Ink and preparation method and application, optoelectronic device and manufacturing method, display device

Abstract

The application relates to an ink, comprising a solvent and an organic functional material dispersed in the solvent, the solvent comprising a first solvent and a second solvent, the first solvent being a good solvent for the organic functional material, the solubility parameter of the first solvent being different from that of the second solvent, and the boiling point of the first solvent being lower than that of the second solvent. The ink provided by the application can increase the driving force for the intermolecular aggregation of the organic functional material during the drying and film forming of the functional layer, and the organic functional material molecules are changed from random orientation to horizontal orientation by means of solvent induction, so that the light loss is reduced when light passes through the functional layer.

Description

Technical Field

[0001] This application relates to the field of optoelectronic technology, and in particular to an ink and its preparation method and application, optoelectronic devices and their fabrication methods, and display devices. Background Technology

[0002] Organic light-emitting diodes (OLEDs) have attracted widespread attention due to their broad application prospects in full-color displays, backlighting, and solid-state lighting. Solution-processed OLEDs based on inkjet printing technology are increasingly favored due to their advantages such as simple device structure, low cost, and ease of large-area fabrication; however, their device performance still needs further improvement.

[0003] The main parameters for measuring the light-emitting performance of organic light-emitting diodes (OLEDs) include: external quantum efficiency, current efficiency, driving voltage, device lifetime, and color purity. Among these, current efficiency is directly proportional to external quantum efficiency. Therefore, improving the external quantum efficiency of the device is the key to improving the light-emitting performance of OLEDs.

[0004] External quantum efficiency (EQE) refers to the ratio of the number of photons emitted to the outside of a device to the number of injected electron-hole pairs. In traditional OLEDs, only 20% of the light emitted to the outside of the device, while the remaining 30% is lost in substrate waveguide mode and 50% in ITO / organic layer waveguide mode. Therefore, maximizing light extraction and increasing transmitted light is a key research focus for OLEDs. Currently, the main methods to effectively improve light extraction include microlens technology, shaped substrates, photonic crystals, and microcavity resonance. Among these, microlens technology, shaped substrates, and photonic crystals have not achieved mass production due to high production costs and difficulty in controlling experimental conditions. Microcavity resonance is a relatively mature mass production technology, but it is mostly used in top-emitting devices, where light is emitted from a semi-transparent top electrode, limiting its application scenarios.

[0005] Ink is a common raw material used in the manufacture of optoelectronic devices. It can be used to form various functional layers of optoelectronic devices through printing, coating and other methods. The film-forming effect of ink also has an important impact on the light extraction effect of the device. Therefore, it is essential to strengthen the research on inks used to prepare functional layers of devices. Summary of the Invention

[0006] Therefore, it is necessary to provide an ink, preparation method and application, optoelectronic device and manufacturing method, and display device that can improve light extraction effect and thus promote device efficiency.

[0007] In a first aspect, this application provides an ink comprising a solvent and an organic functional material dispersed in the solvent. The solvent includes a first solvent and a second solvent. The first solvent is a good solvent for the organic functional material. The solubility parameters of the first solvent and the second solvent are different. The boiling point of the first solvent is lower than that of the second solvent.

[0008] In some embodiments, the difference between the solubility parameter of the second solvent and the solubility parameter of the first solvent is 2[(cal / cm³). 3 ) 1 / 2 ]~15[(cal / cm 3 ) 1 / 2 ]; and / or

[0009] The boiling point of the first solvent is 110℃~200℃; and / or

[0010] The boiling point of the second solvent is 160℃~300℃; and / or

[0011] The volume of the second solvent is 1% to 20% of the volume of the first solvent; and / or

[0012] In the ink, the concentration of the organic functional material is 10 mg / mL to 30 mg / mL.

[0013] In some embodiments, the volume of the second solvent is 8% to 10% of the volume of the first solvent; and / or

[0014] The first solvent includes one or more of toluene and xylene; and / or

[0015] The second solvent includes one or more of 1,8-diiodooctane, 1,8-octanedithiol, and 1,6-hexanedithiol; and / or

[0016] The organic functional materials include 4,4'-bis(N-carbazole)-1,1'-biphenyl:tris[2-(p-tolyl)pyridine-C2,N)iridium(III), 4,4',4”-tris(carbazole-9-yl)triphenylamine:tris[2-(p-tolyl)pyridine-C2,N)iridium, diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials, DBP fluorescent materials, polyacetylene and its derivatives, and poly... One or more of benzene and its derivatives, polythiophene and its derivatives, and polyfluorene and its derivatives, or the organic functional material includes one or more of TFB, CuPc, PVK, Poly-TPD, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, and polyaniline.

[0017] Secondly, this application provides a method for preparing ink, comprising the following steps:

[0018] Mixing solvents with organic functional materials;

[0019] The solvent includes a first solvent and a second solvent. The first solvent is a good solvent for the organic functional material. The solubility parameters of the first solvent and the second solvent are different. The boiling point of the first solvent is lower than that of the second solvent.

[0020] In some embodiments, the difference between the solubility parameter of the second solvent and the solubility parameter of the first solvent is 2[(cal / cm³). 3 ) 1 / 2 ]~15[(cal / cm 3 ) 1 / 2 ]; and / or

[0021] The boiling point of the first solvent is 110℃~200℃; and / or

[0022] The boiling point of the second solvent is 160℃~300℃; and / or

[0023] The volume of the second solvent is 1% to 20% of the volume of the first solvent; and / or

[0024] In the ink, the concentration of the organic functional material is 10 mg / mL to 30 mg / mL.

[0025] In some embodiments, the volume of the second solvent is 8% to 10% of the volume of the first solvent; and / or

[0026] The first solvent includes one or more of toluene and xylene; and / or

[0027] The second solvent includes one or more of 1,8-diiodooctane, 1,8-octanedithiol, and 1,6-hexanedithiol; and / or

[0028] The organic functional materials include 4,4'-bis(N-carbazole)-1,1'-biphenyl:tris[2-(p-tolyl)pyridine-C2,N)iridium(III), 4,4',4”-tris(carbazole-9-yl)triphenylamine:tris[2-(p-tolyl)pyridine-C2,N)iridium, diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials, DBP fluorescent materials, polyacetylene and its derivatives, and poly... One or more of benzene and its derivatives, polythiophene and its derivatives, and polyfluorene and its derivatives, or the organic functional material includes one or more of TFB, CuPc, PVK, Poly-TPD, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, and polyaniline.

[0029] Thirdly, this application provides the use of ink prepared using the ink described in the first aspect of this application or ink prepared using the method described in the second aspect of this application in the fabrication of optoelectronic devices.

[0030] Fourthly, this application provides an optoelectronic device, including a cathode, an anode, and a functional layer disposed between the cathode and the anode;

[0031] At least one of the functional layers is made using ink as described in the first aspect of this application or ink prepared using the method described in the second aspect of this application.

[0032] In some embodiments, the functional layer fabricated using the ink includes at least one of a light-emitting layer, a hole transport layer, a hole injection layer, and an electron transport layer.

[0033] In some embodiments, the functional layer made using the ink includes at least one of a light-emitting layer and a hole injection layer.

[0034] In some embodiments, the optoelectronic device further includes a light extraction layer located on the light-emitting side of the optoelectronic device.

[0035] In some embodiments, the optoelectronic device further includes an encapsulation layer located on the side of the light extraction layer opposite to the cathode and the anode.

[0036] In some embodiments, the material of the light extraction layer includes IZO; and / or

[0037] The encapsulation layer is a TFE encapsulation layer, which comprises alternating layers of inorganic and organic thin films; wherein the inorganic thin film is made of SiNx, and the organic thin film is made of epoxy resin; and / or

[0038] The materials of the anode and the cathode are independently selected from one or more of metals, carbon materials, and metal oxides. The metals include one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg. The carbon materials include one or more of graphite, carbon nanotubes, graphene, and carbon fibers. The metal oxides include doped or undoped metal oxides, including one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, and AMO, or composite electrodes consisting of metal sandwiched between doped or undoped transparent metal oxides. The composite electrodes include one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, IZO / Ag / IZO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2.

[0039] Fifthly, this application provides a method for fabricating an optoelectronic device, comprising the following steps:

[0040] A cathode, an anode, and a functional layer are formed on a substrate, wherein the functional layer is disposed between the cathode and the anode;

[0041] The steps for forming the functional layer include:

[0042] At least one of the functional layers is formed using the ink described in the first aspect of this application or the ink prepared using the method described in the second aspect of this application.

[0043] In a sixth aspect, this application provides a display device, including an optoelectronic device as described in the fourth aspect of this application or an optoelectronic device manufactured by the method described in the fifth aspect of this application.

[0044] In addition to the first solvent, which serves as a good solvent for organic functional materials, the ink provided in this application also contains a second solvent with a certain difference in solubility parameters from the first solvent. The organic functional materials have poor solubility in the second solvent. Due to the low boiling point of the first solvent, it will evaporate first during the drying process of the functional layer. As the amount of the first solvent decreases, the proportion of the second solvent in the ink gradually increases. However, the solubility of the functional materials in the second solvent is weak, thereby increasing the driving force for the aggregation of organic functional material molecules. The organic functional material molecules achieve a change from random orientation to horizontal orientation through solvent induction, and the light loss is reduced when light passes through the functional layer.

[0045] Furthermore, using the aforementioned ink to fabricate optoelectronic devices can greatly improve the light extraction effect of the devices, thereby improving device efficiency. Attached Figure Description

[0046] Figure 1 This is a comparison graph of the external quantum efficiency of the display panels of Example 1 and Comparative Example 1. Detailed Implementation

[0047] To facilitate understanding of the present invention, a more complete description of this application is provided below with reference to embodiments and accompanying drawings. This application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0049] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0050] In a first aspect, this application provides an ink comprising a solvent and an organic functional material dispersed in the solvent. The solvent includes a first solvent and a second solvent. The first solvent is a good solvent for the organic functional material. The solubility parameters of the first solvent and the second solvent are different. The boiling point of the first solvent is lower than that of the second solvent.

[0051] In addition to the first solvent, which serves as a good solvent for organic functional materials, the ink provided in this application also contains a second solvent with a certain difference in solubility parameters from the first solvent. The organic functional materials have poor solubility in the second solvent. Due to the low boiling point of the first solvent, it will evaporate first during the drying process of the functional layer. As the amount of the first solvent decreases, the proportion of the second solvent in the ink gradually increases. However, the solubility of the functional materials in the second solvent is weak, thereby increasing the driving force for the aggregation of organic functional material molecules. The organic functional material molecules achieve a change from random orientation to horizontal orientation through solvent induction, and the light loss is reduced when light passes through the functional layer.

[0052] In some embodiments, the difference between the solubility parameter of the second solvent and the solubility parameter of the first solvent is 2[(cal / cm³). 3 ) 1 / 2 ]~15[(cal / cm 3 ) 1 / 2 ].

[0053] Solubility parameter is a physical constant that measures the compatibility of liquid materials. Its physical meaning is the square root of the material's cohesive energy density.

[0054] In some embodiments, the boiling point of the first solvent is 110°C to 200°C.

[0055] In some embodiments, the boiling point of the second solvent is 160°C to 300°C.

[0056] In some embodiments, the volume of the second solvent is 1% to 20% of the volume of the first solvent. It is understood that the volume of the second solvent may, for example, be, but not limited to, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20% of the volume of the first solvent. Preferably, the volume of the second solvent is 8% to 10% of the volume of the first solvent.

[0057] In some embodiments, the concentration of the organic functional material in the ink is 10 mg / mL to 30 mg / mL. It is understood that the concentration of the functional material in the ink may, for example, be, but not limited to, 10 mg / mL, 15 mg / mL, 20 mg / mL, 25 mg / mL, 30 mg / mL, etc.

[0058] In some embodiments, the first solvent includes one or more of toluene and xylene. The solubility parameter of toluene is 8.9 [(cal / cm³)]. 3 ) 1 / 2 The solubility parameter of xylene is 8.8 [(cal / cm³)]. 3 )1 / 2 ].

[0059] In some embodiments, the second solvent includes one or more of 1,8-diiodooctane, 1,8-octanedithiol, and 1,6-hexanedithiol. The solubility parameter of 1,8-octanedithiol is 18.6 [(cal / cm³)]. 3 ) 1 / 2 The solubility parameter of 1,6-hexanedithiol is 19.2 [(cal / cm³]]. 3 ) 1 / 2 ].

[0060] Organic functional materials include one or more of the following: 4,4'-bis(N-carbazole)-1,1'-biphenyl:tris[2-(p-tolyl)pyridine-C2,N)iridium(III), 4,4',4”-tris(carbazole-9-yl)triphenylamine:tris[2-(p-tolyl)pyridine-C2,N)iridium, diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials, DBP fluorescent materials, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, and polyfluorene and its derivatives. Further, the organic functional material is preferably poly(p-phenylene) and its derivatives, such as MEH-PPV, P-PPV, etc. Further, the organic functional material is preferably polyfluorene and its derivatives, such as PFO, etc.

[0061] In some embodiments, the organic functional material includes one or more of TFB, CuPc, PVK, Poly-TPD, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, and polyaniline.

[0062] Secondly, this application provides a method for preparing ink, comprising the following steps:

[0063] Mixing solvents with organic functional materials;

[0064] The solvent includes a first solvent and a second solvent. The first solvent is a good solvent for organic functional materials. The solubility parameters of the first solvent and the second solvent are different. The boiling point of the first solvent is lower than that of the second solvent.

[0065] Understandably, the mixing process may also include a stirring step to promote uniform dispersion of the functional materials in the solvent.

[0066] The preparation method described in the second aspect of this application can be used to prepare the ink described in the first aspect of this application. Unless otherwise stated, the description of the solvent and functional materials in the ink is as described in the first aspect above.

[0067] Thirdly, this application provides the application of ink prepared using the ink of the first aspect of this application or ink prepared using the method of the second aspect of this application in the fabrication of optoelectronic devices.

[0068] Fourthly, this application provides an optoelectronic device, including a cathode, an anode, and a functional layer disposed between the cathode and the anode;

[0069] At least one of the functional layers is made using ink as described in the first aspect of this application or ink prepared using the method described in the second aspect of this application.

[0070] The light-emitting device provided in the fourth aspect of this application is further fabricated using the ink provided in the first aspect of this application or the ink prepared by the method of the second aspect. Since the organic functional materials in the ink have weak solubility in the second solvent, and the second solvent is a high-boiling-point solvent, when fabricating the functional layer of the light-emitting device, the first solvent, which is the good solvent in the ink, preferentially evaporates, and the proportion of the second solvent gradually increases. This leads to a decrease in the solubility of the organic functional materials in the ink, forming a solvent-induced effect. This promotes the aggregation between the molecules of the organic functional materials in the ink, and promotes the arrangement of the organic functional material molecules from random orientation to horizontal orientation. This helps to reduce the light loss of the device in the SPP mode and improve the light extraction efficiency. Moreover, after the organic functional material molecules become ordered, the electrical balance of the device can be better achieved, which is conducive to improving the efficiency of the device.

[0071] In some embodiments, the functional layer made using ink includes at least one of a light-emitting layer, a hole transport layer, a hole injection layer, and an electron transport layer.

[0072] In some embodiments, the functional layer made using ink includes at least one of a light-emitting layer and a hole injection layer.

[0073] Furthermore, the functional layer fabricated using the ink includes a light-emitting layer. The organic functional materials in the ink include one or more of the following: 4,4'-bis(N-carbazole)-1,1'-biphenyl:tris[2-(p-tolyl)pyridine-C2,N)iridium(III), 4,4',4”-tris(carbazole-9-yl)triphenylamine:tris[2-(p-tolyl)pyridine-C2,N)iridium, diaromatic anthracene derivatives, stilbene aromatic derivatives, pyrene derivatives, fluorene derivatives, TBPe fluorescent materials, TTPX fluorescent materials, TBRb fluorescent materials, DBP fluorescent materials, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, and polyfluorene and its derivatives. Further, the organic functional material is preferably poly(p-phenylene) and its derivatives, such as MEH-PPV, P-PPV, etc. Further, the organic functional material is preferably polyfluorene and its derivatives, such as PFO, etc.

[0074] Furthermore, the functional layer made using ink includes a hole injection layer, and the organic functional materials in the ink include one or more of TFB, CuPc, PVK, Poly-TPD, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine and polyaniline.

[0075] In some embodiments, the optoelectronic device may further include a hole transport layer formed by conventional methods in the art, the material of which includes one or more of TFB, CuPc, PVK, Poly-TPD, DNTPD, TCATA, TCCA, CBP, TPD, NPB, NPD, PEDOT:PSS, TAPC, MCC, F4-TCNQ, HATCN, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, polyaniline, transition metal oxides, transition metal sulfides, transition metal tin compounds, doped graphene, undoped graphene, and C60.

[0076] In some embodiments, the optoelectronic device may also include an electron transport layer formed by conventional methods in the art, the material of which includes one or more of TSPO1 and Liq.

[0077] In some embodiments, the optoelectronic device further includes a light extraction layer located on the light-emitting side of the optoelectronic device.

[0078] In some implementations, the material of the light extraction layer includes IZO.

[0079] In some embodiments, the optoelectronic device further includes an encapsulation layer located on the side of the light extraction layer away from the cathode and anode.

[0080] The encapsulation layer is a TFE encapsulation layer, which includes alternating layers of inorganic and organic thin films; wherein, the inorganic thin film is made of SiNx and the organic thin film is made of epoxy resin.

[0081] Understandably, the materials for the cathode and anode are conventional materials in the art. In some embodiments, the materials of the anode and cathode are independently selected from one or more of metals, carbon materials, and metal oxides. The metals include one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg; the carbon materials include one or more of graphite, carbon nanotubes, graphene, and carbon fibers; the metal oxides include doped or undoped metal oxides, including one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, and AMO, or composite electrodes consisting of metal sandwiched between doped or undoped transparent metal oxides. The composite electrodes include one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, IZO / Ag / IZO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2.

[0082] Preferably, the cathode material includes one or more of Yb, Mg, and Ag.

[0083] Preferably, the anode material includes one or more of ITO, IZO, ITO / Ag / ITO, and IZO / Ag / IZO. Further, the optoelectronic device is a bottom-emitting device, and the anode material is preferably one or more of ITO and IZO. Further, the optoelectronic device is a top-emitting device, and the anode material is preferably one or more of ITO / Ag / ITO and IZO / Ag / IZO.

[0084] Understandably, the optoelectronic device provided in this application can be an upright device or an inverted device. Correspondingly, the anode can be disposed close to the substrate, or the cathode can be disposed close to the substrate.

[0085] In some embodiments, the optoelectronic device includes an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode, a light extraction layer, and an encapsulation layer disposed sequentially on a substrate.

[0086] Understandably, the thickness of each functional layer in an optoelectronic device can be set according to the specific product.

[0087] In some embodiments, the thickness of the anode is 100 nm to 160 nm. Further, the anode is, for example, ITO or IZO with a thickness of 100 nm to 140 nm. Further still, the anode is, for example, a composite electrode composed of ITO / Ag / ITO or IZO / Ag / IZO with thicknesses of 10 nm / 140 nm / 10 nm in sequence.

[0088] In some embodiments, the cathode thickness is 10 nm to 100 nm. Further, the cathode is, for example, Yb and Ag with thicknesses of 1 nm and 100 nm respectively. Further, the cathode is, for example, Yb and Ag with thicknesses of 1 nm and 18 nm respectively. Further, the cathode is, for example, Mg and Ag with thicknesses of 1 nm and 18 nm respectively.

[0089] In some implementations, the thickness of the hole injection layer is 40nm to 100nm. Further, the thicknesses of the hole injection layers for the three sub-pixels R / G / B are, for example, 100nm / 70nm / 40nm respectively.

[0090] In some implementations, the hole transport layer has a thickness of 90 nm to 110 nm. Further, the thicknesses of the hole transport layers for the three sub-pixels R / G / B are, for example, 110 nm / 100 nm / 90 nm, respectively.

[0091] In some embodiments, the thickness of the light-emitting layer is 40nm to 80nm. Further, the thicknesses of the light-emitting layers for the three sub-pixels R / G / B are, for example, 70nm / 60nm / 40nm respectively.

[0092] In some implementations, the thickness of the electron transport layer is 20 nm to 30 nm.

[0093] In some implementations, the thickness of the light extraction layer is 60 nm to 80 nm.

[0094] In some embodiments, the thickness of the encapsulation layer is 10 μm to 20 μm. Further, the thicknesses of the inorganic film / organic film / inorganic film in the encapsulation layer are, for example, 1 μm / 10 μm / 1 μm respectively.

[0095] Fifthly, this application provides a method for fabricating an optoelectronic device, comprising the following steps:

[0096] A cathode, an anode, and a functional layer are formed on a substrate, with the functional layer disposed between the cathode and the anode;

[0097] The steps to form a functional layer include:

[0098] At least one of the functional layers is formed using the ink prepared by the method of the first aspect of this application or the ink prepared by the method of the second aspect of this application.

[0099] In some embodiments, the method for fabricating an optoelectronic device includes the following steps:

[0100] An anode is formed on a substrate; a hole injection layer is formed on the anode; a hole transport layer is formed on the hole injection layer; a light-emitting layer is formed on the hole transport layer; an electron transport layer is formed on the light-emitting layer; a cathode is formed on the electron transport layer; a light extraction layer is formed on the cathode; and an encapsulation layer is formed on the light extraction layer. The light-emitting layer and / or the hole injection layer are fabricated using the aforementioned ink.

[0101] Furthermore, the substrate may have its own anode.

[0102] Furthermore, before the step of forming the functional layer, the step of cleaning and drying the substrate may be included.

[0103] Furthermore, the steps for forming the functional layer include: printing or coating with ink, drying to form a film, and heat treatment.

[0104] Furthermore, the formed functional layer is a hole injection layer, and the heat treatment conditions are heating at 150℃~250℃ for 20min~40min.

[0105] Furthermore, the formed functional layer is a hole transport layer, and the heat treatment conditions are heating at 150℃~250℃ for 20min~40min.

[0106] Furthermore, the formed functional layer is a light-emitting layer, and the heat treatment conditions are heating at 100℃~200℃ for 10min~20min.

[0107] Furthermore, if the electron transport layer is improved, it can be formed using solution methods such as printing or coating with the ink provided in the first aspect of this application; if the electron transport layer is a conventional functional layer structure, it can also be formed using vacuum evaporation, and further, the evaporation rate is... Vacuum degree is (1~3)×10 -4 Pa.

[0108] Furthermore, the cathode can be formed, for example, but not limited to, by vacuum evaporation, and the evaporation rate is... Vacuum degree is (1~3)×10 -4 Pa.

[0109] Furthermore, the optical extraction layer can be formed by, but is not limited to, sputtering, with a sputtering power of 3 kW to 10 kW and a pressure of 0.1 Pa to 10 Pa.

[0110] Furthermore, the encapsulation layer can be formed by, but is not limited to, CVD or IJP processes.

[0111] The fabrication method described in the fifth aspect of this application can produce the optoelectronic device described in the fourth aspect of this application. Unless otherwise stated, the descriptions of the cathode, anode, and functional layers of the optoelectronic device are as described in the fourth aspect above.

[0112] In a sixth aspect, this application provides a display device, characterized in that it includes an optoelectronic device as described in the fourth aspect of this application or an optoelectronic device manufactured by the method described in the fifth aspect of this application.

[0113] Furthermore, the display device may include, but is not limited to, any display screen or display panel with a device, such as a mobile phone, tablet, computer, or television.

[0114] The following are specific examples.

[0115] Example 1

[0116] Step 1: Preparing the Ink

[0117] This ink is used to create the light-emitting layer, and the organic functional material is an organic light-emitting material.

[0118] (1) Red organic luminescent layer ink formulation:

[0119] Solvents: The first solvent is xylene, and the second solvent is 1,8-octanedithiol, with the volume of the second solvent being 8% of the volume of the first solvent;

[0120] The organic light-emitting material is the red fluorescent polymer MEH-PPV, and the total concentration of the organic light-emitting material in the ink is 18 mg / mL.

[0121] The solvent is mixed evenly with the organic light-emitting material to obtain the ink.

[0122] (2) Green organic light-emitting layer ink formulation:

[0123] Solvents: The first solvent is xylene, and the second solvent is 1,8-octanedithiol, with the volume of the second solvent being 8% of the volume of the first solvent;

[0124] The organic light-emitting material is a green fluorescent polymer P-PPV, and the concentration of the organic light-emitting material in the ink is 15 mg / mL.

[0125] The solvent is mixed evenly with the organic light-emitting material to obtain the ink.

[0126] (3) Blue organic light-emitting layer ink formulation:

[0127] Solvents: The first solvent is xylene, and the second solvent is 1,8-octanedithiol, with the volume of the second solvent being 8% of the volume of the first solvent;

[0128] The organic light-emitting material is the blue light-emitting polymer PFO, and the concentration of the organic light-emitting material in the ink is 10 mg / mL.

[0129] The solvent is mixed evenly with the organic light-emitting material to obtain the ink.

[0130] Step 2: Create the display panel

[0131] (1) Cleaning the substrate: The OLED substrate is cleaned and dried for later use. The substrate contains an anode made of ITO / Ag / ITO, and the thicknesses of the ITO / Ag / ITO anodes are 10nm / 140nm / 10nm respectively.

[0132] (2) Fabrication of hole injection layer: Hole injection layer materials of different thicknesses are printed in the R / G / B sub-pixels on the substrate, and after vacuum drying, they are heated at 200℃ for 30 min. The hole injection layer material is PEDOT:PSS, and the hole injection layer thicknesses corresponding to the R / G / B sub-pixels are 100nm, 70nm, and 40nm, respectively.

[0133] (3) Fabrication of hole transport layer: Hole transport layer materials of different thicknesses are printed in the R / G / B sub-pixels above the hole injection layer. After vacuum drying, the film is heated at 200℃ for 30 min. The hole transport layer material is TFB, and the hole transport layer thicknesses corresponding to the R / G / B sub-pixels are 110nm, 100nm, and 90nm, respectively.

[0134] (4) Fabrication of light-emitting layers: In the R / G / B sub-pixels above the hole transport layer, light-emitting layers of corresponding thicknesses are printed using the red organic light-emitting layer ink, green organic light-emitting layer ink, and blue organic light-emitting layer ink from step 1, respectively. After vacuum drying to form a film, the layers are heated at 140°C for 15 minutes. The thicknesses of the light-emitting layers corresponding to the R / G / B sub-pixels are 70nm, 60nm, and 40nm, respectively.

[0135] (5) Fabrication of the electron transport layer: An electron transport layer material is co-deposited on each light-emitting layer. The electron transport layer material is TSPO1 and Liq in a weight ratio of 5:5. The deposition rates of TSPO1 and Liq are controlled at [value missing]. Vacuum degree is 2×10 - 4 The electron transport layer within the Pa;R / G / B sub-pixels is 30nm;

[0136] (6) Fabrication of the metal cathode: A semi-transparent cathode material is deposited on the electron transport layer by vapor deposition. The cathode material is an alloy of Mg and Al with a weight ratio of 1:9. The vapor deposition rates of Mg and Al are controlled as follows: and Vacuum degree is 2×10 -4 The thickness of the cathode within each Pa;R / G / B sub-pixel is 15nm;

[0137] (7) Fabrication of light extraction layer: A thin film of IZO was deposited on the cathode by low temperature sputtering with a sputtering power of 5 kW and a pressure of 1 Pa. The thickness of the IZO film was 70 nm.

[0138] (8) TFE encapsulation: Three overlapping encapsulation film layers are formed on the light extraction layer by CVD and IJP processes. The encapsulation film layers are, in sequence, an inorganic thin film layer, an organic thin film layer, and an inorganic thin film layer. The material of the inorganic thin film layer is SiNx, and the material of the organic thin film layer is epoxy resin. The thicknesses are 1μm, 10μm, and 1μm, respectively.

[0139] Comparative Example 1

[0140] This ink is used to create the light-emitting layer, and the organic functional material is an organic light-emitting material.

[0141] (1) Red organic luminescent layer ink formulation:

[0142] Solvent: The first solvent is xylene;

[0143] The organic light-emitting material is the red fluorescent polymer MEH-PPV, and the total concentration of the organic light-emitting material in the ink is 18 mg / mL.

[0144] The solvent is mixed evenly with the organic light-emitting material to obtain the ink.

[0145] (2) Green organic light-emitting layer ink formulation:

[0146] Solvent: The first solvent is xylene;

[0147] The organic light-emitting material is a green fluorescent polymer P-PPV, and the concentration of the organic light-emitting material in the ink is 15 mg / mL.

[0148] The solvent is mixed evenly with the organic light-emitting material to obtain the ink.

[0149] (3) Blue organic light-emitting layer ink formulation:

[0150] Solvent: The first solvent is xylene;

[0151] The organic light-emitting material is the blue light-emitting polymer PFO, and the concentration of the organic light-emitting material in the ink is 10 mg / mL.

[0152] The solvent is mixed evenly with the organic light-emitting material to obtain the ink.

[0153] Step 2: Fabricating the light-emitting device

[0154] Same as step two in Example 1.

[0155] Example 2

[0156] Step 1: Preparing the Ink

[0157] This ink is used to create the hole injection layer, and the organic functional material is the material used in the hole injection layer.

[0158] Hole injection layer ink formulation:

[0159] Solvents: The first solvent is xylene, and the second solvent is 1,6-hexanedithiol. The volume of the second solvent is 10% of the volume of the first solvent.

[0160] The hole injection layer is made of PEDOT:PSS, and the concentration of the hole injection layer material in the ink is 30 mg / mL.

[0161] The solvent is mixed evenly with the material of the hole injection layer to obtain ink.

[0162] Step 2: Create the display panel

[0163] (1) Cleaning the substrate: The OLED substrate is cleaned and dried for later use. The substrate contains an anode made of ITO / Ag / ITO, and the thicknesses of the ITO / Ag / ITO anodes are 10nm / 140nm / 10nm respectively.

[0164] (2) Fabrication of hole injection layer: Hole injection layer materials of different thicknesses are printed in the R / G / B sub-pixels on the substrate using the hole injection layer ink from step 1. After vacuum drying, the materials are heated at 200°C for 30 minutes. The hole injection layer thicknesses corresponding to the R / G / B sub-pixels are 100nm, 70nm, and 40nm, respectively.

[0165] (3) Fabrication of hole transport layer: Hole transport layer materials of different thicknesses are printed in the R / G / B sub-pixels above the hole injection layer. After vacuum drying, the film is heated at 200℃ for 30 min. The hole transport layer material is TFB, and the hole transport layer thicknesses corresponding to the R / G / B sub-pixels are 110nm, 100nm, and 90nm, respectively.

[0166] (4) Fabrication of the light-emitting layer: The corresponding red organic light-emitting layer, green organic light-emitting layer and blue organic light-emitting layer are printed in the R / G / B sub-pixels above the hole transport layer, respectively. After vacuum drying, the film is heated at 140°C for 15 min. The material of the red organic light-emitting layer is the red fluorescent light-emitting polymer MEH-PPV, the green organic light-emitting layer is the green fluorescent light-emitting polymer P-PPV, and the blue organic light-emitting layer is the blue polymer PFO. The thickness of the light-emitting layer corresponding to the R / G / B sub-pixels is 70nm, 60nm and 40nm respectively.

[0167] (5) Fabrication of the electron transport layer: An electron transport layer material is co-deposited on the light-emitting layer. The electron transport layer material is TSPO1 and Liq in a weight ratio of 5:5. The deposition rates of TSPO1 and Liq are both controlled at [value missing]. Vacuum degree is 2×10 -4 The electron transport layer within the Pa;R / G / B sub-pixels is 30nm;

[0168] (6) Fabrication of the metal cathode: A semi-transparent cathode material is deposited on the electron transport layer by vapor deposition. The cathode material is an alloy of Mg and Al with a weight ratio of 1:9. The vapor deposition rates of Mg and Al are controlled as follows: and Vacuum degree is 2×10 -4 The thickness of the cathode within each Pa;R / G / B sub-pixel is 15nm;

[0169] (7) Fabrication of light extraction layer: A thin film of IZO was deposited on the cathode by low temperature sputtering with a sputtering power of 5 kW and a pressure of 1 Pa. The thickness of the IZO film was 70 nm.

[0170] (8) TFE encapsulation: Three overlapping encapsulation film layers are formed on the light extraction layer by CVD and IJP processes. The encapsulation film layers are, in sequence, an inorganic thin film layer, an organic thin film layer, and an inorganic thin film layer. The material of the inorganic thin film layer is SiNx, and the material of the organic thin film layer is epoxy resin. The thicknesses are 1μm, 10μm, and 1μm, respectively.

[0171] Comparative Example 2

[0172] Step 1: Preparing the Ink

[0173] This ink is used to create the hole injection layer, and the organic functional material is the material used in the hole injection layer.

[0174] Hole injection layer ink formulation:

[0175] Solvent: The first solvent is xylene;

[0176] The hole injection layer is made of PEDOT:PSS, and its concentration in the ink is 30 mg / mL.

[0177] The solvent is mixed evenly with the material of the hole injection layer to obtain ink.

[0178] Step 2: Fabricating the light-emitting device

[0179] Same as step two in Example 2.

[0180] The external quantum efficiency performance of the display panels prepared in Example 1 and Comparative Example 1 was tested, and the test results are as follows: Figure 1 .

[0181] Depend on Figure 1 As can be seen, based on the external quantum efficiency of the display panel prepared in Comparative Example 1, the external quantum efficiency of the display panel prepared in Example 1 is twice that of Comparative Example 1. This indicates that the second solvent xylene added to the ink helps to promote the formation of a solvent-induced effect during the drying and film-forming process. This promotes the aggregation of organic light-emitting material molecules in the ink and changes the arrangement of organic light-emitting material molecules from random orientation to horizontal orientation. This helps to reduce the light loss in the SPP mode of the device and improve the light extraction efficiency. Moreover, after the organic light-emitting material molecules become ordered, the electrical balance of the device can be better achieved, which is conducive to improving the efficiency of the device.

[0182] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0183] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An ink, characterized in that, The invention comprises a solvent and an organic functional material dispersed in the solvent, wherein the solvent includes a first solvent and a second solvent, the first solvent being a good solvent for the organic functional material, the solubility parameters of the first solvent being different from those of the second solvent, and the boiling point of the first solvent being lower than that of the second solvent. The volume of the second solvent is 1% to 20% of the volume of the first solvent; The first solvent is xylene; the second solvent is 1,8-octanedithiol or 1,6-hexanedithiol; The organic functional material is one or more of poly(p-phenylene) and its derivatives and polyfluorene and its derivatives; The concentration of the organic functional material is 10 mg / mL to 30 mg / mL.

2. The ink according to claim 1, characterized in that, The volume of the second solvent is 8% to 10% of the volume of the first solvent; and / or The organic functional materials include one or more of MEH-PPV, P-PPV, and PFO.

3. A method for preparing ink, characterized in that, Includes the following steps: Mixing solvents with organic functional materials; The solvent includes a first solvent and a second solvent. The first solvent is a good solvent for the organic functional material. The solubility parameters of the first solvent and the second solvent are different. The boiling point of the first solvent is lower than that of the second solvent. The volume of the second solvent is 1% to 20% of the volume of the first solvent; The first solvent is xylene; the second solvent is 1,8-octanedithiol or 1,6-hexanedithiol; The organic functional material is one or more of poly(p-phenylene) and its derivatives and polyfluorene and its derivatives; The concentration of the organic functional material is 10 mg / mL to 30 mg / mL.

4. The method for preparing ink according to claim 3, characterized in that, The volume of the second solvent is 8% to 10% of the volume of the first solvent; and / or The organic functional materials include one or more of MEH-PPV, P-PPV, and PFO.

5. The use of the ink according to any one of claims 1 to 2, or the ink prepared by the method according to any one of claims 3 to 4, in the fabrication of optoelectronic devices.

6. An optoelectronic device, characterized in that, It includes a cathode, an anode, and a functional layer disposed between the cathode and the anode; At least one of the functional layers is made using the ink as described in any one of claims 1 to 2 or using the ink prepared by the method as described in any one of claims 3 to 4.

7. The optoelectronic device according to claim 6, characterized in that, The functional layer fabricated using the ink includes at least one of a light-emitting layer, a hole transport layer, a hole injection layer, and an electron transport layer.

8. The optoelectronic device according to claim 7, characterized in that, The functional layer made using the ink includes at least one of a light-emitting layer and a hole injection layer.

9. The optoelectronic device according to any one of claims 6 to 8, characterized in that, The optoelectronic device further includes a light extraction layer, which is located on the light-emitting side of the optoelectronic device.

10. The optoelectronic device according to claim 9, characterized in that, The optoelectronic device further includes an encapsulation layer located on the side of the light extraction layer opposite to the cathode and the anode.

11. The optoelectronic device according to claim 10, characterized in that, The material of the light extraction layer includes IZO; and / or The encapsulation layer is a TFE encapsulation layer, which comprises alternating layers of inorganic and organic thin films; wherein the inorganic thin film is made of SiNx, and the organic thin film is made of epoxy resin; and / or The materials of the anode and the cathode are independently selected from one or more of metals, carbon materials, and metal oxides. The metals include one or more of Al, Ag, Cu, Mo, Au, Ba, Ca, Yb, and Mg. The carbon materials include one or more of graphite, carbon nanotubes, graphene, and carbon fibers. The metal oxides include doped or undoped metal oxides, including one or more of ITO, FTO, ATO, AZO, GZO, IZO, MZO, and AMO, or composite electrodes consisting of metal sandwiched between doped or undoped transparent metal oxides. The composite electrodes include one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, IZO / Ag / IZO, ZnO / Ag / ZnO, ZnO / Al / ZnO, ZnS / Ag / ZnS, ZnS / Al / ZnS, TiO2 / Ag / TiO2, and TiO2 / Al / TiO2.

12. A method for fabricating an optoelectronic device, characterized in that, Includes the following steps: A cathode, an anode, and a functional layer are formed on a substrate, wherein the functional layer is disposed between the cathode and the anode; The steps for forming the functional layer include: At least one of the functional layers is formed using the ink as described in any one of claims 1 to 2 or the ink prepared using the method as described in any one of claims 3 to 4.

13. A display device, characterized in that, This includes the optoelectronic device as described in any one of claims 6 to 11 or the optoelectronic device fabricated by the method described in claim 12.

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