CN111584729A - Organic electroluminescent device and preparation method thereof - Google Patents
Organic electroluminescent device and preparation method thereof Download PDFInfo
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Abstract
The invention provides an organic electroluminescent device and a preparation method thereof, wherein the organic electroluminescent device comprises: the organic electroluminescent device comprises a transparent substrate, an anode, a hole injection layer, an organic light emitting layer, an electron transport layer, a cathode modification layer and a cathode; the preparation method of the organic electroluminescent device comprises the following steps: preparing an anode on a transparent substrate; preparing a hole injection layer on the anode; preparing an organic light emitting layer on the hole injection layer; preparing an electron transport layer on the organic light emitting layer; preparing a cathode modification layer on the electron transport layer; and preparing a cathode on the cathode modification layer. The invention greatly simplifies the preparation process of the organic electroluminescent device and saves materials; the preparation method has the remarkable characteristics of excellent device performance, good flexibility, large-area preparation and no damage to a film layer.
Description
Technical Field
The invention relates to the technical field of display illumination, in particular to an organic electroluminescent device and a preparation method thereof.
Background
In recent years, organic electroluminescent devices have attracted much attention in the display illumination industry. The organic semiconductor material has the advantages of low cost, green color, spin coating of solution, capability of being made into large-area flexible devices and the like, so that the research on the organic electroluminescent devices is concerned. Compared with LED display and liquid crystal display, the organic electroluminescent device has the characteristics of active light emission, high response speed, low energy consumption, wide visual angle and the like, so that the organic electroluminescent device has wide application prospect, can be used for small-area mobile phone screens, large-area television screens and flexible screens and lighting sources.
The organic electroluminescent device is a light emitting device manufactured using an organic semiconductor material having an electroluminescence phenomenon. At present, the solution method of fabricating organic electroluminescent devices is being pursued. The methods that can be used are: firstly, a large number of molecules are mutually bonded and crosslinked into relatively stable molecules with a network structure through a crosslinking reaction, which is usually thermal crosslinking or chemical crosslinking, so that the solvent resistance of the film is improved, and the film layer is prevented from being damaged by a solvent; and secondly, the organic semiconductor materials required by adjacent film layers are dissolved by using different solvents by utilizing different solubilities of the materials in different solvents, so that the prepared film layer is prevented from being dissolved in the solvent of the material of the next film layer. However, because the selection of materials available for the cross-linking reaction is few at present, the solubility of the organic semiconductor material in the organic solvent is similar, the device film interfaces prepared by the two methods can be damaged in different degrees, and the performance of the organic electroluminescent device prepared by the solution method is limited to be further improved. Therefore, at present, a water-soluble solvent spin coating method is commonly used for preparing a hole injection layer in the preparation of an organic electroluminescent device by a solution method, an organic semiconductor material is dissolved in an organic solvent spin coating method for preparing a light-emitting layer, and an electron transport layer and an electrode are prepared by a vacuum evaporation method, but the method is not suitable for mass production on the market.
Therefore, the effective efficiency of the organic electroluminescent device is improved through a more reasonable preparation method.
Disclosure of Invention
The embodiment of the invention provides an organic electroluminescent device and a preparation method thereof, which greatly simplify the preparation process of the organic electroluminescent device and save materials; the preparation method has the remarkable characteristics of excellent device performance, good flexibility, large-area preparation and no damage to a film layer.
An embodiment of the present invention provides an organic electroluminescent device, including:
the organic electroluminescent device comprises a transparent substrate (1), an anode (2), a hole injection layer (3), an organic light-emitting layer (4), an electron transport layer (5), a cathode modification layer (6) and a cathode (7);
the organic light emitting diode is characterized in that the anode (2) is arranged on the transparent substrate (1), the hole injection layer (3) is arranged on the anode (2), the organic light emitting layer (4) is arranged on the hole injection layer (3), the electron transport layer (5) is arranged on the organic light emitting layer (4), the cathode modification layer (6) is arranged on the electron transport layer (5), and the cathode (7) is arranged on the cathode modification layer (6).
Wherein the transparent substrate (1) is a rigid substrate or a flexible substrate;
the hard substrate is glass, silicon dioxide or quartz; the flexible substrate is polyethylene terephthalate, polyethylene naphthalate or polyimide.
Wherein the anode (2) is a transparent anode, and the transparent anode is indium tin oxide; the cathode (7) is aluminum, silver or gold, and the thickness is 80-100 nanometers.
The organic light-emitting layer (4) is made of organic materials, and the organic materials are a host material A and a guest light-emitting material B and exist in a host-guest doped form; or the organic material is a luminescent material C and exists in an undoped form;
the main material A: is at least one of bipolar small molecules and bipolar small molecule derivatives;
the luminescent material B and the luminescent material C are respectively as follows: fluorescent material, phosphorescent material, thermal retardation fluorescent material.
Wherein the electron transport layer (5) is prepared by an organic high molecular polymer D in a non-doped form; the organic high molecular polymer D is an electron transport material.
The embodiment of the invention provides a preparation method of an organic electroluminescent device, which comprises the following steps:
preparing an anode (2) on a transparent substrate (1);
-preparing a hole injection layer (3) on the anode (2);
preparing an organic light-emitting layer (4) on the hole injection layer (3);
preparing an electron transport layer (5) on the organic light emitting layer (4);
preparing a cathode modification layer (6) on the electron transport layer (5);
and preparing a cathode (7) on the cathode modification layer (6).
Wherein the preparation of the anode (2) on the transparent substrate (1) comprises:
plating indium tin oxide on the transparent substrate (1); respectively soaking the substrate (1) in a substrate detergent, deionized water and absolute ethyl alcohol, and cleaning the soaked substrate (1) by using an ultrasonic cleaner; blowing the cleaned substrate (1) by using nitrogen, and treating the dried substrate (1) by using oxygen plasma for 3 minutes to obtain an anode (2);
-said preparation of a hole injection layer (3) on said anode (2), comprising:
and (3) spin-coating PEDOT (PSS) on the anode of the substrate (1) subjected to plasma treatment, and annealing the substrate (1) subjected to spin-coating PEDOT (PSS) on a heating table at 120 ℃ for 20 minutes to obtain a hole injection layer (3).
Wherein the preparation of the organic light-emitting layer (4) on the hole injection layer (3) comprises:
after the hole injection layer (3) is coated with the first organic solution in a spin mode, the hole injection layer is placed on a heating table at the temperature of 60 ℃ for annealing for 20 minutes, and an organic light emitting layer (4) is obtained;
wherein the first organic solution is a host material A and a guest luminescent material B which exist in a host-guest doped form,
the host material A is at least one of bipolar small molecules and bipolar small molecule derivatives, and the guest luminescent material B is one of a fluorescent material, a phosphorescent material and a thermal delay fluorescent material.
Wherein the preparing of the electron transport layer (5) on the organic light emitting layer (4) comprises:
adding water into a culture dish, dripping a second organic solution on the water surface of the culture dish, after the second organic solution is evaporated, sucking the back surface of a substrate (1) by using a vacuum chuck, dipping an organic film on the front surface, transferring the organic film on the water surface onto an organic light-emitting layer (4) by using intermolecular force, and then putting the organic light-emitting layer on a heating table at 70 ℃ for annealing for 20 minutes to obtain an electron transport layer (5);
wherein the second organic solution is: dissolving the organic high molecular polymer in chlorobenzene and additives according to the concentration of 4-10mg/ml, wherein the weight ratio of 10: 1 in a solvent of 1.
Wherein the preparation of the cathode modification layer (6) on the electron transport layer (5) comprises:
evaporating lithium fluoride on the electron transport layer (5), heating and evaporating the lithium fluoride to enable the thickness of the lithium fluoride to be 1 nanometer, and obtaining a cathode modification layer (6);
the preparation of the cathode (7) on the cathode modification layer (6) comprises:
and placing the sample for generating the cathode modification layer (6) into a vacuum cavity of an aluminum ingot, a silver ingot or a gold ingot, and heating and evaporating the aluminum ingot, the silver ingot or the gold ingot to obtain the organic electroluminescent device.
According to the organic electroluminescent device and the preparation method thereof provided by the embodiment of the invention, the electronic transmission layer is prepared by adopting the high molecular polymer, the organic electroluminescent device has excellent film forming property and excellent electronic transmission property, is well matched with the energy level of an organic material of the light-emitting layer, forms a perfect electronic transmission channel, is well contacted with the interface of the light-emitting layer, has few defects, reduces defect quenching of excitons, is beneficial to dipole radiation luminescence of the light-emitting layer, can simplify the preparation process of the organic electroluminescent device, and saves materials; the preparation method has the remarkable characteristics of excellent device performance, good flexibility, large-area preparation and no damage to a film layer.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an organic electroluminescent device according to an embodiment of the present invention;
fig. 2 is a schematic flow chart of a method for manufacturing an organic electroluminescent device according to an embodiment of the present invention;
fig. 3 is a schematic flow chart of another method for manufacturing an organic electroluminescent device according to an embodiment of the present invention;
fig. 4 is a schematic diagram of the luminance and current density of an organic electroluminescent device under different voltages according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of external quantum efficiency of an organic electroluminescent device at different current densities according to an embodiment of the present invention;
fig. 6 is an electroluminescence spectrum of an organic electroluminescence device provided by an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
An embodiment of the present invention provides an organic electroluminescent device, referring to fig. 1, including: the organic electroluminescent device comprises a transparent substrate 1, an anode 2, a hole injection layer 3, an organic light-emitting layer 4, an electron transport layer 5, a cathode modification layer 6 and a cathode 7;
the transparent substrate 1 is provided with the anode 2, the anode 2 is provided with the hole injection layer 3, the hole injection layer 3 is provided with the organic light-emitting layer 4, the organic light-emitting layer 4 is provided with the electron transport layer 5, the electron transport layer 5 is provided with the cathode modification layer 6, and the cathode modification layer 6 is provided with the cathode 7.
The transparent substrate 1 is a hard substrate or a flexible substrate, the hard substrate is glass, silicon dioxide or quartz, and the flexible substrate is polyethylene terephthalate (PET), polyethylene naphthalate (PEN) or Polyimide (PI); the transparent anode 2 is indium tin oxide; the metal cathode 7 is aluminum, silver or gold, and the thickness is 80-100 nanometers;
the organic light-emitting layer 4 is of a host-guest doped structure, and the host material is one or more of 1, 3-di-9-carbazolyl benzene (mCP), 4-di (9-Carbazole) Biphenyl (CBP), 3 '-di (9H-carbazole-9-yl) -1, 1' -biphenyl (mCBP), 9- (4-tert-butylphenyl) -3, 6-bis (triphenylsilicon-based) -9H-Carbazole (CZSi), bis [2- [ (oxo) diphenylphosphino ] phenyl ] ether (DPEPO) and related derivatives of the small molecules; the object luminescent material B is one of a fluorescent material, a phosphorescent material and a thermal delay fluorescent material; the electron transport layer 5 is one of poly (9, 9-bis (3'- (N, N-dimethylamino) propyl) -2,7 fluorene) -2,7- (9, 9-dioctylfluorene) (PFN-DOF) and poly (9, 9-bis (3' - ((N, N-dimethyl) N-ethylammonium) propyl) -2, 7-fluorene) -2,7- (9, 9-dioctylfluorene) (PFNBr).
An embodiment of the present invention provides a method for manufacturing an organic electroluminescent device, which is shown in fig. 2 and includes:
s101: preparing an anode 2 on a transparent substrate 1;
in this step, indium tin oxide is plated on the transparent substrate 1; respectively soaking the substrate 1 in a substrate detergent, deionized water and absolute ethyl alcohol, and cleaning the soaked substrate 1 by using an ultrasonic cleaner; blowing the cleaned substrate 1 by using nitrogen, and treating the dried substrate 1 by using oxygen plasma for 3 minutes to obtain an anode 2;
the transparent substrate is a hard substrate or a flexible substrate, the hard substrate is glass, silicon dioxide or quartz, and the flexible substrate is polyethylene terephthalate, polyethylene naphthalate or polyimide.
It should be noted that, organic matter, impurities and the like on the surface of the substrate can be effectively removed by the ultrasonic cleaning in the step S101, so that a uniform organic film can be formed; blowing the substrate by using nitrogen to remove solid particles attached to the surface of the substrate, and also being beneficial to forming a high-quality uniform organic film; in addition, the wettability of poly (3, 4-ethylenedioxythiophene) -polystyrene sulfonic acid (PEDOT: PSS) on the surface of the substrate can be improved by treating the substrate with oxygen plasma, which is beneficial to uniform film formation.
S102: preparing a hole injection layer 3 on the anode 2;
in this step, PEDOT: PSS is spin-coated on the anode of the substrate 1 subjected to plasma treatment, and the substrate 1 subjected to the spin-coating of the PEDOT: PSS is placed on a heating stage at 120 ℃ for annealing for 20 minutes, so that the hole injection layer 3 is obtained.
Wherein the spin coating speed is 4000 rpm, and the spin coating time is 40 seconds.
S103: preparing an organic light-emitting layer 4 on the hole injection layer 3;
in the step, after the hole injection layer 3 is spin-coated with the first organic solution, the hole injection layer is placed on a heating table at 60 ℃ for annealing for 20 minutes to obtain an organic light-emitting layer 4;
wherein the spin coating rate is 2000-.
In specific implementation, the first organic solution is a host material a and a guest light emitting material B, and exists in a host-guest doped form, or may exist in a non-doped form as a light emitting material C.
The host material A is at least one of bipolar small molecule 1, 3-di-9-carbazolyl benzene (mCP), 4-di (9-Carbazole) Biphenyl (CBP), 3 '-di (9H-carbazole-9-yl) -1, 1' -biphenyl (mCBP), 9- (4-tert-butylphenyl) -3, 6-bis (triphenylsilyl) -9H-Carbazole (CZSi), bis [2- [ (oxo) diphenylphosphino ] phenyl ] ether (DPEPO) and bipolar small molecule derivatives, and the guest luminescent material B and the luminescent material C are respectively: fluorescent material, phosphorescent material, thermal retardation fluorescent material.
It should be noted that, the first organic solution is selected as a host-guest doping form, a host-guest doping solution with a host-guest doping ratio of 5%, 10%, 15% and a concentration of 3mg/ml to 10mg/ml is prepared, and the mixture is heated and stirred at 60 ℃ for 12 hours.
S104: preparing an electron transport layer 5 on the organic light emitting layer 4;
in the present step, the first step is carried out,
adding water into a culture dish, dripping a second organic solution on the water surface of the culture dish by using a pipette, after the second organic solution is paved on the whole water surface and the second organic solution is evaporated, sucking the back surface of a substrate 1 by using a vacuum chuck, dipping an organic film on the front surface of the substrate, transferring the organic film on the water surface to an organic light-emitting layer 4 by using intermolecular force, and then putting the substrate on a heating table at 70 ℃ for annealing for 20 minutes to obtain an electron transport layer 5;
wherein the second organic solution is: dissolving the organic high molecular polymer in chlorobenzene and additives according to the concentration of 4-10mg/ml, wherein the weight ratio of 10: 1 in a solvent of 1. Wherein the additive is specifically additive DIO or additive CN.
The organic polymer D is one of poly (9, 9-bis (3'- (N, N-dimethylamino) propyl) -2, 7-fluorene) -2,7- (9, 9-dioctylfluorene) (PFN-DOF) and poly (9, 9-bis (3' - ((N, N-dimethyl) N-ethylammonium) propyl) -2, 7-fluorene) -2,7- (9, 9-dioctylfluorene) (PFNBr), which are electron transport materials.
In another specific embodiment, the organic high molecular polymer C poly (9, 9-bis (3' - (N, N-dimethylamino) propyl) -2, 7-fluorene) -2,7- (9, 9-dioctylfluorene) (PFN-DOF) was dissolved in chlorobenzene at a concentration of 8mg/ml with additive DIO or additive CN at a ratio of 10: 1 in a solvent of 1; a10 cm diameter dish was filled with an appropriate amount of water until it was spread over the bottom of the dish, and 30. mu.l of the organic solution was taken out with a pipette and dropped on the water surface of the dish. After the solution is paved on the whole water surface, the back surface of the substrate 1 in the step 1 is sucked by a vacuum chuck after the organic solvent is evaporated, the organic film is dipped on the front surface, the organic film on the water surface is transferred to the organic light-emitting layer 4 by utilizing intermolecular force, and then the substrate is placed on a heating table at the temperature of 70 ℃ for annealing for 20 minutes.
The organic molecule PFN-DOF is a high molecular weight compound formed by repeating covalent bonds as a high molecular weight polymer. The high molecular polymer has the advantages of good machining performance, easy film forming and large-area display. The solution method can be used for preparing compact films, and the vapor deposition method can damage molecular chains of the compact films, so that the film forming property is poor. Therefore, when the PFN-DOF electron transport layer is prepared by using film transfer, the film forming is better than the vacuum evaporation method preparation and the solution method micromolecule film forming, and the PFN-DOF electron transport layer is a solid film when transferred onto the light-emitting layer, does not contain organic solvent and cannot damage the light-emitting layer film. Namely, the electron transmission layer is in good and complete contact with the interface of the luminescent layer, which is beneficial to the transmission of electrons, and the high molecular polymer forms a film to form a reticular structure, thereby reducing the defect state of the interface and being beneficial to the radiation luminescence of dipoles. The solution method can realize the preparation of the organic electroluminescent device, and greatly improves the transmission of electrons and the radiation luminescence of dipoles, thereby improving the performance of the organic electroluminescent device.
S105: preparing a cathode modification layer 6 on the electron transport layer 5;
in this step, lithium fluoride (LiF) is evaporated on the electron transport layer 5, and the pressure in the vacuum chamber is lower than 1 × 10-4Heating and evaporating the lithium fluoride (LiF) to enable the thickness of the lithium fluoride to be 1 nanometer to obtain a cathode modification layer 6;
wherein, heating LiF to evaporate at the evaporation rate of 0.01-0.03 nm/s and the evaporation thickness of 1 nm to obtain the cathode modification layer (6).
S106: a cathode 7 is prepared on the cathode modification layer 6.
In this step, the sample for forming the cathode modification layer 6 is placed in a vacuum chamber of an aluminum ingot, a silver ingot or a gold ingot, and the pressure in the vacuum chamber is lower than 1 × 10-4And heating and evaporating an aluminum ingot, a silver ingot or a gold ingot to obtain the organic electroluminescent device.
Wherein, the evaporation rate is 0.1-0.2 nm/s, and the evaporation thickness is 80-100 nm, so as to obtain the complete device.
As can be seen from the above description, in the organic electroluminescent device and the preparation method thereof provided by the embodiments of the present invention, the electron transport layer is prepared by using the high molecular polymer, and the organic electroluminescent device has excellent film forming property, excellent electron transport property, and good energy level matching with the organic material of the light emitting layer, forms a perfect electron transport channel, has good contact with the interface of the light emitting layer and few defects, reduces defect quenching of excitons, is beneficial to dipole radiation luminescence of the light emitting layer, and can also simplify the preparation process of the organic electroluminescent device and save materials; the preparation method has the remarkable characteristics of excellent device performance, good flexibility, large-area preparation and no damage to a film layer.
The embodiment of the invention provides a preparation method of an organic electroluminescent device, which comprises the following processing steps as shown in fig. 3:
step 1: preparing transparent anode ITO on a glass substrate, respectively ultrasonically cleaning the transparent anode ITO for 30 minutes by using a substrate detergent, deionized water and absolute ethyl alcohol, blow-drying the transparent anode ITO by using high-purity gas, and then treating the transparent anode ITO for 3 minutes by using oxygen plasma.
Step 2: and (3) spin-coating PEDOT (PSS) on the ITO-coated glass substrate processed in the step (1), wherein the spin-coating speed is 4000 rpm, the spin-coating time is 40 seconds, and then the substrate is placed on a heating table at the temperature of 120 ℃ for annealing for 20 minutes to remove the moisture in the PEDOT (PSS) film.
Preferably, the hole injection layer 3 is PEDOT: PSS.
And step 3: dissolving the mixture in a volume ratio of 1: 1 of Chloroform (CF) and Chlorobenzene (CB) in a mixed solvent, wherein a solution of a blue light TADF material 10- (4- (4,6-diphenyl-1,3,5-triazin-2-yl) phenyl) -10H-spiro [ acridine-9,9' -fluoro e ] (SpiroAC-TRZ) and a bipolar small molecule host material 3' -bis (9H-carbazol-9-yl) -1,1 ' -biphenyl (mCBP) in a volume ratio of 1: 10, mutually dissolving, heating and stirring for 12 hours to obtain a luminescent layer solution with the mass fraction of 10%. The ITO/PEDOT: PSS substrate was placed, 200. mu.l of organic light emitting solution was dropped, and the spin coating process was 40 seconds spin coating time at 2000 rpm. And after the spin coating is finished, annealing the wet film at 120 ℃ for 20 minutes to obtain a blue light emitting layer.
And 4, step 4: an organic high molecular polymer poly (9, 9-bis (3' - (N, N-dimethylamino) propyl) -2, 7-fluorene) -2,7- (9, 9-dioctylfluorene) (PFN-DOF) was dissolved in chlorobenzene with additive DIO or additive CN in a ratio of 10: 1 for 12 hours at normal temperature, and 30. mu.l of a solution of 8mg/ml was dropped on a petri dish having a diameter of 10cm and a bottom portion filled with water. And when the solvent is evaporated and an electron transport layer film is formed on the water surface, sucking the back surface of the substrate by using a vacuum chuck, and dipping the organic film on the water surface to obtain the electron transport layer.
And 5: evaporating cathode modification layer LiF in vacuum chamber with pressure lower than 1 × 10-4 Pa, evaporation rate of 0.02 nm/s, and evaporation thickness of 1 nm.
Step 6: evaporating silver ingot in vacuum chamber with pressure lower than 1 × 10-4 Pa, evaporation rate of 0.15 nm/s, and evaporation thickness of 100 nm.
The blue light emitting device of the organic electroluminescent device can be prepared by the embodiment, and the luminance-current density graphs under different voltages and the external quantum efficiency graphs under different current densities are respectively shown in fig. 4 and fig. 5.
The blue organic electroluminescent device of the present example prepared by the above method has a peak of 485nm, a maximum luminance of 5000cd/m2 at a voltage of 6.5V, and a maximum External Quantum Efficiency (EQE) of 1.6% at a current density of 0.2mA/mm 2.
Example 4
On the basis of embodiment 3, the luminescent material of the organic luminescent layer 4 is SpiroAC-TRZ, and the specific preparation process is as follows: dissolving a blue TADF material 10- (4- (4,6-diphenyl-1,3,5-triazin-2-yl) phenyl) -10H-spiro [ acridine-9,9' -fluoro ] (SpiroAC-TRZ) in Chloroform (CF) according to a volume ratio of 10mg/ml to Chlorobenzene (CB) according to a volume ratio of 1: 1 for 6 hours, wherein the heating temperature is 60 ℃. Dissolving bipolar small molecule host material 3 '-bis (9H-carbazole-9-yl) -1, 1' -biphenyl (mCBP) according to the volume ratio of 10mg/ml in Chloroform (CF) Chlorobenzene (CB) according to the volume ratio of 1: 1 for 6 hours, wherein the heating temperature is 60 ℃. And mixing the obtained blue light SpiroAC-TRZ solution and the host material CzSi solution according to the volume ratio of 1: 10, and heating and stirring the mixture for 12 hours to obtain 300 microliter of luminescent layer solution with the mass fraction of 10%. Through the steps, a TADF organic electroluminescent device prepared by a solution method can be prepared, and the electroluminescent peak of the luminescent device is shown in figure 3, and the luminescent peak is generated at 485 nm.
The blue light emission is realized by completing the preparation by a full solution method in a film transfer mode. Meanwhile, the product of the invention has the advantages of large-area preparation, low cost, easy processing and the like, and has important application prospect.
In summary, the organic electroluminescent device provided by the embodiment of the present invention has the following advantages:
1. the invention adopts the high molecular polymer to prepare the electron transmission layer, has excellent film forming property and excellent electron transmission performance, has good energy level matching with the organic material of the luminous layer, and forms a perfect electron transmission channel. Good contact with the interface of the luminescent layer and few defects, reduces defect quenching of excitons and is beneficial to dipole radiation luminescence of the luminescent layer.
2. Compared with the traditional solution method of spin coating, ink jet, silk screen printing and the like for preparing the organic electroluminescent device, the method solves the problem of film layer interface generated by mutual solubility of multi-film layer interfaces, and the film transfer can realize the large-area preparation of the organic electroluminescent device. The organic solution is placed in a culture dish which is fully filled with water, after the organic solvent is volatilized, the organic semiconductor material forms a compact film layer on the water surface, the back surface of the substrate is sucked by a vacuum sucker, the organic film layer is dipped by utilizing intermolecular force, the preparation of the electronic transmission layer solution method is realized, the appearance of the luminescent layer film layer cannot be damaged by the organic solvent, and the performance of the device is improved.
3. Compared with an evaporation method for preparing an organic electroluminescent device, the preparation method of the organic electroluminescent device has the advantages of low-temperature preparation, spin coating of solution and the like, and the organic electroluminescent device can utilize the excellent mechanical properties of organic materials and be applied to flexible devices, so that the application field of the organic electroluminescent device is greatly expanded, and particularly foldable equipment is provided.
Generally, the preparation method of the organic electroluminescent device by the solution method provided by the embodiment of the invention has the remarkable characteristics of excellent device performance, good flexibility, large-area preparation, cost reduction and no damage to a film layer, greatly simplifies the preparation process of the organic electroluminescent device, saves materials, widens the application of the organic electroluminescent device in the field of flexible devices, and has important significance for improving the practicability of preparing the organic electroluminescent device by the full-solution method.
The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a necessary general hardware platform, and certainly can also be implemented by hardware. With this understanding in mind, the above-described technical solutions may be embodied in the form of a software product, which can be stored in a computer-readable storage medium such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the methods described in the embodiments or some parts of the embodiments.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. An organic electroluminescent device, comprising: the organic electroluminescent device comprises a transparent substrate (1), an anode (2), a hole injection layer (3), an organic light-emitting layer (4), an electron transport layer (5), a cathode modification layer (6) and a cathode (7);
the organic light emitting diode is characterized in that the anode (2) is arranged on the transparent substrate (1), the hole injection layer (3) is arranged on the anode (2), the organic light emitting layer (4) is arranged on the hole injection layer (3), the electron transport layer (5) is arranged on the organic light emitting layer (4), the cathode modification layer (6) is arranged on the electron transport layer (5), and the cathode (7) is arranged on the cathode modification layer (6).
2. The organic electroluminescent device according to claim 1, characterized in that the transparent substrate (1) is a rigid substrate or a flexible substrate;
the hard substrate is glass, silicon dioxide or quartz; the flexible substrate is polyethylene terephthalate, polyethylene naphthalate or polyimide.
3. The organic electroluminescent device according to claim 1, characterized in that the anode (2) is a transparent anode, which is indium tin oxide; the cathode (7) is aluminum, silver or gold, and the thickness is 80-100 nanometers.
4. The organic electroluminescent device according to claim 1, wherein the organic light-emitting layer (4) is an organic material, and the organic material is a host material A and a guest light-emitting material B and exists in a form of host-guest doping; or the organic material is a luminescent material C and exists in an undoped form;
the main material A: is at least one of bipolar small molecules and bipolar small molecule derivatives;
the luminescent material B and the luminescent material C are respectively as follows: fluorescent material, phosphorescent material, thermal retardation fluorescent material.
5. The organic electroluminescent device according to claim 1, characterized in that the electron transport layer (5) is prepared in undoped form for organic high molecular polymer D; the organic high molecular polymer D is an electron transport material.
6. A method for manufacturing an organic electroluminescent device, comprising:
preparing an anode (2) on a transparent substrate (1);
-preparing a hole injection layer (3) on the anode (2);
preparing an organic light-emitting layer (4) on the hole injection layer (3);
preparing an electron transport layer (5) on the organic light emitting layer (4);
preparing a cathode modification layer (6) on the electron transport layer (5);
and preparing a cathode (7) on the cathode modification layer (6).
7. The method for producing an organic electroluminescent device according to claim 6, wherein the producing of the anode (2) on the transparent substrate (1) comprises:
plating indium tin oxide on the transparent substrate (1); respectively soaking the substrate (1) in a substrate detergent, deionized water and absolute ethyl alcohol, and cleaning the soaked substrate (1) by using an ultrasonic cleaner; blowing the cleaned substrate (1) by using nitrogen, and treating the dried substrate (1) by using oxygen plasma for 3 minutes to obtain an anode (2);
-said preparation of a hole injection layer (3) on said anode (2), comprising:
and (3) spin-coating PEDOT (PSS) on the anode of the substrate (1) subjected to plasma treatment, and annealing the substrate (1) subjected to spin-coating PEDOT (PSS) on a heating table at 120 ℃ for 20 minutes to obtain a hole injection layer (3).
8. The method for producing an organic electroluminescent device according to claim 6, wherein the producing an organic light-emitting layer (4) on the hole injection layer (3) comprises:
after the hole injection layer (3) is coated with the first organic solution in a spin mode, the hole injection layer is placed on a heating table at the temperature of 60 ℃ for annealing for 20 minutes, and an organic light emitting layer (4) is obtained;
wherein the first organic solution is a host material A and a guest luminescent material B which exist in a host-guest doped form,
the host material A is at least one of bipolar small molecules and bipolar small molecule derivatives, and the guest luminescent material B is one of a fluorescent material, a phosphorescent material and a thermal delay fluorescent material.
9. The method for preparing an organic electroluminescent device according to claim 6, wherein the preparing an electron transport layer (5) on the organic light emitting layer (4) comprises:
adding water into a culture dish, dripping a second organic solution on the water surface of the culture dish, after the second organic solution is evaporated, sucking the back surface of a substrate (1) by using a vacuum chuck, dipping an organic film on the front surface, transferring the organic film on the water surface onto an organic light-emitting layer (4) by using intermolecular force, and then putting the organic light-emitting layer on a heating table at 70 ℃ for annealing for 20 minutes to obtain an electron transport layer (5);
wherein the second organic solution is: dissolving the organic high molecular polymer in chlorobenzene and additives according to the concentration of 4-10mg/ml, wherein the weight ratio of 10: 1 in a solvent of 1.
10. The method for preparing an organic electroluminescent device according to claim 6, wherein the preparing the cathode modification layer (6) on the electron transport layer (5) comprises:
evaporating lithium fluoride on the electron transport layer (5), heating and evaporating the lithium fluoride to enable the thickness of the lithium fluoride to be 1 nanometer, and obtaining a cathode modification layer (6);
the preparation of the cathode (7) on the cathode modification layer (6) comprises:
and placing the sample for generating the cathode modification layer (6) into a vacuum cavity of an aluminum ingot, a silver ingot or a gold ingot, and heating and evaporating the aluminum ingot, the silver ingot or the gold ingot to obtain the organic electroluminescent device.
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| CN112531136A (en) * | 2020-12-08 | 2021-03-19 | 北京交通大学 | Preparation method of organic electroluminescent device multilayer film |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102005539A (en) * | 2010-09-27 | 2011-04-06 | 电子科技大学 | White-light organic electroluminescent device and preparation method thereof |
| CN109065729A (en) * | 2018-08-07 | 2018-12-21 | 中国科学院化学研究所 | Bipolarity field effect transistor based on organic and inorganic Van der Waals hetero-junctions |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102005539A (en) * | 2010-09-27 | 2011-04-06 | 电子科技大学 | White-light organic electroluminescent device and preparation method thereof |
| CN109065729A (en) * | 2018-08-07 | 2018-12-21 | 中国科学院化学研究所 | Bipolarity field effect transistor based on organic and inorganic Van der Waals hetero-junctions |
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| CN112531136A (en) * | 2020-12-08 | 2021-03-19 | 北京交通大学 | Preparation method of organic electroluminescent device multilayer film |
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Application publication date: 20200825 |