TW200537971A - Whole-wavelength white-light organic electroluminescent device and its manufacturing method - Google Patents

Abstract

The present invention is related to a whole-wavelength white-light organic electroluminescent device and its manufacturing method. Between the transparent conducting substrate for the anode and the corresponding cathode, the hole transporting layer, light-emitting layer, hole blocking layer, the electron transporting layer and the electron injection layer are disposed. The light-emitting layer is composed of a blue-light material containing the green-light dye of the light-emitting main-body material inside so as to form the light-emitting layer of light source that emits blue (B) and green (G) light. A red-light dye of light-emitting main-body material is doped inside the hole blocking layer so as to make the hole blocking layer capable of emitting red (R) light-source. A whole-wavelength white-light light-emitting apparatus having higher doping concentration capable of emitting light wavelength from 450 nm to 630 nm with equivalent intensity is manufactured and is provided with no change of light color due to the effect of minute concentration variation.

Description

200537971

V. Description of the invention (1) [Technical field to which the invention belongs] The present invention relates to a full-wavelength white light organic electro-excitation light device, in particular, a light of various colors can be balanced and emitted into mixed white light. Film making full color panel. [Previous technology] Organic light emitting diodes (0LEDs) can also be called organic electrical excitation light (

Organic Electroluminescence (referred to as 0EL), simply put, is to apply an external bias to make the electron holes pass through the hole transport layer (

Hole Transporting Layer) and Electron Transport Layer

After entering the "transporting layer" into an organic substance with light-emitting properties, the substance (light-emitting layer) will recombine within it, forming an "exciton", and then release the energy to return to the ground state (gr. und state), and the released energy will excite the fluorescent molecules in the organic material to generate π photons ("photon"), because the selected light-emitting layer materials are different, the energy can be released in the form of different colors of light Out, and form 0LED's luminescence phenomenon. 0. Organic electroluminescence display technology is known for its low cost, long life, low driving voltage, fast response speed, good luminous efficiency and shock resistance, wide viewing angle and thin thickness. This is the next-generation flat-panel display technology. The production of full-color organic EL (Electroluminescence) displays can be violated by using a white light-emitting organic EL with a color filter. However, the search and matching of the material for the white-light-emitting layer Not easy. At present, the general method of making a full-color organic electroluminescent display is to use a shadow mask to locate and emit R (red), g (green), and B (blue

Page 5 200537971 V. Description of the invention (2) ~-), three primary color light side-by-side fractional production, this method must go through three CCD alignment in the manufacturing process. However, with the development of high-resolution displays, 'the text is limited to masking technology and alignment errors, and the yield of the product is not easy to improve'. In addition, the 0LEDs with different color light also have different structural designs, which is very time-consuming in the manufacturing process. At the same time, 0LEDs have different lifespans of the light-emitting layers that emit R, G, and B primary colors, so when one of the color-light emitting layers is attenuated, the overall color deviation of the display will be serious, resulting in difficulty in product stability. control. Therefore, 'Another invention is to improve the above-mentioned shortcomings, and use a single-emitting white light element'. With color filters and color filters, it can become a full-color display, because a single white-light emitting element does not require a photosensitive coupling element. (CCD) alignment and the use of shadow masks to define the position of the luminous body that emits R, G, and B color light. If it can effectively reduce the process error, it will greatly help improve the yield, and it will also be more time-consuming than traditional methods. Way to reduce the time by three times. At present, in order to obtain a white-emitting organic electro-excitation light element, it is necessary to excite a material of more than one molecule, because a single organic molecule does not easily span the entire visible light spectrum region. One of the ways to achieve white light emission according to the characteristics of the covered spectrum is to dope another guest emitter in a host emitter, which can cause energy transfer or carrier capture from the host emitter to the guest emitter at the doped position. Set, incomplete energy transfer can be generated so that both glow simultaneously. It is mentioned in the "Chinese organic patent light emitting device capable of projecting a white light source and its manufacturing method" (see "Figure 1") in the Republic of China Patent Bulletin No. 519852, which is mainly a corresponding anode 10 and cathode 1 with 5 electricity

200537971 V. Description of the invention (3), in which the light-emitting layer (upper m layer 12, light-emitting layer 13, and electron transporting layer 14, and the electron transporting layer " two): there are inner two and the anode 10 is subjected to an applied voltage to the light-emitting field cathode 15 The second dopant may individually feed the first layer 13, the first dopant, and f Ό Λ a to a corresponding third light source (β), the first light source (R), and the second light source (G); The first light-continuous full-band white light source is hybridized by the combination of green and blue primary colors. The optimal structure is 0.025% by DPVBi.

The schematic diagram of 1 e6 70 energy levels is shown in the "Figure 2", where the E-list J empty energy level 'and the XC element conduction energy level (χ is a wide range difference between 10 and 15 elements,') Represents the electronic affinity of the element (a jm ^ es), Εχν represents the vacuum energy level, and the energy level difference between the valence band energy level of χν element (χ is the code of 10 ~ 15 element), which also represents the element's Ion potential (10niZation potential). From the above and illustration, it can be seen that the guest material is doped in the host material. The doping concentration of this guest material is almost less than 1% or even less than 0.1%. It is extremely difficult to control the process parameters, so only a little For the concentration percentage, it changes drastically, and in the design of the double light-emitting layer, it is difficult to make the two light-emitting regions emit light equally. Often, the energy levels of the two light-emitting layers are too close. Changing the light emitting area is also easy to shift with voltage shift. In addition, the light emission spectrum is severely insufficient in the long wavelength portion (as shown in "Figure 3"), and the intensities of the three primary colors of R, G, and B differ greatly. [Summary of the Invention] That is, the main purpose of the present invention is to solve the above-mentioned shortcomings.

The Ming Department proposed that one light-emitting host material is doped in another light-emitting host material, and because it is the same host material, its luminous efficiency is also relatively comparable. At the same time, it requires a higher proportion of impurity concentration and makes process control easier. Another purpose of this month is to provide a hole blocking layer. Using the difference in energy level between the hole blocking layer and the first light-emitting layer, the recombination region of electrons and holes can be limited to the light-emitting host material region and The interface of the hole-blocking layer prevents the emission spectrum of the light-emitting area from greatly changing with the change in voltage. Another object of the present invention is that the hole-blocking layer is doped with a luminescent dye, so that the hole-blocking layer also has hole blocking. The functions of the light-emitting layer and the light-emitting layer, so that a white-light organic electroluminescent device can be fabricated. The invention is a full-wavelength white light organic electro-excitation light device. The structure includes, from bottom to top, a transparent conductive substrate, a hole transfer layer, a light-emitting layer, a hole barrier layer, and an electron transfer layer. An electron injection layer and a cathode, wherein the light emitting layer is a light emitting layer of a blue (β) green (G) light source formed by a blue light material doped with a green light dye, and the hole blocking layer (3 4) is Internally doped with a red light dye so that it can emit a red (r) light source; 俾 By using the device structure design of the present invention, and then selecting an appropriate light-emitting host material, a suitable color filter can be used to make a full-color panel. Full wavelength white light 4 organic electro-excitation light (0LED) element. [Embodiment] The detailed content and technical description of the present invention are described below with reference to the drawings: Please refer to "Figure 4", which is a schematic view of an organic light emitting device of the present invention

Page 8 200537971 V. Description of the Invention (5) " " Figure. As shown in the figure: the full-wavelength white light organic electric excitation light device of the present invention has a structure from bottom to top including: a transparent conductive substrate 31 as an anode, a hole transfer layer 32, a light emitting layer 33, a Hole barrier layer%, an electron transfer layer 35, an electron injection layer 36, and a cathode 37, wherein the light emitting layer 33 is composed of a host material of a blue light material and another host material emitting green light is doped therein The green light dye 333 forms a blue (B) green (G) light emitting layer 33; at the same time, the hole blocking layer 34 is doped with a red light emitting material 344, which makes the hole blocking layer 34 Can emit red (R) light source. The manufacturing method is mainly provided with a hole transfer layer 32, a light emitting layer 33, a hole blocking layer 34, an electron transfer layer 35, and an electron injection layer between a corresponding transparent conductive substrate 31 serving as an anode and a cathode 37. 36. It is characterized in that the light-emitting layer 33 is composed of a blue light material containing a green light dye 333, which is also a light-emitting host material, and a light-emitting layer 33 having a blue (B) green (G) light source formed by the light-emitting layer; The hole blocking layer (34) is doped with a red light dye (344) of a light emitting host material, so that the hole blocking layer (34) is a hole blocking layer (34) that can emit a red (R) light source;俾 The combination of the blue (B) green (G) light source and the red (R) light source becomes a white light source. In this way, a three-wavelength full-wavelength white organic light-emitting organic light-emitting device with a similar luminous intensity can be manufactured. This full-wavelength white-light organic light-emitting organic light-emitting device is very suitable for making a full-color display with a color filter. Among them, the light-emitting layer 33 can be selected from 1; 4-bis (2, 2-diphenyl vinyl) benzene (DPVBi), and a derivative of distyry lary lene (DSA).

200537971 V. Description of Invention (6)

(For example: High-brightness blue light main ship material manufactured by Itomitsu Kosan Co., Ltd., numbered Idel20), bis (2-methyl-8-quinolinato) 4-phenylphenolate aluminum (Ba1q), Po1y (N-vinylcarbazole) (PVK ), 4- {4- [N- (l-naphthyl) -N-phenylaminophenyl]}-l, 7-diphenyl-3,5-dimethyl-l, 7-dihydro-dipyrazolo [3,4-b; 4 ' 3'-e] pyridine (PAP) and one of their combinations. Green light dye 3 33 series can choose one of Coumar ini 6 (C6), Coumarin 545T (C545T), tris (8 'hydroxyquinolinato) aluminum (III) (Alq3), dimethylquinacridones (DMQA) and combinations thereof; and, The volume ratio of the green light dye 333 to the light-emitting layer 33 ranges from 0.1% to 20%. The hole barrier layer 34 can be selected from N-arylbenzimidazoles (TPBi), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), and bis (2-methyl-8-quinolinato) 4 -pheny 1 pheno1 ate aluminum (Balq), 3- (4, -tert-butylphenyl) -4-phenyl-5 ~ (4M- biphenyl) -1,2,4_ triazole (TAZ), 2- (4-biphenylyl) One of -5- (4-tert-butylphenyl) l, 3,4-oxadiazole (PBD) and combinations thereof. The red light dye (344) is optional 4-((1 丨 〇73111〇11161: 11716116) -2-t-butyl-6- (l, 1,7,7-tetramethyljulolidyl-9-enyl)-

Page 10 200537971 V. Description of the invention (7) 4H-pyran (DCJTB), 2- {2- [2_ (1,1,7,7-Tetramethyl-2, 3, 6, 7-tetrahydro- 1H, 5H- pyrido [3, 2, ij] quinolin-9-yl) (PhDCJT), 4- (dicyanomethy1ene) -2-methy 1-6- (4-dimethylaminostyry)-4H-pyran (DCM), 4-dicyanomethylene-2 -methyl + [2- (2,3,6,7-tetrahydro-1H, 5H-benzo [i, j] quinolizin-8-yl) vinyl]-4H-pyran (DCM2) and combinations thereof; and The volume ratio of the red light dye 344 to the hole blocking layer 34 ranges from 0.1% to 5%. Because the light-emitting materials and materials emitting the three primary colors of red (R), green (G), and blue (B) are light-emitting host materials, the concentration of the dyes doped with each color is large, and the tolerance for the process stability error is relatively large. A little concentration The change will not cause obvious deviation of light color, which makes the process easier. Please refer to "Figure 5" for matching, which is a schematic diagram of the energy levels of each component of the embodiment of the device of the present invention. At the same time, an example is used to illustrate the effect of the present invention. The structure of this embodiment is as follows: Hole transfer layer 32 (BPAPF 60 0 Angstrom) / Light emitting layer 33 (PAP ·· 1.50 / 〇 Green light dye 333 (Alq3 2 0 0 Angstrom)) / hole barrier layer 34 (TpBi: 0.8% red light dye 344 (DCJTB 100 angstrom)) / electron transfer layer 35 (Alq 2000 angstrom) / electron injection layer 36 (LiF 7 angstrom) / cathode 37 (A1 150 Angstroms). The schematic diagram of the element energy level is shown in "Figure 5", where & represents the energy level difference between the vacuum energy level and the conduction energy level of xc element (乂 is the code of 31 ~ 37 element), which also represents the Electron affinity (electr0n af f inities); Exv represents vacuum energy level, and valence band energy level of χν element (

200537971 Description of the invention (8) X is the energy difference between 31 and 37 elements, which also represents the ionization potential of the element. As shown in the figure, the larger the electron affinity (Exc) and the distance between the two elements The smaller the energy level difference, the easier it is for electrons to be injected, so when a bias is applied to the device, the electrons will pass from the cathode 37 through the electron transfer layer 35 to the hole blocking layer 34 and the light emitting layer 33, and because of the conduction of the light emitting layer The conduction energy level E ^ c from the energy level E33C to the hole transfer layer 32 is much larger than that of E ^ c to E3%, so the probability of electrons jumping through the light emitting layer 33 to the hole transfer layer 32 is relatively small, so Most of the electrons are injected into the hole blocking layer 34 and the light emitting layer 33. On the other hand, the holes injected into the hole transfer layer _ 32 from the anode of the transparent conductive substrate 31 will be sequentially reduced by the hole transfer layer 32 due to the order of the valence band energy levels (Em3i, Em, I ”). Entering the light-emitting layer 3 3, and because the energy level difference between the valence band energy level E33V of the light-emitting layer 3 3 and the valence band energy level e34V of the hole blocking layer 34 is extremely large, the hole must jump over the hole blocking layer 34 to the electron transfer The probability of layer 35 is relatively small, so most of the injected holes are left at the interface between hole blocking layer 3 4 and light emitting layer 33, so that these two light emitting layers participate in light emission at the same time. Under different operating voltages, because there are The structural design of this energy step makes the re-junction area between the electron and the hole not change, but stays at the interface of the two light-emitting layers. The design of the energy step difference enables the device of the present invention to emit light with a wavelength corresponding to the luminous intensity. As shown in FIG. 6 j, the intensity of a single-color light is 4 50 to 630 nm, and its intensity is consistent. Full-wavelength white light emitting device, and the light intensity within this 4 50 ~ 63Onm wavelength Maintained at more than 3.8 billion, so the three primary colors (450

Page 12 200537971 V. Description of the invention (9) (Light in the wavelength of ~ 630 nm) will be a full-wavelength white light organic electric excitation light device with uniform light intensity of each color, as shown in "Figure 7". Schematic diagram of the white light emitted from the voltages of 10, 11, 12, 13, and 14V in the chromaticity coordinate diagram (CIE). It can be seen that this embodiment is quite good white light, and the chromaticity diagram (CIE) coordinates in the practical area are not There is a large change with the change in voltage, so the full-wavelength white light organic electro-excitation light device of the present invention is very suitable for making a full-color display with a color phosphor film (c ο 1 〇rfi 11 er). However, the above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. That is, any changes and modifications applied for in accordance with the present invention are all covered by the scope of the invention patent.

200537971 Simple description of 圊 --- [Simplified description of drawings] Fig. 1 is a schematic diagram of a conventional organic light emitting device. Fig. 2 'is a schematic diagram of the energy levels of each element of the device of Fig. 1; Fig. 3 'is a comparison chart of the wavelength corresponding to the luminous intensity of the device of Fig. 1. FIG. 4 is a schematic diagram of an organic light emitting device according to the present invention. FIG. 5 is a schematic diagram of the energy levels of each element in the embodiment of the device of the present invention. Fig. 6 is a comparison diagram of the light wavelengths corresponding to the light emission intensities emitted by the embodiment of the present invention. & FIG. 7 is a schematic diagram of the coordinates of white light on the chromaticity coordinate diagram (CIE) emitted by the embodiment of the present invention at voltages of 10, 1 丨, 1, 2, 13 and 14 V. < Explanation of reference numerals of the drawings] 10 anode 11 hole injection layer 12 hole transport layer 13 light emitting layer 14 electron transport layer 15 cathode 31 transparent conductive substrate 32 hole transfer layer 33 light emitting layer 333: green light dye 34:: Hole barrier layer 344: red light dye 35: electron transport layer

Page 14 200537971 Brief description of the drawings 3 6: Electron injection layer 3 7: Cathode (Η p. 15

Claims (1)

200537971 VI. Applying for a patent Fangu '-Including 1 has a full-wavelength white light organic electrical excitation light device, its main structure is a transparent conductive substrate; a hole transmission layer provided on the transparent conductive substrate; A light-emitting layer on the hole-transmitting layer, the light-emitting layer is a light-emitting layer of a blue (B) green (G) light source formed by a blue-light material containing a green-light dye; ^ an electrical device disposed on the light-emitting layer Hole blocking layer, and doped with a red dye, so that the hole blocking layer can emit a red (R) light source; an electron transfer layer provided on the hole blocking layer; < a hole transfer layer An electron injection layer thereon; and a cathode disposed on the electron injection layer. 2 · The full-wavelength white organic light-emitting device as described in item 1 of the patent application range, wherein the light-emitting layer is selected from 1,4-bis (2, 2-diphenyl vinyl) benzene (DPVBi), stilbene Aromatic hydroxyl derivatives (distyrylarylene (DSA)) : C-CH- [Ar] ^ CH = C: , Bis (2-methyl -8-quinolinato) 4-phenylphenolate aluminum (Balq), Poly (N-vinylcarbazole) (PVK), 4- {4- [N- (1-naphthyl) -N-phenylaminophenyl]}-l , 7-diphenyl-3, 5-dimethyl-1, 7-dihydro-dipyrazolo [3,4-b; 4'3'-e] pyridine (PAP) and one of their combinations. Page 16 200537971 VI. Patent application scope 3 · The full-wavelength white organic electro-excitation light device described in item 1 of the patent application scope, in which the green dyes are Coumarin 6 (C6) and Coumarin 545T (C545T) , Tris (8-hy dr oxy qu i no 1 i nai: ο) aluminum (III) (Alq3)-dime thy 1 quinacridones (DMQA) and combinations thereof. 4. The full-wavelength white organic electro-excitation light device according to item 1 of the scope of the patent application, wherein the volume ratio of the green light dye to the light-emitting layer is in the range of 0.1% to 20%. 5. The full-wavelength white light organic electro-excitation light device according to item 1 of the scope of the patent application, wherein the hole blocking layer is selected from N-® arylbenzimidazoles (TPBi), 2,9-dimethyl-4,7-diphenyl -1,10-phenanthroline (BCP), bis (2-methyl- 8- quino 1inatο) 4-pheny1pheno1 ate aluminum (Balq), 3- (4 '-tert-butylphenyl) -4-phenyl-5-(4 丨丨 -biphenyl) -1,2,4-triazole (TAZ), 2- (4-biphenylyl) -5- (4-tert-butylphenyl) l, 3,4-oxadiazole (PBD), or a combination thereof . 6. The full-wavelength white light organic electro-excitation light device according to item 1 of the scope of the patent application, wherein the red light dye is selected from 4- (dicyanomethylenej) -2Uutyl-6- (1,1,7,7-tetramethyljulolidyl -9-enyl) -4H-pyran (DCJTB), 2- {2- [2- (1,1,7, 7-Tetramethyl-2, 3, 6, 7-tetrahydro-1H, 5H-pyrido [3, 2, 1-ij] quinolin- 9- yl) (PhDCJT), 4- (dicyanomethy1ene) -2-methyl-6- (4-dimethyl aminostyry) -4H-pyran (DCM), 4- Page 17 200537971 6. Scope of patent application dicyanoinethylene ~ 2-methyl-6- [2 ^ 2, 3, 6, 7-1etrahydro- 1H, 5H-benzo [i, j] qUin〇iizin —8-yl) vinyl] —4H — One of DCM2 and its combination. A 7. The full-wavelength white organic electro-excitation light device according to item 1 of the scope of the patent application, wherein the volume ratio range of the red light dye to the hole blocking layer is between 0.1% and 5%. 8 · A method for manufacturing a full-wavelength white organic electro-excitation light device, the main structure of which is to provide a hole-transmitting layer, a light-emitting layer, a hole-blocking layer between a corresponding transparent conductive substrate serving as an anode and a cathode, Electron transfer layer and electron injection layer; 丨 It is characterized in that: the light-emitting layer is composed of a green light dye of the material, a layer; a blue-light material containing the same light-emitting host (h0st), and the blue (B) green (G) Luminescence of the light source. The hole blocking layer is doped with a hair material to make the hole blocking layer an emitting light. The blue (B) green (G) is a white light source. The red light dye of the host material, the hole barrier layer of the red (R) light source; the combination of the light source and the red (R) light source Page 18