High-efficiency long-life blue phosphorescent organic light-emitting device, display device

Abstract

The application provides a high-efficiency long-life blue phosphor organic light-emitting device and display device, the blue phosphor organic light-emitting device comprising a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer and an electron transport layer; the light-emitting layer comprises a P-type host material, an N-type host material and a doping material; the light-emission spectrum peak of the P-type host material is 365nm-400nm, and the half-peak width is 35nm-45nm; the light-emission spectrum peak of the N-type host material is 410nm-450nm, and the half-peak width is 60nm-85nm; the light-emission spectrum peak of the doping material is 455nm-470nm, and the half-peak width is 18nm-24nm; the T1 energy level of the P-type host material is greater than the T1 energy level of the doping material; and the T1 energy level of the N-type host material is greater than the T1 energy level of the doping material. The blue phosphor organic light-emitting device provided by the application has high efficiency and long life.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a blue phosphorescent organic light-emitting device with high efficiency and long service life and a display device. BACKGROUND

[0002] Organic electroluminescent display (OLED) technology is the third generation of display technology after cathode ray tube display (CRT) and liquid crystal display (LCD). It has great potential in the fields of lighting and display due to its low energy consumption, wide viewing angle, fast response speed, high definition, ultra-thinness, flexibility and self-luminescence characteristics. It has been widely used in mobile phones, computers, televisions, vehicles, smart wearable devices and other fields.

[0003] According to the difference of light-emitting materials, organic light-emitting semiconductor devices are mainly divided into fluorescent OLEDs, phosphorescent OLEDs and thermally activated delayed fluorescent OLEDs. At present, fluorescent OLEDs and phosphorescent OLEDs are more commonly used in commercial applications. Under electrical excitation, 25% of singlet excitons and 75% of triplet excitons are generated in organic materials. For fluorescent materials, according to the spin conservation principle, only 25% of singlet excitons can generate photons through radiative transitions, resulting in a maximum internal quantum efficiency of no more than 25% for fluorescent OLEDs. Even considering the TTA (triplet-triplet annihilation) effect, the maximum internal quantum efficiency is still no more than 40%. Unlike fluorescent materials, due to the spin-orbit coupling effect of heavy metals, triplet excitons of phosphorescent materials can emit photons through radiative transitions, making the maximum internal quantum efficiency of phosphorescent OLEDs theoretically reach 100%, greatly improving the efficiency of the device. Therefore, most of the mass-produced red and green devices are phosphorescent OLED devices. However, blue phosphorescent devices have low efficiency and short service life, which cannot meet the mass production requirements. Therefore, it is urgent to develop blue phosphorescent OLED devices with high efficiency and long service life. SUMMARY

[0004] The present application aims to provide a blue phosphorescent organic light-emitting device to improve the efficiency of the blue phosphorescent organic light-emitting device and prolong the service life of the blue phosphorescent organic light-emitting device. The specific technical solutions are as follows:

[0005] The first aspect of the present application provides a blue phosphorescent organic light-emitting device, comprising: a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer and an electron transport layer; the light-emitting layer comprises a P-type host material, an N-type host material and a dopant material; the peak of the light-emitting spectrum of the P-type host material is 365-400 nm, and the half-peak width is 35-45 nm; the peak of the light-emitting spectrum of the N-type host material is 410-450 nm, and the half-peak width is 60-85 nm; the peak of the light-emitting spectrum of the dopant material is 455-470 nm, and the half-peak width is 18-24 nm; the T1 energy level of the P-type host material is greater than the T1 energy level of the dopant material; the T1 energy level of the N-type host material is greater than the T1 energy level of the dopant material.

[0006] In some embodiments of the present application, in the blue phosphorescent organic light-emitting device, the difference between the T1 energy level of the P-type host material and the T1 energy level of the dopant material is a first energy level difference, and the first energy level difference is 0.1-0.6 eV; the difference between the T1 energy level of the N-type host material and the T1 energy level of the dopant material is a second energy level difference, and the second energy level difference is 0.1-0.6 eV.

[0007] In some embodiments of the present application, in the blue phosphorescent organic light-emitting device, the HOMO energy level of the hole transport layer is less than the HOMO energy level of the electron blocking layer, the HOMO energy level of the electron blocking layer is equal to the HOMO energy level of the P-type host material; the HOMO energy level of the P-type host material is greater than the HOMO energy level of the dopant material; the LUMO energy level of the dopant material is less than the LUMO energy level of the hole blocking layer, the LUMO energy level of the hole blocking layer is less than the LUMO energy level of the electron transport layer; the LUMO energy level of the N-type host material is equal to the LUMO energy level of the hole blocking layer; the difference between the LUMO energy level of the N-type host material and the LUMO energy level of the dopant material is a third energy level difference, and the third energy level difference is -0.2-0.2 eV.

[0008] In some embodiments of the present application, in the blue phosphorescent organic light-emitting device, the HOMO energy level of the dopant material is 5.4-5.6 eV; the LUMO energy level of the dopant material is 2.5-2.75 eV; the LUMO energy level of the N-type host material is 2.6-2.78 eV; the LUMO energy level of the electron transport layer is 2.8-3.0 eV.

[0009] In some embodiments of the present application, in the blue phosphorescent organic light-emitting device, the HOMO energy level of the P-type host material is greater than the HOMO energy level of the dopant material, and the LUMO energy level of the dopant material is greater than the LUMO energy level of the P-type host material.

[0010] In some embodiments of the present application, in the blue phosphorescent organic light-emitting device, the difference between the HOMO energy level of the P-type host material and the HOMO energy level of the dopant material is a fourth energy level difference, the fourth energy level difference is less than or equal to 0.5 eV; the difference between the LUMO energy level of the dopant material and the LUMO energy level of the P-type host material is a fifth energy level difference, the fifth energy level difference is less than or equal to 0.5 eV; the difference between the LUMO energy level of the N-type host material and the LUMO energy level of the dopant material is a third energy level difference, the third energy level difference is -0.2 eV to 0.2 eV.

[0011] In some embodiments of the present application, in the blue phosphorescent organic light-emitting device, the hole recombination energy of the P-type host material is 0.24 eV-0.28 eV; the electron recombination energy of the N-type host material is 0.5 eV-0.7 eV.

[0012] In some embodiments of the present application, the blue phosphorescent organic light-emitting device satisfies at least one of the following conditions:

[0013] (1) the hole transport layer comprises a compound represented by formula (I):

[0014]

[0015] wherein R1, R2, R3, R4and R5are each independently selected from hydrogen, C 1-40 alkyl, C 6-40 aryl, C 2-60 heteroaryl, C 6-60 aryloxy, C 1-39 alkoxy, C 6-39 arylamino, C 3-39 cycloalkyl, C 3-39 heterocycloalkyl, C 1-39 alkylsilyl, C 1-39 alkylboron, C 6-39 arylboron, C 6-39 arylphosphine, or C 6-39 arylsilyl; the heteroatom in the C 2-60 heteroaryl and the C 3-39 heterocycloalkyl is each independently selected from N, O or S;

[0016] Y1is selected from O or S;

[0017] (2) the N-type host material comprises a compound represented by formula (II):

[0018]

[0019] wherein R 1aEach is independently selected from hydrogen, deuterium, and C. 1-40 Alkyl, C 6-40 Aryl, C 2-60 heteroaryl, C 6-60 aryloxy group, C 1-39 Alkoxy, C 6-39 arylamine, C 3-39 cycloalkyl, C 3-39 Heterocyclic alkyl, C 1-39 Alkyl silyl, C 1-39 Alkylboryl, C 6-39 arylboryl, C 6-39 arylphosphine or C 6-39 Arylsilyl group; the C 2-60 heteroaryl and the C 3-39 The heteroatoms in the heterocyclic alkyl group are each independently selected from N, O, or S;

[0020] m is independently selected from 0, 1, 2, 3 or 4;

[0021] X1, X2, X3, and X4 are each independently selected from C, N, O, or S;

[0022] (3) The electron transport layer comprises the compound shown in formula (III):

[0023]

[0024] Among them, R 1b R 2b R 3b R 4b R 5b and R 6b Each is independently selected from hydrogen, unsubstituted or C-substituted. 6-12 aryl-substituted C 1-40 Alkyl, C 6-40 Aryl, C 2-60 heteroaryl, C 6-60 aryloxy group, C 1-39 Alkoxy, C 6-39 arylamine, C 3-39 cycloalkyl, C 3-39 Heterocyclic alkyl, C 1-39 Alkyl silyl, C 1-39 Alkylboryl, C 6-39 arylboryl, C 6-39 arylphosphine or C 6-39 Arylsilyl group; the C 2-60 heteroaryl and the C 3-39 The heteroatoms in the heterocyclic alkyl group are each independently selected from N, O, or S;

[0025] (4) The P-type host material includes the compound shown in formula (IV):

[0026]

[0027] Among them, R 1c C4 ... 6-40 Aryl, unsubstituted or partially deuterated C 2-60 heteroaryl, C 6-60 aryloxy group, C 1-39 Alkoxy, C 6-39 arylamine, C 3-39 cycloalkyl, C 3-39 Heterocyclic alkyl, C 1-39 Alkyl silyl, C 1-39 Alkylboryl, C 6-39 arylboryl, C 6-39 arylphosphine or C 6-39 Arylsilyl group; the C 2-60 heteroaryl and the C 3-39 The heteroatoms in the heterocyclic alkyl group are each independently selected from N, O, or S;

[0028] R 2c Each is independently selected from hydrogen, deuterium, and C. 6-18 Aryl or C 1-3 alkyl;

[0029] n is independently selected from 0, 1, 2, 3 or 4;

[0030] (5) The doped material includes the compound represented by formula (V):

[0031]

[0032] Among them, R 1d R 3d and R 4d Each is independently selected from hydrogen and C. 1-40 Alkyl, C 6-40 Aryl, C 2-60 heteroaryl, C 6-60 aryloxy group, C 1-39 Alkoxy, C 6-39 arylamine, C 3-39 cycloalkyl, C 3-39 Heterocyclic alkyl, C 1-39 Alkyl silyl, C 1-39 Alkylboryl, C 6-39 arylboryl, C 6-39 arylphosphine or C 6-39 Arylsilyl group; the C 2-60 heteroaryl and the C 3-39The heteroatoms in the heterocyclic alkyl group are each independently selected from N, O, or S;

[0033] R 2d C4 ... 6-40 Aryl, unsubstituted or partially deuterated C 2-60 heteroaryl, C 6-60 aryloxy group, C 1-39 Alkoxy, C 6-39 arylamine, C 3-39 cycloalkyl, C 3-39 Heterocyclic alkyl, C 1-39 Alkyl silyl, C 1-39 Alkylboryl, C 6-39 arylboryl, C 6-39 arylphosphine or C 6-39 Arylsilyl group; the C 2-60 heteroaryl and the C 3-39 The heteroatoms in the heterocyclic alkyl group are each independently selected from N, O, or S;

[0034] p is selected from 0, 1, 2, 3 or 4.

[0035] In some embodiments of this application, in a blue phosphorescent organic light-emitting device,

[0036] In equation (I), R1, R2, R3, R4, and R5 are each independently selected from hydrogen, C, and C. 1-10 Alkyl, C 6-18 Aryl, C 2-18 heteroaryl, C 6-18 aryloxy group, C 1-10 Alkoxy, C 6-18 arylamine, C 3-10 cycloalkyl, C 3-10 Heterocyclic alkyl, C 1-10 Alkyl silyl, C 1-10 Alkylboryl, C 6-18 arylboryl, C 6-18 arylphosphine or C 6-18 Arylsilyl;

[0037] In equation (II), R 1a Each is independently selected from hydrogen, deuterium, and C. 1-10 Alkyl, C 6-18 Aryl, C 2-18 heteroaryl, C 6-18 aryloxy group, C 1-10 Alkoxy, C 6-18 arylamine, C 3-10 cycloalkyl, C 3-10 Heterocyclic alkyl, C 1-10 Alkyl silyl, C 1-10Alkylboryl, C 6-18 arylboryl, C 6-18 arylphosphine or C 6-18 Arylsilyl;

[0038] In equation (III), R 1b R 2b R 3b R 4b R 5b and R 6b Each is independently selected from hydrogen, unsubstituted or phenyl-substituted C. 1-10 Alkyl, C 6-18 Aryl, C 2-18 heteroaryl, C 6-18 aryloxy group, C 1-10 Alkoxy, C 6-18 arylamine, C 3-10 cycloalkyl, C 3-10 Heterocyclic alkyl, C 1-10 Alkyl silyl, C 1-10 Alkylboryl, C 6-18 arylboryl, C 6-18 arylphosphine or C 6-18 Arylsilyl;

[0039] In formula (IV), R 1c Selected from C4 ... 6-18 Aryl, unsubstituted or partially deuterated C 2-30 Mixed aromatics;

[0040] In equation (V), R 1d R 3d R4 and C are each independently selected from hydrogen and C. 1-10 Alkyl, C 6-18 Aryl, C 2-18 heteroaryl, C 6-18 aryloxy group, C 1-10 Alkoxy, C 6-18 arylamine, C 3-10 cycloalkyl, C 3-10 Heterocyclic alkyl, C 1-10 Alkyl silyl, C 1-10 Alkylboryl, C 6-18 arylboryl, C 6-18 arylphosphine or C 6-18 Arylsilyl; R 2d C4 ... 6-18 Aryl, unsubstituted or partially deuterated C 2-18 heteroaryl, C 6-18 aryloxy group, C 1-10 Alkoxy, C6-18 arylamine, C 3-10 cycloalkyl, C 3-10 Heterocyclic alkyl, C 1-10 Alkyl silyl, C 1-10 Alkylboryl, C 6-18 arylboryl, C 6-18 arylphosphine or C 6-18 Arylsilyl group.

[0041] A second aspect of this application provides a display device comprising the blue phosphorescent organic light-emitting device described in the first aspect of this application.

[0042] The beneficial effects of this application are:

[0043] This application provides a blue phosphorescent organic light-emitting device (blue phosphorescent OLED). By controlling the compounds in the P-type host material and the N-type host material to form an excitocomplex, the peak positions of the emission spectra of the P-type host material and the N-type host material (P-type Host + N-type Host) are made close to and overlapped as much as possible with the emission spectrum of the dopant material. Furthermore, the emission spectrum of the P-type Host + N-type Host surrounds the emission spectrum of the dopant, so that the P-type Host + N-type Host can resonate with the dopant when excited, which is beneficial for energy transfer to the dopant, resulting in a blue phosphorescent OLED with high efficiency and long lifetime.

[0044] Of course, implementing any product or method of this application does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained based on these drawings.

[0046] Figure 1 This is a schematic diagram of the structure of a blue phosphorescent organic light-emitting device according to one embodiment of this application;

[0047] Figure 2 This is a schematic diagram of the structure of a blue phosphorescent organic light-emitting device according to another embodiment of this application;

[0048] Figure 3 The emission spectra of BD-PL and P-type Host+N-type Host-PL according to one embodiment of this application;

[0049] Figure 4 This is an energy level diagram of one embodiment of this application;

[0050] Figure 5 This is a schematic diagram of the energy transfer process from Host to Dopant according to one embodiment of this application;

[0051] Figure 6 This is a schematic diagram of a HOMO / LUMO (P-type Host) surrounding a HOMO / LUMO (Dopant) according to one embodiment of this application;

[0052] Figure 7 The emission spectra of P-type Host+N-type Host-PL and BD-PL in Embodiment 1, Comparative Example 1, and Comparative Example 2 of this application are shown.

[0053] Figure 8 These are diagrams showing the exciton recombination regions of the devices in Embodiment 1 and Comparative Example 1 of this application.

[0054] In the figure, 10. Substrate, 11. Anode electrode, 12. Hole injection layer, 13. Hole transport layer, 14. Electron blocking layer, 15. Light emitting layer, 16. Hole blocking layer, 17. Electron transport layer, 18. Electron injection layer, 19. Cathode electrode. Detailed Implementation

[0055] The technical solutions of this application will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this application.

[0056] Because blue light energy is higher than red and green light energy, the T1 energy level of blue phosphorescent materials is higher than that of red and green phosphorescent materials. However, it is difficult to find a blue phosphorescent host material with both a high T1 energy level and good material stability in current technologies. This leads to energy transfer from the dopant material to the host material, resulting in lower efficiency of blue phosphorescent OLEDs. Therefore, finding a suitable host material for blue phosphorescent dopants that can effectively transfer energy to the dopant material to obtain high-efficiency blue phosphorescent devices is an urgent problem to be solved. In addition, since the electron-hole recombination center is close to the center of the emissive layer (EML), reducing the accumulation of T1 energy levels, minimizing energy level quenching, and solving material degradation are also urgent problems to be solved in order to improve the lifetime of blue phosphorescent devices.

[0057] The first aspect of this application provides a blue phosphorescent organic light-emitting device, such as... Figure 1 As shown, it includes a hole transport layer (HTL) 13, an electron blocking layer (EBL) 14, a light-emitting layer (EML) 15, a hole blocking layer (HBL) 16, and an electron transport layer (ETL) 17. In some embodiments of this application, the electron blocking layer 14 is disposed on one side of the light-emitting layer 15; the hole transport layer 13 is disposed on the side of the electron blocking layer 14 away from the light-emitting layer 15; the hole blocking layer 16 is disposed on the side of the light-emitting layer 15 away from the electron blocking layer 14; and the electron transport layer 17 is disposed on the side of the hole blocking layer 16 away from the light-emitting layer 15.

[0058] like Figure 2 As shown, the blue phosphorescent organic light-emitting device described in this application may further include: a substrate 10, an anode electrode 11, a hole injection layer (HIL) 12, an electron injection layer (EIL) 18, and a cathode electrode 19; wherein, the hole injection layer 12 is disposed on the side of the hole transport layer 13 away from the electron blocking layer 14; the anode electrode 11 is disposed on the side of the hole injection layer 12 away from the hole transport layer 13; the substrate 10 is disposed on the side of the anode electrode 11 away from the hole injection layer 12; the electron injection layer 18 is disposed on the side of the electron transport layer 17 away from the hole blocking layer 16; and the cathode electrode 19 is disposed on the side of the electron injection layer 18 away from the electron transport layer 17.

[0059] This application provides Figure 1 and Figure 2 Only the positional relationship between the layers in the blue phosphorescent organic light-emitting device is shown. The height relationship between the layers does not limit the thickness relationship between the layers, which can be adjusted according to actual needs.

[0060] In this application, the light-emitting layer includes a P-type host material for transporting holes, an N-type host material for transporting electrons, and a dopant material. The peak value of the emission spectrum of the P-type host is 365nm-400nm, and the full width at half maximum (FWHM) is 35nm-45nm. The peak value of the emission spectrum of the N-type host is 410nm-450nm, and the FWHM is 60nm-85nm. The peak value of the emission spectrum of the dopant is 455nm-470nm, and the FWHM is 18nm-24nm. The T1 energy level of the P-type host is greater than that of the dopant. The T1 energy level of the N-type host is greater than that of the dopant.

[0061] This application uses a mixture of P-type Host and N-type Host materials as the Host for a blue phosphorescent Dopant material. Figure 3As shown, this application controls the peak value and full width at half maximum (FWHM) of the P-type Host, N-type Host, and Dopant to be within the aforementioned ranges. The relationship between the T1 energy levels of the P-type Host, N-type Host, and Dopant is as described above. The P-type Host + N-type Host under such constraints needs to form an excitocomplex, so that the peak positions of the emission spectrum of the P-type Host + N-type Host and the emission spectrum of the Dopant are as close as possible and overlap. Furthermore, the emission spectrum of the P-type Host + N-type Host surrounds the emission spectrum of the Dopant, allowing the P-type Host + N-type Host to resonate with the Dopant when excited, which is more conducive to transferring energy to the Dopant, thereby obtaining a high-efficiency and long-lifetime blue phosphorescent OLED.

[0062] In some embodiments of this application, the difference between the T1 energy level of the P-type Host and the T1 energy level of the Dopant is defined as the first energy range, which is 0.1 eV-0.6 eV. In some embodiments of this application, the value of the first energy range can be 0.1 eV, 0.2 eV, 0.3 eV, 0.4 eV, 0.5 eV, 0.6 eV, or a range consisting of any two values ​​within this range. Controlling the first energy range within the aforementioned range in this application is beneficial for obtaining blue phosphorescent OLEDs with higher efficiency and longer lifetimes.

[0063] In some embodiments of this application, the difference between the T1 energy level of the N-type Host and the T1 energy level of the Dopant is defined as the second energy range, which is 0.1 eV to 0.6 eV. In some embodiments of this application, the value of the second energy range can be 0.1 eV, 0.2 eV, 0.3 eV, 0.4 eV, 0.5 eV, 0.6 eV, or a range consisting of any two values ​​within this range. Controlling the second energy range within the aforementioned range in this application is beneficial for obtaining blue phosphorescent OLEDs with higher efficiency and longer lifetimes.

[0064] In some embodiments of this application, the HOMO level of the hole transport layer (HTL) is lower than the HOMO level of the electron blocking layer (EBL), and the HOMO level of the electron blocking layer is equal to the HOMO level of the P-type host material; the HOMO level of the P-type host material is greater than the HOMO level of the doped material; the LUMO level of the doped material is lower than the LUMO level of the hole blocking layer (HBL), and the LUMO level of the hole blocking layer is lower than the LUMO level of the electron transport layer (ETL); the LUMO level of the N-type host material is equal to the LUMO level of the hole blocking layer; the difference between the LUMO level of the N-type host material and the LUMO level of the doped material is the third energy range, which is -0.2 eV to 0.2 eV. In some embodiments of this application, the value of the third energy range can be -0.2eV, -0.15eV, -0.1eV, 0eV, 0.1eV, 0.15eV, 0.2eV, or a range consisting of any two values ​​in between. The control device of this application exhibits good HOMO / LUMO energy level matching between the various material layers, which is beneficial for the injection of holes and electrons, thereby obtaining a high-efficiency, long-life blue phosphorescent OLED.

[0065] In this application, as Figure 4 As shown, HOMO(HTL) < HOMO(EBL) = HOMO(P-type Host, i.e. Figure 4 Medium P-Type BH); HOMO (P-type Host)>HOMO (Dopant, that is Figure 4 Medium BD); LUMO (Dopant) < LUMO (HBL) < LUMO (ETL); LUMO (N-type Host, that is Figure 4 In the context of N-type Host (HBL), LUMO(HBL) = LUMO(HBL). The difference between LUMO(N-type Host) and LUMO(Dopant) is -0.2eV to 0.2eV, meaning that LUMO(N-type Host) can be greater than, equal to, or less than LUMO(Dopant).

[0066] In some embodiments of this application, the HOMO energy level of the doped material is 5.4 eV-5.6 eV; the LUMO energy level of the doped material is 2.5 eV-2.75 eV; the LUMO energy level of the N-type host material is 2.6 eV-2.78 eV; and the LUMO energy level of the electron transport layer is 2.8 eV-3.0 eV. In some embodiments of this application, the HOMO energy level of the doped material can be 5.4 eV, 5.5 eV, 5.6 eV, or any two values ​​thereof; the LUMO energy level of the doped material can be 2.5 eV, 2.55 eV, 2.6 eV, 2.65 eV, 2.7 eV, 2.75 eV, or any two values ​​thereof; the LUMO energy level of the N-type host material can be 2.6 eV, 2.65 eV, 2.7 eV, 2.75 eV, 2.78 eV, or any two values ​​thereof; and the LUMO energy level of the electron transport layer can be 2.8 eV, 2.9 eV, 3.0 eV, or any two values ​​thereof. This application controls HOMO (Dopant), LUMO (Dopant), LUMO (N-type Host), and LUMO (ETL) within the above-mentioned range, and the materials in each layer have good HOMO / LUMO energy level matching, which is beneficial to the injection of holes and electrons, thereby obtaining a high-efficiency, long-life blue phosphorescent OLED.

[0067] In some embodiments of this application, the HOMO level of the P-type host material is greater than the HOMO level of the doped material, and the LUMO level of the doped material is greater than the LUMO level of the P-type host material. In this application, HOMO(P-type Host) > HOMO(Dopant), and LUMO(Dopant) > LUMO(P-type Host), that is, HOMO / LUMO(P-type Host) surrounds HOMO / LUMO(Dopant). Figure 5 As shown, the energy transfer process from Host to Dopant involves the P-type Host capturing holes and the N-type Host capturing electron recombination, transferring energy to the BD (Blue Dopant). The BD then absorbs the energy and emits light.

[0068] In some embodiments of this application, the difference between the HOMO energy level of the P-type host material and the HOMO energy level of the doped material is a fourth energy range, which is less than or equal to 0.5 eV; the difference between the LUMO energy level of the doped material and the LUMO energy level of the P-type host material is a fifth energy range, which is less than or equal to 0.5 eV; and the difference between the LUMO energy level of the N-type host material and the LUMO energy level of the doped material is a third energy range, which is -0.2 eV to 0.2 eV. In some embodiments of this application, the value of the fourth energy range can be 0.01 eV, 0.05 eV, 0.1 eV, 0.2 eV, 0.3 eV, 0.4 eV, 0.5 eV, or a range consisting of any two values ​​in between. In some embodiments of this application, the value of the fifth energy range can be 0.01 eV, 0.05 eV, 0.1 eV, 0.2 eV, 0.3 eV, 0.4 eV, 0.5 eV, or a range consisting of any two values ​​in between. In some embodiments of this application, the value of the third energy range can be -0.2 eV, -0.15 eV, -0.1 eV, 0 eV, 0.1 eV, 0.15 eV, 0.2 eV, or a range consisting of any two values ​​in between, i.e., LUMO (N-type Host) can be greater than, equal to, or less than LUMO (Dopant). Figure 5 and Figure 6 As shown, LUMO(N-type Host) is greater than LUMO(Dopant).

[0069] This application controls the fourth energy level difference, the fifth energy level difference, and the third energy level difference to be within the above range. That is, the closer the HOMO of the BD is to the HOMO of the P-type Host, and the closer the LUMO of the BD is to the LUMO of the N-type Host, the shallower the trap is formed, the lower the probability of holes / electrons being trapped, the more electrons and holes are used for recombination and light emission, and the higher the efficiency of the blue phosphorescent OLED device.

[0070] In some embodiments of this application, the hole recombination energy (ROE) of the P-type host material is 0.24 eV-0.28 eV; the electron recombination energy of the N-type host material is 0.5 eV-0.7 eV. In some embodiments of this application, the hole recombination energy of the P-type host can be 0.24 eV, 0.25 eV, 0.26 eV, 0.27 eV, 0.28 eV, or a range of any two values ​​within this range. In some embodiments of this application, the electron recombination energy of the N-type host can be 0.5 eV, 0.55 eV, 0.6 eV, 0.65 eV, 0.7 eV, or a range of any two values ​​within this range. The recombination energy calculation software used in this application is Schrödinger simulation software, and the computer set is B3LYP 6-31G**. In this application, the greater the recombination energy, the greater the degree of molecular distortion when transferring charge, and the less likely it is to transfer charge. Therefore, the smaller the recombination energy, the easier it is to transfer charge, which is beneficial to obtaining high-efficiency, long-life blue phosphorescent OLED devices.

[0071] In some embodiments of this application, the blue phosphorescent organic light-emitting device satisfies at least one of the following conditions:

[0072] (1) The hole transport layer comprises the compound shown in formula (I):

[0073]

[0074] Among them, R1, R2, R3, R4, and R5 are each independently selected from hydrogen and C. 1-40 Alkyl, C 6-40 Aryl, C 2-60 heteroaryl, C 6-60 aryloxy group, C 1-39 Alkoxy, C 6-39 arylamine, C 3-39 cycloalkyl, C 3-39 Heterocyclic alkyl, C 1-39 Alkyl silyl, C 1-39 Alkylboryl, C 6-39 arylboryl, C 6-39 arylphosphine or C 6-39 Arylsilyl group; the C 2-60 heteroaryl and the C 3-39 The heteroatoms in the heterocyclic alkyl group are each independently selected from N, O, or S;

[0075] Y1 is selected from O or S;

[0076] (2) The N-type host material includes the compound shown in formula (II):

[0077]

[0078] Among them, R 1a Each is independently selected from hydrogen, deuterium, and C. 1-40 Alkyl, C 6-40 Aryl, C 2-60 heteroaryl, C 6-60 aryloxy group, C 1-39 Alkoxy, C 6-39 arylamine, C 3-39 cycloalkyl, C 3-39 Heterocyclic alkyl, C 1-39 Alkyl silyl, C 1-39 Alkylboryl, C 6-39 arylboryl, C 6-39 arylphosphine or C 6-39 Arylsilyl group; the C 2-60 heteroaryl and the C 3-39 The heteroatoms in the heterocyclic alkyl group are each independently selected from N, O, or S;

[0079] m is independently selected from 0, 1, 2, 3 or 4;

[0080] X1, X2, X3, and X4 are each independently selected from C, N, O, or S;

[0081] (3) The electron transport layer comprises the compound shown in formula (III):

[0082]

[0083] Among them, R 1b R 2b R 3b R 4b R 5b and R 6b Each is independently selected from hydrogen, unsubstituted or C-substituted. 6-12 aryl-substituted C 1-40 Alkyl, C 6-40 Aryl, C 2-60 heteroaryl, C 6-60 aryloxy group, C 1-39 Alkoxy, C 6-39 arylamine, C 3-39 cycloalkyl, C 3-39 Heterocyclic alkyl, C 1-39 Alkyl silyl, C 1-39 Alkylboryl, C 6-39 arylboryl, C 6-39 arylphosphine or C 6-39 Arylsilyl group; the C 2-60 heteroaryl and the C 3-39 The heteroatoms in the heterocyclic alkyl group are each independently selected from N, O, or S;

[0084] (4) The P-type host material includes the compound shown in formula (IV):

[0085]

[0086] Among them, R 1c C4 ... 6-40 Aryl, unsubstituted or partially deuterated C 2-60 heteroaryl, C 6-60 aryloxy group, C 1-39 Alkoxy, C 6-39 arylamine, C 3-39 cycloalkyl, C 3-39 Heterocyclic alkyl, C 1-39 Alkyl silyl, C 1-39 Alkylboryl, C 6-39 arylboryl, C 6-39 arylphosphine or C 6-39 Arylsilyl group; the C 2-60 heteroaryl and the C 3-39 The heteroatoms in the heterocyclic alkyl group are each independently selected from N, O, or S;

[0087] R 2c Each is independently selected from hydrogen, deuterium, and C. 6-18 Aryl or C 1-3 alkyl;

[0088] n is independently selected from 0, 1, 2, 3 or 4;

[0089] (5) The doped material includes the compound represented by formula (V):

[0090]

[0091] Among them, R 1d R 3d and R 4d Each is independently selected from hydrogen and C. 1-40 Alkyl, C 6-40 Aryl, C 2-60 heteroaryl, C 6-60 aryloxy group, C 1-39 Alkoxy, C 6-39 arylamine, C 3-39 cycloalkyl, C 3-39 Heterocyclic alkyl, C 1-39 Alkyl silyl, C 1-39 Alkylboryl, C 6-39 arylboryl, C 6-39 arylphosphine or C 6-39 Arylsilyl group; the C 2-60 heteroaryl and the C3-39 The heteroatoms in the heterocyclic alkyl group are each independently selected from N, O, or S;

[0092] R 2d C4 ... 6-40 Aryl, unsubstituted or partially deuterated C 2-60 heteroaryl, C 6-60 aryloxy group, C 1-39 Alkoxy, C 6-39 arylamine, C 3-39 cycloalkyl, C 3-39 Heterocyclic alkyl, C 1-39 Alkyl silyl, C 1-39 Alkylboryl, C 6-39 arylboryl, C 6-39 arylphosphine or C 6-39 Arylsilyl group; the C 2-60 heteroaryl and the C 3-39 The heteroatoms in the heterocyclic alkyl group are each independently selected from N, O, or S; p is selected from 0, 1, 2, 3, or 4.

[0093] In some embodiments of this application, in formula (I), R1, R2, R3, R4, and R5 are each independently selected from hydrogen, C, and C. 1-10 Alkyl, C 6-18 Aryl, C 2-18 heteroaryl, C 6-18 aryloxy group, C 1-10 Alkoxy, C 6-18 arylamine, C 3-10 cycloalkyl, C 3-10 Heterocyclic alkyl, C 1-10 Alkyl silyl, C 1-10 Alkylboryl, C 6-18 arylboryl, C 6-18 arylphosphine or C 6-18 Arylsilyl;

[0094] In equation (II), R 1a Each is independently selected from hydrogen, deuterium, and C. 1-10 Alkyl, C 6-18 Aryl, C 2-18 heteroaryl, C 6-18 aryloxy group, C 1-10 Alkoxy, C 6-18 arylamine, C 3-10 cycloalkyl, C 3-10 Heterocyclic alkyl, C 1-10 Alkyl silyl, C 1-10 Alkylboryl, C 6-18 arylboryl, C 6-18 arylphosphine or C6-18 Arylsilyl;

[0095] In equation (III), R 1b R 2b R 3b R 4b R 5b and R 6b Each is independently selected from hydrogen, unsubstituted or phenyl-substituted C. 1-10 Alkyl, C 6-18 Aryl, C 2-18 heteroaryl, C 6-18 aryloxy group, C 1-10 Alkoxy, C 6-18 arylamine, C 3-10 cycloalkyl, C 3-10 Heterocyclic alkyl, C 1-10 Alkyl silyl, C 1-10 Alkylboryl, C 6-18 arylboryl, C 6-18 arylphosphine or C 6-18 Arylsilyl;

[0096] In equation (IV), R 1c Selected from C4 ... 6-18 Aryl, unsubstituted or partially deuterated C 2-30 heteroaryl; for example, R 1c Selected from

[0097] In equation (V), R 1d R 3d and R 4d Each is independently selected from hydrogen and C. 1-10 Alkyl, C 6-18 Aryl, C 2-18 heteroaryl, C 6-18 aryloxy group, C 1-10 Alkoxy, C 6-18 arylamine, C 3-10 cycloalkyl, C 3-10 Heterocyclic alkyl, C 1-10 Alkyl silyl, C 1-10 Alkylboryl, C 6-18 arylboryl, C 6-18 arylphosphine or C 6-18 Arylsilyl;

[0098] R 2d C4 ... 6-18 Aryl, unsubstituted or partially deuterated C 2-18 heteroaryl, C 6-18aryloxy group, C 1-10 Alkoxy, C 6-18 arylamine, C 3-10 cycloalkyl, C 3-10 Heterocyclic alkyl, C 1-10 Alkyl silyl, C 1-10 Alkylboryl, C 6-18 arylboryl, C 6-18 arylphosphine or C 6-18 Arylsilyl group.

[0099] The phrase "partially hydrogen replaced by deuterium" as used in this application can mean that some hydrogen is replaced by deuterium, or that all hydrogen is replaced by deuterium.

[0100] In some embodiments of this application, the hole transport layer comprises at least one compound as shown below:

[0101]

[0102] The N-type host material includes at least one of the following compounds:

[0103]

[0104]

[0105] The electron transport layer comprises at least one of the following compounds:

[0106]

[0107] The P-type host material includes at least one of the following compounds:

[0108]

[0109] The doped material includes at least one of the following compounds:

[0110]

[0111]

[0112] All of the compounds described in this application are commercially available or can be prepared using conventional synthetic methods in the art.

[0113] This application does not have any particular limitation on the materials used for other components such as the hole injection layer, electron blocking layer, and hole blocking layer; any materials commonly used in the field may be used.

[0114] A second aspect of this application provides a display device comprising the blue phosphorescent organic light-emitting device described in the first aspect of this application. The display device includes, but is not limited to, a monitor, a television, a tablet computer, a mobile communication terminal, etc.

[0115] There are no particular limitations on the method for preparing the blue phosphorescent organic light-emitting device of this application; any method known in the art can be used, for example, referring to Figure 2 It can be prepared using the following methods:

[0116] (1) Clean the anode electrode 11 on the OLED device substrate 10 for top light emission. In the cleaning machine, the electrode is cleaned by chemical washing, water washing, brushing, high-pressure water washing, air knife and other steps, and then heated.

[0117] (2) Hole injection material is vacuum-deposited on the anode electrode 11 as a hole injection layer 12;

[0118] (3) Hole transport material is vacuum-deposited on hole injection layer 12 as hole transport layer 13;

[0119] (4) Vacuum evaporation of electron blocking material on hole transport layer 13 to serve as electron blocking layer 14;

[0120] (5) A light-emitting layer 15 is vacuum-deposited on the electron blocking layer 14, wherein the light-emitting layer 15 contains a host material and a dopant material;

[0121] (6) A hole blocking material is vacuum-deposited on the light-emitting layer 15 as a hole blocking layer 16;

[0122] (7) Vacuum evaporation of electron transport material on hole blocking layer 16 serves as electron transport layer 17;

[0123] (8) Vacuum evaporation of electron injection material on electron transport layer 17 to form electron injection layer 18;

[0124] (9) A cathode material is vacuum-deposited on the electron injection layer 18 as a cathode electrode 19.

[0125] The above describes only the structure and fabrication method of a typical blue phosphorescent organic light-emitting device. It should be understood that this application is not limited to this structure. The blue phosphorescent organic light-emitting device can be fabricated using any fabrication method known in the art.

[0126] Example

[0127] The embodiments and comparative examples provided below illustrate the implementation of this application in more detail. Various tests and evaluations were conducted according to the methods described below. Furthermore, unless otherwise specified, "parts" and "%" are quality standards.

[0128] Test methods and equipment:

[0129] 1. Determination of luminescence spectrum

[0130] Fluorescence measurement is an analytical technique that utilizes the intensity, decay rate, and lifetime of fluorescence emitted by a substance after it has been excited to analyze and study the substance. This application employs a fluorescence spectrophotometer to determine the emission spectrum.

[0131] 2. Determination of the T1 energy level

[0132] This application calculates the T1 energy level by measuring phosphorescence using an FLS980 steady-state transient fluorescence / phosphorescence spectrometer. At a low temperature of 77K, the emission spectrum of phosphorescence is measured, a tangent is drawn at the peak of the spectrum, and the value at the intersection of the tangent and the x-axis is taken. Then, 1240 is divided by this value to obtain the energy, thereby determining the excited state energy level of the material.

[0133] 3. Determination of HOMO and LUMO energy levels

[0134] This application uses an AC3 photoelectron spectrophotometer to determine the HOMO and LUMO energy levels. By irradiating the sample with ultraviolet light, the kinetic energy of the secondary electrons at the low energy end is measured, thereby determining the position of the HOMO energy level of the material. Specifically, when the sample is irradiated with ultraviolet light of a specific wavelength, a portion of the energy is used to overcome the electron binding energy, and the remainder allows the electrons to gain kinetic energy. By analyzing the positions of these physical parameters in the spectrum, the HOMO energy level of the material can be obtained. The absorption spectrum of the material is measured, and the intersection of the tangent line of the absorption spectrum with the abscissa is calculated. Dividing 1240 by the intersection point yields Eg, where LUMO = HOMO - Eg.

[0135] 4. Determination of hole recombination energy and electron recombination energy

[0136] This application uses Gaussian molecular simulation software to determine hole recombination energy and electron recombination energy, which mainly relies on quantum chemical calculation methods, especially density functional theory (DFT) methods, to explore the electron transfer process.

[0137] 5. Measurement of the exciton recombination region of the device

[0138] This application uses current and voltage testing equipment to measure the exciton recombination region of the device. By adjusting the thickness of the spacer layer in the light-emitting layer of the device, the position of the exciton recombination region can be effectively controlled, thereby affecting the light-emitting performance of the device, and changes in the exciton recombination region can be observed.

[0139] 6. Performance Measurement of Blue Phosphorescent OLED Devices

[0140] Under the same brightness, the driving voltage (V), current efficiency (Cd / A), and lifetime of the blue phosphorescent OLED devices prepared in each embodiment and comparative example were measured using a digital source meter and luminance meter. Specifically, the voltage was increased at a rate of 0.1V per second, and the voltage when the brightness of the blue phosphorescent OLED device reached 1000 nits was measured, which is the driving voltage. At the same time, the current density at this point was also measured. The ratio of brightness to current density is the current efficiency. The lifetime test of LT95 is as follows: using a luminance meter at a brightness of 1000 nits, a constant current was maintained, and the time it took for the brightness of the blue phosphorescent OLED device to drop to 950 nits was measured in hours. The measurement results are all compared with the result of Comparative Example 1 as 100%, and the relative results of other embodiments and comparative examples are calculated.

[0141] Example 1

[0142] (1) The glass plate coated with ITO transparent conductive layer was ultrasonically treated in commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in acetone-ethanol mixed solvent, baked in a clean environment until the moisture was completely removed, cleaned with ultraviolet light and ozone, and bombarded with low-energy cation beam.

[0143] (2) Place the glass substrate with the anode inside the vacuum chamber and evacuate it to a vacuum level of less than 5 × 10⁻⁶. -8 A hole injection layer is vacuum-deposited on the aforementioned anolyte film. The hole injection layer consists of NPB (Neural Packet Boron) and HATCN (Hyperpendicular Dopant). The deposition is performed using a multi-source co-evaporation method. The deposition rate of NPB is adjusted to 0.2 nm / s, and the deposition rate of HATCN is 2% of the deposition rate of NPB. The film thickness is 10 nm. The structural formulas of NPB and HATCN are as follows:

[0144]

[0145] (3) Hole transport material HTL-A1 is vacuum-deposited on the hole injection layer as a hole transport layer, wherein the deposition rate is 0.2 nm / s and the deposition film thickness is 120 nm. The structural formula of hole transport material HTL-A1 is as follows:

[0146]

[0147] (4) Electron blocking material P-type Host-C1 is vacuum-deposited on the hole transport layer as an electron blocking layer, wherein the deposition rate is 0.2 nm / s and the deposition film thickness is 5 nm. The structural formula of electron blocking material P-type Host-C1 is as follows:

[0148]

[0149] (5) A light-emitting layer is vacuum-deposited on top of the electron blocking layer. The light-emitting layer includes an N-type host material N-type Host-B1, a P-type host material P-type Host-C1, and a dopant material BD-D1. The deposition is performed using a multi-source co-evaporation method. The deposition rates of the N-type host material N-type Host-B1 and the P-type host material P-type Host-C1 are adjusted to 0.2 nm / s, and the deposition rate of the fluorescent dopant BD-D1 is 10% of the deposition rate of the P-type host material P-type Host-C1. The deposition film thickness is 40 nm. The structural formulas of the N-type host material N-type Host-B1, the P-type host material P-type Host-C1, and the dopant material BD-D1 are as follows:

[0150]

[0151] (6) Hole blocking material N-type Host-B1 is vacuum-deposited on the light-emitting layer as a hole blocking layer, wherein the deposition rate is 0.2 nm / s and the deposition film thickness is 5 nm. The structural formula of hole blocking material N-type Host-B1 is as follows:

[0152]

[0153] (7) Electron transport material ETL-E1 is vacuum-deposited on top of the hole blocking layer as an electron transport layer, wherein the deposition rate is 0.2 nm / s and the deposition film thickness is 40 nm. The structural formula of electron transport material ETL-E1 is as follows:

[0154]

[0155] (8) Electron injection material LIQ is vacuum-deposited on the electron transport layer as the electron injection layer, wherein the deposition rate is 0.2 nm / s and the deposition film thickness is 40 nm. The structural formula of the electron injection material LIQ is as follows:

[0156]

[0157] (9) A 100 nm thick Al layer is vacuum-deposited on the electron injection layer as the cathode electrode of the blue phosphorescent organic light-emitting device, wherein the deposition rate is 0.5 nm / s.

[0158] Examples 2-4

[0159] Except for the compounds used as shown in Table 1, everything else is the same as in Example 1.

[0160] Comparative Example 1

[0161] Except for the compounds used as shown in Table 1, everything else is the same as in Example 1.

[0162] Table 1. Compounds used in each example and comparative example.

[0163]

[0164]

[0165] In Table 1, the structural formulas of HTL-A2, HTL-A3, HTL-A4, N-type Host-B2, N-type Host-B3, N-type Host-B4, P-type Host-C2, P-type Host-C3, P-type Host-C4, BD-D2, BD-D3, BD-D4, ETL-E2, ETL-E3, ETL-E4, N-type Host-b1, P-type Host-c1, BD-d1, NPB, and TPBi are shown below:

[0166]

[0167]

[0168]

[0169] Comparative Examples 2-5

[0170] Except for adjusting the compounds used for hole transport materials, N-type host materials, P-type host materials, doped materials, and electron transport materials, everything else is the same as in Example 1.

[0171] The relevant material parameters and performance parameters involved in each embodiment and proportion are shown in Tables 2, 3, 4 and 5, respectively.

[0172] Table 2. Relevant parameters of the emission spectra of each embodiment and comparative example.

[0173]

[0174]

[0175] Table 3. Energy level-related parameters for each embodiment and comparative example.

[0176]

[0177] Table 4. Recombination energy related parameters for each embodiment and comparative example.

[0178]

[0179]

[0180] Table 5 Performance parameters of the blue phosphorescent organic light-emitting devices in each embodiment and comparative example.

[0181] V / V E / Cd / A LT95 @ 1000 nit Example 1 88％ 122％ 281％ Example 2 96％ 229％ 433％ Example 3 92％ 150％ 180％ Example 4 91％ 115％ 190％ Comparative Example 1 100％ 100％ 100％ Comparative Example 2 98％ 105％ 126％ Comparative Example 3 110％ 98％ 118％ Comparative Example 4 128％ 85％ 98％ Comparative Example 5 104％ 72％ 109％

[0182] Figure 7 The images show the emission spectra of P-type Host+N-type Host-PL and BD-PL in Embodiment 1, Comparative Example 1, and Comparative Example 2 of this application. Figure 7 As can be seen from Tables 2 and 5, Example 1 controls the peak values ​​and full width at half maximum (FWHM) of the P-type Host, N-type Host, and Dopant to be within the range of this application, with the first energy range greater than or equal to 0.1 eV and the second energy range greater than or equal to 0.1 eV. This ensures that the peak positions of the emission spectra of the P-type Host + N-type Host and the emission spectra of the Dopant coincide as much as possible, and that the emission spectra of the P-type Host + N-type Host surround the emission spectra of the Dopant. This allows the P-type Host + N-type Host to resonate with the Dopant when excited, better transferring energy to the Dopant, thereby obtaining a high-efficiency and long-lifetime blue phosphorescent OLED. In contrast, neither the P-type Host + N-type Host in Comparative Example 1 nor the P-type Host + N-type Host in Comparative Example 2 surrounds the emission spectra of the Dopant. Furthermore, the peak positions of the emission spectra of the P-type Host + N-type Host and the Dopant emission spectra in Comparative Example 1 differ significantly, resulting in lower luminous efficiency and shorter lifespan for the blue phosphorescent OLED.

[0183] Figure 8 These are diagrams showing the exciton recombination regions of the devices in Embodiment 1 and Comparative Example 1 of this application. From... Figure 1 As can be seen, the device in Comparative Example 1 has a smaller and narrower exciton recombination region, resulting in lower device efficiency and shorter lifespan; while the device in Example 1 has a wider and larger exciton recombination region, resulting in higher device efficiency and longer lifespan.

[0184] As can be seen from Tables 3 and 5, Example 2 controls the HOMO / LUMO energy level relationship between each layer of materials to be within the scope of this application, and the values ​​of HOMO(Dopant), LUMO(Dopant), LUMO(N-type Host), and LUMO(ETL) are within the scope of this application. The materials have good HOMO / LUMO energy level matching, which is beneficial for the injection of holes and electrons, thereby obtaining a high-efficiency, long-lifetime blue phosphorescent OLED. In Comparative Example 3, HOMO(EBL) = HOMO(P-type Host) < 5.75eV, HOMO(Dopant) < 5.4eV, LUMO(Dopant) > 2.8eV, and LUMO(N-type Host) = LUMO(HBL) > 2.8eV are not within the scope of this application. The resulting blue phosphorescent OLED has lower luminous efficiency and shorter lifetime.

[0185] As can be seen from Tables 4 and 5, Examples 3 and 4, by controlling the hole recombination energy of the P-type host material and the electron recombination energy of the N-type host material within the scope of this application, can obtain high-efficiency, long-lifetime blue phosphorescent OLED devices. In Comparative Examples 4 and 5, the hole recombination energy of the P-type host material and the electron recombination energy of the N-type host material are not within the scope of this application, resulting in blue phosphorescent OLEDs with lower luminous efficiency and shorter lifetimes.

[0186] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A blue phosphorescent organic light-emitting device, comprising: Hole transport layer, electron blocking layer, light-emitting layer, hole blocking layer and electron transport layer; The light-emitting layer comprises a P-type host material, an N-type host material, and a doped material; The peak value of the emission spectrum of the P-type host material is 365nm-400nm, and the full width at half maximum (FWHM) is 35nm-45nm. The emission spectrum of the N-type host material has a peak value of 410nm-450nm and a full width at half maximum (FWHM) of 60nm-85nm. The peak value of the emission spectrum of the doped material is 455nm-470nm, and the full width at half maximum (FWHM) is 18nm-24nm. The T1 energy level of the P-type host material is greater than the T1 energy level of the doped material; The T1 energy level of the N-type host material is greater than the T1 energy level of the doped material; (1) The N-type host material includes the compound shown in formula (II): ； Among them, R 1a Each is independently selected from hydrogen, deuterium, and C. 6-18 Aryl; m is independently selected from 0, 1, 2, 3 or 4; X1, X2, X3, and X4 are N; (2) The P-type host material includes the compound shown in formula (IV): ； Among them, R 1c Selected from C4 ... 6-18 Aryl, unsubstituted or partially deuterated C 2-30 heteroaryl; the C 2-30 The heteroatoms in the heteroaryl group are each independently selected from N; R 2c Each is independently selected from hydrogen, deuterium, and C. 6-18 Aryl; n is independently selected from 0, 1, 2, 3 or 4; (3) The doped material includes the compound represented by formula (V): ； Among them, R 1d R 3d and R 4d Each is independently selected from hydrogen and C. 1-10 Alkyl, C 6-18 Aryl; R 2d C4 ... 6-18 Aryl; p is selected from 0, 1, 2, 3 or 4; The compounds in the P-type host material and the compounds in the N-type host material form an excitocomplex, which makes the peak positions of the emission spectra of the P-type host material and the N-type host material close to and overlap with the emission spectra of the doped material as much as possible, and the emission spectra of the P-type host material and the N-type host material surround the emission spectrum of the doped material.

2. The blue phosphorescent organic light-emitting device according to claim 1, wherein, The difference between the T1 energy level of the P-type host material and the T1 energy level of the doped material is the first energy level difference, which is 0.1 eV-0.6 eV. The difference between the T1 energy level of the N-type host material and the T1 energy level of the doped material is the second energy level difference, which is 0.1 eV-0.6 eV.

3. The blue phosphorescent organic light-emitting device according to claim 1, wherein, The HOMO energy level of the hole transport layer is lower than the HOMO energy level of the electron blocking layer, and the HOMO energy level of the electron blocking layer is equal to the HOMO energy level of the p-type host material. The HOMO energy level of the P-type host material is greater than the HOMO energy level of the doped material; The LUMO energy level of the doped material is lower than the LUMO energy level of the hole blocking layer, and the LUMO energy level of the hole blocking layer is lower than the LUMO energy level of the electron transport layer. The LUMO energy level of the N-type host material is equal to the LUMO energy level of the hole blocking layer; The difference between the LUMO energy level of the N-type host material and the LUMO energy level of the doped material is the third energy level difference, which is -0.2 eV to 0.2 eV.

4. The blue phosphorescent organic light-emitting device according to claim 3, wherein, The HOMO energy level of the doped material is 5.4 eV-5.6 eV; The LUMO energy level of the doped material is 2.5 eV-2.75 eV; The LUMO energy level of the N-type host material is 2.6 eV-2.78 eV; The LUMO energy level of the electron transport layer is 2.8 eV-3.0 eV.

5. The blue phosphorescent organic light-emitting device according to claim 1, wherein, The HOMO level of the P-type host material is greater than the HOMO level of the doped material, and the LUMO level of the doped material is greater than the LUMO level of the P-type host material.

6. The blue phosphorescent organic light-emitting device according to claim 5, wherein, The difference between the HOMO energy level of the P-type host material and the HOMO energy level of the doped material is the fourth energy level difference, which is less than or equal to 0.5 eV. The difference between the LUMO energy level of the doped material and the LUMO energy level of the p-type host material is the fifth energy level difference, which is less than or equal to 0.5 eV. The difference between the LUMO energy level of the N-type host material and the LUMO energy level of the doped material is the third energy level difference, which is -0.2 eV to 0.2 eV.

7. The blue phosphorescent organic light-emitting device according to claim 1, wherein, The hole recombination energy of the P-type host material is 0.24 eV-0.28 eV; The electron recombination energy of the N-type host material is 0.5 eV-0.7 eV.

8. The blue phosphorescent organic light-emitting device according to any one of claims 1-7, wherein, The blue phosphorescent organic light-emitting device satisfies at least one of the following conditions: (1) The hole transport layer comprises the compound shown in formula (I): ； Among them, R1, R2, R3, R4, and R5 are each independently selected from hydrogen and C. 1-40 Alkyl, C 6-40 Aryl, C 2-60 heteroaryl, C 6-60 aryloxy group, C 1-39 Alkoxy, C 6-39 arylamine, C 3-39 cycloalkyl, C 3-39 Heterocyclic alkyl, C 1-39 Alkyl silyl, C 1-39 Alkylboryl, C 6-39 arylboryl, C 6-39 arylphosphine or C 6-39 Arylsilyl group; the C 2-60 heteroaryl and the C 3-39 The heteroatoms in the heterocyclic alkyl group are each independently selected from N, O, or S; Y1 is selected from O or S; (2) The electron transport layer comprises the compound shown in formula (III): ； Among them, R 1b R 2b R 3b R 4b R 5b and R 6b Each is independently selected from hydrogen, unsubstituted or C-substituted. 6-12 aryl-substituted C 1-40 Alkyl, C 6-40 Aryl, C 2-60 heteroaryl, C 6-60 aryloxy group, C 1-39 Alkoxy, C 6-39 arylamine, C 3-39 cycloalkyl, C 3-39 Heterocyclic alkyl, C 1-39 Alkyl silyl, C 1-39 Alkylboryl, C 6-39 arylboryl, C 6-39 arylphosphine or C 6-39 Arylsilyl group; the C 2-60 heteroaryl and the C 3-39 The heteroatoms in the heterocyclic alkyl group are each independently selected from N, O or S.

9. The blue phosphorescent organic light-emitting device according to claim 8, wherein, In equation (I), R1, R2, R3, R4, and R5 are each independently selected from hydrogen, C, and C. 1-10 Alkyl, C 6-18 Aryl, C 2-18 heteroaryl, C 6-18 aryloxy group, C 1-10 Alkoxy, C 6-18 arylamine, C 3-10 cycloalkyl, C 3-10 Heterocyclic alkyl, C 1-10 Alkyl silyl, C 1-10 Alkylboryl, C 6-18 arylboryl, C 6-18 arylphosphine or C 6-18 Arylsilyl; In equation (III), R 1b R 2b R 3b R 4b R 5b and R 6b Each is independently selected from hydrogen, unsubstituted or phenyl-substituted C. 1-10 Alkyl, C 6-18 Aryl, C 2-18 heteroaryl, C 6-18 aryloxy group, C 1-10 Alkoxy, C 6-18 arylamine, C 3-10 cycloalkyl, C 3-10 Heterocyclic alkyl, C 1-10 Alkyl silyl, C 1-10 Alkylboryl, C 6-18 arylboryl, C 6-18 arylphosphine or C 6-18 Arylsilyl group.

10. A display device comprising a blue phosphorescent organic light-emitting device according to any one of claims 1-9.

Images