WO2019120085A1 - Printing ink comprising thermally activated delayed fluorescent material and application thereof - Google Patents

Abstract

Printing ink comprising a thermally activated delayed fluorescent material, comprising at least two organic functional materials, H1 and H2, and at least one organic solvent. H1 and H2 form a type II semiconductor heterojunction structure, and H2 has properties of a thermally activated delayed fluorescent material. An organic electronic device can be obtained by the printing ink through printing technology, especially an organic electroluminescent device.

Description

Printing ink containing thermally excited delayed fluorescent material and application thereof

This application claims priority to Chinese Patent Application No. 200911394526.2, entitled "Printing Ink Containing Thermally Excited Delayed Fluorescent Material and Its Application", filed on December 21, 2017, all of which is incorporated herein by reference. The content is incorporated herein by reference.

Technical field

The present invention relates to the field of organic electronic devices, and more particularly to a printing ink comprising a thermally excited delayed fluorescent material. The invention further relates to the use of a printing ink according to the invention in an organic electronic device.

Background technique

Organic light-emitting diodes (OLEDs) are regarded as the most promising next-generation display technology by the industry because of their light weight, active illumination, wide viewing angle, high contrast ratio, high luminous efficiency, low energy consumption, easy preparation of flexible and large-sized panels. . In order to improve the luminous efficiency of organic light-emitting diodes and promote the industrialization process of organic light-emitting diodes, it is urgent to solve the key problems of organic light-emitting diodes for light-emitting performance and lifetime.

In order to obtain high performance organic light emitting diodes, the host material is the key. At present, OLED light-emitting devices are generally prepared by using a single-host material in combination with an illuminant, but a single-host material causes a different carrier transport rate, causing device efficiency to be rolled off at high brightness, resulting in shortened device life. . The use of a double-body material can alleviate some of the problems caused by a single body, especially through a suitable material combination, the selected dual-body material can effectively form a composite exciplex, greatly improving the luminous efficiency and lifetime of the device. Kim et al. (see Kim et al. Adv. Func. Mater. 2013 DOI: 10.1002/adfm. 201300547, and Kim et al. Adv. Func. Mater. 2013, DOI: 10.1002/adfm. 201300187) can be used to form a composite excited state (exciplex). Co-host, plus a metal complex as a phosphorescent emitter, achieves low-roll-off, high-efficiency OLEDs.

Further, in the vapor deposition device, the vapor deposition process can be greatly simplified by preliminarily forming a blend or an organic alloy, and the device life is remarkably improved (Patents US2016141505A1, WO2016060332A1, WO2016068450A1, WO2016068460A1, etc.). However, the vacuum evaporation process is expensive and requires a high degree of processing, such as a shadow mask that is generally required to be extremely limited, thereby limiting the application of the organic light emitting diode as a large-area, low-cost display device and a lighting device. In contrast, solution processing processes such as inkjet printing and roll-to-roll have advantages such as precision shadow masks, greenhouse processes, high material utilization, and good scalability. It has become a very promising technology for the preparation of organic optoelectronic devices, particularly organic light emitting diode displays. In order to achieve the process, suitable printing inks and materials are the key. Patent CN102498120A provides an efficient method of preparing organic small molecule functional materials suitable for solution processing. However, for the inkjet printing process, efficient co-host material systems, film drying processes, ink printability and the like still fail to provide an effective solution.

Therefore, new new materials suitable for the printing process, especially the host material system, and related printing inks are yet to be developed.

Summary of the invention

Based on this, it is an object of the present application to provide a printing ink comprising a thermally excited delayed fluorescent material. Another object of the present application is to provide an application of a printing ink according to the present invention in the preparation of an organic electronic device.

A printing ink comprising at least two organic functional materials H1 and H2, and at least one organic solvent: 1) the printing ink having a viscosity at 25 ° C, in the range of 1 cPs to 100 cPs, and / or its surface The tension is in the range of 19dyne/cm to 50dyne/cm at 25 °C; 2) H1 and H2 form a type II semiconductor heterojunction structure, and min((LUMO(H1)-HOMO(H2), LUMO(H2)) -HOMO(H1)) ≤ min(T1(H1), T1(H2))+0.1eV, where LUMO(H1), HOMO(H1) and T1(H1) are the lowest unoccupied orbits of H1, and the highest occupied orbit , triplet energy level, LUMO (H2), HOMO (H2) and T1 (H2) are the lowest unoccupied orbit of H2, the highest occupied orbit, the triplet level; 3) at least one of H1 and H2 (S1) -T1) ≤ 0.3eV, and S1 is a singlet level.

An application of the printing ink described in the preparation of an organic electronic device.

An organic mixture comprising at least two organic functional materials H1 and H2: 1) wherein the difference in molecular weight between H1 and H2 is ≥200 g/mol or the difference in sublimation temperature between H1 and H2 is ≥50 K; 2) H1 and H2 form type II Semiconductor heterojunction structure, and min((LUMO(H1)-HOMO(H2), LUMO(H2)-HOMO(H1)) ≤ min(S1(H1), S1(H2))+0.1eV, where LUMO (H1), HOMO(H1) and S1(H1) are the lowest unoccupied orbits of H1, respectively. The highest occupied orbit, triplet level, LUMO(H2), HOMO(H2) and S1(H2) are the lowest of H2, respectively. It does not occupy the orbit, the highest occupied orbit, and the triplet level; 3) at least one of H1 and H2 (S1-T1) ≤ 0.3eV, and S1 is the singlet level.

Compared with the prior art, the present application has the following beneficial effects:

The printing ink of the present application comprises at least two organic functional materials and at least one organic solvent, and has good printing performance and film forming performance when used for a host material, and is convenient for high performance through solution processing, particularly printing process. Organic electronic devices, particularly organic electroluminescent devices, provide a cost-effective, high-efficiency manufacturing solution. At the same time, the luminous efficiency and lifetime of the organic electronic device can be effectively improved.

DRAWINGS

1 is a graphical representation of a semiconductor heterojunction structure in an embodiment showing the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) when two organic semiconductor materials H1 and H2 are in contact. There are two possible types of energy level relative positions (type I and type II), wherein the type II semiconductor heterojunction structure is the energy level structure of the printing ink according to the present invention.

Detailed ways

The present invention provides a printing ink comprising a thermally excited delayed fluorescent material and uses thereof. In order to make the objects, technical solutions and effects of the present invention more clear and clear, the present invention will be further described in detail below. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the embodiment of the present invention, the host material, the matrix material, the Host material, and the Matrix material have the same meaning and are interchangeable.

In the embodiment of the present invention, the singlet states and the singlet states have the same meaning and are interchangeable.

In the embodiment of the present invention, the triplet state and the triplet state have the same meaning and are interchangeable.

In the present invention, the printing ink and the composition, or the ink, have the same meaning and are interchangeable.

In the present invention, the complex excited state, exciplex, and Exciplex have the same meaning and are interchangeable.

The term "small molecule" as defined herein refers to a molecule that is not a polymer, oligomer, dendrimer, or blend. In particular, there are no repeating structures in small molecules. The molecular weight of the small molecule is ≤ 3000 g/mol, preferably ≤ 2000 g/mol, preferably ≤ 1500 g/mol.

In the present invention, an aromatic ring system or an aromatic group means a hydrocarbon group containing at least one aromatic ring, and includes a monocyclic group and a polycyclic ring system. A heteroaromatic or heteroaromatic group refers to a hydrocarbyl group (containing heteroatoms) comprising at least one heteroaromatic ring, including monocyclic groups and polycyclic ring systems. These polycyclic rings may have two or more rings in which two carbon atoms are shared by two adjacent rings, a fused ring. At least one of these rings of the polycyclic ring is aromatic or heteroaromatic. For the purposes of the present invention, aromatic or heteroaromatic ring systems include not only aromatic or heteroaromatic systems, but also multiple aryl or heteroaryl groups may also be interrupted by short non-aromatic units (<10%). Non-H atoms, preferably less than 5% of non-H atoms, such as C, N or O atoms). Thus, systems such as 9,9'-spirobifluorene, 9,9-diarylfluorene, triarylamine, diaryl ether, etc., are also considered to be aromatic ring systems for the purposes of the present invention.

In the embodiment of the present invention, the energy level structure of the organic material, the triplet energy level T1, and the singlet energy levels S1, HOMO, and LUMO play a key role. The following is an introduction to the determination of these energy levels.

The HOMO and LUMO levels can be measured by photoelectric effect, such as XPS (X-ray photoelectron spectroscopy) and UPS (UV photoelectron spectroscopy) or by cyclic voltammetry (hereinafter referred to as CV). Recently, quantum chemical methods, such as density functional theory (hereinafter referred to as DFT), have also become effective methods for calculating molecular orbital energy levels.

The triplet level T1 of organic materials can be measured by low temperature time-resolved luminescence spectroscopy or by quantum simulation calculations (eg by Time-dependent DFT), as by the commercial software Gaussian 03W (Gaussian Inc.), specific simulation methods. See WO2011141110 or as described below in the examples.

It should be noted that the absolute values of HOMO, LUMO, T1 depend on the measurement method or calculation method used, and even for the same method, different evaluation methods, such as starting point and peak point on the CV curve, can give different HOMO/LUMO. value. Therefore, reasonable and meaningful comparisons should be made using the same measurement method and the same evaluation method. In the description of the embodiments of the present invention, the values of HOMO, LUMO, and T1 are simulations based on Time-dependent DFT, but do not affect the application of other measurement or calculation methods.

In the invention, (HOMO-1) is defined as the second highest occupied orbital level, (HOMO-2) is the third highest occupied orbital level, and so on. (LUMO+1) is defined as the second lowest unoccupied orbital level, (LUMO+2) is the third lowest occupied orbital level, and so on.

The invention relates to a printing ink comprising at least two organic functional materials H1 and H2, and at least one organic solvent, characterized in that: 1) the printing ink has a viscosity at 25 ° C, in the range of 1 cPs to 100 cPs, and / Or its surface tension is at 25 ° C, in the range of 19 dyne / cm to 50 dyne / cm. 2) H1 and H2 form a type II semiconductor heterojunction structure, and min((LUMO(H1)-HOMO(H2), LUMO(H2)-HOMO(H1)) ≤ min(T1(H1), T1(H2) )) +0.1eV, where LUMO(H1), HOMO(H1) and T1(H1) are the lowest unoccupied orbits of H1, the highest occupied orbit, the triplet level, LUMO(H2), HOMO(H2) and T1 (H2) is the lowest unoccupied orbit of H2, the highest occupied orbit, and the triplet level; 3) (S1-T1) ≤ 0.3eV of at least one of H1 and H2.

In a preferred embodiment, the printing ink, S1(H2)-T1(H2) ≤ 0.25 eV.

In a more preferred embodiment, the printing ink, S1(H2)-T1(H2) ≤ 0.20 eV.

In a more preferred embodiment, the printing ink, S1(H2)-T1(H2) ≤ 0.15 eV.

In another very preferred embodiment, the printing ink, S1(H2)-T1(H2) ≤ 0.1 eV.

In another particularly preferred embodiment, the printing ink, S1(H2)-T1(H2) ≤ 0.08 eV.

In another most preferred embodiment, the printing ink, S1(H2)-T1(H2) ≤ 0.05 eV.

In certain preferred embodiments, the printing inks according to the invention wherein the difference in molecular weight of H1 and H2 is <50 g/mol.

In some preferred embodiments, the printing ink according to the invention wherein the difference in molecular weight of H1 and H2 is ≥ 50 g/mol, preferably ≥ 70 g/mol, more preferably ≥ 90 g/mol, most preferably ≥ 100 g /mol.

In certain embodiments, a printing ink according to the invention wherein the difference in sublimation temperatures of H1 and H2 is <30K.

In some preferred embodiments, the printing ink according to the invention wherein the sublimation temperature of H1 and H2 differs by ≥ 30K, preferably ≥ 40K, more preferably ≥ 50K, and most preferably ≥ 60K.

In the co-host of the vapor-deposited OLED, it is preferred that the two host materials have similar physicochemical properties such as molecular weight and sublimation temperature. The present inventors have found that in solution-processed OLEDs, two host materials having different properties may improve film formation properties, thereby improving device performance. The properties mentioned may be other than molecular weight, sublimation temperature, such as glass transition temperature, different molecular volume, and the like. Therefore, the following conditions can be substituted for the above condition 2):

a) The difference in glass transition temperature between H1 and H2 is ≥ 20K, preferably ≥ 30K, more preferably ≥ 40K, and most preferably ≥ 45K.

b) The difference in molecular volume between H1 and H2 is ≥ 20%, preferably ≥ 30%, more preferably ≥ 40%, and most preferably ≥ 45%. The molecular volume of a compound can be optimized for molecular configuration, such as by Gaussian.

In another preferred embodiment, the printing ink according to the present invention has a viscosity at 25 ° C in the range of 1 cPs to 80 cPs; preferably in the range of 1 cPs to 50 cps; more preferably in the range of 1 cPs to 40 cps; More excellent 1cPs to 30cps range; optimal range of 1.5cps to 20cps. The viscosity herein refers to the viscosity at the ambient temperature at the time of printing, and is usually 15 to 30 ° C, preferably 18 to 28 ° C, more preferably 20 to 25 ° C, and most preferably 23 to 25 ° C. The printing ink thus formulated will be particularly suitable for ink jet printing.

In a preferred embodiment, according to the printing ink of the present invention, the solubility of the H1 and the H2 in the organic solvent is 0.5% by weight or more, and the solubility difference between H1 and H2 in the organic solvent is less than or equal to 0.2 wt%.

In a preferred embodiment, according to the printing ink of the present invention, the solubility of the H1 and the H2 in an organic solvent is 0.5% by weight or more; more preferably, at least one organic functional material is in an organic solvent. The solubility is greater than or equal to 1% by weight; more preferably, the solubility of at least one organic functional material in the organic solvent is greater than or equal to 1.5% by weight; more preferably, the solubility of at least one organic functional material in the organic solvent is greater than or equal to 2% by weight; Preferably, the solubility of at least one of the organic functional materials in the organic solvent is greater than or equal to 2.5 wt%.

In a preferred embodiment, the printing ink according to the present invention has a solubility difference of H1 and H2 in an organic solvent of 0.2% by weight or less; more preferably 0.15% by weight or less; more preferably 0.1% by weight or less. %; most preferably 0.05% by weight or less.

In a preferred embodiment, according to the printing ink of the present invention, the H1 and H2 have a molecular weight of at least one of 600 g/mol or more; more preferably at least one of 800 g/mol or more; more preferably at least one It is 900 g/mol or more; very preferably at least one of 1000 g/mol or more; most preferably at least one of 1100 g/mol or more.

In a preferred embodiment, according to the printing ink of the present invention, the molecular weights of H1 and H2 are both equal to or greater than 600 g/mol; more preferably equal to or greater than 800 g/mol; more preferably equal to or greater than 900 g/mol; Preferably, both are 1000 g/mol or more.

In a preferred embodiment, the printing ink according to the present invention comprises an organic functional material in a weight ratio of the printing ink of from 0.3% to 30% by weight, preferably from 0.5% to 20% by weight, more preferably It is in the range of 0.5% to 15% by weight, more preferably in the range of 0.5% to 10% by weight, most preferably in the range of 1% to 5% by weight.

In a preferred embodiment, according to the printing ink of the present invention, the H1 and the H2 have a glass transition temperature of at least one of 100 ° C or more; more preferably at least one of 120 ° C or more; Preferably, at least one is greater than or equal to 140 ° C; and particularly preferably at least one is greater than or equal to 160 ° C.

In a preferred embodiment, according to the printing ink of the present invention, both the H1 and the H2 have a glass transition temperature of 100 ° C or more; more preferably 120 ° C or more; more preferably, both are It is 140 ° C or more; particularly preferably 160 ° C or more.

In a preferred embodiment, the printing ink according to the present invention has a molar ratio of the first organic functional material H1 to the second organic functional material H2 ranging from 1:9 to 9:1; more preferably 2:8-8:2; more preferably 3:7-7:3; still more preferably 4:6-6:4; most preferably 5:5.

In some embodiments, the first organic functional material H1 has an energy gap less than H2.

In certain preferred embodiments, the first organic functional material H1 has an energy gap greater than H2.

In a preferred embodiment, according to the printing ink of the present invention, the first organic functional material H1 has an electron transporting property, or a hole transporting property.

In a preferred embodiment, according to a printing ink of the present invention, one of H1 and H2 (HOMO-(HOMO-1)) ≥ 0.2 eV, preferably ≥ 0.25 eV, more preferably ≥ 0.3 eV, more preferably ≥ 0.35 eV, very good ≥ 0.4 eV, preferably ≥ 0.45 eV.

In a particularly preferred embodiment, according to the printing ink of the invention, each of said H1 and H2 (HOMO-(HOMO-1)) ≥ 0.2 eV, preferably H2 (HOMO-(HOMO- 1)) ≥ 0.25 eV, more preferably ≥ 0.3 eV, more preferably ≥ 0.35 eV, very preferably ≥ 0.4 eV, preferably ≥ 0.45 eV.

In another preferred embodiment, according to the printing ink of the present invention, ((LUMO+1)-LUMO) of one of H1 and H2 is ≥ 0.15 eV, preferably ≥ 0.20 eV, more preferably ≥ 0.25 eV, more preferably ≥ 0.30 eV, very good ≥ 0.35 eV, preferably ≥ 0.40 eV.

In another particularly preferred embodiment, according to the printing ink of the present invention, ((LUMO+1)-LUMO) of each of H1 and H2 is ≥ 0.15 eV, preferably H1 ((LUMO+1) ) -LUMO) ≥ 0.20 eV, more preferably ≥ 0.25 eV, more preferably ≥ 0.30 eV, very preferably ≥ 0.35 eV, preferably ≥ 0.40 eV.

In a preferred embodiment, the printing ink according to the invention, wherein said H1 has the structure shown in the general formula (I):

among them,

Z ⁴ , Z ⁵ , and Z ⁶ are each independently selected from N or CR ² . In certain embodiments, Z ⁴ , Z ⁵ , Z ⁶ may have one or two or three is N.

Ar ¹ to Ar ^{3 are the} same or different, and are an aromatic or heteroaromatic ring system having 5 to 40 ring atoms, or an aryloxy or heteroaryloxy group having 5 to 40 ring atoms, or non-aromatic group having 5 to 40 ring atoms, or a combination of these systems, in which one or more groups may be further substituted with R ^2, or R ² form a ring system may be further substituted with the group.

Preferably, Ar ¹ to Ar ^{3 are the} same or different, and are an aromatic or heteroaromatic ring system having 5 to 20 ring atoms, or an aryloxy or heteroaryloxy group having 5 to 20 ring atoms. a group, or a non-aromatic group having 5 to 20 ring atoms, or a combination of these systems, wherein one or more groups may be further substituted by R ² or R ² may further form with a substituted group Ring system.

More preferably, Ar ¹ to Ar ^{3 are the} same or different, and are a substituted or unsubstituted aromatic or heteroaromatic ring system having 5 to 15 ring atoms, or an aryloxy group having 5 to 15 ring atoms or a heteroaryloxy group, or a non-aromatic group having 5 to 15 ring atoms, or a combination of these systems, wherein one or more of the groups may be further substituted by R ² or R ² may further Substituted groups form a ring system.

R ² at each occurrence, the same or different, H, D, a linear alkyl, alkoxy or thioalkoxy group having 1 to 20 C atoms, or having 3 to 20 C a branched or cyclic alkyl, alkoxy or thioalkoxy group of an atom or a silyl group, or a substituted keto group having 1 to 20 C atoms, or having 2 to 20 C atom alkoxycarbonyl groups, or an aryloxycarbonyl group having 7 to 20 C atoms, a cyano group (-CN), a carbamoyl group (-C(=O)NH ₂ ), haloformyl group (-C(=O)-X wherein X represents a halogen atom), formyl group (-C(=O)-H), isocyanato group, isocyanate group, sulfur Cyanate group or isothiocyanate group, hydroxyl group, nitro group, CF ₃ group, Cl, Br, F, crosslinkable group or substitution with 5 to 40 ring atoms Or an unsubstituted aromatic or heteroaromatic ring system, or an aryloxy or heteroaryloxy group having 5 to 40 ring atoms, or a combination of these systems.

More preferably, R ² is the same or different at each occurrence, H, D, a linear alkyl, alkoxy or thioalkoxy group having 1 to 10 C atoms, or having 3 a branched or cyclic alkyl, alkoxy or thioalkoxy group of up to 10 C atoms or a silyl group, or a substituted keto group having 1 to 10 C atoms, Or an alkoxycarbonyl group having 2 to 10 C atoms, or an aryloxycarbonyl group having 7 to 10 C atoms, a cyano group (-CN), a carbamoyl group (-C ( =O)NH ₂ ), haloformyl group (-C(=O)-X wherein X represents a halogen atom), formyl group (-C(=O)-H), isocyanato group, isocyanate a group, a thiocyanate group or an isothiocyanate group, a hydroxyl group, a nitro group, a CF ₃ group, a Cl, a Br, a F, a crosslinkable group or having 5 to 20 A substituted or unsubstituted aromatic or heteroaromatic ring system of a ring atom, or an aryloxy or heteroaryloxy group having 5 to 20 ring atoms, or a combination of these systems.

m, m1, m2 are independently 1 or 2 or 3. Preferably it is 1.

In a preferred embodiment, according to the printing ink of the present invention, Ar ¹ -Ar ³ in the formula (I), when multiple occurrences, may be the same or differently selected from one of the following structural groups or Their combination:

Wherein n1 is 1 or 2 or 3 or 4.

In a very preferred embodiment, the printing ink according to the invention, wherein said H1 is a compound of one of the following formulae (II) to (V):

Wherein L ¹ represents an aromatic group or an aromatic hetero group having a ring number of 5 to 60.

L ² represents a single bond or an aromatic group or an aromatic hetero group having a ring number of 5 to 30.

Ar ⁴ -Ar ⁹ independently represent an aromatic or heteroaromatic ring system having 5 to 40 ring atoms.

X represents a single bond, N(R ³ ), C(R ³ ) ₂ , Si(R ³ ) ₂ , O, C=N(R ³ ), C=C(R ³ ) ₂ , P(R ³ ), P(=O)R ³ , S, S=O or SO ₂ .

X ₂ -X ₉ independently represent a single bond, N(R ³ ), C(R ³ ) ₂ , Si(R ³ ) ₂ , O, C=N(R ³ ), C=C(R ³ ) ₂ , P(R ³ ), P(=O)R ³ , S, S=O or SO ₂ , but X ₂ and X _{3 are} not a single bond at the same time, and X ₄ and X _{5 are} not a single bond at the same time, X ₆ and X _{7 is} not a single button at the same time, and X ₈ and X _{9 are} not single buttons at the same time.

R ³ , R ⁴ and R ⁵ each independently represent H, D, F, CN, alkenyl, alkynyl, nitrile, amine, nitro, acyl, alkoxy, carbonyl, sulfone group, carbon number 1 to The alkyl group of 30, the cycloalkyl group having 3 to 30 carbon atoms, the number of ring atoms is 5 to 60 aromatic hydrocarbon groups or the aromatic heterocyclic group, and the linking position of R ⁴ and R ⁵ may be any one of fused rings. There may be any number of carbon atoms on the carbon atom and substituted by R ⁴ and R ⁵ .

N2 represents an integer from 1 to 4. The best is 2. The optimal is 1.

Preferably, at least one of R ³ , R ⁴ , R ⁵ or L ¹ , L ² contains an electron withdrawing group.

In a more preferred embodiment, the printing ink according to the invention, wherein said H1 is a compound of one of the following formulae (II-a) to (V-a):

among them,

The meanings of L1, X ₃ , X ₄ , R ² , R ³ and R ^{4 are} as defined above;

The meaning of L3 is L1;

A ¹ and A ² each independently represent an aromatic group or an aromatic hetero group having 5 to 30 ring atoms;

Y ¹ to Y ¹⁷ each independently represent N and C (R ² ), and adjacent Y ¹ -Y ¹⁷ cannot be N at the same time.

In certain preferred embodiments, printing inks according to the present invention, wherein H1 and H2 are not simultaneously derivatives of carbazole. In a preferred embodiment, the printing ink according to the invention wherein H2 has thermal excitation delayed fluorescence (TADF) characteristics.

According to the principle of thermally excited delayed fluorescent TADF material (see Adachi et al., Nature Vol 492, 234, (2012)), when the organic compound (S1-T1) is sufficiently small, the triplet excitons of the organic compound can pass through the reverse internal Convert to singlet excitons for efficient illumination. In general, TADF materials are obtained by electron donating (Donor) and electron-deficient or acceptor groups directly or through other groups, i.e., having a distinct D-A structure.

According to the printing ink of the present invention, H2 has a small (S1-T1), and generally (S1-T1) ≤ 0.30 eV, preferably ≤ 0.25 eV, preferably ≤ 0.20 eV, more preferably ≤ 0.15 eV. More preferably, it is ≤0.10 eV, particularly preferably ≤0.08 eV, preferably ≤0.05 eV.

In a particularly preferred embodiment, the printing ink according to the invention, wherein H2 comprises at least one electron-donating group, and/or comprises at least one electron-withdrawing group, has the following general formula (VI):

Wherein Ar is a single bond or a substituted or unsubstituted aromatic or heteroaromatic structural unit, and D may be independently selected from the same or different electron-donating groups when it is present multiple times, and A may be independent of each other when it occurs multiple times. selected from the same or different electron-withdrawing group, n, p is an integer between 1 and 6, Ar is further substituted with unsubstituted or R _0, R ₀ is an alkyl group of 1 to 5.

When Ar is a single bond, D and A are directly connected.

Examples of suitable electron-withdrawing groups A are shown below, but are not limited thereto, which may be further optionally substituted:

Examples of suitable electron donating groups D are shown below, but are not limited thereto, which may be further arbitrarily substituted:

Further electron-donating groups D may be selected from structures containing groups having the following groups:

Further electron-withdrawing groups A may be selected from the group consisting of F, cyano or a structure comprising the following groups:

Wherein, o is 1, 2 or 3; X ¹ -X ^{8 is} selected from CR ⁶ or N, and at least one is N; M ¹ , M ² and M ³ independently represent N(R ⁶ ), C (R ⁶ 6R ⁷ ), Si(R ⁶ R ⁷ ), O, C=N(R ⁶ ), C=C(R ⁶ R ⁷ ), P(R), P(=O)R ⁶ , S, S=O , SO ₂ or not; the meaning of R ⁶ , R ^{7 is} as defined in R ³ of claim 9.

In a very preferred embodiment, H2 has the structure shown by the formulae (II) to (V) and contains at least one electron withdrawing group as described above.

In certain preferred embodiments, the printing inks according to the invention, wherein H1 and H2 are not simultaneously derivatives of carbazole.

Further suitable as a TADF material for H2 can be found in the following patent documents: CN103483332(A), TW201309696(A), TW201309778(A), TW201343874(A), TW201350558(A), US20120217869(A1), WO2013133359(A1), WO2013154064(A1), Adachi, et.al. Adv. Mater., 21, 2009, 4802, Adachi, et. al. Appl. Phys. Lett., 98, 2011, 083302, Adachi, et. al. Appl. Phys .Lett., 101, 2012, 093306, Adachi, et. al. Chem. Commun., 48, 2012, 11392, Adachi, et. al. Nature Photonics, 6, 2012, 253, Adachi, et. al. Nature, 492, 2012, 234, Adachi, et. al. J. Am. Chem. Soc, 134, 2012, 14706, Adachi, et. al. Angew. Chem. Int. Ed, 51, 2012, 11311, Adachi, et. Al. Chem. Commun., 48, 2012, 9580, Adachi, et. al. Chem. Commun., 48, 2013, 10385, Adachi, et. al. Adv. Mater., 25, 2013, 3319, Adachi, et .al.Adv.Mater.,25,2013,3707,Adachi,et.al.Chem.Mater.,25,2013,3038,Adachi,et.al.Chem.Mater.,25,2013,3766,Adachi, et.al.J. Mater.Chem.C., 1, 2013, 4599, Adachi, et.al. J. Phys. Chem. A., 117, 2013, 5607, hereby to the above listed patents or article files The entire contents of this application are incorporated herein by reference.

The following are specific examples that can be used as H2, but are not limited to:

In a preferred embodiment, according to the printing ink of the present invention, the first organic functional material H1 is preferably, but not limited to, the following structure:

In a preferred embodiment, the printing ink according to the present invention further comprises a third organic functional material, and the third organic functional material can be selected from a hole (also called a hole) injection or transport material ( HIM/HTM), hole blocking material (HBM), electron injecting or transporting material (EIM/ETM), electron blocking material (EBM), organic matrix material (Host), singlet illuminant (fluorescent illuminant), triple Light emitter (phosphorescent emitter), thermally excited delayed fluorescent material (TADF) and organic dye. Various organic functional materials are described in detail in, for example, O2010135519A1, US20090134784A1, and WO 2011110277A1, the entire contents of each of which is hereby incorporated by reference.

In certain preferred embodiments, the printing inks according to the present invention, wherein H2 and said third organic functional material are not selected from the derivatives of carbazole.

In a most preferred embodiment, the printing ink, wherein the third organic functional material is selected from the group consisting of a singlet illuminant (fluorescent illuminant), a triplet illuminant (phosphorescent illuminant) or TADF luminescence body.

In a preferred embodiment, the printing ink comprises H1 and H2 described above, and a phosphorescent emitter, wherein the phosphorescent emitter has a weight percentage of all functional materials (excluding solvent) ≤ 30 wt%, Preferably, it is ≤ 25 wt%, more preferably ≤ 20 wt%. Particularly preferred, the triplet energy level of the phosphorescent emitter is ≤ min (T1 (H1), T1 (H2).

In another preferred embodiment, the printing ink comprises H1 and H2 described above, and a fluorescent illuminant. The fluorescent illuminant described therein is ≤ 15% by weight, preferably ≤ 10% by weight, more preferably ≤ 8% by weight, based on all functional materials (excluding solvent).

In another preferred embodiment, the printing ink comprises H1 and H2 described above, and a TADF luminescent material. The TADF luminescent material described therein is ≤ 15% by weight, preferably ≤ 10% by weight, more preferably ≤ 8% by weight, based on all functional materials (excluding solvent). The singlet illuminator and the triplet illuminator are described in some detail below (but are not limited thereto).

1. Singlet emitter (Singlet Emitter)

Singlet emitters tend to have longer conjugated pi-electron systems. Heretofore, there have been many examples, such as styrylamine and its derivatives disclosed in JP 2913116 B and WO 2001021729 A1, indenoindoles and derivatives thereof disclosed in WO 2008/006449 and WO 2007/140847, and disclosed in US Pat. No. 7,233,019, KR2006-0006760 A quinone triarylamine derivative.

In a preferred embodiment, the singlet emitter can be selected from the group consisting of monostyrylamine, dibasic styrylamine, ternary styrylamine, quaternary styrylamine, styrene phosphine, styrene ether and aromatic amine.

A monostyrylamine refers to a compound comprising an unsubstituted or substituted styryl group and at least one amine, preferably an aromatic amine. A dibasic styrylamine refers to a compound comprising two unsubstituted or substituted styryl groups and at least one amine, preferably an aromatic amine. A ternary styrylamine refers to a compound comprising three unsubstituted or substituted styryl groups and at least one amine, preferably an aromatic amine. A quaternary styrylamine refers to a compound comprising four unsubstituted or substituted styryl groups and at least one amine, preferably an aromatic amine. A preferred styrene is stilbene, which may be further substituted. The corresponding phosphines and ethers are defined similarly to amines. An arylamine or an aromatic amine refers to a compound comprising three unsubstituted or substituted aromatic ring or heterocyclic systems directly bonded to a nitrogen. At least one of these aromatic or heterocyclic ring systems is preferably selected from the fused ring system and preferably has at least 14 aromatic ring atoms. Preferred examples thereof are aromatic decylamine, aromatic quinone diamine, aromatic decylamine, aromatic quinone diamine, aromatic thiamine and aromatic quinone diamine. An aromatic amide refers to a compound in which a diaryl arylamine group is attached directly to the oxime, preferably at the position of 9. An aromatic quinone diamine refers to a compound in which two diaryl arylamine groups are attached directly to the oxime, preferably at the 9,10 position. The aromatic decylamine, the aromatic guanidine diamine, the aromatic thiamine and the aromatic thiamine are similarly defined, wherein the diarylamine group is preferably bonded to the 1 or 1,6 position of the oxime.

Examples of singlet emitters based on vinylamines and arylamines are also preferred examples and can be found in the following patent documents: WO 2006/000388, WO 2006/058737, WO 2006/000389, WO 2007/065549, WO 2007 /115610, US 7250532 B2, DE 102005058557 A1, CN 1583691 A, JP 08053397 A, US 6251531 B1, US 2006/210830 A, EP 1957606 A1 and US 2008/0113101 A1, the entire contents of which are hereby incorporated by reference. This article is incorporated herein by reference.

An example of a singlet emitter based on a stilbene extreme derivative is US 5121029.

Further preferred singlet emitters are selected from the group consisting of an indeno-amine and an indeno-diamine, as disclosed in WO2006/122630, benzoindolo-amine and benzoindeno-diamine, Dibenzoindolo-amine and dibenzoindenoindole-diamine as disclosed in WO 2008/006449, as disclosed in WO 2007/140847.

Further preferred singlet emitters are selected from the group consisting of ruthenium-based fused ring systems as disclosed in US2015333277A1, US2016099411A1, US2016204355A1.

More preferred singlet emitters may be selected from the derivatives of hydrazine, such as those disclosed in US2013175509A1; triarylamine derivatives of hydrazine, such as triarylamine derivatives of hydrazine containing dibenzofuran units disclosed in CN102232068B; A triarylamine derivative of hydrazine having a specific structure, as disclosed in CN105085334A, CN105037173A. Other materials which can be used as singlet emitters are polycyclic aromatic hydrocarbon compounds, in particular derivatives of the following compounds: for example, 9,10-bis(2-naphthoquinone), naphthalene, tetraphenyl, xanthene, phenanthrene , 芘 (such as 2,5,8,11-tetra-t-butyl fluorene), anthracene, phenylene such as (4,4'-bis(9-ethyl-3-carbazolevinyl)-1 , 1 '-biphenyl), indenyl hydrazine, decacycloolefin, hexacene benzene, anthracene, spirobifluorene, aryl hydrazine (such as US20060222886), arylene vinyl (such as US5121029, US5130603), cyclopentane Alkene such as tetraphenylcyclopentadiene, rubrene, coumarin, rhodamine, quinacridone, pyran such as 4 (dicyanomethylidene)-6-(4-p-dimethylaminobenzene Vinyl-2-methyl)-4H-pyran (DCM), thiopyran, bis(pyridazinyl)imine boron compound (US2007/0092753A1), bis(pyridazinyl)methylene compound, carbostyryl compound, Oxazinone, benzoxazole, benzothiazole, benzimidazole and pyrrolopyrroledione. Materials for some singlet illuminants can be found in the following patent documents: US20070252517A1, US4769292, US6020078, US2007/0252517A1, US2007/0252517A1. The entire contents of the above-listed patent documents are hereby incorporated by reference.

Some examples of suitable singlet emitters are listed in the table below:

2. Triplet emitter (Triplet Emitter)

Triplet emitters are also known as phosphorescent emitters. In a preferred embodiment, the triplet emitter is a metal complex of the formula M(L)n, wherein M is a metal atom, and each occurrence of L may be the same or different and is an organic ligand. It is bonded to the metal atom M by one or more positional bonding or coordination, and n is an integer greater than 1, preferably 1, 2, 3, 4, 5 or 6. Alternatively, these metal complexes are coupled to a polymer by one or more positions, preferably by an organic ligand.

In a preferred embodiment, the metal atom M is selected from a transition metal element or a lanthanide or a lanthanide element, preferably Ir, Pt, Pd, Au, Rh, Ru, Os, Sm, Eu, Gd, Tb, Dy Re, Cu or Ag, with Os, Ir, Ru, Rh, Re, Pd, Au or Pt being particularly preferred.

Preferentially, the triplet emitter comprises a chelating ligand, ie a ligand, coordinated to the metal by at least two bonding sites, with particular preference being given to the triplet emitter comprising two or three identical or different pairs Tooth or multidentate ligand. Chelating ligands are beneficial for increasing the stability of metal complexes.

Examples of the organic ligand may be selected from a phenylpyridine derivative, a 7,8-benzoquinoline derivative, a 2(2-thienyl)pyridine derivative, a 2(1-naphthyl)pyridine derivative, or a 2 benzene. A quinolinol derivative. All of these organic ligands may be substituted, for example by fluorine or trifluoromethyl. The ancillary ligand may preferably be selected from the group consisting of acetone acetate or picric acid.

In a preferred embodiment, the metal complex that can be used as the triplet emitter has the following form:

Wherein M is a metal selected from a transition metal element or a lanthanide or actinide element, particularly preferably Ir, Pt, Au;

Ar ₁ may be the same or different at each occurrence, and is a cyclic group containing at least one donor atom, that is, an atom having a lone pair of electrons, such as nitrogen or phosphorus, through which a cyclic group is coordinated to a metal. Connection; Ar ₂ may be the same or different each time it appears, is a cyclic group containing at least one C atom through which a cyclic group is attached to the metal; Ar ₁ and Ar ₂ are bonded by a covalent bond Together, each may carry one or more substituent groups, which may also be joined together by a substituent group; L' may be the same or different at each occurrence, and is a bidentate chelate auxiliary ligand, preferably Is a monoanionic bidentate chelate ligand; x can be 0, 1, 2 or 3, preferably 2 or 3; y can be 0, 1, 2 or 3, preferably 1 or 0.

Examples of the application of materials for some triplet emitters can be found in the following patent documents and documents: WO 200070655, WO 200141512, WO 200202714, WO 200215645, EP 1191613, EP 1191612, EP 1191614, WO 2005033244, WO 2005019373, US 2005 /0258742, WO 2009146770, WO 2010015307, WO 2010031485, WO 2010054731, WO 2010054728, WO 2010086089, WO 2010099852, WO 2010102709, US 20070087219 A1, US 20090061681 A1, US 20010053462 A1, Baldo, Thompson et al. Nature 403, (2000) ), 750-753, US 20090061681 A1, US 20090061681 A1, Adachi et al. Appl. Phys. Lett. 78 (2001), 1622-1624, J. Kido et al. Appl. Phys. Lett. 65 (1994), 2124, Kido et al. Chem. Lett. 657, 1990, US 2007/0252517 A1, Johnson et al., JACS 105, 1983, 1795, Wrighton, JACS 96, 1974, 998, Ma et al., Synth. Metals 94 , 1998, 245, US 6824895, US 7029766, US 6835469, US 6830828, US 20010053462 A1, WO 2007095118 A1, US 2012004407A1, WO 2012007088A1, WO2012007087A1, WO 2012007086A1, US 2008027220A1, WO 2011157339A1, CN 102282150A, WO 2009118087A1, WO 2013107487A1 , WO 201309 4620A1, WO 2013174471A1, WO 2014031977A1, WO 2014112450A1, WO 2014007565A1, WO 2014038456A1, WO 2014024131A1, WO 2014008982A1, WO2014023377A1. The entire contents of the above-listed patent documents and documents are hereby incorporated by reference.

Some examples of suitable triplet emitters are listed in the table below:

In a preferred embodiment, according to the printing ink of the present invention, the organic solvent is selected from the group consisting of aromatic or heteroaromatic, ester, aromatic ketone or aromatic ether, aliphatic ketone or aliphatic ether, alicyclic Or an olefinic compound, or a mixture of one or more of a borate ester or a phosphate compound.

In another preferred embodiment, according to the printing ink of the present invention, the surface tension of the organic solvent at 25 ° C is in the range of 20 dyne / cm to 45 dyne / cm; more preferably in the range of 22 dyne / cm to 35 dyne / cm It is preferably in the range of 25dyne/cm to 33dyne/cm.

In a preferred embodiment, according to the printing ink of the invention, the at least one organic solvent is selected from the group consisting of aromatic or heteroaromatic based solvents.

Examples of aromatic or heteroaromatic solvents suitable for the present invention are, but are not limited to, p-diisopropylbenzene, pentylbenzene, tetrahydronaphthalene, cyclohexylbenzene, chloronaphthalene, 1,4-dimethylnaphthalene. , 3-isopropylbiphenyl, p-methyl cumene, dipentylbenzene, triphenylbenzene, pentyltoluene, o-diethylbenzene, m-diethylbenzene, p-diethylbenzene, 1,2,3,4 -tetramethylbenzene, 1,2,3,5-tetramethylbenzene, 1,2,4,5-tetramethylbenzene, butylbenzene, dodecylbenzene, dihexylbenzene, dibutylbenzene, p-diisopropylbenzene , cyclohexylbenzene, benzylbutylbenzene, dimethylnaphthalene, 3-isopropylbiphenyl, p-methylisopropylbenzene, 1-methylnaphthalene, 1,2,4-trichlorobenzene, 4,4 -difluorodiphenylmethane, 1,2-dimethoxy-4-(1-propenyl)benzene, diphenylmethane, 2-phenylpyridine, 3-phenylpyridine, N-methyldiphenylamine, 4 -isopropylbiphenyl, -dichlorodiphenylmethane, 4-(3-phenylpropyl)pyridine, benzyl benzoate, 1,1-bis(3,4-dimethylphenyl)ethane, 2-isopropylnaphthalene, quinoline, isoquinoline, methyl 2-furancarboxylate, ethyl 2-furancarboxylate, and the like.

Examples of aromatic ketone solvents suitable for the present invention are, but are not limited to, 1-tetralone, 2-tetralone, 2-(phenyl epoxy) tetralone, 6-(methoxy Tetrendanone, acetophenone, propiophenone, benzophenone, and derivatives thereof, such as 4-methylacetophenone, 3-methylacetophenone, 2-methylacetophenone, 4-methylpropiophenone, 3-methylpropiophenone, 2-methylpropiophenone, and the like.

Examples of aromatic ether-based solvents suitable for the present invention are, but are not limited to, 3-phenoxytoluene, butoxybenzene, p-anisaldehyde dimethyl acetal, tetrahydro-2-phenoxy-2H -pyran, 1,2-dimethoxy-4-(1-propenyl)benzene, 1,4-benzodioxane, 1,3-dipropylbenzene, 2,5-dimethoxy Toluene, 4-ethyl ether, 1,3-dipropoxybenzene, 1,2,4-trimethoxybenzene, 4-(1-propenyl)-1,2-dimethoxybenzene, 1, 3-dimethoxybenzene, glycidyl phenyl ether, dibenzyl ether, 4-tert-butyl anisole, trans-p-propenyl anisole, 1,2-dimethoxybenzene, 1-methyl Oxynaphthalene, diphenyl ether, 2-phenoxymethyl ether, 2-phenoxytetrahydrofuran, ethyl-2-naphthyl ether.

In some preferred embodiments, according to the printing ink of the present invention, the at least one organic solvent may be selected from the group consisting of: an aliphatic ketone, for example, 2-fluorenone, 3-fluorenone, 5-fluorenone, 2 - anthrone, 2,5-hexanedione, 2,6,8-trimethyl-4-indanone, anthrone, phorone, isophorone, di-n-pentyl ketone, etc.; or an aliphatic ether For example, pentyl ether, hexyl ether, dioctyl ether, ethylene glycol dibutyl ether, diethylene glycol diethyl ether, diethylene glycol butyl methyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, Triethylene glycol ethyl methyl ether, triethylene glycol butyl methyl ether, tripropylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, and the like.

In still other preferred embodiments, according to the printing ink of the present invention, the at least one organic solvent may be selected from ester-based solvents: alkyl octanoate, alkyl sebacate, alkyl stearate, benzene. Alkyl formate, alkyl phenylacetate, alkyl cinnamate, alkyl oxalate, alkyl maleate, alkanolide, alkyl oleate, and the like. Particularly preferred are octyl octanoate, diethyl sebacate, diallyl phthalate, isodecyl isononanoate.

In a particularly preferred embodiment, according to the printing ink of the invention, the at least one organic solvent is selected from the group consisting of 1-tetralone, 3-phenoxytoluene, acetophenone, 1-methoxy Naphthalene, p-diisopropylbenzene, pentylbenzene, tetrahydronaphthalene, cyclohexylbenzene, chloronaphthalene, 1,4-dimethylnaphthalene, 3-isopropylbiphenyl, p-methylcumene, dipentylene , o-diethylbenzene, m-diethylbenzene, p-diethylbenzene, 1,2,3,4-tetramethylbenzene, 1,2,3,5-tetramethylbenzene, 1,2,4,5-tetramethylbenzene, Benzene, dodecylbenzene, 1-methylnaphthalene, 1,2,4-trichlorobenzene, diphenyl ether, diphenylmethane, 4-isopropylbiphenyl, benzyl benzoate, 1,1-double (3,4-dimethylphenyl)ethane, 2-isopropylnaphthalene, dibenzyl ether, octyl octanoate, diethyl sebacate, diallyl phthalate, isodecanoic acid ester

The solvent may be used singly or as a mixture of two or more organic solvents.

In certain preferred embodiments, the printing ink according to the present invention comprises an organic functional compound as described above and at least one organic solvent, and may further comprise another organic solvent, and another organic solvent is exemplified. , including but not limited to: methanol, ethanol, 2-methoxyethanol, dichloromethane, chloroform, chlorobenzene, o-dichlorobenzene, tetrahydrofuran, anisole, morpholine, toluene, o-xylene, Meta-xylene, p-xylene, 1,4 dioxane, acetone, methyl ethyl ketone, 1,2 dichloroethane, 3-phenoxytoluene, 1,1,1-trichloroethane Alkane, 1,1,2,2-tetrachloroethane, ethyl acetate, butyl acetate, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, tetrahydronaphthalene, decalin, anthracene and / or a mixture of them.

In some preferred embodiments, the solvent particularly suitable for the present invention is a solvent having Hansen solubility parameters in the following ranges:

δ _d (dispersion force) is in the range of 17.0 to 23.2 MPa ^1/2 , especially in the range of 18.5 to 21.0 MPa ^1/2 ;

range δ _p (polar forces) in the range of 0.2 ~ 12.5MPa ^1/2, especially in the 2.0 ~ 6.0MPa ^1/2;

δ _h (hydrogen bonding) in the range of 0.9 ~ 14.2MPa ^1/2, particularly in a range of 2.0 ~ 6.0MPa ^1/2.

According to the printing ink of the present invention, the organic solvent is selected in consideration of its boiling point parameter. In the present invention, the organic solvent has a boiling point of ≥ 150 ° C; preferably ≥ 180 ° C; more preferably ≥ 200 ° C; more preferably ≥ 250 ° C; optimally ≥ 275 ° C or ≥ 300 ° C. The boiling points within these ranges are beneficial for preventing nozzle clogging of the inkjet printhead. The organic solvent can be evaporated from the solvent system to form a film comprising the functional material.

The invention further relates to the use of the printing ink as a printing ink for the preparation of organic electronic devices, particular preference being given to a preparation process by printing or coating.

Among them, suitable printing or coating techniques include, but are not limited to, inkjet printing, typography, screen printing, dip coating, spin coating, blade coating, roller printing, twist roll printing, lithography, flexography Printing, rotary printing, spraying, brushing or pad printing, slit-type extrusion coating, etc. Preferred are gravure, screen printing and inkjet printing. Gravure printing, ink jet printing will be applied in embodiments of the invention. The solution or suspension may additionally comprise one or more components such as surface active compounds, lubricants, wetting agents, dispersing agents, hydrophobic agents, binders and the like for adjusting viscosity, film forming properties, adhesion, and the like. For information on printing techniques and their requirements for solutions, such as solvents and concentrations, viscosity, etc., please refer to Helmut Kipphan's "Printing Media Handbook: Techniques and Production Methods" (Handbook of Print Media: Technologies and Production Methods). ), ISBN 3-540-67326-1.

In the preparation method as described above, the functional layer is formed to have a thickness of 5 nm to 1000 nm.

The invention further relates to an organic mixture comprising at least two organic functional materials H1 and H2: 1) wherein the difference in molecular weight between H1 and H2 is ≥200 g/mol or the difference in sublimation temperature between H1 and H2 is ≥50 K; 2) H1 and H2 forms a type II semiconductor heterojunction structure, and min((LUMO(H1)-HOMO(H2), LUMO(H2)-HOMO(H1)) ≤ min(S1(H1), S1(H2))+0.1 eV, where LUMO(H1), HOMO(H1) and S1(H1) are the lowest unoccupied orbits of H1, respectively, the highest occupied orbit, the triplet level, LUMO(H2), HOMO(H2) and S1(H2) respectively Is the lowest unoccupied orbit of H2, the highest occupied orbit, triplet level; 3) at least one of H1 and H2 (S1-T1) ≤ 0.3eV, preferably ≤ 0.25eV, more preferably ≤ 0.20eV, Very good is ≤ 0.15 eV, preferably ≤ 0.10 eV.

In a preferred embodiment, the organic mixture wherein the difference in molecular weight of H1 and H2 is ≥250 g/mol, preferably ≥250 g/mol, more preferably ≥300 g/mol, most preferably ≥350 g/mol; Or the difference between the sublimation temperatures of H1 and H2 is ≥ 60K, preferably ≥ 70K, more preferably ≥ 75K, and most preferably ≥ 80K.

More preferably, the organic mixture comprises a third organic functional material, and the third organic functional material is selected from a hole (also called a hole) injection or transport material (HIM/HTM), a cavity. Barrier material (HBM), electron injecting or transporting material (EIM/ETM), electron blocking material (EBM), organic matrix material (Host), singlet emitter (fluorescent emitter), triplet emitter (phosphorescent emitter) ), thermally excited delayed fluorescent material (TADF) and organic dyes. Various organic functional materials are described in detail in, for example, O2010135519A1, US20090134784A1, and WO 2011110277A1, the entire contents of each of which is hereby incorporated by reference.

In a most preferred embodiment, the organic mixture comprising a third organic functional material is selected from the group consisting of a singlet emitter (fluorescent emitter), a triplet emitter (phosphorescent emitter) or TADF.

The invention further relates to an organic electronic device comprising at least a functional layer formed by printing a printing ink as described above. The organic electronic device may be selected from, but not limited to, an organic light emitting diode (OLED), an organic photovoltaic cell (OPV), an organic light emitting cell (OLEEC), an organic field effect transistor (OFET), an organic light emitting field effect transistor, and an organic Lasers, organic spintronic devices, organic sensors and organic plasmon emitting diodes (Organic Plasmon Emitting Diode), etc., particularly preferred are organic electroluminescent devices such as OLED, OLEEC, organic light-emitting field effect transistors.

In some particularly preferred embodiments, the organic electroluminescent device comprises at least one luminescent layer prepared from a printing ink as described above.

In the above light-emitting device, particularly an OLED, a substrate, an anode, at least one light-emitting layer, and a cathode are included.

The substrate can be opaque or transparent. A transparent substrate can be used to make a transparent light-emitting component. See, for example, Bulovic et al. Nature 1996, 380, p29, and Gu et al, Appl. Phys. Lett. 1996, 68, p2606. The substrate can be rigid or elastic. The substrate can be plastic, metal, semiconductor wafer or glass. Preferably, the substrate has a smooth surface. Substrates without surface defects are a particularly desirable choice. In a preferred embodiment, the substrate is flexible, optionally in the form of a polymer film or plastic, having a glass transition temperature Tg of 150 ° C or higher, preferably more than 200 ° C, more preferably more than 250 ° C, preferably More than 300 ° C. Examples of suitable flexible substrates are poly(ethylene terephthalate) (PET) and polyethylene glycol (2,6-naphthalene) (PEN).

The anode can comprise a conductive metal or metal oxide, or a conductive polymer. The anode can easily inject holes into a hole injection layer (HIL) or a hole transport layer (HTL) or a light-emitting layer. In one embodiment, the absolute value of the difference between the work function of the anode and the HOMO level or the valence band level of the illuminant in the luminescent layer or the p-type semiconductor material as the HIL or HTL or electron blocking layer (EBL) is less than 0.5 eV, preferably less than 0.3 eV, and most preferably less than 0.2 eV. Examples of the anode material include, but are not limited to, Al, Cu, Au, Ag, Mg, Fe, Co, Ni, Mn, Pd, Pt, ITO, aluminum-doped zinc oxide (AZO), and the like. Other suitable anode materials are known and can be readily selected for use by one of ordinary skill in the art. The anode material can be deposited using any suitable technique, such as a suitable physical vapor deposition process, including radio frequency magnetron sputtering, vacuum thermal evaporation, electron beam (e-beam), and the like. In certain embodiments, the anode is patterned. Patterned ITO conductive substrates are commercially available and can be used to prepare devices in accordance with the present invention.

The cathode can include a conductive metal or metal oxide. The cathode can easily inject electrons into the EIL or ETL or directly into the luminescent layer. In one embodiment, the work function of the cathode and the LUMO level of the illuminant or the n-type semiconductor material as an electron injection layer (EIL) or electron transport layer (ETL) or hole blocking layer (HBL) in the luminescent layer or The absolute value of the difference in conduction band energy levels is less than 0.5 eV, preferably less than 0.3 eV, and most preferably less than 0.2 eV. In principle, all materials which can be used as cathodes for OLEDs are possible as cathode materials for the devices of the invention. Examples of the cathode material include, but are not limited to, Al, Au, Ag, Ca, Ba, Mg, LiF/Al, MgAg alloy, BaF ₂ /Al, Cu, Fe, Co, Ni, Mn, Pd, Pt, ITO, and the like. The cathode material can be deposited using any suitable technique, such as a suitable physical vapor deposition process, including radio frequency magnetron sputtering, vacuum thermal evaporation, electron beam (e-beam), and the like.

The OLED may further include other functional layers such as a hole injection layer (HIL), a hole transport layer (HTL), an electron blocking layer (EBL), an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer. (HBL). Materials suitable for use in these functional layers are described in detail above and in WO2010135519A1, US20090134784A1, and WO2011110277A1, the entire contents of each of which are hereby incorporated by reference.

The light-emitting device according to the present invention has an emission wavelength of between 300 and 1000 nm, preferably between 350 and 900 nm, more preferably between 400 and 800 nm.

The invention further relates to the use of an electroluminescent device according to the invention in various electronic devices, including, but not limited to, display devices, illumination devices, light sources, sensors and the like.

The present invention will be described with reference to the preferred embodiments thereof, but the present invention is not limited to the embodiments described below. It is to be understood that the scope of the invention is intended to be It is to be understood that the modifications of the various embodiments of the invention are intended to be

Organic functional materials involved in the examples:

The energy level of the organic functional material can be obtained by quantum calculation, for example, by TD-DFT (time-dependent density functional theory) by Gaussian 09W (Gaussian Inc.), and the specific simulation method can be found in WO2011141110. First, the semi-empirical method "Ground State/Semi-empirical/Default Spin/AM1" (Charge 0/Spin Singlet) is used to optimize the molecular geometry, and then the energy structure of the organic molecule is determined by TD-DFT (time-dependent density functional theory) method. Calculated "TD-SCF/DFT/Default Spin/B3PW91" and the base group "6-31G(d)" (Charge 0/Spin Singlet). The HOMO and LUMO levels are calculated according to the following calibration formula, and S1 and T1 are used directly.

HOMO(eV)=((HOMO(G)×27.212)-0.9899)/1.1206

LUMO(eV)=((LUMO(G)×27.212)-2.0041)/1.385

Among them HOMO (G) and LUMO (G) are direct calculation results of Gaussian 09W, the unit is Hartree. The results are shown in Table 1:

Table I

among them,

Compound H1-1 and compound H1-2 are used for the first organic functional material;

Compound H2-1 and Compound H2-2 were used for the second organic functional material.

The synthesis methods of H1-1 (WO2015156449); H1-2 (WO2007063796); H2-1 (WO2008056746); H2-2 (US2012238105) refer to related patents, respectively.

Preparation of printing ink:

EXAMPLES The third organic functional material contained in the printing ink is a metal complex E1 represented by the following formula, which is a phosphorescent guest, and its synthesis is referred to the patent CN102668152.

The printing ink was prepared in the following manner, and the molar ratio of the first organic functional material to the second organic functional material was 1:1.

Example 1: Compound H1-1+ Compound H2-1 (LUMO(H2-1)-HOMO(H1-1)=2.57 eV)

Example 2: Compound H1-1+ compound H2-2 (LUMO(H2-2)-HOMO(H1-1)=2.56 eV)

Example 3: Compound H1-2+ Compound H2-1 (LUMO(H2-1)-HOMO(H1-2)=2.63 eV)

Example 4: Compound H1-2+ Compound H2-2 (LUMO(H2-2)-HOMO(H1-2)=2.62 eV)

The above printing ink is prepared as follows:

Put the stirrer in the vial, clean it and transfer it to the glove box. 9.8 g of 3-phenoxytoluene solvent was prepared in a vial. 0.19 g of the mixture of Examples 1-4 and 0.01 g of E1 were weighed into a glove box, added to the solvent system in the vial, and stirred and mixed. After stirring at a temperature of 60 ° C until the organic mixture was completely dissolved, it was cooled to room temperature. The resulting organic mixture solution was filtered through a 0.2 um PTFE filter, sealed and stored.

The viscosity of the printing ink was tested by a DV-I Prime Brookfield rheometer; the surface tension of the printing ink was tested by a SITA bubble pressure tomometer.

Through the above tests, the viscosity of the four printing inks obtained was in the range of 5.7 ± 0.5 cPs - 6.4 ± 0.5 cPs, and the surface tension was in the range of 32.3 ± 0.5 dyne / cm - 34.1 ± 0.5 dyne / cm.

In a further experiment, the mixtures of Examples 1-4 were prepared in the following solvents: 1-tetralone, 1-methoxynaphthalene, tetrahydronaphthalene, cyclohexylbenzene, chloronaphthalene, 1,4 -dimethylnaphthalene, 3-isopropylbiphenyl, p-methylisopropylbenzene, dipentylbenzene, o-diethylbenzene, p-diethylbenzene, 1,2,3,4-tetramethylbenzene, 1,2, 3,5-tetramethylbenzene, 1,2,4,5-tetramethylbenzene, dodecylbenzene, 1-methylnaphthalene, 4-isopropylbiphenyl, benzyl benzoate, 1,1-double (3 , 4-dimethylphenyl)ethane, 2-isopropylnaphthalene, dibenzyl ether, the obtained printing inks have a viscosity in the range of 2-20 cPs, and the viscosity can be further adjusted by a combination of solvents and other methods. It can be adapted to the needs of technologies such as inkjet printing.

Comparative Example 1:

The composition was prepared in the same manner as in Example 1 above, the only difference being that the compound H2-1 was substituted for the combination of the compound H1-1 + the compound H2-1.

Comparative Example 2:

The composition was prepared in the same manner as in Example 2 above, the only difference being that the compound H2-2 was substituted for the combination of the compound H1-1 + the compound H2-2.

Comparative Example 3:

The composition was prepared in the same manner as in Example 2 above, the only difference being that the combination of Compound H2-1 + Compound H2-2 was replaced with a combination of Compound H2-1 + Compound Host.

Preparation of OLED devices:

With ITO/HIL/HTL/EML (Example 1 - Example 4, Comparative Example 1 - Comparative Example 3) / Al, the preparation steps of the OLED device are as follows:

1) ITO transparent electrode (anode) glass substrate cleaning: ultrasonic treatment with 5% Decon90 cleaning solution for 30 minutes, then ultrasonic cleaning with deionized water several times, then ultrasonic cleaning with isopropanol, nitrogen drying; in oxygen plasma Under treatment for 5 minutes to clean the ITO surface and enhance the work function of the ITO electrode;

2) Preparation of the HIL and HTL: treated in an oxygen plasma after a glass substrate was spin-coated ^{PEDOT: PSS (Clevios TM PEDOT:} PSS Al4083), to give a film of 80nm, annealed in air at 150 deg.] C after completion of the spin coating 20 Minutes, then spin coating on a PEDOT:PSS layer to obtain a 20 nm Poly-TFB film (CAS: 223569-31-1, available from Lumtec. Corp; 5 mg/mL toluene solution), followed by treatment on a hot plate at 180 °C 60 minute;

3) Preparation of luminescent layer: The above printing ink was spin-coated in a nitrogen glove box to obtain an 80 nm film, which was then annealed at 120 ° C for 10 minutes.

4) Cathode preparation: The spin-coated device was placed in a vacuum evaporation chamber, and 2 nm ruthenium and 100 nm aluminum were sequentially evaporated to complete a light-emitting device.

5) All devices are packaged in a UV glove box with UV curable resin and glass cover.

The current-voltage (J-V) characteristics of each OLED device are characterized by characterization equipment while recording important parameters such as efficiency, lifetime and external quantum efficiency. In Table 2, all device data were compared with the relative values of Comparative Example 1.

Table II

The luminous efficiency and lifetime of Example 1 - Example 4 were significantly improved as compared with Comparative Example 1 and Comparative Example 2. It can be seen that the OLED device prepared by using the printing ink of the invention has greatly improved luminous efficiency and lifetime, and the external quantum efficiency is also significantly improved. Compared with the H2-1+ compound Host combination in Comparative Example 3, exciplex can be formed, but the material which does not contain TADF characteristics, the luminous efficiency and the lifetime of Examples 1 and 2 are significantly improved, further illustrating the superiority of the present invention. effect.

In addition, FIG. 1 is a diagram of a semiconductor heterojunction structure showing that when two organic semiconductor materials H1 and H2 are in contact, the energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) are relative. There are two possible types of positions, wherein the type II semiconductor heterojunction structure is the energy level structure of the printing ink according to the present invention.

Claims (18)

1. A printing ink comprising at least two organic functional materials H1 and H2, and at least one organic solvent, characterized in that: 1) the printing ink has a viscosity at 25 ° C, in the range of 1 cPs to 100 cPs, and / or its surface tension at 25 ° C, in the range of 19dyne / cm to 50dyne / cm; 2) H1 and H2 form a type II semiconductor heterojunction structure, and min ((LUMO (H1)-HOMO (H2), LUMO(H2)-HOMO(H1))≤min(T1(H1), T1(H2))+0.1eV, where LUMO(H1), HOMO(H1) and T1(H1) are the lowest unoccupied orbits of H1 in turn. The highest occupied orbit, triplet level, LUMO (H2), HOMO (H2) and T1 (H2) are the lowest unoccupied orbit of H2, the highest occupied orbit, and the triplet level; 3) at least H1 and H2 One (S1-T1) ≤ 0.3eV, and S1 is a singlet energy level.
2. The printing ink according to claim 1, wherein the difference in molecular weight between H1 and H2 is ≥ 50 g/mol or the difference in sublimation temperature between H1 and H2 is ≥ 30K.
3. The printing ink according to any one of claims 1 to 2, wherein the H1 and H2 have a molecular weight of at least one of 800 g/mol or more.
4. The printing ink according to any one of claims 1 to 3, wherein a molar ratio of H1 to H2 in the printing ink ranges from 1:9 to 9:1.
5. The printing ink according to any one of claims 1 to 4, wherein the H1 has an energy gap larger than H2.
6. The printing ink according to any one of claims 1 to 5, wherein the H1 has a hole transporting property or an electron transporting property.
7. The printing ink according to any one of claims 1 to 6, wherein the H1 has a structure represented by the formula (I).

   

   among them,

   Z ⁴ , Z ⁵ , Z ⁶ are independently selected from N or CR ² ;

   Ar ¹ to Ar ^{3 are the} same or different, and are an aromatic or heteroaromatic ring system having 5 to 40 ring atoms, or an aryloxy or heteroaryloxy group having 5 to 40 ring atoms, or a non-aromatic group having 5 to 40 ring atoms, or a combination of these systems, wherein one or more groups may be further substituted by R ² or R ² may further form a ring system with the substituted group;

   R ² at each occurrence, the same or different, H, D, a linear alkyl, alkoxy or thioalkoxy group having 1 to 20 C atoms, or having 3 to 20 C a branched or cyclic alkyl, alkoxy or thioalkoxy group of an atom or a silyl group, or a substituted keto group having 1 to 20 C atoms, or having 2 to 20 C atom alkoxycarbonyl groups, or an aryloxycarbonyl group having 7 to 20 C atoms, a cyano group), a carbamoyl group, a haloformyl group, a formyl group , isocyano group, isocyanate group, thiocyanate group or isothiocyanate group, hydroxyl group, nitro group, CF ₃ group, Cl, Br, F, crosslinkable a group or a substituted or unsubstituted aromatic or heteroaromatic ring system having 5 to 40 ring atoms, or an aryloxy or heteroaryloxy group having 5 to 40 ring atoms, or a combination of these systems ;

   m, m1, m2 are independently 1 or 2 or 3.
8. The printing ink according to claim 7, wherein Ar ¹ -Ar ³ in the formula (I), when multiple occurrences, is the same or differently selected from one of the following structural groups or a combination thereof:

   

   

   Wherein n1 is 1 or 2 or 3 or 4.
9. The printing ink according to any one of claims 1 to 6, wherein the H1 is a compound represented by one of the following formulae (II) to (V):

   

   among them,

   L ¹ represents an aromatic group or an aromatic hetero group having a ring number of 5 to 60;

   L ² represents a single bond, an aromatic group or an aromatic hetero group having a ring number of 5 to 30;

   Ar ⁴ -Ar ⁹ independently represent an aromatic or heteroaromatic ring system having 5 to 40 ring atoms;

   X represents a single bond, N(R ³ ), C(R ³ ) ₂ , Si(R ³ ) ₂ , O, C=N(R ³ ), C=C(R ³ ) ₂ , P(R ³ ), P(=O)R ³ , S, S=O or SO ₂ ;

   X ₂ -X ₉ independently represent a single bond, N(R ³ ), C(R ³ ) ₂ , Si(R ³ ) ₂ , O, C=N(R ³ ), C=C(R ³ ) ₂ , P(R ³ ), P(=O)R ³ , S, S=O or SO ₂ , but X ₂ and X _{3 are} not a single bond at the same time, and X ₄ and X _{5 are} not a single bond at the same time, X ₆ and X _{7 is} not a single button at the same time, and X ₈ and X _{9 are} not single buttons at the same time;

   R ³ , R ⁴ and R ⁵ each independently represent H, D, F, CN, alkenyl, alkynyl, nitrile, amine, nitro, acyl, alkoxy, carbonyl, sulfone group, carbon number 1 to a linear or branched alkyl group of 30, a cycloalkyl group having 3 to 30 carbon atoms, a ring-bonding number of 5 to 60 aromatic hydrocarbon groups or an aromatic heterocyclic group, wherein the linking position of R ⁴ and R ⁵ may be Any number of carbon atoms on the fused ring and substituted by R ⁴ , R ⁵ may have any number of;

   N2 represents an integer from 1 to 4.
10. The printing ink according to any one of claims 1 to 9, wherein the H2 has a structure represented by the general formula (VI):

    

    Wherein Ar is a substituted or unsubstituted aromatic or heteroaromatic structural unit, and D, when multiple occurrences, are independently selected from the same or different electron-donating groups, and A is selected from the same or different independently of each other when it occurs multiple times. The electron withdrawing group, n, p is an integer between 1 and 6.
11. The printing ink according to claim 10, wherein D in the formula (VI) is selected from structural units containing a group:

    
12. The printing ink according to any one of claims 10 to 11, wherein A in the formula (VI) is selected from the group consisting of F, a cyano group or one of the following groups:

    

    Wherein, o is 1, 2 or 3; X ¹ -X ^{8 is} selected from CR ⁶ or N, and at least one is N; M ¹ , M ² and M ³ independently represent N(R ⁶ ), C (R ⁶ 6R ⁷ ), Si(R ⁶ R ⁷ ), O, C=N(R ⁶ ), C=C(R ⁶ R ⁷ ), P(R), P(=O)R ⁶ , S, S=O , SO ₂ or not; the meaning of R ⁶ , R ^{7 is} as defined in R ³ of claim 9.
13. The printing ink according to any one of claims 1 to 12, wherein the printing ink further comprises a third organic functional material, and the third organic functional material is selected for hole injection or transmission. One or more of a material, a hole blocking material, an electron injecting or transporting material, an electron blocking material, an organic matrix material, a singlet illuminant, a triplet illuminant, a thermally excited delayed fluorescent material, and an organic dye.
14. The printing ink according to any one of claims 1 to 13, wherein the organic solvent is selected from the group consisting of aromatic or heteroaromatic, ester, aromatic ketone or aromatic ether, aliphatic ketone or aliphatic ether. , an alicyclic or olefinic compound, or a mixture of one or more of a borate ester or a phosphate compound.
15. Use of a printing ink according to any of claims 1-14 in the preparation of an organic electronic device.
16. The application according to claim 15, wherein the organic electronic device is selected from the group consisting of an organic light emitting diode, an organic photovoltaic cell, an organic light emitting cell, an organic field effect transistor, an organic light emitting field effect transistor, an organic laser, and an organic spintronic device. Device, organic sensor or organic plasmon emitting diode.
17. The use according to any one of claims 15 to 16, wherein the organic electronic device is an organic light emitting diode comprising at least one light emitting layer, and the light emitting layer is made of a claim 1-14 One of the printing inks described is prepared.
18. An organic mixture comprising at least two organic functional materials H1 and H2, characterized in that: 1) wherein the difference in molecular weight between H1 and H2 is ≥200 g/mol or the difference in sublimation temperature between H1 and H2 is ≥50 K; 2) H1 and H2 forms a type II semiconductor heterojunction structure, and min((LUMO(H1)-HOMO(H2), LUMO(H2)-HOMO(H1)) ≤ min(T1(H1), T1(H2))+0.1 eV, where LUMO(H1), HOMO(H1) and T1(H1) are the lowest unoccupied orbits of H1, respectively, the highest occupied orbit, triplet level, LUMO(H2), HOMO(H2) and T1(H2) respectively It is the lowest unoccupied orbit of H2, the highest occupied orbit, and the triplet level; 3) at least one of H1 and H2 (S1-T1) ≤ 0.3eV, and S1 is the singlet level.

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