Patent Application
20180190928
This application claims the benefit of Chinese Patent Application No. CN 201710648482.5, filed with the Chinese Patent Office on Aug. 1, 2017, which is hereby incorporated by reference in its entirety.
The present disclosure relates to the technical field of display, and particularly to an organic light-emitting diode, a display panel and a display device.
The organic electroluminescence is a phenomenon in which organic materials are excited by an electric energy for light emitting. With the advantages of low drive voltage, high luminous brightness, high luminous efficiency, wide luminous viewing angle, high response speed, ultrathin shape, light weight and compatible flexible substrate, the organic light-emitting devices occupy an important position in the field of display.
As a representative product of organic electroluminescent devices, the organic light-emitting diode (OLED) has been extensively studied.
Please refer to
In the related art, in order to solve the above problems, a charge generating layer can be arranged between the first light emitting layer and the second light emitting layer to solve the above technical problem that the luminous color is unstable and the luminous effect is poorer. However, the setting of the charge generating layer will also result in a problem of rising of the drive voltage of the organic light-emitting diode and decreasing of the luminous efficiency.
An organic light-emitting diode provided by an embodiment of the present disclosure includes an anode, a cathode, at least two light emitting layers arranged between the anode and the cathode, and a hole transport element and an electron transport element which are arranged between every two adjacent light emitting layers and arranged in sequence along a direction far away from the cathode. Where the hole transport element includes at least two hole transport layers, where each of the hole transport layers includes a hole transport material and a P-type material doped in the hole transport material, and in the at least two hole transport layers, a volume concentration of the P-type material of a hole transport layer adjacent to the light emitting layer is less than a volume concentration of the P-type material of a hole transport layer adjacent to the electron transport element. The electron transport element includes at least two electron transport layers, where each of the electron transport layer includes an electron transport material and an N-type material doped in the electron transport material, and in the at least two electron transport layers, a volume concentration of the N-type material of an electron transport layer adjacent to the light emitting layer is less than a volume concentration of the N-type material of an electron transport layer adjacent to the hole transport element.
The embodiments of the present disclosure further provide a display panel, and the display panel includes the organic light-emitting diode of any one of the above technical solutions.
In the present embodiments, the drive voltage of the organic light-emitting diode is lower, then the power consumption is lower, the luminous efficiency is higher, and the service life is prolonged.
The embodiments of the present disclosure further provide a display device, and the display device includes the display panel in the above solution.
In order to lower the drive voltage of the organic light-emitting diode, improve the luminous efficiency and prolong the service life of the organic light-emitting diode, the embodiments of the present disclosure provide an organic light-emitting diode, a display panel and a display device. In order to make the objective, technical solution and advantages of the present disclosure clearer, the present disclosure will be further described in detail below with the embodiments as examples.
As shown in
Where the hole transport element 41 includes at least two hole transport layers, where each of the hole transport layers includes a hole transport material and a P-type material doped in the hole transport material, and in the at least two hole transport layers, the volume concentration of the P-type material of the hole transport layer 411 adjacent to the light emitting layer 3 is less than the volume concentration of the P-type material of the hole transport layer 412 adjacent to the electron transport element 42.
The electron transport element 42 includes at least two electron transport layers, where each of the electron transport layer includes an electron transport material and an N-type material doped in the electron transport material, and in the at least two electron transport layers, the volume concentration of the N-type material of the electron transport layer 421 adjacent to the light emitting layer 3 is less than the volume concentration of the N-type material of the electron transport layer 422 adjacent to the hole transport element 41.
As shown in
For the hole transport element 41, in the at least two hole transport layers, the volume concentration of the P-type material of the hole transport layer 411 adjacent to the light emitting layer 3 is less than the volume concentration of the P-type material of the hole transport layer 412 adjacent to the electron transport element 42, if the volume concentration of the P-type material of the hole transport layer 411 adjacent to the light emitting layer 3 is lower, then the P-type material is difficult to permeate into the light emitting layer 3, and it may also isolate the hole transport layer with a higher volume concentration of the P-type material from the light emitting layer 3, such that the P-type material with a higher volume concentration is also difficult to permeate into the light emitting layer 3, and the problem of luminescence quenching is not easily caused. Similarly, for the electron transport element 42, in the at least two electron transport layers, the volume concentration of the N-type material of the electron transport layer 421 adjacent to the light emitting layer 3 is less than the volume concentration of the N-type material of the electron transport layer 422 adjacent to the hole transport element 41, if the volume concentration of the N-type material of the electron transport layer adjacent to the light emitting layer 3 is lower, then the N-type material is difficult to permeate into the light emitting layer, and the problem of luminescence quenching is not easily caused. While the volume concentration of the P-type material of the hole transport layer 412 adjacent to the electron transport element 42 is higher, and the volume concentration of the N-type material of the electron transport layer 422 adjacent to the hole transport element 41 is higher, namely, the doping concentrations of the hole transport layer 412 and the electron transport layer 422 which are in contact with each other are higher, then the hole transport layer 412 and the electron transport layer 422 may produce more electrons and holes after being energized, such that the organic light-emitting diode is more easily to be turned on. Therefore, the solution can further lower the drive voltage of the organic light-emitting diode, and improve the luminous efficiency and prolong the service life of the organic light-emitting diode.
In one embodiment of the present disclosure, the volume concentrations of the P-type materials of the at least two hole transport layers increase in sequence along the direction far away from the cathode; and the volume concentrations of the N-type materials of the at least two electron transport layers increase in sequence along the direction far away from the anode.
In the embodiment of the present disclosure, the volume concentration of the P-type materials of the at least two hole transport layers changes gradually, thereby realizing gradient doping of the hole transport layer, forming a transport path to enable rapid transport of holes, and further speeding up the mobility of holes. Similarly, the layer structures for transporting electrons also adopt the design of the present solution, then a transport path to enable rapid transport of electrons is formed, and the mobility of electrons is sped up, therefore, the present solution can further lower the drive voltage of the organic light-emitting diode, improve the luminous efficiency and prolong the service life of the organic light-emitting diode.
In another embodiment, the thickness of the hole transport layer, adjacent to the light emitting layer, in the at least two hole transport layers is greater than the thickness of the remaining hole transport layers; and the thickness of the electron transport layer, adjacent to the light emitting layer, in the at least two electron transport layers is greater than the thickness of the remaining electron transport layers.
In the embodiment of the present disclosure, the thickness of the hole transport layer with a lower doping concentration of the P-type material and adjacent to the light emitting layer is larger, and the effect of isolating the hole transport layer with a higher volume concentration of the P-type material from the light emitting layer can be improved, such that it is difficult for the P-type material in the hole transport layer with a higher volume concentration of the P-type material to penetrate through the hole transport layer with a lower doping concentration of the P-type material and adjacent to the light emitting layer to thereby permeate into the light emitting layer, and the problem of luminescence quenching is not easily caused. Similarly, the thickness of the electron transport layer with a lower doping concentration of the N-type material and adjacent to the light emitting layer is larger, and the effect of isolating the electron transport layer with a higher volume concentration of the N-type material from the light emitting layer can be improved, such that it is difficult for the N-type material in the electron transport layer with a higher volume concentration of the N-type material to penetrate through the electron transport layer to thereby permeate into the light emitting layer, and the problem of luminescence quenching is not easily caused.
Please refer to
In the embodiment, the hole transport element 41 and the electron transport element 42 respectively include two layer structures, and the structures thereof are simple and the manufacturing is convenient. The volume concentration of the P-type material of the first hole transport layer 415 is less than the volume concentration of the P-type material of the second hole transport layer 416, and the volume concentration of the N-type material of the first electron transport layer 425 is less than the volume concentration of the N-type material of the second electron transport layer 426. This solution solves the technical problem to be solved by the present disclosure with a simple structure, lowers the drive voltage of the organic light-emitting diode, and improves the luminous efficiency and prolongs the service life of the organic light-emitting diode.
As shown in
The related art shown in
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In the present embodiment, the thickness of the first hole transport layer 415 is larger, and the effect of isolating the second hole transport layer 416 with a higher volume concentration of the P-type material from the light emitting layer can be improved, such that it is difficult for the P-type material in the second hole transport layer 416 with a higher volume concentration of the P-type material to penetrate through the first hole transport layer 415, and the problem of luminescence quenching is not easily caused. The setting for the thickness of the electron transport layer is the same as the above reasons, and will not be repeated redundantly herein.
In some embodiments, the thickness of the first hole transport layer 415 is 10 nm-120 nm, and within this thickness range, the effect of isolating the second hole transport layer 416 with a higher volume concentration of the P-type material from the light emitting layer by the first hole transport layer 415 is favorable. For example, the thickness of the first hole transport layer 415 may be 12 nm, 18 nm, 20 nm, 25 nm, 29 nm, 34 nm, 36 nm, 40 nm, 45 nm, 49 nm, 52 nm, 5 nm, 60 nm, 68 nm, 75 nm, 80 nm, 85 nm, 90 nm, 92 nm, 98 nm, 100 nm, 105 nm, 110 nm or 115 nm, etc. The thickness of the second hole transport layer 416 is 5 nm-20 nm, and the second hole transport layer 416 within such a thickness range may be doped with the P-type material with a higher volume concentration, then the hole transport efficiency can be effectively improved, and the drive voltage of the organic light-emitting diode can be effectively lowered. For example, the thickness of the second hole transport layer 416 may be 8 nm, 10 nm, 12 nm, 14 nm, 15 nm, 16 nm or 18 nm, etc. The setting of specific value may be designed by designers in combination with various elements.
In some embodiments, the volume concentration of the P-type materials of the first hole transport layer 415 is 0.05%˜10%, if the volume concentration of the P-type material is within this range, then it is difficult for the P-type material to permeate into adjacent light emitting layers, and the problem of luminescence quenching is not easily caused, For example, the volume concentration of the P-type material of the first hole transport layer 415 may be 0.1%, 0.15%, 0.18%, 0.2%, 0.5%, 1%, 1.5%, 2.2%, 2.5%, 3%, 3.5%, 4.1%, 4.8%, 5%, 5.5%, 6%, 6.2%, 6.7%, 7%, 7.4%, 7.9%, 8.5%, 9%, 9.5% or 9.7%, etc. The volume concentration of the P-type materials of the second hole transport layer 416 may be 1%˜30%, if the volume concentration of the P-type material is within the range, then more holes may be generated, such that the organic light-emitting diode may be more easily turned on, the drive voltage is lowered, the luminous efficiency is improved, and the service life of the organic light-emitting diode is prolonged. For example, the volume concentration of the P-type material of the second hole transport layer 416 may be 1.5%, 2%, 4%, 4.8%, 5.6%, 6.7%, 8%, 9%, 9.5%, 10%, 12%, 13%, 13.5%, 13.8%, 14.2%, 14.7%, 15%, 16%, 16.5%, 17%, 17.8%, 18%, 20%, 21%, 21.5%, 22%, 22.5%, 23%, 24%, 24.5%, 25%, 25.6%, 26%, 26.5%, 27%, 27.5%, 27.8%, 28%, 28.5%, 29% or 29.7%.
In some embodiments, the thickness of the first electron transport layer 425 is 20 nm˜60 nm, and within this thickness range, the effect of isolating the second electron transport layer 426 with a higher volume concentration of the N-type material from the light emitting layer by the first electron transport layer 425 is favorable. For example, the thickness of the first electron transport layer 425 can be 20.5 nm, 22 nm, 23 nm, 25 nm, 26 nm, 27.5 nm, 28 nm, 29.4 nm, 30 nm, 31 nm, 32 nm, 33.5 nm, 34 nm, 38 nm, 40 nm, 42 nm, 45 nm, 50 nm, 52 nm or 58 nm, etc, The thickness of the second electron transport layer 426 is 5 nm-20 nm, and the second electron transport layer 426 within such a thickness range may be doped with the N-type material with a higher volume concentration, then the electron transport efficiency can be effectively improved, and the drive voltage of the organic light-emitting diode can be effectively lowered. For example, the thickness of the second electron transport layer 426 may be 7 nm, 9 nm, 10 nm, 13.5 nm, 15 nm, 16 nm, 16.5 nm, 17 nm, 18 nm, 19 nm or 19.5 nm, etc. The setting of specific value may be designed by designers in combination with various elements.
In some embodiments, the volume concentration of the N-type material of the first electron transport layer 425 is 0.1%-5%, if the volume concentration of the N-type material is within this range, then it is difficult for the N-type materials to permeate into adjacent light emitting layers, and the problem of luminescence quenching is not easily caused. For example, the volume concentration of the N-type material of the first electron transport layer 425 may be 0.15%, 0.2%, 0.5%, 1%, 1.8%, 2.2%, 2.5%, 3.2%, 3.5%, 4.3% or 4.8%, etc. The volume concentration of the N-type material of the second electron transport layer 426 is 1%-30%, if the volume concentration of the N-type material is within the range, then more electrons may be generated, such that the organic light-emitting diode may be more easily turned on, the drive voltage is lowered, the luminous efficiency of the organic light-emitting diode is improved, and the service life is prolonged. For example, the volume concentration of the N-type material of the second electron transport layer 426 may be 2%, 3%, 4.8%, 6%, 6.7%, 8.5%, 9%, 9.5%, 10%, 13%, 13.5%, 14.2%, 14.7%, 15%, 16.5%, 17.8%, 18%, 20%, 21.5%, 22.5%, 23%, 24.5%, 25%, 26%, 26.5%, 27.5%, 28%, 29% or 29.7%.
Please refer to
In the present embodiment, the thickness of the third hole transport layer 413 is larger, and the thickness of the third electron transport layer 423 is also larger, therefore, the problem of luminescence quenching is not easily caused. In addition, the volume concentrations of the P-type material of the multiple hole transport layers change gradually, thereby realizing gradient doping of the hole transport layer; and the volume concentrations of the P-type material of the multiple electron transport layers change gradually, thereby realizing gradient doping of the electron transport layer. By adopting this solution, the drive voltage of the organic light-emitting diode can be further lowered, and the luminous efficiency of the organic light-emitting diode can be improved and the service life can be prolonged.
In the above embodiments, the organic light-emitting diode which includes two light emitting layers is taken as an example, in actual application, as shown in
In an optional embodiment, the N-type material includes an alkali metal, an alkaline-earth metal or a rare-earth metal. Illustratively, the metal material includes the combination of any one or at least two of ytterbium, magnesium, lithium, cesium and calcium. The above metal material is doped in the electron transport layer, and may improve the electron transport capability of the electron transport layer.
In some embodiments, the P-type material includes ab inorganic material, and the inorganic materials include MoO3. The MoO3 is doped in the hole transport materials as a P-type material, and the hole transport capability of the hole transport layer can be improved.
In an optional embodiment, the P-type material includes an organic material, and the organic material includes:
Where R1 to R21 are independently selected from hydrogen atoms, deuterium atoms, alkyl, alkoxy, substituted or unsubstituted aryl; X1, X2 and X3 are independently selected from substituted or unsubstituted aryl, and the substituent in the substituted or unsubstituted aryl at least includes one electron acceptor group.
Where substituted or unsubstituted aryl exemplarily includes phenyl, tolyl, ethyl phenyl, xylyl, dibiphenylyl, naphthyl, or anthryl, etc.
The above compounds may all improve the hole transport capability of the hole transport layer doped with a P-type material, for example, the compound
has more conjugated structures, and the its performance is relatively stable, meanwhile, the nitrogen atoms are connected with three conjugated systems, thereby being beneficial for the approach of the electron cloud towards the nitrogen atoms under the electrophilic effect of the nitrogen atoms, and then more holes are formed. Under the effect of large pi bond, the holes may move rapidly, so the compound may play a role of hole transport, and the transport speed of the holes is high. The holes generated by the P-type semiconductor material may transport rapidly in the hole injection materials, then the movement rate of the holes is improved, and the holes may be rapidly combined with the electrons in the light emitting layer to emit light, thereby improving the luminous efficiency of the organic light-emitting diode.
For another example, the compound
is a radialene compound, and the radialene compound may be used as an organic dopant doped into organic semiconductor to change the electrical property of the semiconductor substrate materials, as a blocker material and a charge injection layer, and as an electrode material. The compound in the embodiment of the present disclosure is connected with an electron acceptor group-CN which has a strong electron withdrawing capability, thereby being beneficial for generating more holes, and improving the hole transport capability of the hole transport layer doped with P-type materials.
In an optional embodiment, the hole transport material includes an aromatic amine material or a carbazole material. The aromatic amine material or carbazole material all have a favorable hole transport performance, and are suitable for being used as hole transport materials.
In an optional embodiment, the electron transport materials includes a biphenyl material, a pyridine material, a benzoylpyridine material or a phenanthroline material. The above materials all have a favorable electron transport performance, and are suitable for being used as electron transport materials.
The embodiment of the present disclosure further provides a display panel, and the display panel includes the organic light-emitting diode in any one of the above technical solutions.
The display panel requires a lower drive voltage, the power consumption is low and the luminous efficiency is high, then the display effect of the display panel is favorable.
The embodiment of the present disclosure further provides a display device, and the display device includes the above display panel.
The display panel included in the display device requires a lower drive voltage, the power consumption is low and the luminous efficiency is higher, then the display effect of the display device can be improved, and the power consumption of the display device is lowered.
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The display panel included in the display device requires a lower drive voltage, the power consumption is low and the luminous efficiency is higher, then the display effect of the display device can be improved, and the power consumption of the display device is lowered.
In the embodiments of the present disclosure, the display device is not limited in specific types, and may be a mobile phone, a display, a tablet computer or a television. For example, the display device shown in
Evidently, those skilled in the art can make various modifications and variations to the present disclosure without departing from the scope of the present disclosure. Accordingly, the present disclosure is also intended to encompass these modifications and variations thereto so long as the modifications and variations come into the scope of the claims appended to the present disclosure and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201710648482.5 | Aug 2017 | CN | national |
