An organic electroluminescent device

Abstract

The present invention relates to an organic electroluminescent device, which comprises a first electrode, a second electrode, and an organic layer located between the first electrode and the second electrode. The organic layer includes a light-emitting layer, a hole transport layer, and an electron transport layer. The hole transport layer includes the compound represented by formula (1), and the electron transport layer includes the compound represented by formula (2). By using the hole transport layer material represented by formula (1) and the electron transport layer material represented by formula (2) in combination, the present invention can effectively balance carriers, thereby reducing the driving voltage of the device, improving the light-emitting efficiency of the device, and prolonging the service life of the device.

Description

Technical Field

[0001] The present invention relates to an organic electroluminescent device, and particularly to an organic light-emitting device with a low driving voltage, high luminous efficiency, and long lifespan. Background Art

[0002] In recent years, optoelectronic devices based on organic materials have become increasingly popular. The inherent flexibility of organic materials makes them very suitable for manufacturing on flexible substrates, and they can be designed and produced into beautiful and cool optoelectronic products according to requirements, obtaining incomparable advantages over inorganic materials. Examples of such organic optoelectronic devices include organic light-emitting diodes (OLEDs), organic field-effect transistors, organic photovoltaic cells, organic sensors, etc. Among them, the development of OLEDs has been particularly rapid, and commercial success has been achieved in the field of information display. OLEDs can provide high-saturation red, green, and blue colors, and full-color display devices made of them do not require an additional backlight source, having advantages such as gorgeous colors, lightness, and softness.

[0003] As OLED products gradually enter the market, people have higher and higher requirements for the performance of such products. Industry insiders have also continuously tried and explored to improve the efficiency and stability of devices. Among them, there are many ways to seek new materials to improve device performance, and a large number of novel materials have been developed and applied to OLED devices. Although it has certain improvements to device performance, there is still carrier imbalance, which restricts the improvement of device efficiency and stability.

[0004] The currently used OLED materials and device structures cannot completely solve various problems such as the efficiency, lifespan, and cost of OLED products.

[0005] The inventors of the present invention have been committed to developing organic functional materials and have proposed various materials suitable for use in the hole transport layer or electron blocking layer. Among them, in Chinese Patent Application CN111606813A, a technical solution of using a compound with the following specific aniline structure as the hole transport layer and electron blocking layer has been disclosed.

[0006]

[0007] The inventors of the present invention have found through in-depth research that the OLED device prepared by the above solution has good performance of reducing voltage and extending the lifespan of the device, but the luminous efficiency of the OLED device still needs to be improved. Therefore, it is necessary to further optimize the matching scheme of each functional layer in the OLED device. Summary of the Invention

[0008] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide an organic electroluminescent device, which has a lower driving voltage, as well as higher luminous efficiency and lifespan.

[0009] The present invention provides an organic electroluminescent device, which includes a first electrode, a second electrode, and an organic layer located between the first electrode and the second electrode. The organic layer includes a hole transport layer, a light-emitting layer, and an electron transport layer, wherein the hole transport layer contains a compound having a structure shown in formula (1):

[0010]

[0011] In formula (1), Ar 1 is selected from a substituted or unsubstituted C10-C50 fused polycyclic aryl group, or a substituted or unsubstituted C6-C50 fused polycyclic heteroaryl group;

[0012] Ar 2 is selected from one of hydrogen, deuterium, a halogen, or a substituted or unsubstituted group selected from the following: a C1-C12 alkyl group, a C3-C30 cycloalkyl group, a C1-C12 alkoxy group, a C3-C30 cycloalkoxy group, a C2-C20 alkenyl group, a C2-C20 alkynyl group, a carbonyl group, a cyano group, a C6-C50 aryl group, a C3-C30 heteroaryl group, a C10-C50 fused polycyclic aryl group, a C6-C50 fused polycyclic heteroaryl group;

[0013] L 1 and L 2 are independently selected from a single bond, a substituted or unsubstituted C1-C12 alkylene group, a substituted or unsubstituted C6-C50 arylene group, a substituted or unsubstituted C3-C30 heteroarylene group, a substituted or unsubstituted C10-C50 fused polycyclic arylene group, a substituted or unsubstituted C6-C50 fused polycyclic heteroarylene group;

[0014] G 1 is selected from a substituted or unsubstituted group selected from the following: a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, a fluorene group, a spirofluorene group, a dibenzofuran group, a dibenzothiophene group, a dibenzoselenophene group, an azafluorene group, an azadibenzofuran group, an azadibenzothiophene group, an azadibenzoselenophene group;

[0015] G 2 is selected from a substituted or unsubstituted group selected from the following: a C6-C50 aryl group, a C3-C30 heteroaryl group, a C10-C50 fused polycyclic aryl group, a C6-C50 fused polycyclic heteroaryl group;

[0016] n is an integer from 0 to 5;

[0017] When the above groups are substituted in formula (1), the substituents are independently selected from one of deuterium, halogen, C1-C12 alkyl, C3-C30 cycloalkyl, C1-C12 alkoxy, C3-C30 cycloalkoxy, C2-C20 alkenyl, C2-C20 alkynyl, carbonyl, cyano, C6-C50 aryl, C3-C30 heteroaryl, C10-C50 fused-ring aryl, C6-C50 fused-ring heteroaryl;

[0018] The electron transport layer contains a compound having a structure represented by formula (2):

[0019]

[0020] In formula (2), X 1 ~X 4 are each independently N or CR; different Rs are each independently H, halogen, cyano, nitro, hydroxy, C1-C12 alkyl, C1-C12 alkoxy, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C3-C60 heteroaryl; different Rs may be connected to form an aliphatic ring or an aromatic ring,

[0021] L 3 is a single bond, an m+1-valent substituted or unsubstituted C6-C60 aryl residue, an m+1-valent substituted or unsubstituted C3-C60 heteroaryl residue; L 4 is a single bond, a p+1-valent substituted or unsubstituted C6-C60 aryl residue, a p+1-valent substituted or unsubstituted C3-C60 heteroaryl residue;

[0022] m and p are integers from 1 to 3; when L 3 is a single bond, m is 1; when L 4 is a single bond, p is 1;

[0023] Ar 3 and Ar 4 are each independently selected from H, C1-C12 alkyl, C1-C12 alkoxy, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C3-C60 heteroaryl, cyano or a combination thereof; Ar 3 and Ar 4 are not both H at the same time, Ar 3 and Ar 4 are not both C1-C12 alkyl at the same time, Ar 3 and Ar 4 are not both C1-C12 alkoxy at the same time;

[0024] In formula (2), when the above-mentioned groups are substituted, the substituents are independently selected from the group consisting of halogen, nitro, cyano, aryl having 6 to 60 carbon atoms, heteroaryl having 3 to 60 carbon atoms, alkyl having 1 to 30 carbon atoms, alkoxy having 1 to 30 carbon atoms, aryloxy having 6 to 60 carbon atoms, amino, silyl having 1 to 30 carbon atoms, arylamino having 6 to 60 carbon atoms, heteroarylamino having 3 to 60 carbon atoms, or a combination of at least two of the above groups.

[0025] For the organic electroluminescent device provided by the present invention, a compound having the structure shown in formula (1) is selected as the hole transport layer material, and a compound having the structure shown in formula (2) is selected as the electron transport layer material. More preferably, as the host material in the electron transport layer, Liq is doped as the guest material. The above-mentioned combination of materials in the hole transport layer and the electron transport layer can balance the carriers in the organic layer of the device, increase the recombination region of holes and electrons in the organic layer of the device, and thus can effectively reduce the driving voltage of the device and achieve the invention purposes of improving the luminous efficiency and the device lifetime.

[0026] Preferably, in the organic electroluminescent device of the present invention, the hole transport layer contains one or two of the following compounds:

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036] Preferably, in the organic electroluminescent device of the present invention, the electron transport layer contains a compound having the structure shown in formula (3):

[0037]

[0038] In formula (3), the R 3 ~R 6Each independently is H, halogen, cyano, nitro, hydroxy, C1-C12 alkyl, C1-C12 alkoxy, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C3-C60 heteroaryl; R 3 ~R 6 may be connected to form an aliphatic ring or an aromatic ring,

[0039] L 3 is a single bond, a substituted or unsubstituted C6-C30 aryl residue of m+1 valence, a substituted or unsubstituted C3-C30 heteroaryl residue of m+1 valence; L 4 is a single bond, a substituted or unsubstituted C6-C30 aryl residue of p+1 valence, a substituted or unsubstituted C3-C30 heteroaryl residue of p+1 valence;

[0040] Ar 3 、Ar 4 、m, p have the same meanings as those indicated in claim 1. When the above groups are substituted, the substituents are independently selected from one or a combination of at least two of halogen, nitro, cyano, C6-C60 aryl, C3-C60 heteroaryl, C1-C30 alkyl, C1-C30 alkoxy, C6-C60 aryloxy, amino, C1-C30 silyl, C6-C60 arylamino, C3-C60 heteroarylamino;

[0041] Preferably, L 3 and L 4 are not both single bonds at the same time;

[0042] More preferably, L 3 is a single bond, a substituted or unsubstituted phenyl residue of m+1 valence, a substituted or unsubstituted naphthyl residue of m+1 valence, a substituted or unsubstituted anthryl residue of m+1 valence, a substituted or unsubstituted phenanthryl residue of m+1 valence, a substituted or unsubstituted pyrenyl residue of m+1 valence; L 4 is a single bond, a substituted or unsubstituted phenyl residue of p+1 valence, a substituted or unsubstituted naphthyl residue of p+1 valence, a substituted or unsubstituted anthryl residue of p+1 valence, a substituted or unsubstituted phenanthryl residue of p+1 valence, a substituted or unsubstituted pyrenyl residue of p+1 valence.

[0043] Preferably, in formula (3), Ar 3 and Ar 4 each independently is selected from one or a combination of two or more of the following substituted or unsubstituted groups:

[0044]

[0045]

[0046] Among them, the wavy line marked part represents the bonding site of the group with L 3 or L 4 ;

[0047] The above-mentioned groups can be substituted by one or a combination of at least two groups selected from halogen, nitro, cyano, aryl with 6 to 60 carbon atoms, heteroaryl with 3 to 60 carbon atoms, alkyl with 1 to 30 carbon atoms, alkoxy with 1 to 30 carbon atoms, aryloxy with 6 to 60 carbon atoms, amino, silyl with 1 to 30 carbon atoms, arylamino with 6 to 60 carbon atoms, heteroarylamino with 3 to 60 carbon atoms;

[0048] Preferably, at least one of Ar 3 and Ar 4 is an electron-deficient group.

[0049] It should be noted that in this specification, the expression of Ca-Cb represents that the group has a carbon atom number of a-b. Generally, unless otherwise specified, the carbon atom number does not include the carbon atom number of the substituent. In the present invention, for the expression of chemical elements, unless otherwise specified, it usually includes the concept of isotopes with the same chemical properties. For example, the expression of "hydrogen" also includes the concepts of "deuterium" and "tritium" with the same chemical properties. Carbon (C) includes 12 C, 13 C, etc., which will not be elaborated here.

[0050] In the structural formulas disclosed in this specification, the expression of the ring structure crossed by "-" indicates that the bonding site is at any position on the ring structure capable of forming a bond.

[0051] In this specification, unless otherwise specified, aryl and heteroaryl both include monocyclic and fused-ring cases. The so-called monocyclic aryl refers to a molecule containing at least one phenyl group. When the molecule contains at least two phenyl groups, the phenyl groups are independent of each other and are connected by single bonds. Exemplarily, such as phenyl, biphenyl, terphenyl, etc.; fused-ring aryl refers to a molecule containing at least two benzene rings, but the benzene rings are not independent of each other, but share ring edges and are fused together. Exemplarily, such as naphthyl, anthracenyl, etc.; monocyclic heteroaryl refers to a molecule containing at least one heteroaryl group. When the molecule contains a heteroaryl group and other groups (such as aryl, heteroaryl, alkyl, etc.), the heteroaryl group and other groups are independent of each other and are connected by single bonds. Exemplarily, such as pyridine, furan, thiophene, etc.; fused-ring heteroaryl refers to being fused by at least one phenyl group and at least one heteroaryl group, or being fused by at least two heteroaromatic rings. Exemplarily, such as quinoline, isoquinoline, benzofuran, dibenzofuran, benzothiophene, dibenzothiophene, etc.

[0052] In this specification, the substituted or unsubstituted C6-C60 aryl group is preferably a C6-C30 aryl group, more preferably a group selected from the group consisting of phenyl, naphthyl, anthracenyl, benzanthracenyl, phenanthryl, benzophenanthryl, pyrenyl, chrysenyl, perylenyl, fluoranthenyl, tetraphenylenyl, pentaphenylenyl, benzopyrenyl, biphenyl, terphenyl, triphenylenyl, tetraphenyl, fluorene, spirobifluorene, dihydrophenanthryl, dihydropyrenyl, tetrahydropyrenyl, cis- or trans-indeno[1,2-b]fluorene, truxene, isotruxene, spirotruxene, spiroisotruxene. Specifically, biphenyl is selected from 2-biphenyl, 3-biphenyl and 4-biphenyl; terphenyl includes p-terphenyl-4-yl, p-terphenyl-3-yl, p-terphenyl-2-yl, m-terphenyl-4-yl, m-terphenyl-3-yl and m-terphenyl-2-yl; the naphthyl group includes 1-naphthyl or 2-naphthyl; anthracenyl is selected from the group consisting of 1-anthracenyl, 2-anthracenyl and 9-anthracenyl; the fluorene group is selected from the group consisting of 1-fluorene, 2-fluorene, 3-fluorene, 4-fluorene and 9-fluorene; the pyrenyl group is selected from the group consisting of 1-pyrenyl, 2-pyrenyl and 4-pyrenyl; tetraphenylenyl is selected from the group consisting of 1-tetraphenylenyl, 2-tetraphenylenyl and 9-tetraphenylenyl. As a preferred example of the aryl group in the present invention, a group selected from the group consisting of phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthryl, indenyl, fluorene and its derivatives, fluoranthenyl, triphenylene, pyrenyl, perylenyl, and tetraphenylenyl can be cited. The biphenyl is selected from 2-biphenyl, 3-biphenyl and 4-biphenyl; the terphenyl includes p-terphenyl-4-yl, p-terphenyl-3-yl, p-terphenyl-2-yl, m-terphenyl-4-yl, m-terphenyl-3-yl and m-terphenyl-2-yl; the naphthyl group includes 1-naphthyl or 2-naphthyl; the anthracenyl is selected from the group consisting of 1-anthracenyl, 2-anthracenyl and 9-anthracenyl; the fluorene group is selected from the group consisting of 1-fluorene, 2-fluorene, 3-fluorene, 4-fluorene and 9-fluorene; the fluorene derivatives are selected from the group consisting of 9,9-dimethylfluorene, 9,9-spirobifluorene and benzofluorene; the pyrenyl group is selected from the group consisting of 1-pyrenyl, 2-pyrenyl and 4-pyrenyl; the tetraphenylenyl is selected from the group consisting of 1-tetraphenylenyl, 2-tetraphenylenyl and 9-tetraphenylenyl. The C6-C60 aryl group of the present invention may also be a group formed by combining the above groups through single bonds or / and condensation.

[0053] Specific examples of the m + 1-valent and p + 1-valent aryl residues in the present invention may include divalent groups obtained by removing one hydrogen atom from the above examples of aryl groups.

[0054] The heteroatoms in the present invention generally refer to those selected from N, O, S, P, Si and Se, preferably selected from N, O, S.

[0055] In the present specification, the substituted or unsubstituted C3-C60 heteroaryl group is preferably a C3-C30 heteroaryl group, more preferably a nitrogen-containing heteroaryl group, an oxygen-containing heteroaryl group, a sulfur-containing heteroaryl group, etc. Specific examples include: furyl, thienyl, pyrrolyl, pyridyl, benzofuryl, benzothienyl, isobenzofuryl, isobenzothienyl, indolyl, isoindolyl, dibenzofuryl, dibenzothienyl, carbazolyl and its derivatives, quinolinyl, isoquinolinyl, acridinyl, phenanthridinyl, benzo-5,6-quinolinyl, benzo-6,7-quinolinyl, benzo-7,8-quinolinyl, phenothiazinyl, phenazinyl, pyrazolyl, indazolyl, imidazolyl, benzimidazolyl, naphthimidazolyl, phenanthrimidazolyl, pyridinimidazolyl, pyrazinimidazolyl, quinoxalinimidazolyl, oxazolyl, benzoxazolyl, naphthoxazolyl, anthroxazolyl, phenanthroxazolyl, 1,2-thiazolyl, 1,3-thiazolyl, benzothiazolyl, pyridazinyl, benzopyridazinyl, pyrimidinyl, benzopyrimidinyl, quinoxalinyl, 1,5-diazaanthracenyl, 2,7-diazapyrenyl, 2,3-diazapyrenyl, 1,6-diazapyrenyl, 1,8-diazapyrenyl, 4,5-diazapyrenyl, 4,5,9,10-tetraazapyrenyl, pyrazinyl, phenazinyl, phenothiazinyl, naphthyridinyl, azacarbazolyl, benzocarbazolyl, phenanthroline, 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, benzothiadiazole, etc. Preferred examples of the heteroaryl group in the present invention are, for example, furyl, thienyl, pyrrolyl, benzofuryl, benzothienyl, isobenzofuryl, indolyl, dibenzofuryl, dibenzothienyl, carbazolyl and its derivatives, wherein the carbazolyl derivative is preferably 9-phenylcarbazole, 9-naphthylcarbazole benzocarbazole, dibenzocarbazole or indolocarbazole. The C3-C60 heteroaryl group of the present invention may also be a group formed by combining the above groups through single bonds or / and fusion.

[0056] Specific examples of the m+1-valent and p+1-valent heteroaryl residues in the present invention may include divalent groups obtained by removing one hydrogen atom from the examples of the above heteroaryl groups.

[0057] In this specification, the concept of alkyl includes cycloalkyl. Examples of C1-C30 alkyl include: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, neopentyl, n-hexyl, cyclohexyl, adamantyl, neohexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, 2-ethylhexyl, trifluoromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl, and the like.

[0058] In this specification, cycloalkyl includes monocycloalkyl and polycycloalkyl, and examples thereof may be cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and the like.

[0059] In this specification, examples of C1-C30 alkoxy include: methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, tert-butoxy, pentyloxy, isopentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, and the like. Among them, methoxy, ethoxy, n-propoxy, isopropoxy, tert-butoxy, sec-butoxy, isobutoxy, and isopentyloxy are preferred, and methoxy is more preferred.

[0060] In this specification, examples of C1-C30 silyl may be silyl groups substituted with the groups exemplified in the above C1-C30 alkyl, and specific examples include: methylsilyl, dimethylsilyl, trimethylsilyl, ethylsilyl, diethylsilyl, triethylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl, and other groups.

[0061] In this specification, examples of halogen include: fluorine, chlorine, bromine, iodine, and the like.

[0062] More specifically, as the above R 3 ~R 6groups, and preferably, examples thereof may include hydrogen, 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, benzanthracenyl, phenanthryl, benzophenanthryl, pyrenyl, chrysenyl, perylenyl, fluoranthenyl, tetraphenylenyl, pentaphenylenyl, benzopyrenyl, biphenyl, azobenzene, terphenyl, triphenylenyl, quaterphenyl, fluorenyl, spirobifluorenyl, dihydrophenanthryl, dihydropyrenyl, tetrahydropyrenyl, cis- or trans-indeno[1,2-b]fluorene, trindene, isotrindene, spirotrindene, spiroisotrindene, furyl, benzofuryl, isobenzofuryl, dibenzofuryl, thienyl, benzothienyl, isobenzothienyl, dibenzothienyl, pyrrolyl, isoindolyl, carbazolyl, indolocarbazolyl, pyridyl, quinolinyl, isoquinolinyl, acridinyl, phenanthridinyl, benzo[5,6]quinolinyl, benzo[6,7]quinolinyl, benzo[7,8]quinolinyl, pyrazolyl, indazolyl, imidazolyl, benzimidazolyl, naphthimidazolyl, phenanthrimidazolyl, pyridimidazolyl, pyrazinimidazolyl, quinoxalinimidazolyl, oxazolyl, benzoxazolyl, naphthoxazolyl, anthraoxazolyl, phenanthroxazolyl, 1,2-thiazolyl, 1,3-thiazolyl, benzothiazolyl, pyridazinyl, benzopyridazinyl, pyrimidinyl, benzopyrimidinyl, quinoxalinyl, 1,5-diazaanthracenyl, 2,7-diazapyrenyl, 2,3-diazapyrenyl, 1,6-diazapyrenyl, 1,8-diazapyrenyl, 4,5-diazapyrenyl, 4,5,9,10-tetraazaperylenyl, pyrazinyl, phenazinyl, phenothiazinyl, naphthyridinyl, azacarbazolyl, benzocarbazolyl, phenanthrolinyl, 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, benzothiadiazolyl, or a combination selected from the above two groups. However, R 3 ~R 6 is not limited to these groups.

[0063] Ar 3 、Ar 4independently selected from C1-C12 alkyl, C1-C12 alkoxy, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C3-C60 heteroaryl, cyano, or a combination thereof, and refers to a group obtained by connecting or condensing the above-listed various groups through a single bond.

[0064] In the present invention, the "substituted or unsubstituted" group may be substituted with one substituent or multiple substituents. When there are multiple substituents, they may be selected from different substituents. When the same expression is involved in the present invention, it has the same meaning, and the selection range of substituents is as shown above and will not be elaborated one by one.

[0065] Furthermore, when at least one of Ar 3 and Ar 4 is an electron-deficient group, the technical effect of the present invention is more excellent. The so-called "electron-deficient group" refers to a group that reduces the electron cloud density on the benzene ring after substituting the hydrogen on the benzene ring. Generally, the Hammett value of such a group is greater than 0.6. The Hammett value is a characterization of the charge affinity of a specific group and is a measure of an electron-withdrawing group (positive Hammett value) or an electron-donating group (negative Hammett value). The Hammett equation is described in more detail on pages 143-151 of Thomas H. Lowry and Katheleen Schueller Richardson, "Mechanism and Theory In Organic Chemistry", New York, 1987, and is hereby incorporated by reference. Such groups can be exemplified but not limited to: triazinyl, pyrimidinyl, benzopyrimidinyl, benzopyridyl, phthalazinyl, phenanthrolinyl, pyrazinyl, quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, pyridazinyl, and the above groups substituted with alkyl or aryl. Such groups are preferably triazine, pyrimidine, aryl cyanide, pyridine, quinazoline and other groups.

[0066] Preferably, in the organic electroluminescent device of the present invention, the electron transport layer contains a compound having a structure represented by formula (III-1)-(III-8):

[0067]

[0068] In the formula, R 3 ~R 6 has the same meaning as expressed in claim 3;

[0069] Y is C, N, O or S; X is a single bond, C, N, O or S;

[0070] Z 1 ~Z 6 are each independently N or CR, and the R, R7 ~R 10 Each independently is one or a combination of at least two selected from halogen, nitro, cyano, aryl having 6 to 60 carbon atoms, heteroaryl having 3 to 60 carbon atoms, alkyl having 1 to 30 carbon atoms, alkoxy having 1 to 30 carbon atoms, aryloxy having 6 to 60 carbon atoms, amino, silyl having 1 to 30 carbon atoms, arylamino having 6 to 60 carbon atoms, and heteroarylamino having 3 to 60 carbon atoms.

[0071] Preferably, in the organic electroluminescent device of the present invention, the electron transport layer contains one or two of the following compounds:

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088] Preferably, in the organic electroluminescent device of the present invention, the thickness of the hole transport layer is 1 nm to 150 nm, such as 50 nm, 70 nm, 80 nm, 90 nm, 110 nm, 130 nm, 150 nm, etc., and preferably 70 nm to 90 nm.

[0089] Preferably, in the organic electroluminescent device of the present invention, the thickness of the electron transport layer is 10 nm to 50 nm, such as 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 40 nm, 50 nm, etc., and preferably 20 nm to 30 nm.

[0090] Preferably, in the organic electroluminescent device of the present invention, the compound having the structure shown in formula (2) included in the electron transport layer is used as the host material in the electron transport layer, and Liq is further included as the guest material in the electron transport layer. The doping ratio of the guest material in the host material in the electron transport layer is 10% - 200% (molar ratio), such as 10%, 50%, 100%, 120%, 150%, 200%, etc., and preferably 50% - 150% (molar ratio).

[0091] In the organic electroluminescent device of the present invention, the organic layer further includes at least one of a hole injection layer, a hole blocking layer, an electron injection layer, and an electron blocking layer.

[0092] In the organic electroluminescent device of the present invention, it is prepared by vacuum deposition, and other methods can also be used, not limited to vacuum deposition. The device prepared by vacuum deposition in the present invention is used for illustration.

[0093] Its preparation method includes substrate cleaning, drying, pretreatment, and loading into the chamber, and sequentially vacuum depositing a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode.

[0094] Among them, the substrate is a rigid substrate or a flexible substrate. The rigid substrate includes a glass substrate, a Si substrate, etc., and the flexible substrate includes a polyvinyl alcohol (PVA) film, a polyimide (PD) film, a polyester (PET) film, etc.; the substrate of the present invention is preferably a rigid glass substrate.

[0095] For the anode, a conductive compound, alloy, metal, and a mixture of such materials with a relatively large work function can be preferably used. Inorganic materials can be used, and the inorganic materials include metals or metal oxides, laminates formed by alternating metals with metals or metals with non-metals, etc. The metal oxides include indium tin oxide (ITO), zinc oxide (ZnO), indium zinc oxide (IZO), tin oxide (SnO), etc., and the metals include gold, silver, copper, aluminum, etc. with a relatively high work function; the anode of the present invention is preferably ITO.

[0096] The hole injection layer is selected as m-MTDATA doped with 6% of f4-TCNQ, and the structure is as follows:

[0097]

[0098] The host material of the blue light-emitting layer is selected from any one or at least two combinations of the compounds shown in BFH-1 to BFH-17 as follows:

[0099]

[0100] The host material of the blue light emitting layer is selected from any one or at least two combinations of the compounds shown in BFD-1 to BFD-24 as follows:

[0101]

[0102]

[0103] The host material of the phosphorescent light emitting layer is selected from any one or at least two combinations of the compounds shown in PH-1 to PH-85 as follows:

[0104]

[0105]

[0106]

[0107]

[0108] The host material of the phosphorescent light emitting layer is selected from any one or at least two combinations of the compounds shown in GPD-1 to GPD-47 as follows or any one or at least two combinations of the compounds shown in RPD-1 to RPD-28:

[0109]

[0110]

[0111]

[0112] The guest doping material of the electron transport layer is Liq, and its structural formula is:

[0113]

[0114] The cathode is a magnesium-silver mixture, LiF / Al, ITO and other metals, metal mixtures, oxides, etc. The present invention preferably uses Yb / magnesium-silver mixture.

[0115] Compared with the prior art, the organic electroluminescent device provided by the present invention has the advantages of reducing the driving voltage of the device, improving the luminous efficiency, and improving the lifespan of the device. Description of the Drawings

[0116] Figure 1 It is a schematic structural diagram of the organic electroluminescent device provided in Embodiment 1 of the present invention;

[0117] Among them, 1 - anode, 2 - hole injection layer, 3 - hole transport layer, 4 - light-emitting layer, 5 - electron transport layer, 6 - electron injection layer, 7 - cathode. Detailed implementation mode

[0118] To facilitate the understanding of the present invention, the following examples are listed for the present invention. Those skilled in the art should understand that the said examples are only to help understand the present invention and should not be regarded as specific limitations on the present invention.

[0119] The compound with the structure shown in the general formula (1) in the above-mentioned present invention can be prepared according to the method disclosed in the patent application CN111606813A.

[0120] The compound with the structure described in the general formula (2) in the above-mentioned present invention can be prepared according to the method in the patent application No. 202011092633.1. The present invention will not elaborate on the preparation method.

[0121] Example 1

[0122] The embodiment of the present invention provides an organic electroluminescent device, and the structure of the organic electroluminescent device is as shown in the attached Figure 1 description, specifically including an anode 1, a hole injection layer (HIL layer) 2, a hole transport layer (HTL layer) 3, a light-emitting layer (EML layer) 4, an electron transport layer (ETL layer) 5, an electron injection layer (EIL layer) 6 and a cathode 7.

[0123] The preparation method of the organic electroluminescent device is as follows:

[0124] On an anode glass substrate with a film thickness of 150 nm formed with indium tin oxide (ITO) / Ag / indium tin oxide (ITO), using the vacuum deposition method, when the vacuum degree reaches 2×10 -4Deposition of each film layer was carried out under Pa. First, an m-MTDATA:6% f4-TCNQ thin film was formed on ITO as the hole injection layer (6% refers to the doping ratio of f-4TCNQ in the hole injection layer). The evaporation rate ratio of m-MTDATA to f4-TCNQ was 1:0.06, the evaporation rate of m-MTDATA was 1 Å / s, and the total thickness was 100 nm. Then, 80 nm of C4 was deposited as the hole transport layer with an evaporation rate of 1 Å / s. Above the hole transport layer, co-evaporation of the blue light host BFH-1 and 3% guest BFD-1 (3% refers to the doping ratio of the guest material in the light-emitting layer) from different evaporation sources was carried out as the blue light-emitting layer (B-EML layer). The evaporation rate ratio was 1:0.03, the evaporation rate of BFH-1 was 1 Å / s, and the thickness of the blue light-emitting layer was 20 nm. 25 nm thick D27:100% Liq (100% refers to the doping molar ratio of Liq as the guest material in the host material D27 in the electron transport layer) was deposited as the electron transport layer, and the evaporation rates of D27 and Liq were both 1 Å / s. Then, 1 nm of LiF was deposited as the electron injection layer with an evaporation rate of 0.1 Å / s. An Al layer with a thickness of 150 nm was used as the cathode of the device.

[0125] Example 2

[0126] The difference from Example 1 is only that the evaporation thickness of the hole transport layer material C4 is 50 nm.

[0127] Example 3

[0128] The difference from Example 1 is only that the evaporation thickness of the hole transport layer material C4 is 70 nm.

[0129] Example 4

[0130] The difference from Example 1 is only that the evaporation thickness of the hole transport layer material C4 is 90 nm.

[0131] Example 5

[0132] The difference from Example 1 is only that the evaporation thickness of the hole transport layer material C4 is 110 nm.

[0133] Example 6

[0134] The difference from Example 1 is only that the evaporation thickness of the hole transport layer material C4 is 130 nm.

[0135] Example 7

[0136] The difference from Example 1 is only that the evaporation thickness of the hole transport layer material C4 is 150 nm.

[0137] Example 8

[0138] The difference from Example 1 is only that the evaporation thickness of the electron transport layer is 10 nm.

[0139] Example 9

[0140] The difference from Example 1 is only that the evaporation thickness of the electron transport layer is 15 nm.

[0141] Example 10

[0142] The difference from Example 1 is only that the evaporation thickness of the electron transport layer is 20 nm.

[0143] Example 11

[0144] The difference from Example 1 is only that the evaporation thickness of the electron transport layer is 30 nm.

[0145] Example 12

[0146] The difference from Example 1 is only that the evaporation thickness of the electron transport layer is 40 nm.

[0147] Example 13

[0148] The difference from Example 1 is only that the evaporation thickness of the electron transport layer is 50 nm.

[0149] Example 14

[0150] The difference from Example 1 is only that the doping ratio of the electron transport layer guest in the host is adjusted to 10%.

[0151] Example 15

[0152] The difference from Example 1 is only that the doping ratio of the electron transport layer guest in the host is adjusted to 50%.

[0153] Example 16

[0154] The difference from Example 1 is only that the doping ratio of the electron transport layer guest in the host is adjusted to 120%.

[0155] Example 17

[0156] The difference from Example 1 is only that the doping ratio of the electron transport layer guest in the host is adjusted to 150%.

[0157] Example 18

[0158] The difference from Example 1 is only that the doping ratio of the electron transport layer guest in the host is adjusted to 200%.

[0159] Example 19

[0160] The difference from Example 1 is only that the hole transport layer material C4 is replaced by C4 + C169.

[0161] Example 20

[0162] The difference from Example 1 is only that the electron transport layer host material D27 is replaced by D27 + D122.

[0163] Example 21

[0164] The difference from Example 1 is only that the light-emitting layer is prepared as a red light-emitting layer (R-EML), that is, the preparation method of the light-emitting layer is replaced by evaporating 40 nm of the red light host PH-4 and the red light dye RPD-2, and the dye doping ratio is 3%.

[0165] Example 22

[0166] The difference from Example 1 is only that the light-emitting layer is prepared as a green light-emitting layer (G-EML), that is, the preparation method of the light-emitting layer is replaced by evaporating 35 nm of the green light host PH-15 and the green light dye GPD-27, and the dye doping ratio is 10%.

[0167] Comparative Example 1

[0168] The difference from Example 1 is only that the hole transport layer C4 is replaced by the compound HT-4:

[0169]

[0170] Comparative Example 2

[0171] The difference from Example 1 is only that the compound D27 of the present invention is replaced by the compound ET-19:

[0172]

[0173] Comparative Example 3

[0174] The difference from Example 1 is only that the hole transport layer C4 is replaced by the compound HT-4, and the compound D27 of the electron transport layer is replaced by the compound ET-19.

[0175] Comparative Example 4

[0176] The difference from Comparative Example 3 is only that the light-emitting layer is replaced by evaporating 40 nm of the red light host PH-4 and the red light dye RPD-2, and the dye doping ratio is 3%.

[0177] Comparative Example 5

[0178] The difference from Example 3 is only that the light-emitting layer is replaced by evaporating 35 nm of the green light host PH-15 and the green light dye GPD-27, and the dye doping ratio is 10%.

[0179] Performance test

[0180] (1) Under the same brightness, measure the driving voltage, current efficiency, and device lifetime of the organic electroluminescent devices prepared in the examples and comparative examples. Specifically, increase the voltage at a rate of 0.1 V per second, and measure when the brightness of the organic electroluminescent device is 1000 cd / m in blue light 2 , 10000 cd / m in green light 2 , and 3000 cd / m in red light 2 The voltage is the driving voltage (V), and the current density is measured at the same time; the ratio of brightness to current density is the current efficiency (CE, cd / A);

[0181] (2) The lifetime test of LT97 is as follows: Under 400 A / m 2 , for green light under 400 A / m 2 , for red light under 600 A / m 2 , keep a constant current, and measure the time when the brightness of the organic electroluminescent device drops to 97% of the initial brightness, in hours.

[0182] The test results are shown in Table 1.

[0183] Table 1;

[0184]

[0185]

[0186] As can be seen from Table 1, in the present invention, by using the compound of formula (1) as the hole transport layer material and the compound of formula (2) as the electron transport layer material in combination, blue light devices (Examples 1-20), red light devices (Example 21), and green light devices (Example 22) are respectively prepared. Compared with the blue light devices, red light devices, and green light devices prepared by the combination schemes of the hole transport layer materials and electron transport layer materials using the prior art materials in Comparative Examples 1 to 5, Examples 1-22 of the present invention have relatively reduced the driving voltage of the device, improved the current efficiency of the device, and at the same time, the lifetime of the device has also been significantly improved, thus generally effectively improving the performance of the OLED display device.

[0187] 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 to the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc. all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. An organic electroluminescent device, comprising a first electrode, a second electrode, and an organic layer located between the first electrode and the second electrode, characterized in that, The organic layer includes a hole transport layer, a light-emitting layer, and an electron transport layer. The hole transport layer contains a compound having a structure represented by formula (1): In formula (1), Ar 1 is a C10 fused aromatic group; Ar 2 selected from one of hydrogen, deuterium, a halogen, or the following substituted or unsubstituted groups: C1-C12 alkyl, C3-C30 cycloalkyl, C1-C12 alkoxy, C3-C30 cycloalkoxy, C2-C20 alkenyl, C2-C20 alkynyl, carbonyl, cyano, C6-C50 aryl, C3-C30 heteroaryl; L 1 and L 2 independently selected from the group consisting of a single bond, a substituted or unsubstituted C6 arylene group; G 1 One selected from the following substituted or unsubstituted groups: phenyl, biphenyl, terphenyl, naphthyl, fluorenyl; G 2 One selected from the following substituted or unsubstituted groups: C6-C30 aryl, dibenzofuranyl, dibenzothiophenyl; n is 0; When the above group is substituted in formula (1), the substituent is independently selected from one of deuterium, halogen, C1-C12 alkyl, C1-C12 alkoxy, and C6 aryl; The electron transport layer contains a compound having a structure represented by formula (III-6) as a host material of the electron transport layer, and also contains Liq as a guest material in the electron transport layer: Among them, the R 3 ~R 6 is H; L 3 is a single bond, a substituted or unsubstituted phenyl residue of m + 1 valence, a substituted or unsubstituted biphenyl residue of m + 1 valence, or a substituted or unsubstituted naphthyl residue of m + 1 valence; L 4 is a single bond, a substituted or unsubstituted phenyl residue of p + 1 valence, a substituted or unsubstituted biphenyl residue of p + 1 valence, or a substituted or unsubstituted naphthyl residue of p + 1 valence; and L 3 and L 4 are not simultaneously single bonds; m and p are 1; when L 3 is a single bond, m is 1; when L 4 is a single bond, p is 1; Ar 3 selected from one of the following substituted or unsubstituted groups: When L 3 、L 4 、Ar 3 groups are substituted, the substituents are independently selected from one or a combination of at least two of halogen, nitro, cyano, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, neopentyl, n-hexyl; represents substituted the substituted wherein the substituent is selected from phenyl, biphenyl or naphthyl; Among them, the wavy line marked part represents the bonding key of the group with L 3 or L 4 ; The thickness of the hole transport layer is 1 nm - 150 nm; the thickness of the electron transport layer is 10 nm - 50 nm, and the doping ratio of the guest material in the electron transport layer in the host material is 10% - 200%.

2. The organic electroluminescent device according to claim 1, wherein, The hole transport layer contains one or two of the following compounds:

3. The organic electroluminescent device according to claim 1, characterized in that, The L 3 is a single bond, an (m + 1)-valent substituted or unsubstituted phenyl residue, or an (m + 1)-valent substituted or unsubstituted naphthyl residue; L 4 is a single bond, a (p + 1)-valent substituted or unsubstituted phenyl residue, or a (p + 1)-valent substituted or unsubstituted naphthyl residue.

4. The organic electroluminescent device according to claim 1, wherein, The electron transport layer contains one or two of the following compounds:

5. The organic electroluminescent device according to any one of claims 1-4, characterized in that, The thickness of the hole transport layer is 70 nm - 90 nm.

6. The organic electroluminescent device according to any one of claims 1-4, characterized in that, The thickness of the electron transport layer is 20 nm - 30 nm.

7. The organic electroluminescent device according to claim 1, wherein The doping ratio of the guest material in the electron transport layer in the host material is 50% - 150%.

8. The organic electroluminescent device according to claim 1, wherein The organic layer further includes at least one of a hole injection layer, a hole blocking layer, an electron injection layer, and an electron blocking layer.

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