OLED manufacturing method and light-emitting structure capable of independently adjusting light-emitting color

Abstract

The present invention provides an OLED manufacturing method and a light-emitting structure capable of independently adjusting the luminous color, including three color pixels of red, green and blue, wherein the red / green / blue pixels are made of luminous color adjustable materials or PN junctions; 1) luminous color adjustable materials are made: PO-T2T is inkjet printed or evaporated on the pixels as an acceptor layer, mCBP is used as a luminous color adjustment layer, and m-MTDATA is used as a donor layer; 2) PN junction is made: a) P-type main material TAPC or Pentacene is thermally evaporated or inkjet printed, and N-type main material PPV or TmPyTZ is combined with a PN junction; b) the PN junction and the prefabricated substrate are peeled off by a physical or chemical mechanism, and a transition substrate is used to carry the PN junction; c) the PN junction is transferred by a transfer tool and bonded to a color pixel of a required PN junction type in an electrode; 3) another electrode is made by evaporation or sputtering technology.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor technology and relates to a light-emitting structure, in particular to an OLED manufacturing method and a light-emitting structure capable of independently regulating the light-emitting color. Background Art

[0002] The OLED light-emitting structure under the existing technical solution is basically composed of hole injection, hole transport, organic light-emitting layer, electron transport and electron injection layer. When emitting light, the energy released by the excitons of the organic molecules migrating to the ground state is extracted in the form of light. The energy of the excitons is as high as about 0.5eV. It is extremely difficult to arbitrarily control the exciton energy of the same molecule. Therefore, to achieve full-color display, organic molecules that emit three colors of light, R, G, and B, must be used.

[0003] In full-color technology, OLED is realized through independent RGB pixel emission, light color conversion and color filter film technology. Light color conversion uses blue light OLED combined with light color conversion film array. After preparing blue light OLED devices, blue light is used to excite light color conversion materials to obtain red and green light, thereby obtaining full color; color filter film technology uses white light OLED combined with color filter film. After preparing white light OLED devices, three primary colors are obtained through color filter film to achieve color display; RGB pixel independent emission is currently the most widely used color mode. This technology uses precise masks and high-precision pixel alignment technology to prepare red, green and blue primary color emission centers and then adjust the color mixing ratio of the three color combinations to produce true color, so that the three-color OLED components emit light independently to form a pixel.

[0004] For example, Chinese patent literature has disclosed an exciplex OLED light-emitting structure driven by an AC power supply [Chinese Patent No.: CN201911201311.3]. The present invention relates to an exciplex OLED light-emitting structure driven by an AC power supply. It includes a transparent substrate, a transparent conductive film positive electrode, a hole injection / transport layer, a P-type donor layer, an N-type acceptor layer, an electron injection / transport layer and a metal negative electrode arranged in sequence from bottom to top, a first dielectric layer is provided between the transparent conductive film positive electrode and the hole injection / transport layer; a second dielectric layer is provided between the electron injection / transport layer and the metal negative electrode; the first dielectric layer and the second dielectric layer generate an alternating electric field between the transparent conductive film positive electrode and the metal negative electrode under an AC power supply, thereby realizing direct drive by an AC power supply. The first dielectric layer and the second dielectric layer of the present invention enable the exciplex OLED light-emitting structure to achieve the best light-emitting effect under the drive of a set frequency AC power supply; by changing the donor and acceptor materials, the OLED device can emit light of any color; under a limited voltage, its brightness can be adjusted by frequency.

[0005] The above technical solution, which is composed of hole injection, hole transport, organic light-emitting layer, electron transport and electron injection layer, uses organic molecules of three colors, R, G and B, to make devices. The three color pixels cannot be adjusted independently of each other, and face problems such as low luminous efficiency, short life of red light materials and insufficient material purity. Summary of the invention

[0006] The purpose of the present invention is to address the above-mentioned problems in the existing technology and to propose an OLED production method and a light-emitting structure that can independently control the light-emitting color by combining the two methods of light-emitting color control and PN junction, or by each independently, to achieve overall light-emitting performance improvement.

[0007] The object of the present invention can be achieved by the following technical solutions: a method for manufacturing an OLED capable of independently adjusting the luminous color, comprising three color pixels, namely, red pixel, green pixel and blue pixel, wherein the red / green / blue pixel is made of a luminous color adjustable material or a PN junction;

[0008] 1) Steps for making materials with adjustable luminous color:

[0009] Inkjet printing or vapor deposition of PO-T2T {2,4,6-tris[3-(diphenylphosphino)phenyl]-1,3,5-triazine} as an acceptor layer, mCBP [3,3′-di(9H-carbazole-9-yl)-1,1′-biphenyl] as a luminescent color regulating layer, and m-MTDATA [4,4′,4′-tris(N-3-methylphenyl-N-phenylamino)triphenylamine] as a donor layer on the pixel, thereby completing the production of a pixel of a luminescent color adjustable material;

[0010] 2) PN junction production steps:

[0011] a. Thermal evaporation or inkjet printing of a P-type host material containing TAPC {4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline]} or pentacene, and an N-type host material containing TmPyTZ {2,4,6-tris[3-(pyridin-3-yl)phenyl]-triazine} or polyethylene (PPV), respectively making a P junction and an N junction on a prefabricated substrate, and combining the two to form an organic PN junction at the pixel level;

[0012] b. Use physical or chemical mechanisms to peel off the PN junction and the prefabricated substrate, and use a transition substrate to support the PN junction;

[0013] c. Use a transfer tool to transfer the PN junctions in batches and bond them to color pixels of a required PN junction type in an electrode;

[0014] 3) Make another electrode by evaporation or sputtering technology.

[0015] In terms of improving luminous efficiency, adding iridium (Ir), platinum (Pt) and rhenium (Re) to organic molecules can form a strong spin-orbit coupling effect in organic materials, causing electrons to transition from the triplet state back to the ground state, thereby improving the luminous efficiency of fluorescence. Another way is to use thermally active delayed fluorescence materials (TADF), which minimize the energy difference "ΔEST" between the singlet state and the triplet state, so that the triplet excitons instantly transition to the singlet state, thereby avoiding the triplet annihilation (TTA) phenomenon caused by the interaction of triplet excitons. The efficiency of singlet state fluorescence can theoretically reach 57%. TADF materials are expected to change OLED's dependence on phosphorescent materials and bring new changes in luminous efficiency and red light material life. The third way is to use an organic PN junction instead of the traditional OLED pixel structure, and by changing the PN junction interface material and ratio, adjust the luminous color, reduce process errors, and improve process repeatability, so as to achieve the purpose of improving the overall performance of OLED.

[0016] In the above-mentioned method for manufacturing an OLED capable of independently adjusting the emission color, in step 1), the thickness range of the emission color adjustment layer is

[0017] In the above-mentioned method for producing an OLED capable of independently adjusting the emission color, in step 2)a, the P:N ratio in the host material is (1-10):(1-10).

[0018] In the above-mentioned method for manufacturing an OLED capable of independently adjusting the emission color, in step 2)c, the transfer tool is a selective stripping tool.

[0019] In the above-mentioned OLED production method with independently adjustable luminous color, when there are both pixels of luminous color adjustable material type and PN junction type pixels among the red pixels, green pixels and blue pixels, the PN junction type pixels are first blocked by a high-precision mask to produce pixels of luminous color adjustable material type.

[0020] In the above-mentioned OLED production method with independently adjustable luminous color, when the number of pixels of the material type with adjustable luminous color among the red pixels, green pixels and blue pixels is at least 2, only one color pixel is exposed in one operation, and the remaining color pixels are blocked by a high-precision mask, and the pixels of the material type with adjustable luminous color are produced separately in sequence until all are completed.

[0021] In the above-mentioned method for manufacturing an OLED with independently adjustable emission color, the remaining blocked color pixels include any combination of PN junction type pixels, pixels not manufactured with adjustable emission color materials, and pixels manufactured with adjustable emission color materials.

[0022] If there are two pixels of the color-adjustable material type, when making the first one, block the pixels of the PN junction type and the pixels that have not been made with the color-adjustable material; when making the second one, block the pixels of the PN junction type and the pixels that have been made with the color-adjustable material. If there are three pixels of the color-adjustable material type, when making the first one, block the remaining two pixels that have not been made with the color-adjustable material; when making the second one, block the pixels that have been made with the color-adjustable material and the pixels that have not been made with the color-adjustable material; when making the third one, block the remaining two pixels that have been made with the color-adjustable material.

[0023] In the above-mentioned method for manufacturing an OLED with independently adjustable emission color, among the red pixel, the green pixel and the blue pixel, at least one color pixel is made of an adjustable emission color material, and at least one color pixel is made of a PN junction.

[0024] In the above-mentioned method for manufacturing an OLED with independently adjustable emission color, the red pixel, green pixel and blue pixel are all made of materials with adjustable emission color, or the red pixel, green pixel and blue pixel are all made of PN junction.

[0025] A light-emitting structure is provided, comprising a light-emitting structure produced by the above-mentioned OLED production method capable of independently adjusting the light-emitting color.

[0026] Compared with the prior art, the OLED manufacturing method and light-emitting structure capable of independently adjusting the light-emitting color have the following advantages:

[0027] 1. By using a color control layer with higher excitation energy than the electron acceptor and electron donor, and controlling the thickness of the color control layer to improve the thermally activated delayed fluorescence (TADF) characteristics of the exciton, the exciton energy and exciton lifetime can be controlled, thereby achieving three-color conversion according to process requirements, and the luminous efficiency can be increased by more than 8 times.

[0028] 2. Using a pure organic PN junction structure, light is emitted at the junction interface. By changing the composition and proportion of the PN junction interface material, the luminescent color can be adjusted. The luminescence of the pure organic PN junction structure is the result of the synergistic energy released by P-type and N-type materials. PN-OLED has a lower driving voltage than traditional OLED. The PN-OLED obtained thereby exhibits a peak external quantum efficiency of up to 12%, bringing a 20% light output coupling efficiency to the element, which is converted into an internal quantum efficiency of 60%, exceeding the theoretical maximum efficiency of the traditional fluorescent light-emitting structure by 25%.

[0029] 3. There is no need to use organic molecules of the three colors of R, G, and B. RGB independent full-color display can be achieved through a single organic color control layer or PN junction, which avoids the problems of uneven color mixing, impure colors, and difficulty in control caused by the production of devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a product diagram of Example 1 of the OLED production method capable of independently adjusting the luminous color.

[0031] Figure 2 This is a product diagram of Example 2 of the OLED production method capable of independently adjusting the luminous color.

[0032] Figure 3 This is a product diagram of Example 3 of the OLED production method that can independently control the luminous color. DETAILED DESCRIPTION

[0033] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0034] Embodiment 1

[0035] like Figure 1 As shown, among the red pixels, green pixels and blue pixels, there are both pixels of the type of luminescent color adjustable material and pixels of the PN junction type. Specifically, the green pixel is a pixel of the type of luminescent color adjustable material, and the red pixel and the blue pixel are pixels of the PN junction type.

[0036] 1) Reserve green pixels to form an exposed state, and use a high-precision mask to cover red and blue pixels;

[0037] 2) Inkjet printing or vapor deposition of PO-T2T {2,4,6-tris[3-(diphenylphosphino)phenyl]-1,3,5-triazine} as an acceptor layer, mCBP [3,3′-di(9H-carbazole-9-yl)-1,1′-biphenyl] as a luminescent color regulating layer, and m-MTDATA [4,4′,4′-tris(N-3-methylphenyl-N-phenylamino)triphenylamine] as a donor layer on the green pixel, thereby completing the production of a pixel with adjustable luminescent color;

[0038] 3) a. Thermal evaporation or inkjet printing of a main material comprising TAPC {4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline]} and TmPyTZ {2,4,6-tris[3-(pyridin-3-yl)phenyl]-triazine}, wherein the ratio of TAPC:TmPyTZ in the main material is 1:1; a P junction and an N junction are separately made on a prefabricated substrate, and the two are combined to form the first batch of organic PN junctions at the pixel level; thermal evaporation or inkjet printing of a main material comprising pentacene (Pentacene) and polyethylene (PPV), wherein the ratio of Pentacene:PPV is 1:2; a P junction and an N junction are separately made on a prefabricated substrate, and the two are combined to form the second batch of organic PN junctions at the pixel level;

[0039] b. Use physical or chemical mechanisms to peel off the PN junction and the prefabricated substrate, and use a transition substrate to support the PN junction;

[0040] c. Use a transfer tool to transfer the PN junction in batches and bond it to the red pixel and the blue pixel in one electrode to complete the production of PN junction type pixels;

[0041] 4) Make another electrode by evaporation or sputtering technology.

[0042] In step 2), the thickness range of the luminescent color regulating layer is According to the requirements of luminescent color, the ligand material is adjusted accordingly.

[0043] In step 3) c, the transfer tool is a selective stripping tool, such as an ultraviolet stripping tool or a thermal volatile stripping tool.

[0044] Embodiment 2

[0045] like Figure 2 As shown, the red pixel, the green pixel and the blue pixel are all pixels of the type of material with adjustable luminescent color.

[0046] 1) Reserve red pixels to form an exposed state, and use a high-precision mask to cover the unmade green and blue pixels;

[0047] 2) Inkjet print or evaporate PO-T2T {2,4,6-tris[3-(diphenylphosphino)phenyl]-1,3,5-triazine} as an acceptor layer, mCBP [3,3′-di(9H-carbazole-9-yl)-1,1′-biphenyl] as a luminescent color regulating layer, and m-MTDATA [4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine] as a donor layer on the red pixel to complete the production of the red pixel;

[0048] 3) Reserve green pixels to form an exposed state, and use a high-precision mask to cover the prepared red pixels and unprepared blue pixels;

[0049] 4) Inkjet print or evaporate PO-T2T {2,4,6-tris[3-(diphenylphosphino)phenyl]-1,3,5-triazine} on the reserved green pixel as an acceptor layer; adjust the thickness of mCBP [3,3′-di(9H-carbazole-9-yl)-1,1′-biphenyl] according to pixel requirements, inkjet print or evaporate mCBP [3,3′-di(9H-carbazole-9-yl)-1,1′-biphenyl], and finally inkjet print or evaporate m-MTDATA [4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine] as a donor layer to complete the production of green pigment;

[0050] 5) Reserve blue pixels to form an exposed state, and use high-precision masks to cover the prepared red and green pixels;

[0051] 6) Inkjet print or evaporate PO-T2T {2,4,6-tris[3-(diphenylphosphino)phenyl]-1,3,5-triazine} on the reserved blue pixel as an acceptor layer; adjust the thickness of mCBP [3,3′-di(9H-carbazole-9-yl)-1,1′-biphenyl] according to pixel requirements, inkjet print or evaporate mCBP [3,3′-di(9H-carbazole-9-yl)-1,1′-biphenyl], and finally inkjet print or evaporate m-MTDATA [4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine] as a donor layer to complete the production of blue pixels;

[0052] 7) Make another electrode by evaporation or sputtering technology.

[0053] The thickness range of the luminescent color regulating layer is According to the requirements of luminescent color, the ligand material is adjusted accordingly.

[0054] Embodiment 3

[0055] like Figure 3 As shown, the red pixel, the green pixel and the blue pixel are all PN junction type pixels.

[0056] 1) Thermal evaporation or inkjet printing of a main material containing TAPC {4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline]} and TmPyTZ {2,4,6-tris[3-(pyridin-3-yl)phenyl]-triazine}, wherein the ratio of TAPC:TmPyTZ in the main material is 1:1; a P junction and an N junction are separately made on a prefabricated substrate, and the two are combined to form the first batch of organic PN junctions at the pixel level;

[0057] 2) Thermal evaporation or inkjet printing of a main material comprising TAPC {4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline]} and polyethylene (PPV), wherein the TAPC:PPV ratio in the main material is 2:1; a P junction and an N junction are separately made on a prefabricated substrate, and the two are combined to form a second batch of organic PN junctions at the pixel level;

[0058] 3) Thermal evaporation or inkjet printing of a main material containing pentacene and polyethylene (PPV), with a pentacene:PPV ratio of 1:2; making a P junction and an N junction on a prefabricated substrate, respectively, and combining the two to form a third batch of organic PN junctions at the pixel level;

[0059] 4) Use physical or chemical mechanisms to peel off the PN junction and the prefabricated substrate, and use a transition substrate to carry the PN junction;

[0060] 5) Use a transfer tool to transfer the PN junction in batches and bond it to the red pixel, green pixel, and blue pixel in one electrode to complete the production of PN junction type pixels;

[0061] 6) Make another electrode by evaporation or sputtering technology.

[0062] The transfer tool is a selective stripping tool, such as a UV stripping tool or a thermal volatile stripping tool.

[0063] Embodiment 4

[0064] Based on the first to third embodiments, the differences of this embodiment are as follows:

[0065] A light-emitting structure is provided, comprising a light-emitting structure produced by the above-mentioned OLED production method capable of independently adjusting the light-emitting color.

[0066] Compared with the prior art, the OLED manufacturing method and light-emitting structure capable of independently adjusting the light-emitting color have the following advantages:

[0067] 1. By using a color control layer with higher excitation energy than the electron acceptor and electron donor, and controlling the thickness of the color control layer to improve the thermally activated delayed fluorescence (TADF) characteristics of the exciton, the exciton energy and exciton lifetime can be controlled, thereby achieving three-color conversion according to process requirements, and the luminous efficiency can be increased by more than 8 times.

[0068] 2. Using a pure organic PN junction structure, light is emitted at the junction interface. By changing the ratio of PN junction interface materials, the luminescent color can be adjusted. The luminescence of the pure organic PN junction structure is the result of the synergistic energy released by P-type and N-type materials. PN-OLED has a lower driving voltage than traditional OLED. The PN-OLED obtained thereby exhibits a peak external quantum efficiency of up to 12%, bringing a 20% light output coupling efficiency to the element, which is converted into an internal quantum efficiency of 60%, exceeding the theoretical maximum efficiency of 25% of the traditional fluorescent light-emitting structure.

[0069] 3. There is no need to use organic molecules of the three colors of R, G, and B. RGB independent full-color display can be achieved through a single organic color control layer or PN junction, which avoids the problems of uneven color mixing, impure colors, and difficulty in control caused by the production of devices.

[0070] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A method for manufacturing an OLED capable of independently adjusting the color of light emission, comprising three color pixels: red pixel, green pixel and blue pixel, characterized in that: Red / green / blue pixels are made of luminous color adjustable materials or PN junctions; 1) Steps for making materials with adjustable luminous color: Inkjet printing or vapor deposition of PO-T2T {2,4,6-tris[3-(diphenylphosphino)phenyl]-1,3,5-triazine} as an acceptor layer, mCBP [3,3′-di(9H-carbazole-9-yl)-1,1′-biphenyl] as a main luminescent color regulating layer, and m-MTDATA [4,4′,4′-tris(N-3-methylphenyl-N-phenylamino)triphenylamine] as a donor layer on the pixel, thereby completing the production of a pixel of a luminescent color adjustable material; 2) PN junction production steps: a. Thermal evaporation or inkjet printing of a P-type host material containing TAPC {4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline]} or pentacene, and an N-type host material containing TmPyTZ {2,4,6-tris[3-(pyridin-3-yl)phenyl]-triazine} or polyethylene (PPV), respectively making a P junction and an N junction on a prefabricated substrate, and combining the two to form an organic PN junction at the pixel level; b. Use physical or chemical mechanisms to peel off the PN junction and the prefabricated substrate, and use a transition substrate to support the PN junction; c. Use a transfer tool to transfer the PN junctions in batches and bond them to color pixels of a required PN junction type in an electrode; 3) Make another electrode by evaporation or sputtering technology.

2. The method for manufacturing an OLED capable of independently adjusting the emission color according to claim 1, characterized in that: In step 1), the thickness range of the luminescent color regulating layer is 3. The method for manufacturing an OLED capable of independently adjusting the emission color according to claim 1, characterized in that: In step 2)a, the P:N ratio in the main material is (1-10):(1-10).

4. The method for manufacturing an OLED capable of independently adjusting the emission color according to claim 1, characterized in that: In step 2) c, the transfer tool is a selective stripping tool.

5. The method for manufacturing an OLED capable of independently adjusting the emission color according to claim 1, characterized in that: When there are both pixels of the luminous color adjustable material type and pixels of the PN junction type in the red pixels, the green pixels and the blue pixels, the pixels of the PN junction type are first blocked by a high-precision mask to produce pixels of the luminous color adjustable material type.

6. The method for manufacturing an OLED capable of independently adjusting the emission color according to claim 1, characterized in that: When the number of pixels of the material type with adjustable luminous color among the red pixels, green pixels and blue pixels is at least 2, only one color pixel is exposed in one operation, and the remaining color pixels are blocked by high-precision masks, and the pixels of the material type with adjustable luminous color are produced separately in sequence until all are completed.

7. The method for manufacturing an OLED capable of independently adjusting the emission color according to claim 6, characterized in that: The remaining blocked color pixels include any combination of two of PN junction type pixels, pixels not made of luminescent color adjustable materials, and pixels made of luminescent color adjustable materials.

8. The method for manufacturing an OLED capable of independently adjusting the emission color as claimed in claim 1, characterized in that: Among the red pixel, the green pixel and the blue pixel, at least one color pixel is made of a material with adjustable luminescent color, and at least one color pixel is made of a PN junction.

9. The method for manufacturing an OLED capable of independently adjusting the emission color according to claim 1, characterized in that: The red pixel, the green pixel and the blue pixel are all made of materials with adjustable luminescent colors, or the red pixel, the green pixel and the blue pixel are all made of PN junctions.

10. A light emitting structure, characterized in that: The OLED is prepared by the method for preparing an OLED capable of independently adjusting the luminous color as described in any one of claims 1 to 9.

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