Green organic electroluminescent material, device and display device

Abstract

The invention discloses a green organic electroluminescent material, a device and a display device, and belongs to the technical field of display. The embodiment of the invention provides a green organic electroluminescent material, the green organic electroluminescent material comprises a host material, a fluorescent material and a phosphorescent material, and the horizontal emission dipole ratios of the fluorescent material and the phosphorescent material are 80%-100% respectively. The phosphorescent material and the fluorescent material both have high-level emission dipole orientation, so that the emission dipole moment directions of the phosphorescent material and the fluorescent material are more consistent, the dipole-dipole interaction is enhanced, # imgabs0 # energy transfer between the phosphorescent material and the fluorescent material is facilitated, Dexter energy transfer is inhibited, triplet exciton consumption is promoted, and the luminous efficiency is improved. And triplet-triplet annihilation and triplet-polaron annihilation are inhibited, so that the service life of the device is prolonged, and the efficiency of the device is improved.

Description

Technical Field

[0001] The present application relates to the field of display technologies, and particularly to a green organic electroluminescent material, a device and a display device. Background Art

[0002] Currently, the BT.2020 standard with ultra-high color gamut has gradually become the focus of competition in display technologies. However, the large difference in color coordinates of green light devices is a key limiting factor for achieving the BT.2020 standard.

[0003] In green organic light-emitting diode (OLEDs) devices using phosphorescent sensitized fluorescence, the triplet exciton lifetime of the phosphorescent material is long, and the energy transfer between the phosphorescent material and the fluorescent material is still insufficient, which easily causes triplet-triplet annihilation and triplet-polaron annihilation, thereby damaging the device lifetime and efficiency. Summary of the Invention

[0004] Embodiments of the present application provide a green organic electroluminescent material, a device and a display device, which can improve the device lifetime and efficiency. The technical solutions are as follows:

[0005] On the one hand, embodiments of the present application provide a green organic electroluminescent material, which includes: a host material, a fluorescent material and a phosphorescent material;

[0006] The horizontal emission dipole ratios of the fluorescent material and the phosphorescent material are 80% to 100% respectively;

[0007] The structural general formula of the fluorescent material is shown as (I):

[0008]

[0009] Wherein, R1 and R2 are each independently selected from any one of hydrogen, C1-C20 alkyl, C1-C20 alkoxy, C3-C12 cycloalkyl, and C6-C24 aryl, and at least one of R1 and R2 is aryl;

[0010] R3 is selected from deuterated C6-C30 aryl;

[0011] The structural general formula of the phosphorescent material is shown as (II):

[0012]

[0013] Wherein, Y is selected from O, S or Se;

[0014] R4 to R9 are each independently selected from hydrogen, deuterium, a halogen, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C3-C20 cycloalkyl group, a substituted or unsubstituted C1-C20 heteroalkyl group, a substituted or unsubstituted C3-C20 heterocyclic group, a substituted or unsubstituted C7-C30 aralkyl group, a substituted or unsubstituted C1-C20 alkoxy group, a substituted or unsubstituted C6-C30 aryloxy group, a substituted or unsubstituted C2-C20 alkenyl group, a substituted or unsubstituted C3-C20 silyl group, an amino group, an acyl group, a carbonyl group, a carboxylic acid group, an ester group, a cyano group, an isocyano group, a hydroxyl group, a mercapto group, a sulfinyl group, a sulfonyl group or a phosphino group.

[0015] In one possible implementation, the host material includes: a hole-transporting host material and an electron-transporting host material;

[0016] The molar ratio of the hole-transporting host material to the electron-transporting host material is 1:9 to 9:1.

[0017] In another possible implementation, the structural general formula of the hole-transporting host material is as shown in (III):

[0018]

[0019] Wherein, R 10 to R 17 are each independently selected from hydrogen, deuterium, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C6-C30 aryl group or a substituted or unsubstituted C2-C30 heteroaryl group;

[0020] L1 and L2 are each independently selected from a single bond, a substituted or unsubstituted C6-C30 arylene group or a substituted or unsubstituted C2-C30 heteroarylene group;

[0021] Ar1 and Ar2 are each independently selected from hydrogen, deuterium, a substituted or unsubstituted C1-C30 alkyl group, a substituted or unsubstituted C3-C30 cycloalkyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted C6-C30 arylamino group, a substituted or unsubstituted C1-C30 alkoxy group, a substituted or unsubstituted C3-C40 silyl group, a substituted or unsubstituted C1-C30 alkylthiol group, a substituted or unsubstituted C6-C30 arylthiol group, a halogen, a halogen-containing group, a cyano group, a hydroxyl group, an amino group or a nitro group.

[0022] In another possible implementation, -L1-Ar1 and -L2-Ar2 are each independently selected from one of the following groups:

[0023]

[0024]

[0025] In another possible implementation, the structural general formula of the electron-transporting host material is as shown in (IV):

[0026]

[0027] wherein, R 18 to R 22 are each independently selected from hydrogen, deuterium, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C2-C30 heteroaryl;

[0028] Ar3 is selected from Structure A or B;

[0029]

[0030] X is independently selected from O, S, NR, CRR', SiRR', or GeRR';

[0031] R 23 to R 34 , R, and R' are each independently selected from hydrogen, deuterium, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl.

[0032] In another possible implementation, two adjacent substituents among R 23 to R 34 form a ring, and the ring is a substituted or unsubstituted ring;

[0033] If there are substituents on the ring, the substituents are selected from hydrogen, deuterium, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl.

[0034] In another possible implementation, the absolute value of the HOMO energy level of the fluorescent material and the absolute value of the HOMO energy level of the phosphorescent material are both less than the absolute value of the HOMO energy level of the host material;

[0035] and the absolute value of the LUMO energy level of the fluorescent material and the absolute value of the LUMO energy level of the phosphorescent material are both greater than the absolute value of the LUMO energy level of the host material;

[0036] wherein, the absolute value of the HOMO energy level of the host material is the minimum value of the absolute values of the HOMO energy levels of the hole-transporting host material and the electron-transporting host material;

[0037] The absolute value of the LUMO energy level of the host material is the maximum of the absolute values of the LUMO energy levels of the hole-transporting host material and the electron-transporting host material.

[0038] In another possible implementation, the energy of the lowest triplet excited state of the host material > the energy of the lowest triplet excited state of the phosphorescent material > the energy of the lowest triplet excited state of the fluorescent material;

[0039] The energy of the lowest singlet excited state of the host material > the energy of the lowest singlet excited state of the phosphorescent material > the energy of the lowest singlet excited state of the fluorescent material;

[0040] The energy of the lowest triplet excited state of the phosphorescent material is greater than the energy of the lowest singlet excited state of the fluorescent material.

[0041] In another possible implementation, the photoluminescence emission spectrum of the phosphorescent material overlaps with the absorption spectrum of the fluorescent material, and the spectral overlap area is greater than or equal to 50% of the absorption spectrum area of the fluorescent material.

[0042] In another possible implementation, the mole fraction of the host material is 83% - 94.5%;

[0043] The mole fraction of the phosphorescent material is 5% - 15%;

[0044] The mole fraction of the fluorescent material is 0.5% - 2%.

[0045] On the other hand, the embodiments of the present application provide a green organic electroluminescent device, which includes an anode, a light-emitting functional layer, a cathode, and a light extraction layer arranged in a stacked manner in sequence, wherein the light-emitting functional layer includes the green organic electroluminescent material described in any one of the above.

[0046] In a possible implementation, if the green organic electroluminescent device is a single-layer device, the light-emitting functional layer includes: a first transport unit, a green organic electroluminescent layer, and a second transport unit, and the first transport unit, the green organic electroluminescent layer, and the second transport unit are arranged in a stacked manner in sequence from the anode to the cathode direction, and the green organic electroluminescent layer includes the green organic electroluminescent material;

[0047] Wherein, the first transport unit includes at least one of a hole injection layer, a hole transport layer, a color adjustment layer, and an electron blocking layer;

[0048] The second transport unit includes at least one of a hole blocking layer, an electron transport layer, and an electron injection layer.

[0049] In another possible implementation, if the green organic electroluminescent device is a tandem device, the light-emitting functional layer includes: a hole injection layer, a third transport unit, a first green organic electroluminescent layer, a fourth transport unit, a charge generation layer, a fifth transport unit, a second green organic electroluminescent layer, a sixth transport unit, and an electron injection layer. The hole injection layer, the third transport unit, the first green organic electroluminescent layer, the fourth transport unit, the charge generation layer, the fifth transport unit, the second green organic electroluminescent layer, the sixth transport unit, and the electron injection layer are sequentially stacked in the direction from the anode to the cathode. Both the first green organic electroluminescent layer and the second green organic electroluminescent layer include the green organic electroluminescent material;

[0050] Wherein, the third transport unit includes at least one of a first hole transport layer, a first color adjustment layer, and a first electron blocking layer;

[0051] The fourth transport unit includes at least one of a first hole blocking layer and a first electron transport layer;

[0052] The charge generation layer includes a P-type charge generation layer and an N-type charge generation layer;

[0053] The fifth transport unit includes at least one of a second hole transport layer, a second color adjustment layer, and a second electron blocking layer;

[0054] The sixth transport unit includes at least one of a second hole blocking layer and a second electron transport layer.

[0055] In another possible implementation, the structural type of the hole blocking layer material is:

[0056] D-E, D-F-E, E-D-E or E-F-D-E;

[0057] Wherein, D is selected from a substituted or unsubstituted pyrenyl group, a substituted or unsubstituted triphenylenyl group, a substituted or unsubstituted group, a substituted or unsubstituted anthryl group, a substituted or unsubstituted phenanthryl group, or a substituted or unsubstituted perylenyl group;

[0058] E is selected from a substituted or unsubstituted pyrazino[2,3-h]phenanthrolinyl group, a substituted or unsubstituted benzo[h]phenanthrolinyl group, a substituted or unsubstituted phenanthrolinyl group, a substituted or unsubstituted acridinyl group, a substituted or unsubstituted phenazinyl group, a substituted or unsubstituted dibenzo-γ-pyrone group, a substituted or unsubstituted 1,8-naphthyridinyl group, or a substituted or unsubstituted 1,5-naphthyridinyl group;

[0059] F is selected from a substituted or unsubstituted aryl group having 6 to 30 carbon atoms or a substituted or unsubstituted heteroaryl group having 5 to 30 carbon atoms.

[0060] In another possible implementation, the substituents in D, E, and F are each independently selected from deuterium, halogen, -CN, C1-C12 alkyl, C1-C12 alkoxy, C1-C12 haloalkyl, C2-C6 alkenyl, C3-C10 cycloalkyl, C6-C30 aryl, or C5-C30 heteroaryl.

[0061] In another possible implementation, the lifetime of the triplet excitons of the hole blocking layer material is 1 μs to 1 s.

[0062] In another possible implementation, the energy of the lowest triplet excited state of the electron transport layer material and the energy of the lowest triplet excited state of the phosphorescent material are both greater than the energy of the lowest triplet excited state of the hole blocking layer material.

[0063] In another possible implementation, the absolute value of the HOMO energy level of the electron transport layer material > the absolute value of the HOMO energy level of the hole blocking layer material > the absolute value of the HOMO energy level of the host material;

[0064] and the absolute value of the LUMO energy level of the electron transport layer material > the absolute value of the LUMO energy level of the hole blocking layer material > the absolute value of the LUMO energy level of the host material;

[0065] wherein, the absolute value of the HOMO energy level of the host material is the minimum value of the absolute values of the HOMO energy levels of the hole transporting host material and the electron transporting host material;

[0066] the absolute value of the LUMO energy level of the host material is the maximum value of the absolute values of the LUMO energy levels of the hole transporting host material and the electron transporting host material.

[0067] In another possible implementation, it is characterized in that the thickness of the green organic electroluminescent layer is 10 nm to 100 nm.

[0068] On the other hand, an embodiment of the present application provides a display device, and the display device includes the green organic electroluminescent device described in any one of the above.

[0069] An embodiment of the present application provides a green organic electroluminescent material. Since both the phosphorescent material and the fluorescent material used have a high level of emission dipole orientation, the emission dipole moment directions of the phosphorescent material and the fluorescent material are more consistent, and the dipole-dipole interaction is enhanced. Therefore, this is beneficial to the Energy transfer, inhibiting Dexter energy transfer, promoting the consumption of triplet excitons, inhibiting triplet-triplet annihilation and triplet-polaron annihilation, thereby enhancing the device lifetime and efficiency. Description of the Drawings

[0070] Figure 1 It is a schematic diagram of a vertical-emitting dipole and a horizontal-emitting dipole provided by an embodiment of the present application;

[0071] Figure 2 It is a schematic structural diagram of a single-layer device provided by an embodiment of the present application;

[0072] Figure 3 It is a schematic structural diagram of another single-layer device provided by an embodiment of the present application;

[0073] Figure 4 It is a schematic structural diagram of a tandem device provided by an embodiment of the present application;

[0074] Figure 5 It is a schematic structural diagram of another tandem device provided by an embodiment of the present application;

[0075] Figure 6 It is a schematic diagram of the spectral overlap between a phosphorescent material and a fluorescent material provided by an embodiment of the present application;

[0076] Figure 7 It is an EL spectrum diagram of the device corresponding to Example 2 provided by an embodiment of the present application;

[0077] Figure 8 It is an EL spectrum diagram of the device corresponding to Example 14 provided by an embodiment of the present application;

[0078] Figure 9 It is a schematic diagram of the lifetime decay of the device corresponding to Example 14 provided by an embodiment of the present application;

[0079] Figure 10 It is an EL spectrum diagram of the device corresponding to Example 18 provided by an embodiment of the present application;

[0080] Figure 11 It is an EL spectrum diagram of the device corresponding to Example 27 provided by an embodiment of the present application;

[0081] Figure 12 It is a schematic diagram of the lifetime decay of the device corresponding to Example 27 provided by an embodiment of the present application. Detailed Embodiments

[0082] To make the technical solutions and advantages of the present application clearer, the following further describes the embodiments of the present application in detail.

[0083] An embodiment of the present application provides a green organic electroluminescent material, which includes a host material, a fluorescent material, and a phosphorescent material.

[0084] Among them, the horizontal emission dipole ratios of the fluorescent material and the phosphorescent material are 80% - 100% respectively.

[0085] The structural general formula of the fluorescent material is as shown in (I):

[0086]

[0087] Wherein, R1 and R2 are each independently selected from any one of hydrogen, C1 - C20 alkyl, C1 - C20 alkoxy, C3 - C12 cycloalkyl, and C6 - C24 aryl, and at least one of R1 and R2 is an aryl;

[0088] R3 is selected from deuterated C6 - C30 aryl.

[0089] The structural general formula of the phosphorescent material is as shown in (II):

[0090]

[0091] Wherein, Y is selected from O, S, or Se;

[0092] R4 to R9 are each independently selected from hydrogen, deuterium, halogen, substituted or unsubstituted C1 - C20 alkyl, substituted or unsubstituted C3 - C20 cycloalkyl, substituted or unsubstituted C1 - C20 heteroalkyl, substituted or unsubstituted C3 - C20 heterocyclic group, substituted or unsubstituted C7 - C30 aralkyl, substituted or unsubstituted C1 - C20 alkoxy, substituted or unsubstituted C6 - C30 aryloxy, substituted or unsubstituted C2 - C20 alkenyl, substituted or unsubstituted C3 - C20 silyl, amino, acyl, carbonyl, carboxyl, ester, cyano, isocyano, hydroxyl, mercapto, sulfinyl, sulfonyl, or phosphino.

[0093] For the above - mentioned green organic electroluminescent material, some examples of the arylene involved can be as follows: phenylene, biphenylene, naphthylene, anthrylene, phenanthrylene, terphenylenyl, etc.

[0094] Some examples of the aryl involved can be as follows: phenyl, biphenyl, terphenyl, naphthyl, anthryl, phenanthryl, perylenyl, fluoranthenyl, triphenylenyl, picenyl, pyrenyl, tetracenyl, pentacenyl, fluorenyl, indenyl, acenaphthylenyl, benzofluorenyl, spirofluorenyl, etc.

[0095] The heteroatoms contained in the involved heteroaryls can be O, S, N, etc. And some examples of heteroaryls can be as follows: pyridinyl, thienyl, furyl, pyrimidinyl, quinolinyl, benzothienyl, carbazolyl, etc.

[0096] The involved alkyl groups can be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methylbutyl, 1-ethylbutyl, n-pentyl, isopentyl, neopentyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methylpentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, octyl, etc.

[0097] The involved alkenyl groups can be vinyl, propen-1-yl, propen-2-yl, propen-3-yl, buten-1-yl, buten-2-yl, buten-3-yl, buten-4-yl, 1-methylpropen-1-yl, 2-methylpropen-1-yl, 1-ethyl-vinyl-1-yl, 2-methyl-propen-3-yl, buta-1,3-dienyl, buta-1,2-dienyl, buta-1,2-dien-4-yl, pentenyl, hexenyl, heptenyl, octenyl, etc.

[0098] The involved cycloalkyl groups can be cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, adamantyl, norbornyl, etc.

[0099] The involved heteroalkyl groups can be methoxy, ethylthio, aminopropyl, dimethylaminomethyl, trifluoromethoxy, mercaptoethoxy, pyrrolidinylpropyl, etc.

[0100] The involved heterocyclic groups can be pyridinyl, thienyl, furyl, pyrimidinyl, quinolinyl, imidazolyl, tetrahydrofuryl, etc.

[0101] The involved aralkyl groups can be benzyl, phenethyl, naphthylmethyl, biphenylmethyl, terphenylpropyl, phenylpropyl, phenanthrylmethyl, anthracenylethyl, etc.

[0102] The involved silyl groups can be trimethylsilyl, tert-butyldimethylsilyl, triisopropylsilyl, phenyldimethylsilyl, triphenylsilyl, diphenylmethylsilyl, vinyltrimethylsilyl, etc.

[0103] The involved alkoxy groups can be methoxy, ethoxy, propoxy, butoxy, pentyloxy, etc.

[0104] In this application, the horizontal emission dipole ratios of the fluorescent material and the phosphorescent material are respectively 80% - 100%. Among them, the horizontal emission dipole ratio of the fluorescent material can be 80%, 82%, 85%, 88%, 90%, 92%, 95%, 98%, 100%, etc., and the horizontal emission dipole ratio of the phosphorescent material can be 80%, 82%, 85%, 88%, 90%, 92%, 95%, 98%, 100%, etc.

[0105] The horizontal emission dipole ratio is the ratio of the horizontal emission dipole moment to the sum of the horizontal emission dipole moment and the vertical emission dipole moment, that is where Θ / / represents the horizontal emission dipole ratio, p / / represents the horizontal emission dipole moment, and p ⊥ represents the vertical emission dipole moment. See Figure 1 , Figure 1 is a schematic diagram of the vertical emission dipole and the horizontal emission dipole, Figure 1 which includes: a cathode and a packaging layer 101, a vertically oriented dipole moment 102, a horizontally oriented dipole moment 103, a positive charge 104, a negative charge 105, an anode and a substrate 106.

[0106] The embodiments of this application provide a green organic electroluminescent material. Since both the phosphorescent material and the fluorescent material used have a high level of horizontal emission dipole orientation, the emission dipole moment directions of the phosphorescent material and the fluorescent material are more consistent, and the dipole-dipole interaction is enhanced, which is beneficial to the energy transfer between the phosphorescent material and the fluorescent material, inhibits Dexter energy transfer, promotes the consumption of triplet excitons, and inhibits triplet-triplet annihilation and triplet-polaron annihilation, thereby improving the device lifetime and efficiency.

[0107] Moreover, according to the structural general formula of the fluorescent material, after modifying the structure with boron and nitrogen as the core in the benzene ring derivative-modified fluorescent material, the π-π interaction between the fluorescent material and the phosphorescent material is increased, which is beneficial to improving the horizontal emission dipole orientation, making the transition dipole moment parallel to the substrate, and increasing the light extraction efficiency. According to the structural general formula of the phosphorescent material, after modifying the main ligand of the iridium complex with a benzene ring, the increase in the π-π interaction between the phosphorescent material and the fluorescent material is beneficial to improving the horizontal emission dipole orientation, making the transition dipole moment parallel to the substrate, and increasing the light extraction efficiency.

[0108] The green organic electroluminescent material provided by this application is composed of a host material, a phosphorescent material, and a fluorescent material. Among them, the phosphorescent material is a sensitizer, and the fluorescent material is a luminescent material. First, the sensitization mechanism of the phosphorescent material as a sensitizer is introduced as follows: Under the action of an electric field, carriers are injected through the electrodes and then transported by the carrier transport layer to the light-emitting layer, where singlet excitons and triplet excitons are formed on the host material and pass through Energy is transferred to the phosphorescent sensitizer by Förster resonance energy transfer (FRET) and Dexter energy transfer (DET). The spin - orbit coupling of the phosphorescent sensitizer is very strong, resulting in a considerable dipole strength for the donor triplet - acceptor singlet transition, thus enabling the FRET mechanism for the triplet state. Due to the doping of only a trace amount of luminescent material, the FRET from the phosphorescent sensitizer to the luminescent material is enhanced, the DET from the host material and the phosphorescent sensitizer to the luminescent material is suppressed, and the situation where the luminescent material directly captures carriers and emits light is also suppressed. Therefore, the host material and the phosphorescent sensitizer are basically transferred to the singlet state of the luminescent material through FRET, and the singlet state rapidly decays by radiation and emits light.

[0109] In this application, a phosphorescent material and a fluorescent material are co - doped into the host material to fabricate a phosphorescent - sensitized fluorescent organic light - emitting diode (PSF - OLEDs) device, which can not only achieve ultra - high efficiency but also maintain a narrow - band intrinsic spectrum. In addition, the carrier transport region, exciton recombination center, and light - emitting center are effectively separated, making the device more stable.

[0110] In the embodiments of this application, some examples of fluorescent materials can be shown as follows:

[0111]

[0112]

[0113]

[0114] In the embodiments of this application, some examples of phosphorescent materials can be shown as follows:

[0115]

[0116]

[0117] In the embodiments of this application, the host material includes: a hole - transporting host material and an electron - transporting host material;

[0118] The molar ratio of the hole - transporting host material to the electron - transporting host material is 1:9 to 9:1.

[0119] Among them, the molar ratio of the hole - transporting host material to the electron - transporting host material can be 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, 9:1, etc. For example, the molar ratio of the hole - transporting host material to the electron - transporting host material is adjusted between 1:9 and 5:5 or between 9:1 and 5:5.

[0120] In the embodiments of the present application, a hole-transporting host material and an electron-transporting host material are compounded as the host material, and controlling the molar ratio of the two within the above range can achieve efficient carrier recombination, improve exciton generation efficiency, and thus enhance the external quantum efficiency of the device.

[0121] In the embodiments of the present application, the hole-transporting host material is a carbazole derivative, and the electron-transporting host material is a triazine derivative. The hole-transporting host material and the electron-transporting host material are introduced below respectively.

[0122] In a possible implementation manner, the structural general formula of the hole-transporting host material is shown as (III):

[0123]

[0124] Wherein, R 10 to R 17 are each independently selected from hydrogen, deuterium, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C2-C30 heteroaryl;

[0125] L1 and L2 are each independently selected from a single bond, substituted or unsubstituted C6-C30 arylene, or substituted or unsubstituted C2-C30 heteroarylene;

[0126] Ar1 and Ar2 are each independently selected from hydrogen, deuterium, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted carbazolyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C3-C40 silyl, substituted or unsubstituted C1-C30 alkylthiol, substituted or unsubstituted C6-C30 arylthiol, halogen, halogen-containing group, cyano, hydroxyl, amino, or nitro.

[0127] In a possible implementation manner, -L1-Ar1 and -L2-Ar2 are each independently selected from one of the following groups:

[0128]

[0129]

[0130] According to the structural formulas of these groups, these groups are benzene rings or their derivatives. When -L1-Ar1 and -L2-Ar2 are each independently selected from one of these groups, they can form a conjugated structure with the N nitrogen atom in formula (III), which is beneficial to increasing the π-π interaction between the host material and the phosphorescent material or fluorescent material, thereby increasing the light extraction efficiency.

[0131] Combined with the hole-transporting host materials mentioned above, some examples of hole-transporting host materials can be shown as follows:

[0132]

[0133] In a possible implementation, the general structural formula of the electron-transporting host material is shown as (IV):

[0134]

[0135] Wherein, R 18 to R 22 are each independently selected from hydrogen, deuterium, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C2-C30 heteroaryl;

[0136] Ar3 is selected from structure A or B;

[0137]

[0138] X is independently selected from O, S, NR, CRR’, SiRR’, GeRR’;

[0139] R 23 to R 34 , R, and R’ are each independently selected from hydrogen, deuterium, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl.

[0140] In a possible implementation, two adjacent substituents in R 23- R 34 form a ring.

[0141] For example, if R 23 is adjacent to R 24 , then R 23 and R 24 can form a ring. If R 24 is adjacent to R 25 , then R 24 and R 25 can also form a ring.

[0142] Moreover, the ring can have substituents or no substituents.

[0143] If there are substituents on the ring, the substituents can be selected from hydrogen, deuterium, C1-C20 alkyl groups which may be substituted or unsubstituted, C6-C50 aryl groups which may be substituted or unsubstituted, or C2-C50 heteroaryl groups which may be substituted or unsubstituted.

[0144] Combined with the above-mentioned electron-transporting host materials, some examples of electron-transporting host materials can be shown as follows:

[0145]

[0146] In the embodiments of the present application, the hole-transporting host material is a P-type material, and the electron-transporting host material is an N-type material. The hole mobility of the P-type material is at least one order of magnitude higher than the electron mobility, the electron mobility of the N-type material is at least one order of magnitude higher than the hole mobility, and the hole mobility of the P-type material and the electron mobility of the N-type material are within one order of magnitude, and the P-type material and the N-type material can form an exciplex.

[0147] In a possible implementation manner, the absolute value of the HOMO energy level of the fluorescent material and the absolute value of the HOMO energy level of the phosphorescent material are both smaller than the absolute value of the HOMO energy level of the host material;

[0148] and the absolute value of the LUMO energy level of the fluorescent material and the absolute value of the LUMO energy level of the phosphorescent material are both larger than the absolute value of the LUMO energy level of the host material;

[0149] Among them, the absolute value of the HOMO energy level of the host material is the minimum value of the absolute values of the HOMO energy levels of the hole-transporting host material and the electron-transporting host material;

[0150] The absolute value of the LUMO energy level of the host material is the maximum value of the absolute values of the LUMO energy levels of the hole-transporting host material and the electron-transporting host material.

[0151] Among them, the HOMO (Highest Occupied Molecular Orbital) energy level is the highest-energy electron-occupied orbital in the molecule, and the LUMO (Lowest Unoccupied Molecular Orbital) energy level is the lowest-energy molecular orbital among the unoccupied molecular orbitals in the molecule.

[0152] In the embodiments of the present application, let |HOMO(GH)|, |HOMO(PGD)|, and |HOMO(FGD)| respectively represent the absolute values of the HOMO energy levels of the host material, the phosphorescent material, and the fluorescent material. Then the relationship among the three is: |HOMO(GH)| > |HOMO(PGD)|, |HOMO(GH)| > |HOMO(FGD)|. Among them, |HOMO(GH)| is the smaller value of the absolute values of the HOMO energy levels in the P-type material and the N-type material.

[0153] Let |LUMO(GH)|, |LUMO(PGD)|, and |LUMO(FGD)| respectively represent the absolute values of the LUMO energy levels of the host material, the phosphorescent material, and the fluorescent material. Then the relationship among the three is: |LUMO(GH)| < |LUMO(PGD)|, |LUMO(GH)| is less than |LUMO(FGD)|. Among them, |LUMO(GH)| is the larger value of the absolute values of the LUMO energy levels in the P-type material and the N-type material.

[0154] In the embodiments of the present application, when the HOMO energy levels and LUMO energy levels among the host material, the phosphorescent material, and the fluorescent material satisfy the above relationships, the triplet exciton density of the light-emitting layer can be reduced, and the device lifetime can be improved.

[0155] In a possible implementation, the energy of the lowest triplet excited state of the host material > the energy of the lowest triplet excited state of the phosphorescent material > the energy of the lowest triplet excited state of the fluorescent material;

[0156] The energy of the lowest singlet excited state of the host material > the energy of the lowest singlet excited state of the phosphorescent material > the energy of the lowest singlet excited state of the fluorescent material;

[0157] The energy of the lowest triplet excited state of the phosphorescent material is greater than the energy of the lowest singlet excited state of the fluorescent material.

[0158] In this implementation, let T1(GH), T1(PGD), and T1(FGD) respectively represent the energies of the lowest triplet excited states of the host material, the phosphorescent material, and the fluorescent material. Then the relationship among the three is: T1(GH) > T1(PGD) > T1(FGD).

[0159] Let S1(GH), S1(PGD), and S1(FGD) respectively represent the energies of the lowest singlet excited states of the host material, the phosphorescent material, and the fluorescent material. Then the relationship among the three is: S1(GH) > S1(PGD) > S1(FGD).

[0160] And, T1(PGD) > S1(FGD).

[0161] In the embodiments of the present application, the energies of the lowest triplet excited state and the lowest singlet excited state of the host material, phosphorescent material, and fluorescent material satisfy the above relationships, which can improve the energy transfer efficiency and avoid energy back-transfer, resulting in energy loss.

[0162] In a possible implementation, there is an overlap between the photoluminescence spectrum of the phosphorescent material and the absorption spectrum of the fluorescent material, and after normalization, the spectral overlap area is greater than or equal to 50% of the absorption spectrum area of the fluorescent material.

[0163] Among them, the peak position difference between the normalized electroluminescence spectrum of the phosphorescent material and the normalized absorption spectrum of the fluorescent material in the range of 490 nm to 550 nm is not greater than 20 nm. The peak range of the photoluminescence (PL) of the phosphorescent material is 510 nm to 540 nm, and the full width at half maximum is 20 nm to 50 nm. The peak range of the photoluminescence (PL) of the fluorescent material is 510 nm to 530 nm, and the full width at half maximum is 15 nm to 30 nm.

[0164] In the embodiments of the present application, there is a large overlap area between the photoluminescence spectrum of the phosphorescent material and the absorption spectrum of the fluorescent material, which can make the energy transfer more sufficient and the transfer efficiency higher, thereby improving the device lifetime.

[0165] In a possible implementation, the mole fraction of the host material is 83% to 94.5%, the mole fraction of the phosphorescent material is 5% to 15%, and the mole fraction of the fluorescent material is 0.5% to 2%.

[0166] In this implementation, the mole fraction of the host material is the ratio of the molar amount of the host material to the total molar amount. Similarly, the mole fraction of the phosphorescent material is the ratio of the molar amount of the phosphorescent material to the total molar amount, and the mole fraction of the fluorescent material is the ratio of the molar amount of the fluorescent material to the total molar amount. The total molar amount is the sum of the molar amounts corresponding to the host material, phosphorescent material, and fluorescent material respectively.

[0167] Exemplarily, the mole fraction of the host material can be 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 94.5%, etc., the mole fraction of the phosphorescent material can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, etc., and the mole fraction of the fluorescent material can be 0.5%, 1%, 1.5%, 2%, etc.

[0168] In the embodiments of the present application, when the molar fractions of the host material, the phosphorescent material, and the fluorescent material are respectively within their respective ranges, the voltage of the organic light-emitting device can be reduced, and the efficiency and lifespan of the device can be improved. If the doping of the fluorescent material is relatively high, greater than 2%, it is likely to cause fluorescence quenching; if the doping of the fluorescent material is relatively low, less than 0.5%, it is likely to make the process difficult to implement and the energy transfer insufficient.

[0169] In the embodiments of the present application, the green organic light-emitting material includes a fluorescent material, a phosphorescent material, and a host material. Since both the phosphorescent material and the fluorescent material adopted have a high level of emission dipole orientation, the emission dipole moment directions of the phosphorescent material and the fluorescent material are more consistent, and the dipole-dipole interaction is enhanced, which is beneficial to the energy transfer between the phosphorescent material and the fluorescent material, inhibits Dexter energy transfer, promotes the consumption of triplet excitons, inhibits triplet-triplet annihilation and triplet-polaron annihilation, thereby improving the lifespan and efficiency of the device.

[0170] Moreover, the phosphorescent material is an iridium(III) complex, which has a high bond energy, a stable molecular structure, and a high luminescence efficiency. In addition, the host material is an exciplex formed by a P-type material and an N-type material. This combination is beneficial to carrier transport, reduces the driving voltage, expands the exciton recombination center, inhibits the formation of adducts and charge traps, and inhibits triplet-triplet annihilation (TTA) and triplet-polaron annihilation (TPA), thereby further improving the lifespan and efficiency of the device and reducing efficiency roll-off.

[0171] In addition, the embodiments of the present application provide a preparation method of a fluorescent material, and the preparation method includes:

[0172] Step 1: Provide reactants A1, A2, and A3.

[0173] Among them, the general formulas of reactants A1 and A2 are as follows:

[0174]

[0175] Reactant A3 can be BX3. X in reactants A1 and A3 is a halogen. Exemplarily, X can be F, Cl, Br, or I.

[0176] Step 2: React reactants A1 and A2 to obtain a first intermediate.

[0177] The reaction process of reactants A1 and A2 is as follows:

[0178]

[0179] Step 3: React the first intermediate and reactant A3 to obtain the fluorescent material.

[0180] The process of the reaction between the first intermediate and reactant A3 is shown as follows:

[0181]

[0182] In the embodiments of the present application, reactants A1 and A2 can be designed according to the chemical structure of the fluorescent material. Among them, reactants A1 and A2 can be obtained by purchasing known compound products or prepared by themselves, and no specific limitation is made thereto.

[0183] The embodiments of the present application also provide a preparation method of a phosphorescent material, and the preparation method includes:

[0184] Step 1: Provide reactants B1, B2 and B3.

[0185] Among them, the general structural formulas of reactants B1 and B2 are shown as follows:

[0186]

[0187] Reactant B3 can be IrX3·H2O. X is a halogen, and by way of example, X can be F, Cl, Br or I.

[0188] Step 2: React reactants B1, B2 and B3 to obtain a phosphorescent material.

[0189] The process of the reaction between reactants B1, B2 and B3 is shown as follows:

[0190]

[0191] In the embodiments of the present application, reactants B1 and B2 can be designed according to the chemical structure of the phosphorescent material. Among them, reactants B1 and B2 can be obtained by purchasing known compound products or prepared by themselves, and no specific limitation is made thereto.

[0192] The embodiments of the present application also provide a preparation method of a hole-transporting host material, and the preparation method includes:

[0193] Step 1: Provide reactants G1 and G2.

[0194] The general structural formulas of reactants G1 and G2 are shown as follows:

[0195]

[0196] Step 2: React reactants G1 and G2 to obtain a hole-transporting host material.

[0197] The process of the reaction between reactant G1 and reactant G2 is as follows:

[0198]

[0199] In the embodiments of the present application, reactants G1 and G2 can be designed according to the chemical structure of the hole - transporting host material. Among them, reactants G1 and G2 can be obtained by purchasing known compound products or can be prepared by oneself, and no specific limitation is made in this regard.

[0200] The embodiments of the present application also provide a preparation method of an electron - transporting host material, and the preparation method includes:

[0201] Step 1: Provide reactant H1 and reactant H2.

[0202] Among them, the general structural formula of reactant H1 is as follows:

[0203]

[0204] According to the above, Ar3 is selected from structure A or B. If Ar3 is selected from structure A, the general structural formula of reactant H2 is as shown in (V) below. If Ar3 is selected from structure B, the general structural formula of reactant H2 is as shown in (VI) below:

[0205]

[0206] Step 2: React reactant H1 and reactant H2 to obtain the electron - transporting host material.

[0207] If the general structural formula of reactant H2 is as shown in (V), the reaction process of reactant H1 and reactant H2 is as follows:

[0208]

[0209] If the general structural formula of reactant H2 is as shown in (VI), the reaction process of reactant H1 and reactant H2 is as follows:

[0210]

[0211] In the embodiments of the present application, reactants H1 and H2 can be designed according to the chemical structure of the electron - transporting host material. Among them, reactants H1 and H2 can be obtained by purchasing known compound products or can be prepared by oneself, and no specific limitation is made in this regard.

[0212] The embodiment of the present application also provides a green organic electroluminescent device, which includes an anode, a light-emitting functional layer, a cathode, and a light extraction layer arranged in a stacked manner in sequence, wherein the light-emitting functional layer includes the green organic electroluminescent material of any one of the above.

[0213] In the embodiment of the present application, the green organic electroluminescent device can be a single-layer device (i.e., a Single device) or a tandem device (i.e., a Tandem device), and no specific limitation is made thereto.

[0214] If the green organic electroluminescent device is a single-layer device, the light-emitting functional layer includes a first transport unit, a green organic electroluminescent layer, and a second transport unit. The first transport unit, the green organic electroluminescent layer, and the second transport unit are arranged in a stacked manner in sequence from the anode to the cathode direction, and the green organic electroluminescent layer includes the green organic electroluminescent material.

[0215] Among them, the first transport unit includes at least one of a hole injection layer, a hole transport layer, a color adjustment layer, and an electron blocking layer;

[0216] The second transport unit includes at least one of a hole blocking layer, an electron transport layer, and an electron injection layer.

[0217] In a possible implementation manner, the first transport unit includes a hole injection layer, wherein the anode, the hole injection layer, and the green organic electroluminescent layer are arranged in a stacked manner in sequence.

[0218] In a possible implementation manner, the first transport unit includes a hole injection layer and a hole transport layer, wherein the anode, the hole injection layer, the hole transport layer, and the green organic electroluminescent layer are arranged in a stacked manner in sequence.

[0219] In a possible implementation manner, the first transport unit includes a hole injection layer, a hole transport layer, and an electron blocking layer, wherein the anode, the hole injection layer, the hole transport layer, the electron blocking layer, and the green organic electroluminescent layer are arranged in a stacked manner in sequence.

[0220] In a possible implementation manner, the first transport unit includes a hole injection layer, a hole transport layer, a color adjustment layer, and an electron blocking layer, wherein the anode, the hole injection layer, the hole transport layer, the color adjustment layer, the electron blocking layer, and the green organic electroluminescent layer are arranged in a stacked manner in sequence.

[0221] In a possible implementation manner, the second transport unit includes an electron transport layer, wherein the cathode, the electron transport layer, and the green organic electroluminescent layer are arranged in a stacked manner in sequence.

[0222] In a possible implementation, the second transmission unit includes an electron transport layer and a hole blocking layer, wherein the cathode, the electron transport layer, the hole blocking layer, and the green organic electroluminescent layer are sequentially stacked.

[0223] In a possible implementation, the second transmission unit includes an electron transport layer, a hole blocking layer, and an electron injection layer, wherein the cathode, the electron injection layer, the electron transport layer, the hole blocking layer, and the green organic electroluminescent layer are sequentially stacked.

[0224] For example, the green organic electroluminescent device is a single-layer device. Refer to Figure 2 , and the device is sequentially stacked in the direction from the anode to the cathode: anode (Anode), hole injection layer (HIL), hole transport layer (HTL), electron blocking layer (EBL), green organic electroluminescent layer (EML), hole blocking layer (HBL), electron transport layer (ETL), electron injection layer (EIL), cathode (Cathode), and light extraction layer (CPL).

[0225] For example, the green organic electroluminescent device is a single-layer device. Refer to Figure 3 , and the device is sequentially stacked in the direction from the anode to the cathode: anode (Anode), hole injection layer (HIL), hole transport layer (HTL), color adjustment layer (CCL), electron blocking layer (EBL), green organic electroluminescent layer (EML), hole blocking layer (HBL), electron transport layer (ETL), electron injection layer (EIL), cathode (Cathode), and light extraction layer (CPL).

[0226] If the green organic electroluminescent device is a tandem device, the light-emitting functional layer includes: a hole injection layer, a third transmission unit, a first green organic electroluminescent layer, a fourth transmission unit, a charge generation layer, a fifth transmission unit, a second green organic electroluminescent layer, a sixth transmission unit, and an electron injection layer. The hole injection layer, the third transmission unit, the first green organic electroluminescent layer, the fourth transmission unit, the charge generation layer, the fifth transmission unit, the second green organic electroluminescent layer, the sixth transmission unit, and the electron injection layer are sequentially stacked in the direction from the anode to the cathode. Both the first green organic electroluminescent layer and the second green organic electroluminescent layer include the above-mentioned green organic electroluminescent material.

[0227] Among them, the third transmission unit includes at least one of a first hole transport layer, a first color adjustment layer, and a first electron blocking layer;

[0228] The fourth transmission unit includes at least one of a first hole blocking layer and a first electron transport layer;

[0229] The charge generation layer includes a P-type charge generation layer and an N-type charge generation layer;

[0230] The fifth transmission unit includes at least one of a second hole transport layer, a second color adjustment layer, and a second electron blocking layer;

[0231] The sixth transmission unit includes at least one of a second hole blocking layer and a second electron transport layer.

[0232] For example, the green organic electroluminescent device is a tandem device. Refer to Figure 4 , and the device is stacked in sequence from the anode to the cathode: anode (Anode), hole injection layer (HIL), first hole transport layer (HTL1), first electron blocking layer (EBL1), first green organic electroluminescent layer (EML1), first hole blocking layer (HBL1), N-type charge generation layer, P-type charge generation layer, second hole transport layer (HTL2), second electron blocking layer (EBL2), second green organic electroluminescent layer (EML2), second hole blocking layer (HBL2), electron transport layer (ETL), electron injection layer (EIL), cathode (Cathode), light extraction layer (CPL).

[0233] For example, the green organic electroluminescent device is a tandem device. Refer to Figure 5 , and the device is stacked in sequence from the anode to the cathode: anode (Anode), hole injection layer (HIL), first hole transport layer (HTL1), first color adjustment layer (CCL1), first electron blocking layer (EBL1), first green organic electroluminescent layer (EML1), first hole blocking layer (HBL1), first electron transport layer (ETL1), N-type charge generation layer, P-type charge generation layer, second hole transport layer (HTL2), second color adjustment layer (CCL1), second electron blocking layer (EBL2), second green organic electroluminescent layer (EML2), second hole blocking layer (HBL2), second electron transport layer (ETL2), electron injection layer (EIL), cathode (Cathode), light extraction layer (CPL).

[0234] In a possible implementation, the thickness of the green organic electroluminescent layer is 10 nm to 100 nm.

[0235] Among them, the thickness of the green organic electroluminescent layer can be 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, etc.

[0236] It should be noted that the green organic electroluminescent layer here can be the green organic electroluminescent layer in a single-layer device, or the first green organic electroluminescent layer or the second green organic electroluminescent layer in a tandem device, and no specific limitation is made thereto.

[0237] The PSF-OLED device provided by this application has all the advantages of the green organic electroluminescent layer, and the PSF-OLED device provided by this application can achieve efficient and stable full-color OLEDs.

[0238] In the embodiments of this application, the anode is an electrode material with a high work function. The electrodes of bottom-emitting devices can be indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), zinc oxide (ZnO), with a thickness of 80 nm to 200 nm. The electrodes of top-emitting devices can be Ag / ITO, Ag / IZO, Ag / SnO2, Ag / ZnO, Al / ITO, Al / IZO, with a metal layer thickness of 80 nm to 100 nm and an oxide layer thickness of 5 nm to 20 nm. The average reflectivity reference value of the anode in the visible light region is 85% to 95%.

[0239] Among them, the metal layer thickness can be 80 nm, 82 nm, 85 nm, 88 nm, 90 nm, 92 nm, 95 nm, 98 nm, 100 nm, etc., and the oxide layer thickness can be 5 nm, 8 nm, 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, etc.

[0240] The main function of the hole injection layer (HIL) is to reduce the hole injection barrier and improve the hole injection efficiency. Hole injection materials such as HATCN, MnO3, CuPc, etc. can be selected; P-type doping can also be carried out in the hole transport material, such as NPB:F4TCNQ, TAPC:MnO3, etc. The thickness of the hole injection layer is 5 nm to 20 nm, and the P-type doping concentration is 0.5% to 10%. This layer can be formed by co-evaporation from multiple sources.

[0241] Among them, the thickness of the hole injection layer can be 5 nm, 8 nm, 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, etc. The P-type doping concentration can be 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc.

[0242] The main function of the hole transport layer (HTL) is to transfer holes. This layer can be prepared by evaporation using carbazole-based materials with a relatively high hole mobility. The HOMO energy level of the material of this layer needs to be between -5.2 eV and -5.6 eV, and the thickness is 10 nm to 150 nm. For top-emitting devices, according to the principle of the micro-resonator, the color coordinates of the blue element can be adjusted by changing the thickness of this layer.

[0243] Among them, the thickness of the hole transport layer can be 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, etc.

[0244] The color - tuning layer (CCL) uses hole - transporting materials with high hole mobility. For top - emission devices, according to the principle of micro - resonator, on the basis of fixing the thickness of the hole - transporting layer, the color coordinates of the red / green light - emitting elements can be adjusted by changing the thickness of this layer. The difference between the HOMO energy levels of the material of this layer and the material of the red / green electron - blocking layer is no more than 0.2 eV, which can reduce the energy barrier for holes to transport from the color - tuning layer to the electron - blocking layer, reduce the hole accumulation at the interface, and improve the carrier migration efficiency.

[0245] The main function of the electron - blocking layer (EBL) is to block electrons and excitons generated in the light - emitting layer and transfer holes. The energy of the lowest triplet excited state of the material of this layer is greater than the energy of the lowest triplet excited state of the transition - metal complex material in the light - emitting layer, and the difference is greater than or equal to 0.2 eV, so as to block excitons and avoid energy waste. Moreover, the HOMO energy level of the material of this layer is deeper than the HOMO energy level of the host material in the light - emitting layer, and the difference is less than or equal to 0.2 eV. The thickness of the electron - blocking layer is 1 nm - 20 nm.

[0246] Among them, the thickness of the electron - blocking layer can be 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, etc.

[0247] It should be noted that if the selected material meets the requirements of both the color - tuning layer and the electron - blocking layer, then on the premise of meeting the optics of the top - emission device, the color - tuning layer and the electron - blocking layer can be combined into one layer.

[0248] The N - type charge - generation layer (NCGL) is formed by doping a low - work - function active metal into an electron - transporting material. Among them, the active metal can be Li, Ca, Yb, etc., the doping ratio is 0.6% - 2%, and the thickness is 10 nm - 20 nm.

[0249] The thickness of the N - type charge - generation layer can be 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, etc., and the doping ratio of the active metal can be 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.2%, 1.5%, 1.8%, 2%, etc.

[0250] The P - type charge - generation layer (PCGL) is formed by doping a hole - transporting material with a P - type dopant such as molybdenum oxide, etc., the doping ratio is 5% - 15%, and the thickness is 10 nm - 20 nm.

[0251] The thickness of the P-type charge generation layer can be 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, etc., and the doping ratio of the P-type dopant can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, etc.

[0252] The main functions of the electron transport layer (ETL) are to transport electrons and block excitons. This layer is a Liq-doped electron transport material with a doping ratio of 10:1 to 1:1 and a thickness of 10 nm to 70 nm. The electron transport materials can be imidazole-based, pyridine-based, pyrimidine-based, triazine-based, thiophene-based, azine-based derivatives, etc. For example, the groups in the electron transport materials contain at least one of the following groups: The structural formula of Liq is:

[0253] The thickness of the electron transport layer can be 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, etc., and the doping ratio can be 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, 1:1, etc.

[0254] In a possible implementation, let T1(HBM) and T1(ETM) represent the energies of the lowest triplet excited states of the hole blocking layer material and the electron transport layer material respectively, then the relationship between the two satisfies: T1(ETM) > T1(HBM).

[0255] In the embodiments of the present application, the energy of the lowest triplet excited state of the electron transport layer material is higher than that of the hole blocking layer material, which can avoid energy backtransfer, reduce energy loss, and thus improve the luminescence efficiency of the device.

[0256] In a possible implementation, let |HOMO(ETM)| and |HOMO(HBM)| represent the absolute values of the HOMO energy levels of the electron transport layer material and the hole blocking layer material respectively, then the relationship between the two satisfies: |HOMO(ETM)| > |HOMO(HBM)|.

[0257] Let |LUMO(ETM)| and |LUMO(HBM)| represent the absolute values of the LUMO energy levels of the electron transport layer material and the hole blocking layer material respectively, then the relationship between the two satisfies: |LUMO(ETM)| > |LUMO(HBM)|.

[0258] In the embodiments of the present application, the absolute value of the HOMO energy level of the electron transport layer material is higher than the absolute value of the HOMO energy level of the hole blocking layer material, which can limit the radiative transition of excitons in the light-emitting layer, thereby improving the light-emitting efficiency. At the same time, the absolute value of the LUMO energy level of the electron transport layer material is higher than the absolute value of the LUMO energy level of the hole blocking layer material, which can enable electrons to be preferentially injected into the light-emitting layer, reduce the electron transport barrier, and improve the carrier injection balance.

[0259] The main function of the electron injection layer (EIL) is to inject electrons. The electron injection layer material may include materials such as Yb, Li, LiF, NaCl, CsF, Li2O, BaO, Liq, etc., or combinations of these materials. The thickness of the electron injection layer is 0.5 nm to 2 nm.

[0260] The device provided by the present application can be encapsulated with UV glue or by means of thin film encapsulation, etc., and no specific limitation is made thereto.

[0261] The main functions of the hole blocking layer are to transport electrons, block holes, and excitons generated in the light-emitting layer. The thickness of the hole blocking layer is 1 nm to 10 nm. Exemplarily, the thickness of the hole blocking layer can be 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, etc.

[0262] The hole blocking layer material will be introduced below.

[0263] In the embodiments of the present application, the structural type of the hole blocking layer material is: D-E, D-F-E, E-D-E or E-F-D-E.

[0264] Among them, D is selected from a substituted or unsubstituted pyrenyl group, a substituted or unsubstituted triphenylenyl group, a substituted or unsubstituted group, a substituted or unsubstituted anthryl group, a substituted or unsubstituted phenanthryl group or a substituted or unsubstituted perylenyl group;

[0265] E is selected from a substituted or unsubstituted pyrazino[2,3-f]phthalazinyl group, a substituted or unsubstituted benzo[h]quinolinyl group, a substituted or unsubstituted phenanthrolinyl group, a substituted or unsubstituted acridinyl group, a substituted or unsubstituted phenazinyl group, a substituted or unsubstituted dibenzo-γ-pyrone group, a substituted or unsubstituted 1,8-naphthyridinyl group or a substituted or unsubstituted 1,5-naphthyridinyl group;

[0266] F is selected from a substituted or unsubstituted C6-C30 aryl group or a substituted or unsubstituted C5-C30 heteroaryl group.

[0267] If there are substituents in D, E, and F, the substituents in D, E, and F are each independently selected from deuterium, halogen, -CN, C1-C12 alkyl, C1-C12 alkoxy, C1-C12 haloalkyl, C2-C6 alkenyl, C3-C10 cycloalkyl, C6-C30 aryl, or C5-C30 heteroaryl.

[0268] In the embodiments of the present application, some examples of hole blocking layer materials can be shown as follows:

[0269]

[0270]

[0271]

[0272] In one possible implementation, the lifetime of the triplet excitons of the hole blocking layer material is 1 μs to 1 s.

[0273] Exemplarily, the lifetime of the triplet excitons of the hole blocking layer material can be 1 μs, 2 μs, 5 μs, 10 μs, 20 μs, 30 μs, 50 μs, 100 μs, 200 μs, 300 μs, 400 μs, 500 μs, 600 μs, 700 μs, 800 μs, 900 μs, 1000 μs, 2000 μs, 3000 μs, 4000 μs, 5000 μs, 6000 μs, 7000 μs, 8000 μs, 9000 μs, 10000 μs, 100000 μs, 200000 μs, 500000 μs, 1 s, etc.

[0274] In the embodiments of the present application, when the lifetime of the triplet excitons of the hole blocking layer material is in the range of 1 μs to 1 s, the triplet energy can be transferred to the light-emitting layer through FRET and Dexter energy transfer (DET) methods, thereby improving the light-emitting efficiency of the device.

[0275] In one possible implementation, the energy of the lowest triplet excited state of the electron transport layer material and the energy of the lowest triplet excited state of the phosphorescent material are both greater than the energy of the lowest triplet excited state of the hole blocking layer material.

[0276] In this implementation, let T1(HBM), T1(ETM), and T1(PGD) represent the energies of the lowest triplet excited states of the hole blocking layer material, the electron transport layer material, and the phosphorescent material, respectively. Then the relationship among the three is: T1(HBM) < T1(PGD), T1(HBM) < T1(ETM).

[0277] In the embodiments of the present application, the energy of the lowest triplet excited state of the electron transport layer material and the energy of the lowest triplet excited state of the phosphorescent material are both greater than the energy of the lowest triplet excited state of the hole blocking layer material, which can avoid energy back transfer and reduce energy loss, thereby improving the light emission efficiency of the device.

[0278] In a possible implementation, the absolute value of the HOMO energy level of the electron transport layer material > the absolute value of the HOMO energy level of the hole blocking layer material > the absolute value of the HOMO energy level of the host material;

[0279] And the absolute value of the LUMO energy level of the electron transport layer material > the absolute value of the LUMO energy level of the hole blocking layer material > the absolute value of the LUMO energy level of the host material;

[0280] Among them, the absolute value of the HOMO energy level of the host material is the minimum value of the absolute values of the HOMO energy levels of the hole-transporting host material and the electron-transporting host material;

[0281] The absolute value of the LUMO energy level of the host material is the maximum value of the absolute values of the LUMO energy levels of the hole-transporting host material and the electron-transporting host material.

[0282] In this implementation, let |HOMO(ETM)|, |HOMO(GH)|, and |HOMO(HBM)| represent the absolute values of the HOMO energy levels of the electron transport layer material, the host material, and the hole blocking layer material respectively, then the relationship among the three is: |HOMO(ETM)| > |HOMO(HBM)| > |HOMO(GH)|. Among them, |HOMO(GH)| is the smaller value of the absolute values of the HOMO energy levels of the P-type material and the N-type material.

[0283] Let |LUMO(ETM)|, |LUMO(GH)|, and |LUMO(HBM)| represent the absolute values of the LUMO energy levels of the electron transport layer material, the host material, and the hole blocking layer material respectively, then the relationship among the three is: |LUMO(ETM)| > |LUMO(HBM)| > |LUMO(GH)|. Among them, |LUMO(GH)| is the larger value of the absolute values of the LUMO energy levels of the P-type material and the N-type material.

[0284] In the embodiments of the present application, the absolute value of the HOMO energy level of the hole blocking layer material is higher than the absolute value of the HOMO energy level of the host material, which can effectively block the transfer of holes from the light-emitting layer to the electron transport layer, forcing the holes to recombine with electrons in the light-emitting layer and improving the exciton formation efficiency. At the same time, the absolute value of the HOMO energy level of the electron transport layer material is higher than the absolute value of the HOMO energy level of the hole blocking layer material, which can further limit the radiative transition of excitons in the light-emitting layer, thereby improving the light emission efficiency.

[0285] The absolute value of the LUMO energy level of the hole blocking layer material is higher than that of the host material, which can block the diffusion of electrons to the hole blocking layer. At the same time, the absolute value of the LUMO energy level of the electron transport layer material is higher than that of the hole blocking layer material, which can enable electrons to be preferentially injected into the light-emitting layer, reduce the electron transport barrier, and improve the carrier injection balance.

[0286] In a possible implementation, the difference between the LUMO energy level of the hole blocking layer material and the LUMO energy level of the host material is less than or equal to 0.4 eV, that is, |LUMO(HBM)-LUMO(GH)|≤0.4 eV.

[0287] In the embodiments of the present application, when the difference between the LUMO energy level of the hole blocking layer material and the LUMO energy level of the host material is less than or equal to 0.4 eV, the energy barrier for electrons to transfer from the light-emitting layer to the hole blocking layer is relatively low, which promotes the efficient injection of electrons into the hole blocking layer and their transfer to the cathode, reducing the energy loss at the interface. Moreover, it can also prevent the accumulation of electrons in the light-emitting layer, improving the device current density and external quantum efficiency.

[0288] It should be noted that the main energy driving mechanisms for the short lifetime of green PSF-OLEDs are TTA and / or TPA. These reactions approximately double the energy of the excited state, which is sufficient to break the intramolecular bonds and convert the organic molecules into non-radiative quenching centers. In order to minimize the occurrence probability of high-energy annihilation events while maintaining high efficiency, the triplet exciton density in the light-emitting layer should be reduced to avoid triplet accumulation. However, in the related art, the energy of triplet excitons in the PSF-OLED light-emitting layer is high, and exciton accumulation at high brightness is likely to cause TTA and TPA, resulting in molecular bond breakage and material instability, ultimately leading to a short device lifetime.

[0289] In the present application, by designing a hole blocking layer material with an energy lower than the triplet energy of the fluorescent material, the density of triplet excitons in the light-emitting layer is reduced, triplet exciton accumulation is avoided, and the occurrence probability of TTA and / or TPA events is reduced, thereby suppressing the deterioration of the hole blocking layer material and extending the device lifetime. Moreover, the hole blocking layer material provided in the present application can also realize the energy reuse of triplet excitons, enabling the device to maintain high efficiency.

[0290] The embodiments of the present application also provide a preparation method for a hole blocking layer material, which includes:

[0291] Step 1: If the structural type of the hole blocking layer material is D-E, provide reactants D and E; make reactants D and E react to obtain the hole blocking layer material.

[0292] Step 2: If the structural type of the hole blocking layer material is D-F-E, provide reactants D, F, and E; react reactants D and F to obtain M1, and react reactant M1 with E to obtain the hole blocking layer material; or react reactants F and E to obtain M2, and react reactant M2 with D to obtain the hole blocking layer material.

[0293] Step 3: If the structural type of the hole blocking layer material is E-D-E, provide reactants E and D, and react reactants E and D to obtain the hole blocking layer material.

[0294] Step 4: If the structural type of the hole blocking layer material is E-F-D-E, provide reactants E, reactant F, and reactant D; react reactants E and reactant F to obtain M3; react reactant D and reactant E to obtain M4; and react M3 and M4 to obtain the hole blocking layer material.

[0295] An embodiment of the present application also provides a display device, which includes any one of the above-mentioned green organic electroluminescent devices.

[0296] The display device provided by the embodiment of the present application has all the advantages of the green organic electroluminescent device. Exemplarily, the display device includes but is not limited to: OLED TVs, tablet computers, in-vehicle displays, MP3 players, smart watches, fitness trackers, virtual reality (VR) headsets, augmented reality (AR) glasses, etc.

[0297] The exemplary embodiments of the present application will be described in more detail below. Although the exemplary embodiments of the present application are described below, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein.

[0298] Synthesis Example 1

[0299] This synthesis example synthesized a fluorescent material GD-1, and the fluorescent material GD-1 was prepared by the following method:

[0300]

[0301] Step 1: In a nitrogen atmosphere, add 0.1 mol of reactant 1a, 0.2 mol of reactant 1b, 0.03 mol of Pd(OAc)2, 0.03 mol of tBu3P·HBF4, and 0.03 mol of tBuONa to a toluene solution, react at 110 °C for 12 hours, and then purify to obtain 0.07 mol of intermediate 1.

[0302] Molecular formula of intermediate 1: C 60 H 35 D5N2.

[0303] Elemental analysis: Theoretical values: C 90.76; H 5.71; N 14.49, actual values: C 90.52; H 5.83; N 14.17.

[0304] The NMR data are as follows: 1 H NMR (400 MHz, DMSO-d6): δ (ppm) = 8.47 (d, 2H, -Ph), 8.18 (s, 2H, -Ph), 8.03 - 7.96 (m, 4H, -Ph), 7.83 (d, 4H, -Ph), 7.70 (d, 2H, -Ph), 7.59 - 7.41 (m, 21H, -Ph).

[0305] Step 2: Under a nitrogen atmosphere, 0.1 mol of intermediate 1, 0.2 mol of BBr3, and 0.1 mol of EtN(iPr)2 were added to a toluene solution. After reacting at 60 °C for 24 hours, purification was carried out to obtain 0.06 mol of product GD-1.

[0306] The molecular formula of GD1: C 60 H 32 D5BN2.

[0307] Elemental analysis: Theoretical values: C 89.88; H 5.28; N 3.49, actual values: C 90.07; H 5.34; N 3.52.

[0308] The NMR data are as follows: 1 H NMR (400 MHz, DMSO-d6): δ (ppm) = 8.19 (s, 2H, -Ph), 8.04 - 7.96 (m, 4H, -Ph), 7.82 (d, 4H, -Ph), 7.58 - 7.41 (m, 22H, -Ph).

[0309] The preparation methods of GD-2 to GD-10 are the same as that of GD-1, which will not be elaborated here.

[0310] Synthesis Example 2

[0311] In this synthesis example, a phosphorescent material PGD-1 was synthesized. The phosphorescent material PGD-1 was prepared by the following method:

[0312]

[0313] Under a nitrogen atmosphere, 0.1 mol of reactant 2a, 0.1 mol of reactant 2b, and 0.1 mol of IrCl3·H2O were added to a mixed solution of ethylene glycol monoethyl ether and water. After reacting at 110 °C for 24 hours, purification was carried out to obtain 0.08 mol of product PGD-1.

[0314] Molecular formula of PGD1: C 51 H 34 IrN3O.

[0315] Elemental analysis: Theoretical values: C 68.28; H 3.82; N 4.68; O 1.78, Actual values: C 68.37; H 3.83; N 4.72; O 1.83.

[0316] NMR data are as follows: 1 1H NMR (400 MHz, DMSO-d6): δ (ppm) = 8.76 (d, 2H, -Py), 8.53 (d, 1H, -Py), 8.42 (s, 2H, -Ph), 8.19 (d, 2H, -Ph), 8.01 - 7.92 (m, 4H, -Ph / -Py), 7.83 - 7.75 (m, 5H, -Ph / -Py), 7.55 - 7.31 (m, 17H, -Ph / -Py), 6.923 (m, 1H, -Py).

[0317] The preparation methods of PGD-2 to PGD-10 are the same as that of PGD-1, which will not be elaborated here.

[0318] Synthesis Example 3

[0319] In this synthesis example, a hole-transporting host material P-1 was synthesized. The hole-transporting host material P-1 was prepared by the following method:

[0320]

[0321] In a nitrogen atmosphere, 0.1 mol of reactant 3a, 0.1 mol of reactant 3b and 0.2 mol of DDQ were added to a mixed solution of MSA and DCM. After reacting at room temperature for 12 hours, it was purified to obtain 0.09 mol of product P-1.

[0322] Molecular formula of P-1: C 36 H 24 N2.

[0323] Elemental analysis: Theoretical values: C 89.23; H 4.99; N 5.78, Actual values: C 89.11; H 4.95; N 5.69.

[0324] NMR data are as follows: 11H NMR (400 MHz, DMSO-d6): δ (ppm) = 8.54 (d, 1H, -Ph), 8.30 (d, 1H, -Ph), 8.19 - 8.13 (m, 2H, -Ph), 8.01 - 7.88 (m, 4H, -Ph), 7.76 (d, 1H, -Ph), 7.63 - 7.51 (m, 12H, -Ph), 7.35 (s, 1H, -Ph), 7.21 - 7.15 (m, 2H, -Ph).

[0325] The preparation method of P-2 is the same as that of P-1, which will not be elaborated here.

[0326] Synthesis Example 4

[0327] In this synthesis example, an electron-transporting host material N-1 was synthesized. The electron-transporting host material N-1 was prepared by the following method:

[0328]

[0329] In a nitrogen atmosphere, 0.1 mol of reactant 4a, 0.1 mol of reactant 4b, 0.01 mol of Pd2(dba)3, 0.01 mol of tBu3P, and 0.03 mol of tBuONa were added to a toluene solution. After refluxing for 12 hours, purification was carried out to obtain 0.08 mol of product N-1.

[0330] Molecular formula of N-1: C 45 H 29 N5.

[0331] Elemental analysis: Theoretical values: C 84.48; H 4.57; N 10.95, Actual values: C 84.32; H 4.54; N 10.91.

[0332] The NMR data are as follows: 1 1H NMR (400 MHz, DMSO-d6): δ (ppm) = 8.55 (d, 1H, -Ph), 8.34 (d, 2H, -Ph), 8.19 (d, 1H, -Ph), 7.95 - 7.90 (m, 3H, -Ph), 7.76 (d, 2H, -Ph), 7.58 - 7.40 (m, 16H, -Ph), 7.24 - 7.16 (m, 4H, -Ph).

[0333] The preparation method of N-3 is the same as that of N-1, which will not be elaborated here.

[0334] Synthesis Example 5

[0335] In this synthesis example, a hole-blocking layer material HB-3 was synthesized. The hole-blocking layer material HB-3 was prepared by the following method:

[0336]

[0337] Step 1: In a nitrogen atmosphere, 0.1 mol of reactant 5a, 0.1 mol of reactant 5b, 0.01 mol of Pd2(dba)3, 0.01 mol of tBu3P, and 0.03 mol of K2CO3 were added to a toluene solution respectively. After refluxing for 12 hours, purification was carried out to obtain 0.08 mol of intermediate 2.

[0338] Molecular formula of intermediate 2: C 19 H 12 BrN.

[0339] Elemental analysis: Theoretical values: C 68.28; H 3.62; N 4.19, Actual values: C 68.34; H 3.67; N 4.15.

[0340] NMR data are as follows: 1 H NMR (400 MHz, DMSO-d6): δ (ppm) = 8.40 (d, 1H, -Ph), 8.25 (s, 1H, -Ph), 8.24 - 7.33 (m, 7H, -Ph / -Py), 7.42 (s, 3H, -Ph).

[0341] Step 2: In a nitrogen atmosphere, 0.1 mol of intermediate 2, 0.1 mol of reactant 5c, 0.01 mol of Pd2(dba)3, 0.01 mol of tBu3P, and 0.03 mol of K2CO3 were added to a toluene solution respectively. After refluxing for 12 hours, purification was carried out to obtain 0.07 mol of product HB-3.

[0342] Molecular formula of HB-3: C 35 H 12 D9N.

[0343] Elemental analysis: Theoretical values: C 90.48; H 6.50; N 3.01, Actual values: C 90.34; H 6.47; N 3.11.

[0344] NMR data are as follows: 1 H NMR (400 MHz, DMSO-d6): δ (ppm) = 8.38 (d, 1H, -Ph), 8.23 (s, 1H, -Ph), 8.11 - 8.04 (m, 2H, -Ph), 7.96 - 7.74 (m, 7H, -Ph / -NHC), 7.61 (d, 1H, -Ph).

[0345] The preparation method of HB-4 is the same as that of HB-3, which will not be elaborated here.

[0346] I. Optical Physical Properties of Materials

[0347] (I) Orientation of Horizontal Emission Dipoles

[0348] The orientation degrees of horizontal emission dipoles of several fluorescent materials and phosphorescent materials are introduced below respectively.

[0349] Among them, the orientation degree of the horizontal emission dipole can be represented by the horizontal emission dipole ratio Θ / / The horizontal emission dipole ratios of the fluorescent material and the phosphorescent material can be referred to Table 1 and Table 2 respectively.

[0350] Table 1

[0351] Fluorescent material <![CDATA[Θ / / > GD-ref 82％ GD-1 90％ GD-2 89％ GD-3 93％ GD-4 94％ GD-5 92％ GD-6 92％ GD-7 90％ GD-8 91％ GD-9 93％ GD-10 92％

[0352] Table 2

[0353]

[0354]

[0355] Among them, GD-ref represents the reference compound of the fluorescent material, and PGD-ref represents the reference compound of the phosphorescent material, which are shown as follows:

[0356]

[0357] It can be seen from Table 1 and Table 2 that the orientation degrees of the horizontal emission dipoles of the fluorescent material and the phosphorescent material provided in the embodiments of the present application are both relatively high.

[0358] (II) Spectral Overlap

[0359] Refer to Figure 6 , Figure 6 which is a schematic diagram of spectral overlap between the normalized photoluminescence spectrum of the phosphorescent material PGD-1 solution and the normalized absorption spectrum of the pure thin film of the fluorescent material GD-1. It can be seen from Figure 6 that the spectral overlap area between the phosphorescent material and the fluorescent material is relatively high, which is beneficial to FRET and thus beneficial to obtaining a highly efficient and stable green light device.

[0360] (III) Triplet Exciton Lifetime, Energy of the Lowest Triplet Excited State, HOMO Energy Level Value, LUMO Energy Level Value

[0361] Refer to Table 3, which shows the triplet exciton lifetime, energy of the lowest triplet excited state, HOMO energy level value, and LUMO energy level value of the host material (GH), phosphorescent material (PGD), fluorescent material (FGD), hole blocking layer material (HB), and electron transport layer material (ETM).

[0362] Table 3

[0363]

[0364]

[0365] Among them, GH-1 (P:N = 6:4) indicates that the molar ratio of the hole-transporting host material P-1 to the electron-transporting host material N-1 in the host material is 6:4.

[0366] It can be seen from Table 3 that the triplet exciton lifetimes of HB-3 and HB-4 are relatively long, and their T1 values are both lower than that of FGD-1. This is beneficial to the FRET from PGD-1 to FGD-1, thereby reducing TTA and TPA at the interface between the light-emitting layer and the light-emitting layer, improving the device efficiency and extending the device lifetime.

[0367] II. Optoelectronic properties of the device

[0368] (1) When testing based on the light-emitting layer, the device structure is: ITO / Ag / ITO(150 nm) / HIL(10 nm) / HTL(100 nm) / CCL(25 nm) / EBL(5 nm) / EML(40 nm) / HBL(5 nm) / ETL(30 nm) / EIL(1.5 nm) / Mg:Ag(16 nm) / CPL(70 nm).

[0369] (1) When testing based on the light-emitting layer, the device structure is: ITO / Ag / ITO(150 nm) / HIL(10 nm) / HTL(100 nm) / CCL(25 nm) / EBL(5 nm) / EML(40 nm) / HBL(5 nm) / ETL(30 nm) / EIL(1.5 nm) / Mg:Ag(16 nm) / CPL(70 nm).

[0370] Among them, the material used for the hole-blocking layer (HBL) is HB-4. For the light-emitting layer, Comparative Examples 1 to 3 and Examples 1 to 12 were set up, and the materials used are as follows:

[0371] Comparative Example 1: P-1(60):N-1(40):PGD-ref:GD-ref(89%:10%:1%);

[0372] Comparative Example 2: P-1(60):N-1(40):PGD-ref:GD-1(89%:10%:1%);

[0373] Comparative Example 3: P-1(60):N-1(40):PGD-1:GD-ref(89%:10%:1%);

[0374] Example 1: P-1(60):N-1(40):PGD-1:GD-1(89%:10%:1%);

[0375] Example 2: P-1(60):N-1(40):PGD-2:GD-2(89%:10%:1%);

[0376] Example 3: P-1(60):N-1(40):PGD-3:GD-3 (89%:10%:1%);

[0377] Example 4: P-1(60):N-1(40):PGD-2:GD-3 (89%:10%:1%);

[0378] Example 5: P-1(60):N-1(40):PGD-2:GD-4 (89%:10%:1%);

[0379] Example 6: P-1(60):N-1(40):PGD-4:GD-6 (89%:10%:1%);

[0380] Example 7: P-1(60):N-1(40):PGD-6:GD-10 (89%:10%:1%);

[0381] Example 8: P-1(60):N-1(40):PGD-9:GD-5 (89%:10%:1%);

[0382] Example 9: P-1(60):N-1(40):PGD-8:GD-7 (89%:10%:1%);

[0383] Example 10: P-1(50):N-1(50):PGD-1:GD-1 (89%:10%:1%);

[0384] Example 11: P-1(60):N-1(40):PGD-1:GD-1 (91%:8%:1%);

[0385] Example 12: P-2(60):N-3(40):PGD-1:GD-1 (89%:10%:1%).

[0386] Among them, P-1(60):N-1(40) means that the mole fractions of the hole-transporting host material P-1 and the electron-transporting host material N-1 are 60% and 40% respectively, and 89%:10%:1% respectively represent the mole fractions of the host material, the phosphorescent material and the fluorescent material.

[0387] Except for the light-emitting layer and the hole-blocking layer, the materials involved in the other layers are shown as follows:

[0388] EIL: Yb;

[0389] HIL: The mole fractions of the two are 98% and 2% respectively;

[0390]

[0391] ETL: The doping ratio of Liq is 50%;

[0392]

[0393] Use the IVL test equipment to obtain the voltage, emission wavelength (λ 2 ) and current efficiency (CE) of the organic light-emitting device at 5 mA / cm EL . Use the service life test equipment to obtain the LT95 (the time when the brightness decays from the initial value to 95%, i.e., LT 2 , unit: hour) of the organic light-emitting device under the conditions of 35 mA / cm 95 and 35 °C. See Table 4 for the test results.

[0394] Table 4

[0395] Device λ (nm) V (V) CE (cd / A) <![CDATA[LT 95 (h)]]> Comparative Example 1 536 3.72 254 145 Comparative Example 2 536 3.65 263 157 Comparative Example 3 536 3.66 265 152 Example 1 536 3.49 285 182 Example 2 536 3.50 292 190 Example 3 536 3.48 278 180 Example 4 536 3.52 284 178 Example 5 536 3.49 280 183 Example 6 536 3.46 294 175 Example 7 536 3.47 286 170 Example 8 536 3.45 280 184 Example 9 536 3.48 279 172 Example 10 536 3.48 276 185 Example 11 536 3.49 282 180 Example 12 536 3.51 287 188

[0396] It can be seen from Table 4 that: at the same wavelength, the devices corresponding to Examples 1 to 12 have lower device voltage, higher current efficiency, and longer lifespan. Thus, it can be shown that after modifying the fluorescent material and phosphorescent material with phenyl or phenyl derivatives, the corresponding phosphorescent-sensitized fluorescent organic light-emitting diode devices have more excellent performance.

[0397] In addition, see Figure 7 , Figure 7 for the EL spectrum of the device corresponding to Example 2. It can be seen from Figure 7 that the peak of the electroluminescence wavelength of this device is indeed 536 nm.

[0398] (2) When testing based on the hole blocking layer, the device structure is: ITO / Ag / ITO(150 nm) / HIL(10 nm) / HTL(110 nm) / CCL(40 nm) / EBL(6 nm) / EML(35 nm) / HBL(5 nm) / ETL(30 nm) / EIL(1 nm) / Mg:Ag(15 nm) / CPL(70 nm).

[0399] Among them, the materials used for the light-emitting layer are P-1(60):N-1(40):PGD-1:GD-1(89%:10%:1%), and the materials involved in each layer remain unchanged.

[0400] For the hole blocking layer, Examples 13 to 14 are set, and the materials used are as follows:

[0401] Example 13: HB-3; Example 14: HB-4.

[0402] Use the IVL test equipment to obtain the organic light-emitting device at 5 mA / cm2 The voltage and current efficiency (CE). The service life test device obtains the LT95 (the time when the brightness decays from the initial value to 95%, i.e., LT 2 ), of the organic electroluminescent device under the conditions of 35 mA / cm 95 and 35 °C. The color coordinates CIEx and CIEy of the organic electroluminescent device are obtained using a color difference meter. The test results are shown in Table 5.

[0403] Table 5

[0404] Device Voltage (V) CIEx CIEy CE (cd / A) <![CDATA[LT 95 (h)]]> Example 13 3.47 0.170 0.780 255.6 84 Example 14 3.48 0.170 0.781 248.2 80

[0405] It can be seen from Table 5 that: The lifetimes of the triplet excitons of the hole blocking layer materials in Example 13 and Example 14 are relatively long. The energy of the first triplet excited state is lower than that of the triplet first excited state of the fluorescent material, and the HOMO energy level and LUMO energy level are matched. Therefore, the carrier transport performance of the Single device is excellent, the exciton recombination center is wide, TTA and TPA are suppressed, and the lifetime and efficiency of the device are more excellent.

[0406] See Figure 8 , Figure 8 for the EL spectrum of the device corresponding to Example 14. It can be seen from Figure 8 that: The peak of the electroluminescence wavelength of this device is 536 nm.

[0407] See Figure 9 , Figure 9 for the lifetime decay schematic diagram of the device corresponding to Example 14. It can also be seen from Figure 9 that: The LT 95 lifetime of the device corresponding to Example 14 is indeed 80 h. It can thus be shown that: The hole blocking layer material used in this application can indeed improve the lifetime of the device.

[0408] (2) Photovoltaic properties of the Tandem device

[0409] (1) When testing based on the light-emitting layer, the device structure is: ITO / Ag / ITO (150 nm) / HIL (10 nm) / HTL1 (30 nm) / EBL1 (5 nm) / EML1 (35 nm) / HBL1 (5 nm) / NCGL (15 nm) / PCGL (10 nm) / HTL2 (10 - 100 nm) / EBL2 (5 nm) / EML2 (35 nm) / HBL2 (5 nm) / ETL (35 nm) / EIL (1 nm) / Mg:Ag (1:9, 15 nm) / CPL (70 nm).

[0410] Among them, the materials used for HIL, ETL, EIL, and CPL are the same as those used for HIL, ETL, EIL, and CPL in the Single device; the materials used for HTL1 and HTL2 are the same and are the same as the material used for HTL in the Single device; the materials used for EBL1 and EBL2 are the same and are the same as the material used for EBL in the Single device; the materials used for HBL1 and HBL2 are the same and are the same as the material used for HBL in the Single device.

[0411] PCGL: The molar fractions of the two are 90% and 10% respectively;

[0412] NCGL: and Yb, and the doping ratio of Yb is 2%.

[0413] For the light-emitting layer, the materials used for EML1 and EML2 are the same and are the same as the material used for EML in the Single device. The set comparative examples and examples are as follows:

[0414] Comparative Example 4: P-1(60):N-1(40):PGD-ref:GD-ref(89%:10%:1%);

[0415] Comparative Example 5: P-1(60):N-1(40):PGD-ref:GD-1(89%:10%:1%);

[0416] Comparative Example 6: P-1(60):N-1(40):PGD-1:GD-ref(89%:10%:1%);

[0417] Example 15: P-1(60):N-1(40):PGD-1:GD-1(89%:10%:1%);

[0418] Example 16: P-1(60):N-1(40):PGD-2:GD-2(89%:10%:1%);

[0419] Example 17: P-1(60):N-1(40):PGD-3:GD-3(89%:10%:1%);

[0420] Example 18: P-1(60):N-1(40):PGD-2:GD-3(89%:10%:1%);

[0421] Example 19: P-1(60):N-1(40):PGD-2:GD-4(89%:10%:1%);

[0422] Example 20: P-1(60):N-1(40):PGD-4:GD-6(89%:10%:1%);

[0423] Example 21: P-1(60):N-1(40):PGD-6:GD-10(89%:10%:1%);

[0424] Example 22: P-1(60):N-1(40):PGD-9:GD-5(89%:10%:1%);

[0425] Example 23: P-1(60):N-1(40):PGD-8:GD-7(89%:10%:1%);

[0426] Example 24: P-1(50):N-1(50):PGD-1:GD-1(89%:10%:1%);

[0427] Example 25: P-1(60):N-1(40):PGD-1:GD-1(91%:8%:1%);

[0428] Example 26: P-2(60):N-3(40):PGD-1:GD-1(89%:10%:1%).

[0429] For the optoelectronic performance test results of the top-emitting devices, see Table 6 below.

[0430] Table 6

[0431] Device CIEx CIEy CE (cd / A) Comparative Example 4 0.234 0.744 470 Comparative Example 5 0.232 0.743 487 Comparative Example 6 0.231 0.745 485 Example 15 0.234 0.742 530 Example 16 0.235 0.743 568 Example 17 0.234 0.745 542 Example 18 0.233 0.742 540 Example 19 0.232 0.744 530 Example 20 0.234 0.743 565 Example 21 0.233 0.743 554 Example 22 0.233 0.744 530 Example 23 0.235 0.741 537 Example 24 0.234 0.742 532 Example 25 0.234 0.743 535 Example 26 0.236 0.740 540

[0432] It can be seen from Table 6 that after the fluorescent material and the phosphorescent material are modified by phenyl or phenyl derivatives, the performance of the corresponding phosphorescent-sensitized fluorescent organic light-emitting diode devices is more excellent.

[0433] See Figure 10 , Figure 10 is the EL spectrum of the device corresponding to Example 18. It can be seen from Figure 10 that the peak of the electroluminescence wavelength of this device is 536 nm.

[0434] (2) When testing based on the hole blocking layer, the device structure is: ITO / Ag / ITO(150nm) / HIL(10nm) / HTL1(30nm) / CCL1(7nm) / EBL1(7nm) / EML1(30nm) / HBL1(7nm) / ETL1(13nm) / NCGL(15nm) / PCGL(10nm) / HTL2(25nm) / CCL2(17nm) / EBL2(7nm) / EML2(30nm) / HBL2(7nm) / ETL2(35nm) / EIL(1nm) / Mg:Ag(1:9, 14nm) / CPL(70nm).

[0435] Among them, the materials used for HIL, EIL, and CPL are the same as those used for HIL, EIL, and CPL in the Single device respectively; the materials used for HTL1 and HTL2 are the same and are the same as the material used for HTL in the Single device; the materials used for EBL1 and EBL2 are the same and are the same as the material used for EBL in the Single device; the materials used for CCL1 and CCL2 are the same and are the same as the material used for CCL in the Single device; the materials used for ETL1 and ETL2 are the same and are the same as the material used for ETL in the Single device; the materials used for PCGL and NCGL are the same as those used for PCGL and NCGL in the Tandem device (1) respectively.

[0436] For the hole blocking layer, the materials used for HBL1 and HBL2 are the same and are the same as the material used for HBL in the Single device. The set examples are shown as follows:

[0437] Example 27: HB-3; Example 28: HB-4.

[0438] See Table 7 for the test results.

[0439] Table 7

[0440] Device Voltage (V) CIEx CIEy CE (cd / A) <![CDATA[LT 95 (h)]]> Example 27 6.82 0.163 0.768 476.3 148 Example 28 6.84 0.162 0.769 480.2 150

[0441] It can be seen from Table 7 that: the triplet excited state lifetimes of the hole blocking layer materials in Examples 27 and 28 are relatively long, the first triplet excited state energy is lower than that of the fluorescent material, and the HOMO energy level and LUMO energy level are matched. Therefore, the carrier transport performance of the Tandem device is excellent, the exciton recombination center is wide, TTA and TPA are suppressed, and the lifetime and efficiency of the device are more excellent.

[0442] See Figure 11 , Figure 11 for the EL spectrum of the device corresponding to Example 27. From Figure 11It can be seen that the peak of the electroluminescence wavelength of the device is 536 nm.

[0443] See Figure 12 , Figure 12 which is the schematic diagram of the lifetime decay of the device corresponding to Example 27. It can also be seen from Figure 12 that the LT 95 lifetime of the device corresponding to Example 27 is indeed 148 h. This shows that the hole blocking layer material used in this application can indeed improve the lifetime of the device.

[0444] In summary, according to the performance tests of the above-mentioned Single device and Tandem device, the devices prepared by using the host material, fluorescent material, phosphorescent material, and hole blocking layer material provided in this application meet the DCI-P3 color gamut, and at the same time have ultra-high efficiency and long lifetime.

[0445] The above description is only for the convenience of those skilled in the art to understand the technical solution of this application, and is not intended to limit this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the protection scope of this application.

Claims

1. A green organic electroluminescent material, characterized in that, The green organic electroluminescent material includes: a host material, a fluorescent material, and a phosphorescent material; The horizontal emission dipole ratios of the fluorescent material and the phosphorescent material are 80% to 100% respectively; The structural general formula of the fluorescent material is as shown in (I): Wherein, R1 and R2 are each independently selected from any one of hydrogen, C1-C20 alkyl, C1-C20 alkoxy, C3-C12 cycloalkyl, and C6-C24 aryl, and at least one of R1 and R2 is an aryl; R3 is selected from deuterated C6-C30 aryl; The structural general formula of the phosphorescent material is as shown in (II): Wherein, Y is selected from O, S, or Se; R4 to R9 are each independently selected from hydrogen, deuterium, halogen, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C1-C20 heteroalkyl, substituted or unsubstituted C3-C20 heterocyclic group, substituted or unsubstituted C7-C30 aralkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C6-C30 aryloxy, substituted or unsubstituted C2-C20 alkenyl, substituted or unsubstituted C3-C20 silyl, amino, acyl, carbonyl, carboxylic acid group, ester group, cyano, isocyano, hydroxy, mercapto, sulfinyl, sulfonyl, or phosphino.

2. The green organic electroluminescent material according to claim 1, wherein The host material includes: a hole-transporting host material and an electron-transporting host material; The molar ratio of the hole-transporting host material to the electron-transporting host material is 1:9 to 9:

1.

3. The green organic electroluminescent material according to claim 2, wherein The structural general formula of the hole-transporting host material is as shown in (III): Among them, R 10 to R 17 are each independently selected from hydrogen, deuterium, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C2-C30 heteroaryl; L1 and L2 are each independently selected from a single bond, substituted or unsubstituted C6-C30 arylene, or substituted or unsubstituted C2-C30 heteroarylene; Ar1 and Ar2 are each independently selected from hydrogen, deuterium, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted carbazolyl, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C3-C40 silyl, substituted or unsubstituted C1-C30 alkylthiol, substituted or unsubstituted C6-C30 arylthiol, halogen, halogen-containing group, cyano, hydroxy, amino, or nitro.

4. The green organic electroluminescent material according to claim 3, wherein -L1-Ar1 and -L2-Ar2 are each independently selected from one of the following groups:

5. The green organic electroluminescent material according to claim 2, wherein The structural general formula of the electron-transporting host material is as shown in (IV): wherein, R 18 to R 22 are each independently selected from hydrogen, deuterium, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C2-C30 heteroaryl; Ar3 is selected from Structure A or B; X is independently selected from O, S, NR, CRR’, SiRR’, or GeRR’; R 23 to R 34 R, R, and R’ are independently selected from hydrogen, deuterium, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl.

6. The green organic electroluminescent material according to claim 5, characterized in that, R 23 to R 34 two adjacent substituents form a ring, and the ring is a substituted or unsubstituted ring; If there are substituents on the ring, the substituents are selected from hydrogen, deuterium, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl.

7. The green organic electroluminescent material according to claim 2, characterized in that, The absolute value of the HOMO energy level of the fluorescent material and the absolute value of the HOMO energy level of the phosphorescent material are both less than the absolute value of the HOMO energy level of the host material; and the absolute value of the LUMO energy level of the fluorescent material and the absolute value of the LUMO energy level of the phosphorescent material are both greater than the absolute value of the LUMO energy level of the host material; wherein, the absolute value of the HOMO energy level of the host material is the minimum value of the absolute values of the HOMO energy levels of the hole-transporting host material and the electron-transporting host material; the absolute value of the LUMO energy level of the host material is the maximum value of the absolute values of the LUMO energy levels of the hole-transporting host material and the electron-transporting host material.

8. The green organic electroluminescent material according to claim 1, characterized in that, The energy of the lowest triplet excited state of the host material > the energy of the lowest triplet excited state of the phosphorescent material > the energy of the lowest triplet excited state of the fluorescent material; The energy of the lowest singlet excited state of the host material > the energy of the lowest singlet excited state of the phosphorescent material > the energy of the lowest singlet excited state of the fluorescent material; The energy of the lowest triplet excited state of the phosphorescent material is greater than the energy of the lowest singlet excited state of the fluorescent material.

9. The green organic electroluminescent material according to claim 1, wherein The photoluminescence emission spectrum of the phosphorescent material overlaps with the absorption spectrum of the fluorescent material, and the spectral overlap area is greater than or equal to 50% of the area of the absorption spectrum of the fluorescent material.

10. The green organic electroluminescent material according to claim 1, wherein The mole fraction of the host material is 83% to 94.5%; The mole fraction of the phosphorescent material is 5% to 15%; The mole fraction of the fluorescent material is 0.5% to 2%.

11. A green organic electroluminescent device, characterized in that, The green organic light-emitting device includes an anode, a light-emitting functional layer, a cathode, and a light extraction layer that are sequentially stacked. Among them, the light-emitting functional layer includes the green organic light-emitting material according to any one of claims 1 to 10.

12. The green organic electroluminescent device according to claim 11, wherein If the green organic light-emitting device is a single-layer device, the light-emitting functional layer includes: a first transport unit, a green organic light-emitting layer, and a second transport unit. The first transport unit, the green organic light-emitting layer, and the second transport unit are sequentially stacked in the direction from the anode to the cathode, and the green organic light-emitting layer includes the green organic light-emitting material; wherein, the first transport unit includes at least one of a hole injection layer, a hole transport layer, a color adjustment layer, and an electron blocking layer; The second transport unit includes at least one of a hole blocking layer, an electron transport layer, and an electron injection layer.

13. The green organic electroluminescent device according to claim 11, wherein If the green organic electroluminescent device is a tandem device, the light-emitting functional layer includes: a hole injection layer, a third transport unit, a first green organic electroluminescent layer, a fourth transport unit, a charge generation layer, a fifth transport unit, a second green organic electroluminescent layer, a sixth transport unit, and an electron injection layer. The hole injection layer, the third transport unit, the first green organic electroluminescent layer, the fourth transport unit, the charge generation layer, the fifth transport unit, the second green organic electroluminescent layer, the sixth transport unit, and the electron injection layer are sequentially stacked in the direction from the anode to the cathode. Both the first green organic electroluminescent layer and the second green organic electroluminescent layer include the green organic electroluminescent material; Wherein, the third transport unit includes at least one of a first hole transport layer, a first color adjustment layer, and a first electron blocking layer; The fourth transport unit includes at least one of a first hole blocking layer and a first electron transport layer; The charge generation layer includes a P-type charge generation layer and an N-type charge generation layer; The fifth transport unit includes at least one of a second hole transport layer, a second color adjustment layer, and a second electron blocking layer; The sixth transport unit includes at least one of a second hole blocking layer and a second electron transport layer.

14. The green organic electroluminescent device according to claim 12 or 13, characterized in that, The structural type of the hole blocking layer material is: D-E, D-F-E, E-D-E or E-F-D-E; Among them, D is selected from a substituted or unsubstituted pyrenyl group, a substituted or unsubstituted triphenylenyl group, a substituted or unsubstituted group, a substituted or unsubstituted anthryl group, a substituted or unsubstituted phenanthryl group, or a substituted or unsubstituted perylenyl group; E is selected from a substituted or unsubstituted pyrazino[2,3-f]phenanthrolinyl group, a substituted or unsubstituted benzo[h]phenanthrolinyl group, a substituted or unsubstituted phenanthrolinyl group, a substituted or unsubstituted acridinyl group, a substituted or unsubstituted phenazinyl group, a substituted or unsubstituted dibenzo-γ-pyrone group, a substituted or unsubstituted 1,8-naphthyridinyl group, or a substituted or unsubstituted 1,5-naphthyridinyl group; F is selected from a substituted or unsubstituted C6-C30 aryl group or a substituted or unsubstituted C5-C30 heteroaryl group.

15. The green organic electroluminescent device according to claim 14, wherein The substituents in D, E, and F are each independently selected from deuterium, halogen, -CN, a C1-C12 alkyl group, a C1-C12 alkoxy group, a C1-C12 haloalkyl group, a C2-C6 alkenyl group, a C3-C10 cycloalkyl group, a C6-C30 aryl group, or a C5-C30 heteroaryl group.

16. The green organic electroluminescent device according to claim 14, characterized in that, The lifetime of the triplet exciton of the hole blocking layer material is 1 μs to 1 s.

17. The green organic electroluminescent device according to claim 12 or 13, characterized in that, The energy of the lowest triplet excited state of the electron transport layer material and the energy of the lowest triplet excited state of the phosphorescent material are both greater than the energy of the lowest triplet excited state of the hole blocking layer material.

18. The green organic electroluminescent device according to claim 12 or 13, characterized in that, The absolute value of the HOMO energy level of the electron transport layer material > the absolute value of the HOMO energy level of the hole blocking layer material > the absolute value of the HOMO energy level of the host material; And the absolute value of the LUMO energy level of the electron transport layer material > the absolute value of the LUMO energy level of the hole blocking layer material > the absolute value of the LUMO energy level of the host material; Wherein, the absolute value of the HOMO energy level of the host material is the minimum value of the absolute values of the HOMO energy levels of the hole transport type host material and the electron transport type host material; The absolute value of the LUMO energy level of the host material is the maximum of the absolute values of the LUMO energy levels of the hole-transporting host material and the electron-transporting host material.

19. The green organic electroluminescent device according to claim 12 or 13, characterized in that, The thickness of the green organic electroluminescent layer is 10 nm to 100 nm.

20. A display device, characterized in that, The display device includes the green organic electroluminescent device according to any one of claims 11 to 19.

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