (ie, the light 16 ) will be mixed into white light due to constructive interference, thereby providing a white light organic electroluminescent component 1 . Preferably, the thickness of the organic layer 12 is (X+120N) nanometers, where 85≦X≦125, and N=0, 1 or 2. That is, the thickness range of the organic layer 12 is preferably: 85≤X≤125, 205≤X≤245, or 325≤X≤365.

The second embodiment of the present invention is an organic electroluminescent display 2 , as shown in FIG. 2 . Microscopically, the organic electroluminescent display 2 includes three white organic electroluminescent components 21 as described in the previous embodiments, three color filters 23 , and three corresponding driving circuits 25 . The three color filters 23 are respectively corresponding to the three white light organic electroluminescent components 21, so as to respectively convert the white light emitted by the three white light organic electroluminescent components 21 into the first color light 22 and the second color light 24. and the third color light 26, and the first color light 22 is red light, the second color light 24 is blue light, and the third color light 26 is green light. The three corresponding driving circuits 25 respectively control the switches of red light, blue light and green light to display different colors.

FIG. 3 is an exploded view of the above-mentioned organic electroluminescent display 2 . Macroscopically, the organic electroluminescent display 2 includes not only the white organic electroluminescent element 21 and the color filter 23 , but also a display surface substrate 31 , a dark light absorbing structure 33 and a driving circuit element 35 . The display substrate 31 has an inner surface 311 and an outer surface 313 . The dark light-absorbing structure 33 , the driving circuit assembly 35 and the white organic electroluminescent assembly 21 are all formed on the inner surface 311 side of the display substrate 31 , while the color filter 23 is preferably formed on the outer surface 313 side of the display substrate 31 . The inner surface 311 of the display substrate 31 has a light-emitting area 32 and a non-light-emitting area 34 . As can be seen from the above description, the present invention can achieve full-color display 2 only through the white light organic electroluminescence component 21 and the color filter 23, without restrictions on the working environment or materials used, and can simplify the full-color manufacturing process , Expand the scope of work of the process.

The above-mentioned embodiments are only used to illustrate the implementation of the present invention and explain the technical features of the present invention, and are not intended to limit the scope of the present invention. Any change or equivalence arrangement that can be easily accomplished by any technology in the art belongs to the scope of the present invention, and the scope of the present invention should be determined by the claims.

Claims (8)

1. A white light organic electroluminescent component, comprising: an anode provided by a material selected from the group consisting of silver, aluminium, aluminum neodymium, molybdenum and chromium; a cathode provided by a material selected from the group consisting of metals, transparent metal oxides, and combinations thereof, and the cathode is positioned over the anode; a cover layer positioned over the cathode; an organic layer positioned between the anode and the cathode, Wherein, the organic layer includes a blue light emitting layer, and the thickness of the organic layer is X+120N nanometers, where 85≤X≤125, and N=1 or 2. 2. The white light organic electroluminescence module as claimed in claim 1, wherein the cover layer is provided by a material selected from the group consisting of tris-(8-hydroxyquinoline)aluminum (Alq ₃ ), tin dioxide (SnO ₂ ) , tellurium dioxide (TeO ₂ ), zinc selenide (ZnSe) and zinc telluride (ZnTe). 3. The white-light organic electroluminescent component of claim 1, further comprising an electron injection layer located between the cathode and the organic layer, wherein the electron injection layer is provided by a material selected from the group consisting of: alkali metal, alkaline earth Metals and combinations of the above. 4. The white light organic electroluminescence component according to claim 1, wherein the organic layer further comprises an electron transport layer located between the blue light emitting layer and the cathode; and a hole transport layer located between the blue light emitting layer and the blue light emitting layer between the anodes. 5. The white light organic electroluminescent device as claimed in claim 4, wherein the blue light emitting layer has a thickness of 10 to 50 nanometers. 6. The white light organic electroluminescent device as claimed in claim 4, wherein the electron transport layer has a thickness of 10 to 50 nanometers. 7. The white light organic electroluminescent device as claimed in claim 4, wherein the hole transport layer has a thickness of 40 nm to 50 nm. 8. The white light organic electroluminescent component of claim 1, wherein the blue light emitting layer is doped with p-bis[p-N,N-diphenyl-amino-styryl]benzene (DSA-Ph) 2-(methyl)-9,10-bis-(2-naphthyl)anthracene (MADN) layer. the

Images