Organic electroluminescent element and preparation method thereof

Abstract

The present invention relates to an organic electroluminescent element and a preparation method thereof. The organic electroluminescent element comprises a substrate, an anode conductive layer and a cathode conductive layer located on the substrate, and a light-emitting layer and an organic functional layer located between the anode conductive layer and the cathode conductive layer; the organic functional layer comprises an electron blocking layer, the electron blocking layer comprises a first electron blocking layer material and a second electron blocking layer material, the first electron blocking layer material is different from the second electron blocking layer material; the first electron blocking layer material has a structure shown in formula (1). In the present invention, the compound shown in formula (1) is used in combination with other types of electron blocking layer materials to play a role superior to that of the compound itself, and the synergistic effect of the two materials can further improve the luminous efficiency of the device, reduce the driving voltage, and prolong the service life.

Description

Technical Field

[0001] The present invention relates to the technical field of organic electroluminescence, and in particular to an organic electroluminescence element and a preparation method thereof. Background Art

[0002] OLED (Organic Light Emitting Diode) is a semiconductor light-emitting device based on organic light-emitting materials. Its classic structure is a three-layer hamburger structure, which is an anode, a light-emitting layer, and a cathode. However, due to the large electron injection barrier between the cathode and the light-emitting layer, functional layers such as an electron transport layer, an electron injection layer, and a hole blocking layer are added to reduce the electron injection barrier and increase the transmission speed of electrons. Similarly, due to the large hole injection barrier between the anode and the light-emitting layer, functional layers such as a hole injection layer, a hole transport layer, and an electron blocking layer are added to reduce the hole injection barrier and accelerate the transmission of holes. Electroluminescent devices have gradually developed from the initial sandwich structure to the current multilayer structure, including a Prime layer (EBL, electron blocking layer) arranged between the hole transport layer and the light-emitting layer. The increase of EBL can better improve the photoelectric performance of the device, or can better extend the service life of the device. However, no suitable electron blocking material has been found to improve the photoelectricity and life of the device at the same time.

[0003] CN109994633A discloses an organic electroluminescent device. The organic electroluminescent device includes a light-emitting layer, which includes a main material and a fluorescent doping material. The main material adopts an aggregation-induced delayed fluorescent material. In the aggregated state, the molecules have a large torsion angle, which increases the distance between molecules and reduces the interaction between molecules. At the same time, the excitons of the aggregation-induced delayed fluorescent material are mainly distributed on the core of the molecule in the excited state, which can effectively reduce the triplet triplet annihilation and triplet polaron quenching of the excited state of the main molecule in the aggregated state, and reduce the device efficiency roll-off. Furthermore, the aggregation-induced delayed fluorescent material is limited in molecular vibration and rotation under aggregation, which can effectively reduce the non-radiative relaxation energy loss of the main body in the device, thereby improving the luminous efficiency of the device. The invention improves the performance of the device by selecting the material of the light-emitting layer.

[0004] CN109593042A discloses an organic electroluminescent material and an organic electroluminescent device containing the same. On the basis of the symmetrical structure of the double (triarylamine), adamantane is introduced as a new core group, which changes the molecular morphology and reduces the symmetry of the structure, thereby improving the film-forming property of the material; the adamantane group itself has a large steric hindrance and a rigid structure, and its non-conjugated molecular structure does not affect the electronic energy level of the triarylamine, thereby ensuring the hole transport performance of the material; the compound containing the adamantane group has excellent hole transport performance, and can be used to make an organic electroluminescent device, especially as a hole transport layer material in an organic electroluminescent device, which can effectively improve the luminous efficiency and service life of the organic light-emitting device. The invention improves the performance of the device by selecting a hole transport layer material.

[0005] CN109207145A discloses a dihydrobenzindazole organic electroluminescent material, an organic electroluminescent device and a display. This compound is used in the electron transport layer material or the main material of the organic electroluminescent device, which improves the luminous efficiency of the organic electroluminescent device and reduces the driving voltage of the organic electroluminescent device. The invention improves the performance of the device by selecting the electron transport layer material.

[0006] Therefore, this field urgently needs to study a new organic electroluminescent device starting from the electron blocking layer, while improving the photoelectric performance and life of the device. Summary of the invention

[0007] In view of the shortcomings of the prior art, one of the purposes of the present invention is to provide an organic electroluminescent element, wherein the photoelectric performance and life of the organic electroluminescent element are improved.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] The present invention provides an organic electroluminescent element, which comprises a base substrate, an anode conductive layer and a cathode conductive layer located on the base substrate, and a light-emitting layer and an organic functional layer located between the anode conductive layer and the cathode conductive layer;

[0010] The organic functional layer comprises an electron blocking layer, the electron blocking layer comprises a first electron blocking layer material and a second electron blocking layer material, the first electron blocking layer material is different from the second electron blocking layer material;

[0011] The first electron blocking layer material has a structure shown in formula (1);

[0012]

[0013] In formula (1), X is selected from O, S, CR 5 R6 NR 7 or SiR 8 R 9 ;

[0014] In formula (1), L 1 Selected from single bonds, substituted or unsubstituted C6-C 30 Arylene, substituted or unsubstituted C3-C 30 A group formed by connecting one or at least two of the heteroarylene groups;

[0015] For example, L 1 It may be selected from a group formed by a substituted or unsubstituted C6-C30 arylene group and a substituted or unsubstituted C3-C30 heteroarylene group connected by a single bond;

[0016] In formula (1), Ar 1 Selected from substituted or unsubstituted C6-C 30 Aryl or condensed ring aromatic group, substituted or unsubstituted C3-C 30 A group formed by connecting one or at least two of heteroaryl groups or condensed-ring heteroaryl groups;

[0017] In formula (1), R 1 , R 2 and R 3 are each independently selected from hydrogen, substituted or unsubstituted C6-C 30 Aryl, substituted or unsubstituted C3-C 30 Heteroaryl, substituted or unsubstituted C1-C 30 Alkyl, substituted or unsubstituted C1-C 30 Alkoxy, substituted or unsubstituted C3-C 30 Cycloalkyl, substituted or unsubstituted C1-C 30 One of silane and carbonyl

[0018] In formula (1), R 4 Selected from substituted or unsubstituted C6-C 30 Aryl or condensed ring aromatic group, substituted or unsubstituted C3-C 30 One of heteroaryl or fused ring heteroaryl; said R 4 There is only a single bond between the benzene ring and the attached benzene ring, or R 4 The benzene ring connected to it is connected by O, S, CR 10 R 11 NR 12 or SiR 13 R 14 Connect into a ring;

[0019] For example, R 4 It can be connected to the connected benzene ring to form a cyclic group with the following structure:

[0020]

[0021] In formula (1), m, n, p and q are independently selected from zero to the maximum possible integer value; wherein the maximum possible integer value depends on the maximum number of substitutable sites on the parent core; illustratively, m, n, p and q can be 0, 1, 2, 3, 4 or 5; when m, n, p and q are selected from 2 and above, two or more R 1 Same or different, R 2 , R 3 and R 4 Similarly, when the same expressions are mentioned below, they have the same meaning;

[0022] The R 5 To R 14 Each independently selected from hydrogen, C1-C 18 Alkyl, C1-C 18 Alkoxy, C3-C 30 Cycloalkyl, C2-C 18 Alkenyl, C2-C 18 Alkynyl, halogen, cyano, substituted or unsubstituted C6-C 30 Aryl, substituted or unsubstituted C3-C 30 Heteroaryl, substituted or unsubstituted C6-C 30 Arylamine, substituted or unsubstituted C3-C 30 A group formed by connecting one or at least two of the heteroaromatic amine groups, preferably R 5 and R 6 C1-C 18 Alkyl, more preferably methyl;

[0023] When the above groups have substituents, the substituents are independently selected from halogen, C1-C 10 Alkyl, C3-C 10 Cycloalkyl, C2-C 10 alkenyl, C1-C6 alkoxy, C1-C6 thioalkoxy, cyano, nitro, amine, carboxyl, carbonyl, ester, C6-C 30 Monocyclic aromatic hydrocarbons or condensed aromatic hydrocarbon groups, C3-C 30 A combination of one or more of a monocyclic heteroaromatic hydrocarbon group or a condensed-ring heteroaromatic hydrocarbon group.

[0024] When the above-mentioned "substituted or unsubstituted" group has a substituent, one or more of the above substituents may be selected, that is, it may be a combination of the above two substituents.

[0025] In some embodiments, m, n, p and q are independently selected from zero to the maximum possible integer value, that is, the upper limit of each substitutable position, for example, m can be an integer between 0-5, n can be an integer between 0-4, p and q are each independently an integer between 0-5, and p+q≤5. 1 , R 2 , R 3 or R 4 When multiple R 1 , R 2 , R 3 or R 4 Each may be the same or different group.

[0026] In the present invention, the representation of the connecting bond of the substituent group as "—" crossing the ring structure indicates that the connecting site is at any position on the ring structure that can form a bond.

[0027] The electron blocking layer of the organic electroluminescent element provided by the present invention comprises two different types of electron blocking materials, one of which has a structure shown in formula (1). The compound shown in formula (1) is used in combination with the other type of electron blocking layer material to exert a better effect than itself. The synergistic effect of the two materials can further improve the luminous efficiency of the device, reduce the driving voltage, and prolong the service life.

[0028] Preferably, the first electron blocking layer material has a structure shown in formula (2);

[0029]

[0030] In formula (2), X is selected from O, S or CR 5 R 6 ;

[0031] In formula (2), the L 1 Selected from single bonds, substituted or unsubstituted C6-C 30 Arylene, substituted or unsubstituted C3-C 30 A heteroarylene group;

[0032] In formula (2), Ar 1 Selected from substituted or unsubstituted C6-C 30 Aryl or condensed ring aromatic group, substituted or unsubstituted C3-C 30 One of heteroaryl or fused-ring heteroaryl;

[0033] In formula (2), R 1 , R 2 , R 3 , R 4 , R 5 , R 6All have the same limited range as in formula (1);

[0034] When the above groups have substituents, the substituents are independently selected from halogen, C1-C 10 Alkyl, C3-C 10 Cycloalkyl, C2-C 10 alkenyl, C1-C6 alkoxy, C1-C6 thioalkoxy, cyano, nitro, amine, carboxyl, carbonyl, ester, C6-C 30 Monocyclic aromatic hydrocarbons or condensed aromatic hydrocarbon groups, C3-C 30 A combination of one or more of monocyclic heteroaromatic hydrocarbons or condensed-ring heteroaromatic hydrocarbon groups;

[0035] Alternatively, the first electron blocking layer material has a structure shown in formula (3);

[0036]

[0037] In formula (3), X is selected from CR 5 R 6 ;

[0038] In formula (3), L 1 Selected from single bonds, substituted or unsubstituted C6-C 30 Arylene, substituted or unsubstituted C3-C 30 A heteroarylene group;

[0039] In formula (3), Ar 1 Selected from substituted or unsubstituted C6-C 30 Aryl or condensed ring aromatic group, substituted or unsubstituted C3-C 30 One of the heteroaryl or condensed-ring heteroaryl groups;

[0040] In formula (3), R 1 , R 2 , R 3 , R 4 , R 5 , R 6 All have the same limited range as formula (1);

[0041] When the above groups have substituents, the substituents are independently selected from halogen, C1-C 10 Alkyl, C3-C 10 Cycloalkyl, C2-C 10 alkenyl, C1-C6 alkoxy, C1-C6 thioalkoxy, cyano, nitro, amine, carboxyl, carbonyl, ester, C6-C 30 Monocyclic aromatic hydrocarbons or condensed aromatic hydrocarbon groups, C3-C 30 A combination of one or more of monocyclic heteroaromatic hydrocarbons or condensed-ring heteroaromatic hydrocarbon groups;

[0042] Alternatively, the first electron blocking layer material has a structure shown in formula (4);

[0043]

[0044] In formula (4), X is selected from CR 5 R 6 ;

[0045] In formula (4), L 1 Selected from single bonds, substituted or unsubstituted C6-C 30 Arylene, substituted or unsubstituted C3-C 30 A heteroarylene group;

[0046] In formula (4), Ar 1 Selected from substituted or unsubstituted C6-C 30 Aryl or condensed ring aromatic group, substituted or unsubstituted C3-C 30 One of heteroaryl or fused-ring heteroaryl;

[0047] In formula (4), R 1 , R 2 , R 3 , R 4 , R 5 , R 6 All have the same limited range as formula (1);

[0048] When the above groups have substituents, the substituents are independently selected from halogen, C1-C 10 Alkyl, C3-C 10 Cycloalkyl, C2-C 10 alkenyl, C1-C6 alkoxy, C1-C6 thioalkoxy, cyano, nitro, amine, carboxyl, carbonyl, ester, C6-C 30 Monocyclic aromatic hydrocarbons or condensed aromatic hydrocarbon groups, C3-C 30 A combination of one or more of a monocyclic heteroaromatic hydrocarbon group or a condensed-ring heteroaromatic hydrocarbon group.

[0049] Preferably, the L 1 is selected from a single bond or phenylene.

[0050] Preferably, Ar 1 A group formed by connecting one or at least two selected from phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, anthracenyl, fluoranthene, carbazole, fluorene, dibenzofuran and dibenzothiophene.

[0051] Preferably, the R 4A group selected from one or at least two of phenyl, biphenyl, terphenyl, naphthyl, fluorenyl, phenanthryl, anthracenyl, fluoranthenyl, carbazolyl, dibenzofuranyl, dibenzothiophenyl, preferably R 4 Selected from phenyl or biphenyl.

[0052] Preferably, the R 1 , R 2 and R 3each independently selected from hydrogen, or selected from the following substituted or unsubstituted groups: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, neopentyl, n-hexyl, cyclohexyl, neohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, trifluoromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl, phenyl, naphthyl, anthracenyl, benzanthryl, phenanthrenyl, triphenylenyl, pyrenyl, chrysene, peryl, fluoranthenyl, naphthacene, pentacene, benzopyrenyl, biphenyl, phenylene, terphenyl, triphenylene, quaternaryl, fluorenyl , spirobifluorenyl, dihydrophenanthryl, dihydropyrenyl, tetrahydropyrenyl, cis- or trans-indenofluorenyl, trimerized indenyl, isotrimerized indenyl, spirotrimerized indenyl, spiroisotrimerized indenyl, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, thienyl, benzothienyl, isobenzothienyl, dibenzothienyl, pyrrolyl, isoindolyl, carbazolyl, indenocarbazolyl, pyridinyl, quinolyl, isoquinolyl, acridinyl, phenanthridinyl, benzo-5,6-quinolyl, benzo-6,7-quinolyl, benzo-7,8-quinolyl, phenothiazinyl, phenazinyl, pyrazolyl, indazolyl, imidazolyl, benzimidazolyl, naphthoimidazolyl, phenanthrene imidazolyl, pyridinimidazolyl, pyrazinimidazolyl, quinoxalinimidazolyl, oxazolyl, benzoxazolyl, naphthoxazolyl, anthrazolyl, phenanthrozolyl, 1,2-thiazolyl, 1,3-thiazolyl, benzothiazolyl, pyridazinyl, benzopyridazinyl, pyrimidinyl, benzopyrimidinyl, quinoxalinyl, 1,5-diazaanthryl, 2,7-diazapyrenyl, 2,3-diazapyrenyl, 1,6-diazapyrenyl, 1,8-diazapyrenyl, 4,5-diazapyrenyl, 4,5,9,10-tetraazaperyl, pyrazinyl, phenazinyl, phenothiazinyl, naphthyridinyl, azacarbazolyl, benzocarbolinyl, phenanthroline A group formed by connecting one or at least two of the following: 1,2,3-triazolyl, 1,2,4-triazolyl, benzotriazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, 1,2,5-oxadiazolyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,2,5-thiadiazolyl, 1,3,4-thiadiazolyl, 1,3,5-triazinyl, 1,2,4-triazinyl, 1,2,3-triazinyl, tetrazolyl, 1,2,4,5-tetrazinyl, 1,2,3,4-tetrazinyl, 1,2,3,5-tetrazinyl, purinyl, pteridinyl, indolizinyl and benzothiadiazolyl.

[0053] Preferably, the first electron blocking layer material includes any one or a combination of at least two of the compounds shown in C1 to C2243.

[0054] Preferably, the compound represented by formula (1) can be synthesized by referring to the following synthetic route:

[0055]

[0056] It should be noted that obtaining the compound is not limited to the method and route used in the present invention, and those skilled in the art may also select other methods or routes to obtain the novel compound proposed in the present invention.

[0057] Preferably, the second electron blocking layer material has a structure shown in formula (I);

[0058]

[0059] In formula (I), L' represents a single bond, a substituted or unsubstituted C6-C 30 Arylene, substituted or unsubstituted C3-C 30 One of the heteroarylene groups, preferably the substituted or unsubstituted C6-C 30 Arylene is C6-C 10 Arylene, as C6-C 30 Examples of the arylene group include phenyl, biphenylene, terphenylene, naphthylene, anthracene, phenanthrenyl, fluorenylene, pyrenylene, phenylene, fluoranthenylene, benzo[a]anthrylene, benzo[c]phenanthrylene, triphenylene, benzo[k]fluoranthenylene, benzo[g] phenylene, benzo[b]triphenylene, naphthylene, perylene, etc., among which phenylene, naphthylene, biphenylene are preferred, and phenylene is more preferred;

[0060] In formula (I), R a’ and R b’ Each independently selected from C1-C 20 Alkyl, C1-C 20 Alkenyl, C1-C 20 One of the alkynyl groups, wherein R a’ and R b’ These groups may be linked to form a ring structure or not, and examples of these groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, neopentyl, n-hexyl, cyclohexyl, neohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, trifluoromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl, vinyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, ethynyl, propynyl, butynyl, pentynyl, hexynyl or octynyl, R a’ and R b’ More preferably C1-C 12 Alkyl, as C1-C 12Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, pentyl, isopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl. Among them, methyl, ethyl, n-propyl, and isopropyl are preferred. a’ and R b’ More preferably methyl;

[0061] R a’ and R b’ Can be connected to form a ring structure, can be connected to each other to form a ring, such a ring is preferably a five-membered ring and a six-membered ring, for example, can be a cyclohexane ring, cyclopentane, 2,2-biphenylene connected to form a ring structure (forming a spiral spirofluorene structure at the X position);

[0062] In formula (I), R' is selected from C1-C 20 Alkyl, C1-C 20 Alkenyl, C1-C 20 Alkynyl, C1-C 20 Alkoxy, C6-C 30 Aryl, C3-C 30 One of the heteroaryl groups, preferably C1-C 12 Alkyl, C6-C 30 Aryl, C3-C 30 One of the heteroaryl groups, as C1-C 12 Examples of the alkyl group include the same examples as above, as C6-C 30 Examples of the aryl group include phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthrenyl, fluorenyl, pyrenyl, phenyl, fluoranthene, benzo[a]anthryl, benzo[c]phenanthryl, triphenylene, benzo[k]fluoranthene, benzo[g] as C3-C 30 Specific examples of heteroaryl groups include pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, quinolyl, isoquinolyl, naphthyridinyl, phthalazinyl, quinoxalinyl, quinazolinyl, phenanthridinyl, acridinyl, phenanthrolinyl, pyrrolyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, indolyl, benzimidazolyl, indazolyl, imidazopyridinyl, benzotriazolyl, carbazolyl, furanyl, thienyl, oxadiazolyl, thiophene, oxadiazolyl, pyrazolyl, triazolyl, tetrazolyl, indolyl, benzimidazolyl, indazolyl, imidazopyridinyl, benzotriazolyl, carbazolyl, furanyl, thienyl, oxadiazolyl, pyraz ... oxazolyl, thiazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, thiadiazolyl, benzofuranyl, benzothiophenyl, benzoxazolyl, benzothiazolyl, benzisoxazolyl, benzisothiazolyl, benzoxadiazolyl, benzothiadiazolyl, dibenzofuranyl, dibenzothiophenyl, piperidinyl, pyrrolidinyl, piperazinyl, morpholinyl, phenazinyl, phenothiazinyl, phenoxazinyl and the like, but are not limited to these;

[0063] Preferred groups for R' include benzene, naphthalene, anthracene, benzanthracene, phenanthrene, triphenylene, pyrene, chrysene, perylene, fluoranthene, tetracene, pentacene, benzopyrene, biphenyl, isophenyl, terphenyl, trimerene, tetraphenyl, fluorene, spirobifluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene, cis- or trans-indenofluorene, trimerized indene, isotrimerized indene, spirotrimerized indene, spiroisotrimerized indene, furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiophene, isobenzothiophene, dibenzothiophene, pyridine, pyridine, indole, isoindole, carbazole, indolecarbazole, indenocarbazole, pyridine, quinoline, isoquinoline, acridine, phenanthridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline, phenothiazine, phenoxazine, pyrazole, indazole, imidazole, benzimidazole, naphthymidazole, phenanthroimidazole, pyridimidazole, pyrazinimidazole, quinoxalineimidazole, oxazole, benzoxazole, naphthymidazole, anthraquinone, phenanthroquinone, isoxazole, 1,2-thiazole, 1,3-thiazole , benzothiazole, pyridazine, benzopyridazine, pyrimidine, benzopyrimidine, quinoxaline, 1,5-diazaanthracene, 2,7-diazapyrene, 2,3-diazapyrene, 1,6-diazapyrene, 1,8-diazapyrene, 4,5-diazapyrene, 4,5,9,10-tetraazaperylene, pyrazine, phenazine, phenoxazine, phenothiazine, fluorescein ring, naphthyridine, azacarbazole, benzocarboline, phenanthroline, 1,2,3-triazole, 1,2,4-triazole, benzotriazole, 1,2,3-oxa oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, tetrazole, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine, purine, pteridine, indolizine and benzothiadiazole, or a combination of the above groups. A more preferred group for R' is phenyl or naphthyl;

[0064] In formula (I), p' is an integer of 0-7, such as 1, 2, 3, 4, 5, 6, etc., preferably 0 or 1;

[0065] In formula (I), Ar' is selected from a heteroaryl group represented by formula (A'), or a substituted or unsubstituted C6-C 30 Aryl;

[0066]

[0067] In formula (A'), * represents the connection site with the mother core;

[0068] In formula (A'), the L 1’ Selected from single bonds, substituted or unsubstituted C6-C 30 Arylene, substituted or unsubstituted C3-C30 One of the heteroarylene groups, preferably a substituted or unsubstituted C6-C 30 Arylene is C6-C 10 arylene;

[0069] In formula (A'), R 1’ Selected from C1-C 20 Alkyl, C1-C 20 Alkenyl, C1-C 20 Alkynyl, C1-C 20 Alkoxy, C6-C 30 Aryl, C3-C 30 One of the heteroaryl groups, multiple R 1’ The same or different, q' is an integer from 0 to 7, preferably 0 or 1, two R in adjacent positions 1’ The ring may be connected or not connected to form a ring, and such a ring may be an aliphatic ring or an aromatic ring, for example, R 1’ They can be connected to form ring structures such as benzene ring and fluorene ring;

[0070] In formula (A'), X' is selected from O, S, NR 2’ 、SiR 3’ R 4’ One of the following, preferably NR 2’ , O, S;

[0071] The R 2’ , R 3’ , R 4’ Each independently selected from C1-C 12 Alkyl, substituted or unsubstituted C6-C 30 Aryl, substituted or unsubstituted C3-C 30 A heteroaryl group, R 3’ and R 4’ Connected to each other to form a ring or not connected to form a ring;

[0072] When the above groups have substituents, the substituents are selected from halogen, C1-C 12 Alkyl, C1-C 12 Alkoxy, C6-C 12 Aryl, C3-C 12 One or more combinations of heteroaryl, cyano and hydroxyl.

[0073] C1-C above 12 Alkyl, C6-C 12 Aryl, C3-C 12 Examples of heteroaryl groups can refer to the same examples as above, as C1-C 12 Alkoxy groups include the above-mentioned C1-C 12Examples of alkyl groups connected to -O- include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, etc., among which methoxy, ethoxy, propoxy, and methoxy are preferred.

[0074] The present invention preferably uses the compound represented by formula (I) as the second electron blocking layer material, and mixes it with the first electron blocking layer material represented by formula (1), which can improve the efficiency of the device and extend the service life of the device. In addition, a method for preparing an organic electroluminescent element is also provided.

[0075] Preferably, the second electron blocking layer material has a structure shown in formula (II) or formula (III);

[0076]

[0077] In formula (II) and formula (III), the R a’ , R b’ is selected from C1-C6 alkyl, R a’ , R b’ connected to form a ring structure or not connected to form a ring structure;

[0078] In formula (II) and formula (III), p' is 0 or 1, and R' is a substituted or unsubstituted C6~C 12 Aryl, preferably phenyl, biphenyl or naphthyl, Ar' has the same definition as in formula (I);

[0079] In formula (II) and formula (III), when Ar' is formula (A'), L 1’ Indicates a single bond or C6-C 10 Arylene, R 1’ Selected from C6-C 30 Aryl, C3-C 30 One of the heteroaryl groups, q' is 0 or 1, and X' is preferably NR 2’ , O, S; R 2’ is substituted or unsubstituted C6-C 30 Aryl; the purpose of this is also to achieve better planarity, thereby improving charge transfer efficiency.

[0080] When the above groups have substituents, the substituents are selected from halogen, C1-C 12 Alkyl, C1-C 12 Alkoxy, C6-C 12 Aryl, C3-C 12 One or more combinations of heteroaryl, cyano and hydroxyl.

[0081] When the second electron blocking layer material is selected from the compound represented by formula (II) or formula (III), it can provide better hole transport performance or electron blocking performance, further improve the luminous efficiency of the device, reduce the driving voltage, and extend the service life.

[0082] Preferably, in formula (I), Ar' is selected from the heteroaryl group represented by formula (A1');

[0083]

[0084] In formula (A1'), * represents the linking site with the mother nucleus;

[0085] In formula (A1'), X' is selected from N-Ph, O, S;

[0086] In formula (A1'), R 1’ Selected from C6-C 12 Aryl, r' is 0 or 1, t' is 0 or 1, and r' and t' are not 1 at the same time, Ph represents phenyl, L 1’ represents a single bond, or a substituted or unsubstituted phenylene group, naphthylene group, or biphenylene group;

[0087] When the above groups have substituents, the substituents are selected from halogen, C1-C 12 Alkyl, C1-C 12 Alkoxy, C6-C 12 Aryl, C3-C 12 One or more combinations of heteroaryl, cyano and hydroxyl.

[0088] It is further preferred that Ar' is selected from the heteroaryl group represented by formula (A1'), which can further achieve better planarity and thus improve the charge transport efficiency.

[0089] Preferably, the second electron blocking layer material has a structure shown in formula (IV);

[0090]

[0091] In formula (IV), n'=an integer from 0 to 10;

[0092] In formula (IV), L' and Ar' have the same limited ranges as in formula (I), and Ar' is further preferably a group formed by condensing two aromatic rings or heteroaromatic rings, in which the π electrons can be delocalized over a larger range, and its preferred examples are the same as above.

[0093] Preferably, Ar' is selected from one of quinoline, benzopyrazole, and pyridopyridine.

[0094] Preferably, the second electron blocking layer has a structure shown in formula (V);

[0095]

[0096] In formula (V), n', L' and Ar' have the same defined ranges as in formula (IV).

[0097] Preferably, the second electron blocking layer material includes any one of Compound 1 to Compound 267 or a combination of at least two thereof.

[0098] Preferably, the compound of formula (I) can be synthesized according to the following method:

[0099]

[0100] Preferably, the difference in decomposition temperature between the first electron blocking layer material and the second electron blocking layer material is ≤20°C, for example, 10°C, 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C, etc.

[0101] Preferably, the difference in glass transition temperature between the first electron blocking layer material and the second electron blocking layer material is ≤15°C, for example, 5°C, 6°C, 7°C, 8°C, 9°C, 10°C, 11°C, 12°C, 13°C, 14°C, etc.

[0102] Preferably, the difference in evaporation temperature between the first electron blocking layer material and the second electron blocking layer material is ≤10°C, for example, 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C, etc.

[0103] Preferably, the difference in decomposition temperature between the first electron blocking layer material and the second electron blocking layer material is ≤20°C, the difference in glass transition temperature is ≤15°C, and the difference in evaporation temperature is ≤10°C.

[0104] Preferably, the evaporated thickness of the electron blocking layer is 5-150 nm, for example, 6 nm, 10 nm, 50 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 145 nm, etc., preferably 15-20 nm.

[0105] Preferably, the mass ratio of the second electron blocking layer material to the first electron blocking layer material is 20:1-1:20, for example, 19:1, 18:1, 17:1, 16:1, 15:1, 12:1, 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 2:1, 1:1, 0.2:1, 0.1:1, etc., preferably 9:1-11:1

[0106] Preferably, the organic functional layer further comprises one or at least two of a hole injection layer, an electron injection layer, an electron transport layer, a hole transport layer and a hole blocking layer.

[0107] Preferably, the electron blocking layer is located between the light emitting layer and the hole injection layer.

[0108] Preferably, the light-emitting layer includes any one of a green light-emitting layer, a red light-emitting layer, a blue light-emitting layer and a yellow light-emitting layer, or a combination of at least two of them.

[0109] Preferably, the organic electroluminescent element includes a display panel.

[0110] A second object of the present invention is to provide a method for preparing the organic electroluminescent element described in the first object, the method comprising the following steps:

[0111] (1) forming an anode layer on a substrate;

[0112] (2) a light-emitting layer and an organic functional layer are formed on the anode layer, wherein the organic functional layer includes an electron blocking layer, and optionally includes one or at least two layers of a hole injection layer, an electron injection layer, an electron transport layer, a hole transport layer and a hole blocking layer;

[0113] (3) forming a cathode layer on the organic functional layer to obtain the organic electroluminescent element;

[0114] The electron blocking layer comprises a premixed mixture of a first electron blocking layer material and a second electron blocking layer material, the first electron blocking layer material is different from the second electron blocking layer material, and the first electron blocking layer material has a structure shown in formula (1).

[0115] An organic electroluminescent element (OLED) includes a cathode and an anode, and an organic functional layer between the two electrodes. The organic functional layer includes multiple layers of organic materials, such as a hole injection layer, a hole transport region, a light-emitting layer, an electron transport region, an electron injection layer, etc.

[0116] In a specific embodiment, the anode or cathode is sputtered or deposited on the substrate. The substrate may include glass or polymer materials, and the main features are mechanical strength, thermal stability, light transmittance, etc. In addition, thin film transistors (TFTs) are also an indispensable part of the display substrate.

[0117] The anode material can be selected from oxides such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO), etc., and the cathode material can be selected from metals or metal alloys such as magnesium (Mg), silver (Ag), magnesium-silver (Mg-Ag), aluminum (Al), etc.

[0118] The organic functional layer can be formed on the electrode by vacuum thermal evaporation, spin coating, inkjet printing, etc. The material used for the organic functional layer can be an organic polymer compound or an organic small molecule compound.

[0119] The hole transport region is located between the anode and the light emitting layer. The hole transport region can be a single-layer hole transport layer (HTL) or a multi-layer structure including at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL).

[0120] The material of the hole transport region can be selected from, but not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene ethylene, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), aromatic amine derivatives, etc., as shown in the following compounds HT-1 to HT-34.

[0121]

[0122]

[0123] The hole injection layer is located between the anode and the hole transport layer. The hole injection layer can be a single compound material or a combination of multiple compounds. For example, the hole injection layer can use one or more compounds of HT-1 to HT-34 mentioned above, or one or more compounds of HI-1 to HI-3 below; or one or more compounds of HT-1 to HT-34 can be doped with one or more compounds of HI-1 to HI-3 below.

[0124]

[0125] The light-emitting layer may include a single organic compound or multiple compounds. The multiple compounds include a host material (Host) and a light-emitting dye (i.e., dopant) that emits different wavelength spectra. The light-emitting layer may be a monochromatic light-emitting layer that emits a single color such as red, green, and blue, or a single color light-emitting layer that can simultaneously emit different colors such as red, green, and blue.

[0126] In one aspect of the present invention, the blue light-emitting layer adopts fluorescent electroluminescence technology. The fluorescent host material of the blue light-emitting layer can be selected from, but not limited to, one or more combinations of BFH-1 to BFH-17 listed below.

[0127]

[0128] In one aspect of the present invention, the blue light emitting layer adopts fluorescent electroluminescence technology. The fluorescent dopant of the blue light emitting layer can be selected from, but not limited to, one or more combinations of BFD-1 to BFD-12 listed below.

[0129]

[0130]

[0131] In one aspect of the present invention, the green light emitting layer adopts phosphorescent electroluminescence technology. The main material of the green light emitting layer is selected from, but not limited to, one or more combinations of GPH-1 to GPH-80.

[0132]

[0133]

[0134]

[0135] In one aspect of the present invention, the green light emitting layer adopts phosphorescent electroluminescence technology. The phosphorescent dopant of the green light emitting layer can be selected from, but not limited to, one or more combinations of GPD-1 to GPD-47 listed below.

[0136]

[0137]

[0138]

[0139] In one aspect of the present invention, the red light emitting layer adopts phosphorescent electroluminescence technology. The main material of the red light emitting layer is selected from, but not limited to, one or more combinations of RH-1 to RH-31.

[0140]

[0141]

[0142] In one aspect of the present invention, the red light emitting layer adopts phosphorescent electroluminescence technology. The phosphorescent dopant of the red light emitting layer can be selected from, but not limited to, one or more combinations of RPD-1 to RPD-28 listed below.

[0143]

[0144]

[0145] The OLED organic functional layer also includes an electron transport layer between the light-emitting layer and the cathode. The electron transport layer can be a single-layer electron transport layer (ETL) or a multi-layer structure including at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

[0146] In one aspect of the present invention, the electron transport layer material can be selected from, but not limited to, one or more combinations of ET-1 to ET-57 listed below.

[0147]

[0148]

[0149]

[0150] The OLED device also includes an electron injection layer located between the electron transport layer and the cathode. The electron injection layer material includes but is not limited to one or more combinations listed below.

[0151] LiQ, LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li or Ca.

[0152] Compared with the prior art, the present invention has the following beneficial effects:

[0153] The electron blocking layer of the organic electroluminescent element provided by the present invention comprises two different types of electron blocking materials, one of which has a structure shown in formula (1). The compound shown in formula (1) is used in combination with the other type of electron blocking layer material to exert a better effect than itself. The synergistic effect of the two materials can further improve the luminous efficiency of the device, reduce the driving voltage, and prolong the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0154] Figure 1 is a schematic cross-sectional view of an organic electroluminescent element provided in one specific embodiment of the present invention;

[0155] Among them, 10 is the anode, 20 is the hole injection layer, 30 is the hole transport layer, 40 is the electron blocking layer, 50 is the light emitting layer, 60 is the hole blocking layer, 70 is the electron transport layer, 80 is the electron injection layer and 90 is the cathode. DETAILED DESCRIPTION

[0156] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0157] Synthesis example 1

[0158] This synthesis example provides a preparation method of compound C94, which is as follows:

[0159]

[0160] (1) Synthesis of intermediate M1:

[0161] The raw material 4-aminobiphenyl (50.0g, 295mmol) was dissolved in 350mL of N,N-dimethylbenzene formamide solvent, placed in a three-necked flask equipped with a constant pressure dropping funnel, and cooled to 0°C with an ice-water bath. N-bromosuccinimide (52.6g, 295mmol) was dissolved in 300mL of N,N-dimethylbenzene formamide, placed in a constant pressure dropping funnel, and the solution was slowly dripped into the reaction bottle, the reaction temperature was kept between 0°C and 5°C, and the addition was completed in about one hour, and the reaction was kept warm for half an hour, and the raw material was monitored for complete reaction, and then the reaction solution was poured into 1000mL of ice water, extracted with ethyl acetate (500mL, three times), the organic phases were combined, washed once with saturated brine, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain a brown oil, which was then purified by silica gel chromatography (petroleum ether / ethyl acetate, 10 / 1) to obtain 60g of a light yellow solid (compound M1-1), with a yield of 82%;

[0162] The compound M1-1 synthesized in the previous step (50.0g, 202mmol), 9,9-dimethylfluorene-2-boric acid (52.8g, 222mol), potassium carbonate (36.2g, 262mmol) were placed in a 1000mL three-necked flask, and the mixture was thoroughly stirred. The air on the flask was then replaced with nitrogen three times. Tetrakistriphenylphosphine palladium (4.66g, 4.03mmol) was added to the reaction solution under nitrogen protection, and the temperature was raised to 100°C for 18h. After cooling, the reaction solution was poured into a saturated aqueous ammonium chloride solution, extracted with ethyl acetate (500mL, three times), the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain a brown-red oil. The crude product was purified by silica gel chromatography (petroleum ether / ethyl acetate, 10 / 1) to obtain 60g of an off-white solid with a yield of 84%;

[0163] (2) Synthesis of compound C94:

[0164] Intermediate M1 (10.0 g, 33.9 mmol) and 4-bromobiphenyl (8.6 g, 37.2 mmol) were placed in a 250 mL three-necked flask, and then sodium tert-butoxide (3.9 g, 40.6 mmol) and toluene (150 mL) were added. After sufficient stirring, the air in the flask was replaced by nitrogen. Then, catalyst [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride (248 mg, 0.448 mmol) and 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl (278 mg, 0.678 mmol) were added, and the temperature was raised to 100 °C for reaction for 16 h. After cooling to room temperature, the reaction solution was poured into a saturated aqueous ammonium chloride solution and extracted with ethyl acetate (100 mL, three times). The organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate, filtered and concentrated to obtain a brown oil, which was purified by silica gel column chromatography (petroleum ether / dichloromethane, 15 / 1) to obtain 15 g of a white solid (compound C94-1), with a yield of 90%;

[0165] Take compound C94-1 (15 g, 30.8 mmol), (5.3g, 33.8mmol) and sodium tert-butoxide (3.55g, 36.9mmol) were loaded into a 500mL three-necked flask containing 200mL toluene, and fully stirred to dissolve. Then the air in the bottle was fully converted with nitrogen, and then the catalyst tri(dibenzylideneacetone)dipalladium (282mg, 0.308mmol) and 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl (505mg, 1.23mmol) were added to the reaction solution, and the temperature was raised to reflux reaction for 18h. After cooling, the reaction solution was poured into a saturated aqueous ammonium chloride solution, extracted with ethyl acetate (200mL, three times), the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain a brown-black oil. The crude product was purified with a silica gel layer column (petroleum ether / dichloromethane, 15 / 1) to obtain a light yellow solid. The solid was recrystallized twice from toluene and methanol and further purified by sublimation to obtain 9.0 g of a pale yellow solid with a purity of 99.9%, namely compound C94. MS-TOF (M+H): 757.

[0166] The MS-TOF characterization results of the compounds of the present invention were obtained by testing with a time-of-flight mass spectrometer (manufacturer Waters, model XevoG2-XS Tof).

[0167] Synthesis example 2

[0168] This synthesis example provides a preparation method of compound C142, which is as follows:

[0169]

[0170] The synthesis method of C142 is different from that of Synthesis Example 1 in that the raw material 2-(4-bromophenyl)dibenzofuran is replaced with an equal amount of 2-(3-bromophenyl)triphenylene. MS-TOF (M+H): 816.

[0171] Synthesis example 3

[0172] This synthesis example provides a preparation method of compound C1200, which is as follows:

[0173]

[0174] The difference between the synthesis method of C1200 and that of Synthesis Example 1 is that 9,9-dimethylfluorene-2-boric acid is replaced by an equal amount of dibenzothiophene-3-boric acid, 4-bromobiphenyl is replaced by an equal amount of 3-bromo-9,9-dimethylfluorene, and 2-(4-bromophenyl)dibenzofuran is replaced by an equal amount of 3-(2-bromophenyl)-9,9-dimethylfluorene. MS-TOF (M+H): 812.

[0175] Synthesis example 4

[0176] This synthesis example provides a preparation method of compound-7, which is as follows:

[0177]

[0178] The difference between the synthesis method of compound-7 and synthesis example 1 is that 9,9-dimethylfluorene-2-boric acid is replaced by an equal amount of phenylboric acid, 4-bromobiphenyl is replaced by an equal amount of 2-bromo-9,9-dimethylfluorene, and 2-(4-bromophenyl)dibenzofuran is replaced by an equal amount of 9-(4-bromophenyl)phenanthrene. MS-TOF (M+H): 797.

[0179] Synthesis example 5

[0180] This synthesis example provides a preparation method of compound-58, which is as follows:

[0181]

[0182] The difference between the synthesis method of compound 58 and synthesis example 1 is that 9,9-dimethylfluorene-2-boric acid is replaced by an equal amount of phenylboric acid, 4-bromobiphenyl is replaced by an equal amount of 2-bromo-9,9-dimethylfluorene, and 2-(4-bromophenyl)dibenzofuran is replaced by an equal amount of 6-(4-bromophenyl)-2-phenyldibenzothiophene. MS-TOF (M+H): 773.

[0183] Synthesis example 6

[0184] This synthesis example provides a preparation method of compound-70, which is as follows:

[0185]

[0186] The synthesis method of compound 70 is different from that of synthesis example 1 in that 9,9-dimethylfluorene-2-boric acid is replaced by phenylboric acid, 4-bromobiphenyl is replaced by 2-bromo-9,9-dimethylfluorene, and 2-(4-bromophenyl)dibenzofuran is replaced by 4-(4-biphenyl)-6-bromodibenzothiophene. MS-TOF (M+H): 773.

[0187] The structures of the devices prepared in the following examples and comparative examples are as follows: Figure 1 As shown, it specifically includes an anode 10, a hole injection layer 20, a hole transport layer 30, an electron blocking layer 40, a light emitting layer 50, a hole blocking layer 60, an electron transport layer 70, an electron injection layer 80 and a cathode 90.

[0188] Comparative Example 1

[0189] This comparative example provides a method for preparing an organic electroluminescent element, which is as follows:

[0190] The glass plate coated with the ITO transparent conductive layer was ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in a mixed solvent of acetone:ethanol, baked in a clean environment to completely remove the water, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam;

[0191] Place the glass substrate with the anode in a vacuum chamber and evacuate to 1×10 -5 ~9×10 -3 Pa, vacuum evaporating HT1:HI-2 on the above anode layer as a hole injection layer, the evaporation rate is 0.1nm / s:0.007nm / s, and the evaporation film thickness is 10nm;

[0192] HT1 was vacuum-deposited on the hole injection layer as the hole transport layer of the device, with a deposition rate of 0.1 nm / s and a total deposition thickness of 80 nm.

[0193] The above HT-11 was vacuum-deposited on the hole transport layer as the electron blocking layer of the device, with a deposition rate of 0.1 nm / s and a total deposition film thickness of 5 nm;

[0194] The light-emitting layer of the device is vacuum-deposited on the electron blocking layer. The evaporation rate of the main material BFH-1 is adjusted to 0.1nm / s by using the multi-source co-evaporation method. The evaporation rate of the dye BFD-1 is set at 3% ratio, and the total evaporation film thickness is 35nm.

[0195] The electron transport layer material ET-1 of the device is vacuum-deposited on the light-emitting layer, with a deposition rate of 0.1 nm / s and a total deposition film thickness of 20 nm;

[0196] LiF with a thickness of 0.5 nm was vacuum-evaporated on the electron transport layer (ETL) as an electron injection layer, and an Al layer with a thickness of 150 nm was used as the cathode of the device.

[0197] Comparative Example 2

[0198] This comparative example provides a method for preparing an organic electroluminescent element, which is as follows:

[0199] The glass plate coated with the ITO transparent conductive layer was ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in a mixed solvent of acetone:ethanol, baked in a clean environment to completely remove the water, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam;

[0200] Place the glass substrate with the anode in a vacuum chamber and evacuate to 1×10 -5 ~9×10 -3 Pa, vacuum evaporating HT1:HI-2 on the above anode layer as a hole injection layer, the evaporation rate is 0.1nm / s:0.007nm / s, and the evaporation film thickness is 10nm;

[0201] HT1 was vacuum-deposited on the hole injection layer as the hole transport layer of the device, with a deposition rate of 0.1 nm / s and a total deposition thickness of 80 nm.

[0202] The above HT-15 was vacuum-deposited on the hole transport layer as the electron blocking layer of the device, with a deposition rate of 0.1 nm / s and a total deposition film thickness of 35 nm;

[0203] The light-emitting layer of the device is vacuum-deposited on the electron blocking layer. The evaporation rate of the main material GPH-1 is adjusted to 0.1nm / s by using the multi-source co-evaporation method. The evaporation rate of the dye GPD-1 is set at 3% and the total evaporation film thickness is 35nm.

[0204] The electron transport layer material ET-1 of the device is vacuum-deposited on the light-emitting layer, with a deposition rate of 0.1 nm / s and a total deposition film thickness of 20 nm;

[0205] LiF with a thickness of 0.5 nm was vacuum-evaporated on the electron transport layer (ETL) as an electron injection layer, and an Al layer with a thickness of 150 nm was used as the cathode of the device.

[0206] Comparative Example 3

[0207] This comparative example provides a method for preparing an organic electroluminescent element, which is as follows:

[0208] The glass plate coated with the ITO transparent conductive layer was ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in a mixed solvent of acetone:ethanol, baked in a clean environment to completely remove the water, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam;

[0209] Place the glass substrate with the anode in a vacuum chamber and evacuate to 1×10 -5 ~9×10 -3 Pa, vacuum evaporating HT1:HI-2 on the above anode layer as a hole injection layer, the evaporation rate is 0.1nm / s:0.007nm / s, and the evaporation film thickness is 10nm;

[0210] HT1 was vacuum-deposited on the hole injection layer as the hole transport layer of the device, with a deposition rate of 0.1 nm / s and a total deposition thickness of 80 nm.

[0211] The above HT-19 was vacuum-deposited on the hole transport layer as the electron blocking layer of the device, with a deposition rate of 0.1 nm / s and a total deposition film thickness of 78 nm;

[0212] The light-emitting layer of the device is vacuum-deposited on the electron blocking layer. The evaporation rate of the main material RH-1 is adjusted to 0.1nm / s by using the multi-source co-evaporation method. The evaporation rate of the dye RPD-1 is set at 3% ratio, and the total evaporation film thickness is 35nm.

[0213] The electron transport layer material ET-1 of the device is vacuum-deposited on the light-emitting layer, with a deposition rate of 0.1 nm / s and a total deposition film thickness of 20 nm;

[0214] LiF with a thickness of 0.5 nm was vacuum-evaporated on the electron transport layer (ETL) as an electron injection layer, and an Al layer with a thickness of 150 nm was used as the cathode of the device.

[0215] Example 1

[0216] This embodiment provides a method for preparing an organic electroluminescent element, which is as follows:

[0217] The glass plate coated with the ITO transparent conductive layer was ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in a mixed solvent of acetone:ethanol, baked in a clean environment to completely remove the water, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam;

[0218] Place the glass substrate with the anode in a vacuum chamber and evacuate to 1×10 -5 ~9×10 -3Pa, vacuum evaporating HT1:HI-2 on the above anode layer as a hole injection layer, the evaporation rate is 0.1nm / s:0.007nm / s, and the evaporation film thickness is 10nm;

[0219] HT1 was vacuum-deposited on the hole injection layer as the hole transport layer of the device, with a deposition rate of 0.1 nm / s and a total deposition thickness of 80 nm.

[0220] The above-mentioned compound-7 and C94 were vacuum-deposited on the hole transport layer as the electron blocking layer of the device (mass ratio was 9:1), the evaporation rate was 0.1 nm / s, and the total evaporation film thickness was 15 nm;

[0221] The light-emitting layer of the device is vacuum-deposited on the electron blocking layer. The evaporation rate of the main material BFH-1 is adjusted to 0.1nm / s by using the multi-source co-evaporation method. The evaporation rate of the dye BFD-1 is set at 3% ratio, and the total evaporation film thickness is 35nm.

[0222] The electron transport layer material ET-1 of the device is vacuum-deposited on the light-emitting layer, with a deposition rate of 0.1 nm / s and a total deposition film thickness of 20 nm;

[0223] LiF with a thickness of 0.5 nm was vacuum-evaporated on the electron transport layer (ETL) as an electron injection layer, and an Al layer with a thickness of 150 nm was used as the cathode of the device.

[0224] Example 2

[0225] The device was prepared by the same method as in Example 1, except that the thickness of the electron blocking layer was 35 nm. The light-emitting layer was prepared by multi-source co-evaporation, with the evaporation rate of the main material GPH-1 adjusted to 0.1 nm / s, the evaporation rate of the dye GPD-1 set at 3%, and the total evaporation film thickness was 35 nm.

[0226] Example 3

[0227] The device was prepared by the same method as in Example 1, except that the thickness of the electron blocking layer was 78 nm;

[0228] The light-emitting layer uses a multi-source co-evaporation method to adjust the evaporation rate of the main material RH-1 to 0.1nm / s, the evaporation rate of the dye RPD-1 is set at 3%, and the total evaporation film thickness is 35nm.

[0229] Example 4

[0230] The device was prepared by the same method as in Example 1, except that Compound-7 was replaced by HT-11.

[0231] Example 5

[0232] The device was prepared by the same method as in Example 1, except that Compound-7 was replaced by HT-15.

[0233] Example 6

[0234] The device was prepared by the same method as in Example 1, except that Compound-7 was replaced by HT-19.

[0235] Example 7

[0236] The device was prepared by the same method as in Example 1, except that compound C94 was replaced by C142, and compound-7 was replaced by compound-58.

[0237] Example 8

[0238] The device was prepared by the same method as in Example 1, except that compound C94 was replaced by C1200, and compound-7 was replaced by compound-70.

[0239] Example 9

[0240] The device was manufactured by the same method as in Example 1, except that the total thickness of the electron blocking layer evaporated was changed to 5 nm.

[0241] Example 10

[0242] The device was manufactured by the same method as in Example 1, except that the total thickness of the electron blocking layer evaporated was changed to 20 nm.

[0243] Embodiment 11

[0244] The device was manufactured by the same method as in Example 1, except that the total film thickness of the electron blocking layer evaporated was changed to 100 nm.

[0245] Example 12

[0246] The device was manufactured by the same method as in Example 1, except that the total thickness of the electron blocking layer evaporated was changed to 150 nm.

[0247] Example 13

[0248] The device was prepared by the same method as in Example 1, except that the ratio of compound-7 to compound C94 was changed to 20:1.

[0249] Embodiment 14

[0250] The device was prepared by the same method as in Example 1, except that the ratio of compound-7 to compound C94 was changed to 11:1.

[0251] Embodiment 15

[0252] The device was prepared by the same method as in Example 1, except that the ratio of compound-7 to compound C94 was changed to 1:20.

[0253] Example 16

[0254] A device was prepared in the same manner as in Comparative Example 1, except that the compound HT-11 was replaced by a mixture of HT-11 and C94 at a doping ratio of 9:1.

[0255] Embodiment 17

[0256] A device was prepared in the same manner as in Comparative Example 2, except that the compound HT-15 was replaced by a mixture of HT-15 and C94 at a doping ratio of 9:1.

[0257] Embodiment 18

[0258] A device was prepared in the same manner as in Comparative Example 3, except that the compound HT-19 was replaced by a mixture of HT-19 and C94 at a doping ratio of 9:1.

[0259] Embodiment 19

[0260] The device was prepared by the same method as in Example 1, except that compound C94 was replaced by C265, and compound-7 was replaced by compound-171.

[0261] Embodiment 20

[0262] The device was prepared by the same method as in Example 1, except that compound C94 was replaced by C1417, and compound-7 was replaced by compound-96.

[0263] Embodiment 21

[0264] The device was prepared by the same method as in Example 1, except that compound C94 was replaced by C1446, and compound-7 was replaced by compound-150.

[0265] Comparative Example 4

[0266] A device was prepared by the same method as in Example 1, except that compound C94 was replaced by compound D1.

[0267]

[0268] Comparative Example 5

[0269] A device was prepared by the same method as in Example 1, except that Compound-7 was not used.

[0270] Performance Testing:

[0271] (1) Under the same brightness, the driving voltage and current efficiency of the organic electroluminescent devices prepared in the examples and comparative examples and the life of the devices were measured using a PR 750 photoradiometer, ST-86LA luminance meter (Beijing Normal University Photoelectric Instrument Factory) and Keithley 4200 test system. Specifically, the voltage was increased at a rate of 0.1 V per second to measure the brightness of the organic electroluminescent device at a blue light level of 1000 cd / m 2 , Green light 10000cd / m 2 , red light 5000cd / m 2 The voltage at this time is the driving voltage (V), and the current density at this time is measured at the same time; the ratio of brightness to current density is the current efficiency (CE, cd / A);

[0272] (2) The life test of LT97 is as follows: using ST-86LA luminance meter (Beijing Normal University Optoelectronic Instrument Factory) with blue light at 3000cd / m 2 , green light at 20000cd / m 2 , red light at 10000cd / m 2 Under the brightness, maintain a constant current and measure the time for the brightness of the organic electroluminescent device to drop to 97% of the initial brightness, in hours.

[0273] The above performance test results are shown in Table 1.

[0274] Table 1

[0275]

[0276]

[0277]

[0278] As can be seen from Table 1, the only difference between Examples 16-18 and Comparative Examples 1-3 is that the compound represented by formula (1) is doped into the electron blocking layer material. Compared with the undoped device (Comparative Examples 1-3), the driving voltage of the doped devices (Examples 16-18) is reduced, the current efficiency is improved, and the service life is longer. This proves that the technical solution provided by the present invention of using the compound represented by formula (1) together with other types of materials as the electron blocking layer material can effectively improve the performance of the device and extend the service life of the device.

[0279] By comparing Example 1 with Comparative Examples 4 and 5, it can be seen that whether two electron blocking materials that do not contain the compound of formula (1) are used (Comparative Example 4) or a single compound of formula (1) is used as an electron blocking material (Comparative Example 5), the effect produced by the combination of the compound of formula (1) and another blocking material cannot be achieved.

[0280] By comparing Example 1 and Example 4, it can be seen that when the electron blocking layer material is a mixture of compounds of two specific structures of formula (1) and formula (I) (Example 1), compared with the mixture of the compound of formula (1) and HT-11 (Example 4), the performance of the device can be further improved, the driving voltage can be reduced, the current efficiency can be improved, and the service life can be extended.

[0281] (3) Decomposition temperature, glass transition temperature and evaporation temperature test process of the electron blocking layer material in the embodiment and comparative example:

[0282] The decomposition temperature Td is tested by a thermogravimetric analyzer TGA. The temperature is controlled by a certain program to obtain the relationship between the mass of the measured sample and the temperature change, thereby obtaining the temperature when the mass of the material is reduced to 5%, that is, the decomposition temperature.

[0283] The glass transition temperature Tg is tested by using a differential scanning calorimeter DSC, which outputs different powers to the measured object and the reference object, measures the relationship between this difference and temperature, and thus obtains the temperature at which the material changes from a highly elastic state to a glassy state, i.e., the glass transition temperature.

[0284] The evaporation temperature is obtained during the evaporation process. The heating source at the bottom of the crucible heats the material carried inside the crucible. The temperature detection device detects this temperature. The rate detection device in the evaporation chamber is used to detect the evaporation rate, thereby obtaining the evaporation temperature of the material at a certain rate.

[0285] The above test results are shown in Table 2.

[0286] Table 2

[0287]

[0288]

[0289] The above results show that the display device of the present invention is used in an organic electroluminescent device, which can effectively reduce the driving voltage and improve the current efficiency, and at the same time can reduce the process cost and improve the finished product yield of the OLED display device.

[0290] The applicant declares that the present invention illustrates the detailed process equipment and process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process equipment and process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An organic electroluminescent element, characterized in that: The organic electroluminescent element comprises a base substrate, an anode conductive layer and a cathode conductive layer located on the base substrate, and a light emitting layer and an organic functional layer located between the anode conductive layer and the cathode conductive layer; The organic functional layer comprises an electron blocking layer, the electron blocking layer comprises a first electron blocking layer material and a second electron blocking layer material, the first electron blocking layer material is different from the second electron blocking layer material; The first electron blocking layer material has a structure shown in formula (1); In formula (1), X is selected from O, S or CR 5 R 6 ; said R 5 , R 6 is methyl; In formula (1), L 1 is selected from a single bond or phenylene; In formula (1), Ar 1 One selected from the following substituted or unsubstituted groups: phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, anthracenyl, fluoranthene, carbazolyl, fluorenyl, dibenzofuranyl, dibenzothiophenyl; In formula (1), R 4 One selected from the following substituted or unsubstituted groups: one of phenyl, biphenyl, terphenyl, naphthyl, fluorenyl, phenanthryl, anthracenyl, fluoranthenyl, carbazolyl, dibenzofuranyl, and dibenzothiophenyl; In formula (1), p is 0, 1 or 2; When the above groups have substituents, the substituents are independently selected from C1-C 10 One of alkyl or phenyl; The second electron blocking layer material has a structure shown in formula (I); In formula (I), L' represents a single bond or a phenylene group; In formula (I), R a’ and R b’ Each independently selected from one of C1-C6 alkyl groups, said R a’ and R b’ Not connected to form a ring structure; In formula (I), the R' is selected from phenyl, biphenyl or naphthyl; In formula (I), p' is 0 or 1; In formula (I), Ar' is selected from a heteroaryl group represented by formula (A'), or a C6-C 30 Aryl; In formula (A'), * represents the connection site with the mother core; In formula (A'), the L 1’ One selected from a single bond, a phenylene group, a naphthylene group, and a biphenylene group; In formula (A'), R 1’ Selected from C6-C 12 One of the aromatic groups, q' is 0 or 1; In formula (A'), X' is selected from O, S, NR 2’ 、SiR 3’ R 4’ One of; The R 2’ , R 3’ , R 4’ Each independently selected from methyl or phenyl, R 3’ and R 4’ Not connected into a ring.

2. An organic electroluminescent element, characterized in that: The organic electroluminescent element comprises a base substrate, an anode conductive layer and a cathode conductive layer located on the base substrate, and a light emitting layer and an organic functional layer located between the anode conductive layer and the cathode conductive layer; The organic functional layer comprises an electron blocking layer, the electron blocking layer comprises a first electron blocking layer material and a second electron blocking layer material, the first electron blocking layer material is different from the second electron blocking layer material; The first electron blocking layer material has a structure shown in formula (1); In formula (1), X is selected from O, S or CR 5 R 6 ; said R 5 , R 6 is methyl; In formula (1), L 1 is selected from a single bond or phenylene; In formula (1), Ar 1 One selected from the following substituted or unsubstituted groups: phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, anthracenyl, fluoranthene, carbazolyl, fluorenyl, dibenzofuranyl, dibenzothiophenyl; In formula (1), R 4 One selected from the following substituted or unsubstituted groups: one of phenyl, biphenyl, terphenyl, naphthyl, fluorenyl, phenanthryl, anthracenyl, fluoranthenyl, carbazolyl, dibenzofuranyl, and dibenzothiophenyl; In formula (1), p is 0, 1 or 2; When the above groups have substituents, the substituents are independently selected from C1-C 10 One of alkyl or phenyl; The second electron blocking layer material is selected from any one or a combination of at least two of the following compounds:

3. The organic electroluminescent element according to claim 1 or 2, characterized in that: The first electron blocking layer material has a structure shown in formula (2); In formula (2), X is selected from O, S or CR 5 R 6 ; In formula (2), L 1 is selected from a single bond or phenylene; In formula (2), Ar 1 One selected from the following substituted or unsubstituted groups: phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, anthracenyl, fluoranthene, carbazolyl, fluorenyl, dibenzofuranyl, dibenzothiophenyl; In formula (2), R 4 , R 5 , R 6 All have the same limited range as in formula (1); When the above groups have substituents, the substituents are independently selected from C1-C 10 One of alkyl or phenyl; Alternatively, the first electron blocking layer material has a structure shown in formula (3); In formula (3), X is selected from CR 5 R 6 ; In formula (3), L 1 is selected from a single bond or phenylene; In formula (3), Ar 1 One selected from the following substituted or unsubstituted groups: phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, anthracenyl, fluoranthene, carbazolyl, fluorenyl, dibenzofuranyl, dibenzothiophenyl; In formula (3), R 4 , R 5 , R 6 All have the same limited range as formula (1); When the above groups have substituents, the substituents are independently selected from C1-C 10 One of alkyl or phenyl; Alternatively, the first electron blocking layer material has a structure shown in formula (4); In formula (4), X is selected from CR 5 R 6 ; In formula (4), L 1 is selected from a single bond or phenylene; In formula (4), Ar 1 One selected from the following substituted or unsubstituted groups: phenyl, biphenyl, terphenyl, naphthyl, phenanthryl, anthracenyl, fluoranthene, carbazolyl, fluorenyl, dibenzofuranyl, dibenzothiophenyl; In formula (4), R 4 , R 5 , R 6 All have the same limited range as formula (1); When the above groups have substituents, the substituents are independently selected from C1-C 10 One of alkyl or phenyl.

4. The organic electroluminescent element according to claim 1 or 2, characterized in that: The R 4 Selected from phenyl or biphenyl.

5. The organic electroluminescent element according to claim 1 or 2, characterized in that: The first electron blocking layer material includes any one or a combination of at least two of the following compounds:

6. The organic electroluminescent element according to claim 1, characterized in that: In formula (A'), X' is selected from NR 2’ , O, S.

7. The organic electroluminescent element according to claim 1, characterized in that: The second electron blocking layer material has a structure shown in formula (II) or formula (III); In formula (II) and formula (III), the R a’ , R b’ is selected from C1-C6 alkyl, R a’ , R b’ Not connected to form a ring structure; In formula (II) and formula (III), p' is 0 or 1, R' is phenyl, biphenyl or naphthyl, and Ar' has the same definition as in formula (I); In formula (II) and formula (III), when Ar' is formula (A'), L 1’ represents a single bond, phenylene, naphthylene, biphenylene or phenylene, R 1’ Selected from C6-C 12 One of the aromatic groups, q' is 0 or 1, and X' is NR 2’ , O, S; R 2’ It is phenyl.

8. The organic electroluminescent element according to claim 1, characterized in that: In formula (I), Ar' is selected from the heteroaryl group represented by formula (A1'); In formula (A1'), * represents the linking site with the mother nucleus; In formula (A1'), X' is selected from N-Ph, O, S; In formula (A1'), R 1’ Selected from C6-C 12 Aryl, r' is 0 or 1, t' is 0 or 1, and r' and t' are not 1 at the same time, Ph represents phenyl, L 1’ It represents a single bond, a phenylene group, a naphthylene group, or a biphenylene group.

9. The organic electroluminescent element according to claim 1, characterized in that: The second electron blocking layer material includes any one or a combination of at least two of the following compounds:

10. The organic electroluminescent element according to claim 1 or 2, characterized in that: The difference in decomposition temperature between the first electron blocking layer material and the second electron blocking layer material is ≤20°C.

11. The organic electroluminescent element according to claim 1 or 2, characterized in that: The difference in glass transition temperature between the first electron blocking layer material and the second electron blocking layer material is ≤15°C.

12. The organic electroluminescent element according to claim 1 or 2, characterized in that: The difference in evaporation temperature between the first electron blocking layer material and the second electron blocking layer material is ≤10°C.

13. The organic electroluminescent element according to claim 1 or 2, characterized in that: The difference in decomposition temperature between the first electron blocking layer material and the second electron blocking layer material is ≤20°C, the difference in glass transition temperature is ≤15°C, and the difference in evaporation temperature is ≤10°C.

14. The organic electroluminescent element according to claim 1 or 2, characterized in that: The evaporated thickness of the electron blocking layer is 5-150nm.

15. The organic electroluminescent element according to claim 14, characterized in that: The evaporated thickness of the electron blocking layer is 15-20 nm.

16. The organic electroluminescent element according to claim 1 or 2, characterized in that: The mass ratio of the second electron blocking layer material to the first electron blocking layer material is 20:1-1:

20.

17. The organic electroluminescent element according to claim 16, characterized in that: The mass ratio of the second electron blocking layer material to the first electron blocking layer material is 9:1-11:

1.

18. The organic electroluminescent element according to claim 1 or 2, characterized in that: The organic functional layer further includes one or at least two of a hole injection layer, an electron injection layer, an electron transport layer, a hole transport layer and a hole blocking layer.

19. The organic electroluminescent element according to claim 18, characterized in that: The electron blocking layer is located between the light emitting layer and the hole injection layer.

20. The organic electroluminescent element according to claim 1 or 2, characterized in that: The light-emitting layer includes any one of a green light-emitting layer, a red light-emitting layer, a blue light-emitting layer and a yellow light-emitting layer, or a combination of at least two of them.

21. The organic electroluminescent element according to claim 1 or 2, characterized in that: The organic electroluminescent element includes a display panel.

22. A method for preparing an organic electroluminescent element according to claim 1, characterized in that: The preparation method comprises the following steps: (1) forming an anode layer on a substrate; (2) a light-emitting layer and an organic functional layer are formed on the anode layer, wherein the organic functional layer includes an electron blocking layer, and optionally includes one or at least two layers of a hole injection layer, an electron injection layer, an electron transport layer, a hole transport layer and a hole blocking layer; (3) forming a cathode layer on the organic functional layer to obtain the organic electroluminescent element; The electron blocking layer comprises a premixed mixture of a first electron blocking layer material and a second electron blocking layer material, the first electron blocking layer material is different from the second electron blocking layer material, the first electron blocking layer material has a structure as shown in formula (1) as claimed in claim 1, and the second electron blocking layer material has a structure as shown in formula (I) as claimed in claim 1.

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