Luminescent material, luminescent device, display panel and display device

Abstract

Disclosed are a light-emitting material, a light-emitting device, a display panel and a display device, the light-emitting material comprising: a light-emitting compound, by which it is possible to solve the problem that hole injection is difficult to improve while giving consideration to both a high T1 energy level and a shallow HOMO, so that the energy levels of HOMO and LOMO are more matched, the light-emitting material has high T1 energy level and shallow HOMO energy level, hole injection can be improved, and the light-emitting material has excellent light-emitting performance. And the formation of exciplexes is inhibited, so that holes and electrons can be injected into the light-emitting layer more smoothly.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of display, and particularly relates to a luminescent material, a luminescent device, a display panel and a display device. BACKGROUND

[0002] With the development of display technology, the application scenarios of display panels are more and more, and the display types and performance requirements are also different. In the luminescent layer of the display screen, luminescence is often realized by phosphor materials. Phosphor materials can emit phosphor under external excitation. Blue phosphor is an important research direction of the OLED industry. Compared with blue fluorescence, blue phosphor can obtain about 1.5 times efficiency, but due to low life, it cannot be used for mass production. SUMMARY

[0003] The purpose of the embodiments of the present application is to provide a luminescent material, a luminescent device, a display panel and a display device, so as to solve the problem that it is difficult to improve hole injection while taking into account high T1 energy level and shallow HOMO.

[0004] In a first aspect, the embodiments of the present application provide a luminescent material, comprising: a luminescent compound, a structural formula of the luminescent compound comprising a main structure and a group structure connected to the main structure, wherein the main structure is selected from the structural formula:

[0005]

[0006]

[0007] X1, X2, X3 are selected from C or Si, R1, R2, R3 are independently selected from aryl, arylene, heteroaryl;

[0008] The wavy line represents the site of the group structure connected to the main structure;

[0009] Optionally, the structural formula of the group structure is selected from structural formula a1 to structural formula a24, and the structural formula a1 to structural formula a24 are:

[0010]

[0011] In structural formula a1 to structural formula a24, the dashed circle represents an aromatic ring or a heteroaromatic ring connected to the benzene ring.

[0012] Optionally, the structural formula of the group structure is selected from structural formula a25 to structural formula a72, and the structural formula a25 to structural formula a72 are:

[0013]

[0014] Optionally, the structural formula of the light-emitting compound is selected from structural formula a73 to structural formula a88, and the structural formula a73 to structural formula a88 are as follows:

[0015]

[0016] Optionally, the light-emitting compound is a phosphorescent material.

[0017] Optionally, the light-emitting compound is a phosphorescent host material.

[0018] Optionally, the T1 energy level of the light-emitting material is greater than 3.0 eV.

[0019] Optionally, the HOMO energy level of the light-emitting material is 4.8-5.2 eV.

[0020] In a second aspect, an embodiment of the present application provides a light-emitting device, comprising:

[0021] The light-emitting material in the above embodiment.

[0022] Optionally, the light-emitting device comprises:

[0023] A light-emitting layer, wherein the light-emitting layer comprises the light-emitting material.

[0024] Optionally, the light-emitting layer comprises a host material and a guest material, and the host material is the light-emitting material.

[0025] In a third aspect, an embodiment of the present application provides a display panel, comprising:

[0026] The light-emitting device in the above embodiment.

[0027] In a fourth aspect, an embodiment of the present application provides a display device, comprising:

[0028] The display panel in the above embodiment.

[0029] The light-emitting material in the embodiment of the present application comprises a light-emitting compound, which can solve the problem that it is difficult to improve hole injection while taking into account high T1 energy level and shallow HOMO (Highest Occupied Molecular Orbital), so that the energy levels of HOMO and LOMO (Lowest Occupied Molecular Orbital) are more matched, has high T1 energy level, shallow HOMO energy level, can improve hole injection, inhibit the formation of exciplex, and can make holes and electrons more smoothly injected into the inside of the light-emitting layer. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1To compare the spectrum of compound F in Example 1;

[0031] Figure 2 To illustrate the spectrum of compound G in Example 1;

[0032] Figure 3 for Figure 1 and Figure 2 A combination diagram of the spectra of the materials in the middle;

[0033] Figure 4 Represents the JV curve;

[0034] Figure 5 Represents the Roll-off curve;

[0035] Figure 6 Represents the lifespan curve;

[0036] Figure 7 The hydrogen spectrum of compound G prepared in this invention;

[0037] Figure 8 This is the carbon spectrum of compound G prepared in this invention;

[0038] Figure 9 The hydrogen spectrum of the compound having structural formula 77 prepared in this invention;

[0039] Figure 10 The carbon spectrum of the compound having structural formula 77 prepared in this invention;

[0040] Figure 11 The hydrogen spectrum of the compound having structural formula 79 prepared in this invention;

[0041] Figure 12 This is the carbon spectrum of the compound with structural formula 79 prepared in this invention. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] The terms "first," "second," etc., used in the specification and claims of this invention are used to distinguish similar objects and are not used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention can be implemented in orders other than those illustrated or described herein. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0044] The luminescent material of this invention includes: a luminescent compound, wherein the structural formula of the luminescent compound includes a main structure and a group structure connected to the main structure, wherein the main structure is selected from the following structural formula:

[0045]

[0046]

[0047] X1, X2, and X3 are selected from C or Si, and R1, R2, and R3 are independently selected from aryl, arylene, and heteroaryl groups;

[0048] The wavy line indicates the site where the group structure is attached to the main structure;

[0049] The main structure can be selected from the structural formula:

[0050]

[0051]

[0052] The structural formula of the group can be selected from structural formula a1 to structural formula a24, and structural formulas a1 to a24 can be:

[0053]

[0054] In structural formulas a1 to a24, the dashed arcs represent aromatic or heteroaromatic rings attached to the benzene ring.

[0055] The luminescent material in this invention includes a luminescent compound that can solve the problem of difficulty in improving hole injection while balancing high T1 energy level and shallow HOMO. This results in a better match between the HOMO and LOMO energy levels, possessing both a high T1 energy level and a shallow HOMO energy level, which improves hole injection, inhibits the formation of excitocomplexes, and allows holes and electrons to be injected more smoothly into the luminescent layer.

[0056] Optionally, the structural formula of the group is selected from structural formulas a25 to a72, where structural formulas a25 to a72 are:

[0057]

[0058] Optionally, the structural formula of the luminescent compound is selected from structural formulas a73 to a88, where structural formulas a73 to a88 are:

[0059]

[0060]

[0061] Optionally, the luminescent compound is a phosphorescent material.

[0062] Optionally, the luminescent compound is a phosphorescent host material.

[0063] Optionally, the T1 energy level of the luminescent material is greater than 3.0 eV.

[0064] In some embodiments, the HOMO energy level of the luminescent material is 4.8–5.2 eV. It should be noted that the actual value of the HOMO energy level is negative; however, the negative sign is omitted in this invention, and the HOMO energy level refers to the absolute value of the actual HOMO energy level.

[0065] The light-emitting device of this invention includes:

[0066] The luminescent material described in the above embodiments.

[0067] The light-emitting layer in the light-emitting device of the present invention can be incorporating this light-emitting material. The light-emitting compound can solve the problem of difficulty in improving hole injection while balancing high T1 energy level and shallow HOMO, making the energy levels of HOMO and LOMO more matched, possessing high T1 energy level and shallow HOMO energy level, which can improve hole injection, inhibit the formation of excitocomplex, and allow holes and electrons to be injected more smoothly into the light-emitting layer, thereby improving the light emission effect.

[0068] Optionally, the light-emitting device includes:

[0069] A light-emitting layer, wherein the light-emitting layer comprises the light-emitting material.

[0070] Optionally, the light-emitting layer comprises a host material and a guest material, wherein the host material is the light-emitting material. The content of the guest material can be 0.2%-1.5% of the sum of the mass of the host material and the guest material, and the specific ratio can be selected according to actual conditions.

[0071] Optionally, the light-emitting device may also include:

[0072] The light-emitting layer is disposed between the hole injection layer and the electron injection layer, and is stacked with the hole injection layer and the electron injection layer. Holes can be injected into the light-emitting layer through the hole injection layer, and electrons can be injected into the light-emitting layer through the electron injection layer, thereby causing the light-emitting layer to emit light.

[0073] Optionally, the light-emitting device may also include:

[0074] A hole transport layer and an electron transport layer are both present. The hole transport layer can be positioned between the hole injection layer and the light-emitting layer, while the electron transport layer can be positioned between the electron injection layer and the light-emitting layer. The hole transport layer collects and transports holes, facilitating electron-hole separation. It also promotes the transport of holes generated at the anode to the light-emitting layer, allowing them to combine with electrons injected from the cathode, thereby exciting light emission. Positioning a hole transport layer between the hole injection layer and the light-emitting layer promotes stable hole transport. Similarly, the electron transport layer facilitates electron injection and transport while preventing hole injection. Positioning an electron transport layer between the electron injection layer and the light-emitting layer promotes electron transport.

[0075] Optionally, the light-emitting device may also include:

[0076] An electron blocking layer and a hole blocking layer are used. The electron blocking layer can be disposed between the hole transport layer and the light-emitting layer, and the hole blocking layer can be disposed between the electron transport layer and the light-emitting layer. The electron blocking layer can block electrons from the cathode, allowing holes and electrons to effectively combine at the interface of the light-emitting layer and excite radiative emission, which is beneficial to improving the luminous efficiency and brightness of the light-emitting device. The hole blocking layer can prevent holes injected from the anode from transporting to the cathode, allowing electrons and holes to effectively combine in the light-emitting layer and excite radiative emission, which is beneficial to improving the luminous efficiency and brightness of the light-emitting device.

[0077] The organic electroluminescent device of this application can be applied to a top-emitting structure light-emitting device, which can sequentially include a first electrode (anode), an organic layer (including a hole injection layer (HIL), a hole transport layer (HTL), an emissive layer (EML), an electron transport layer (ETL), an electron injection layer (EIL)), and a second electrode (transparent or semi-transparent cathode) on a substrate.

[0078] The organic electroluminescent device of this application can also be used in a bottom-emitting structure light-emitting device, which can sequentially include a first electrode (transparent or semi-transparent anode), an organic layer (including a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer) and a second electrode (cathode) structure on a substrate.

[0079] The organic electroluminescent device of this application can also be applied to a light-emitting device with a dual-sided light-emitting structure, which can sequentially include a first electrode (transparent or semi-transparent anode), an organic layer (hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer) and a second electrode (transparent or semi-transparent cathode) structure on a substrate.

[0080] Additionally, an electron blocking layer (EBL) can be present between the hole transport layer and the light-emitting layer, and a hole blocking layer (HBL) can be present between the light-emitting layer and the electron transport layer. A light extraction layer can be disposed on the transparent electrode on the light-emitting side. However, the structure of the organic electroluminescent device of this application is not limited to the specific structure described above. If necessary, the above layers can be omitted or added. This application does not impose any particular limitation on the thickness of the above layers, as long as it can achieve the purpose of this application. For example, the organic electroluminescent device can sequentially include a first electrode (anode) made of metal or metal oxide (thickness can be 50nm to 100nm), a hole injection layer (5nm to 40nm), a hole transport layer (5nm to 60nm), an electron blocking layer (5nm to 20nm), a light-emitting layer (15nm to 80nm), a hole blocking layer (5nm to 20nm), an electron transport layer (5nm to 60nm), an electron injection layer (1nm to 10nm), and a second electrode (transparent or semi-transparent cathode) (80nm to 200nm) on a substrate. The specific thickness can be selected according to actual needs.

[0081] In this application, the structure of the organic electroluminescent device can be: ITO (indium tin oxide) / HIL (HTL: P-Dopant) (10nm, film thickness ratio 98%:2%) / HTL (110nm) / EBL (5nm) / EML: (luminescent compound in this invention: SiTrzCz2:Pt dopant) (30nm, film thickness ratio 7:3:10%) / HBL (5nm) / ETL:LIQ (35nm, film thickness ratio 1:1) / YB (1nm) / Mg:Ag (11nm, mass ratio 2:8) / CPL (70nm). Wherein, "film thickness ratio 98%:2%" indicates that the film thickness ratio of HTL to P-Dopant is 98%:2%; "film thickness ratio 7:3:10%" indicates that the Pt dopant vapor-deposited film thickness accounts for 10% of the total thickness of the luminescent layer, the sum of the vapor-deposited film thicknesses of the luminescent compound and SiTrzCz2 in this invention accounts for 90% of the total thickness of the luminescent layer, the vapor-deposited film thickness ratio of the luminescent compound to SiTrzCz2 in this invention is 7:3, LIQ is 8-hydroxyquinoline-lithium, and CPL (Capping layer) is a capping layer. The luminescent compound in this invention can be compound G, or it can be a compound with other structural formulas in this invention.

[0082] The display panel of this invention includes the light-emitting device described in the above embodiments.

[0083] The light-emitting layer of the light-emitting device in this embodiment of the invention contains the light-emitting material. The light-emitting compound can make the energy levels of HOMO and LOMO more matched, with a high T1 energy level and a shallow HOMO energy level. It can improve hole injection, inhibit the formation of excitocomplex, and allow holes and electrons to be injected more smoothly into the light-emitting layer, thereby improving the light-emitting effect and enhancing the display effect of the display panel.

[0084] The display device of this invention includes: the display panel described in the above embodiments.

[0085] The display device with the display panel in the embodiment of the present invention has good display effect and stable display.

[0086] The present invention will be further illustrated below through some specific embodiments.

[0087] Preparation of compound G of the present invention

[0088] (1) Preparation of compound A, the specific steps include:

[0089]

[0090] Under a nitrogen atmosphere, iodobenzene (98.03 mmol), 2,3-dihydro-1H-benzo[2,1-d]imidazol-2-amine (98.03 mmol), tripotassium phosphate (90.49 mol), cuprous iodide, dimethyl sulfoxide (180 mL), and 8-hydroxyquinoline (49.02 mmol) were added sequentially to a 500 mL three-necked flask. The mixture was heated to 65 °C and refluxed for 8 h. After the system temperature cooled to room temperature, the reaction solution was poured into 1000 mL of deionized water, extracted with dichloromethane, and the organic phase was collected, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. Subsequently, toluene was used as the eluent, and the mixture was filtered through a silica gel column to remove inorganic salts and excess catalyst impurities. The crude product was then concentrated by rotary evaporation. The crude product was recrystallized from n-heptane / dichloromethane to finally obtain solid A (yield 62.23%).

[0091] (2) Preparation of compound B, the specific steps include:

[0092]

[0093] Under a nitrogen atmosphere, A (86.53 mmol) and (b1) (96.54 mmol), along with cesium carbonate (70.64 mmol) and dimethyl sulfoxide (200 mL), were added sequentially to a 500 mL three-necked flask. The mixture was heated to 110 °C, extracted with dichloromethane, and the organic phase was collected, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. The reaction mixture was refluxed for 10 h. After the system temperature cooled to room temperature, the reaction solution was poured into 1000 mL of deionized water. Subsequently, toluene was used as the eluent, and the mixture was purified by silica gel column chromatography to remove inorganic salts and excess catalyst impurities. The crude product was then concentrated by rotary evaporation. The crude product was recrystallized from n-heptane / dichloromethane to finally obtain solid B (yield 68.95%).

[0094] (3) Preparation of compound C, the specific steps include:

[0095]

[0096] Under a nitrogen atmosphere, substance B (95.55 mmol), stannous chloride (190.10 mmol), and ethanol (950 mL) were added sequentially to a 500 mL three-necked flask. The mixture was heated to 78 °C and refluxed for 8 h. After the system temperature cooled to room temperature, the reaction solution was poured into 1200 mL of deionized water, extracted with dichloromethane, and the organic phase was collected, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. Subsequently, toluene was used as the eluent, and the mixture was purified by silica gel column chromatography to remove inorganic salts and excess catalyst impurities. The crude product was then concentrated by rotary evaporation. The crude product was recrystallized from n-heptane / dichloromethane to finally obtain solid C (yield 60.42%).

[0097] (4) Preparation of compound D, the specific steps include:

[0098]

[0099] Under a nitrogen atmosphere, substances C (95.53 mmol) and (b2) (99.24 mmol), along with Pd2(dba)3, X-Phos, t-BuONa, and toluene, were added sequentially to a 500 mL three-necked flask. The mixture was heated to 65 °C and refluxed for 7 h. After the system cooled to room temperature, the reaction solution was poured into 1000 mL of deionized water, extracted with dichloromethane, and the organic phase was collected, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. Subsequently, toluene was used as the eluent, and the mixture was purified by silica gel column chromatography to remove inorganic salts and excess catalyst impurities. The crude product was then concentrated by rotary evaporation. The crude product was recrystallized from n-heptane / dichloromethane to finally obtain solid B (yield 68.95%).

[0100] (5) Preparation of compound E, the specific steps include:

[0101]

[0102] Under a nitrogen atmosphere, substances D (86.53 mmol) and (b3) (79.54 mmol), along with Pd(Oac)2, K3PO4, and DMA (dimethyl adipate), were added sequentially to a 500 mL three-necked flask. The mixture was then heated to 110 °C and refluxed for 12 h. After the system temperature cooled to room temperature, the reaction solution was poured into 800 mL of deionized water, extracted with dichloromethane, and the organic phase was collected, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. Subsequently, toluene was used as the eluent, and the mixture was purified by silica gel column chromatography to remove inorganic salts and excess catalyst impurities. The crude product was then concentrated by rotary evaporation. The crude product was recrystallized from n-heptane / dichloromethane to finally obtain solid E (yield 59.65%).

[0103] (6) The specific steps for preparing compound G of the present invention include:

[0104]

[0105] Under a nitrogen atmosphere, E (95.23 mmol) and (b4) (98.14 mmol), along with pd2(dba)3, S-phos (2-bicyclohexylphosphine-2',6'-dimethoxy-1,1'-diphenyl), t-BuONa, and toluene, were added sequentially to a 500 mL three-necked flask. The mixture was then heated to 65 °C and refluxed for 9 h. After the system temperature cooled to room temperature, the reaction solution was poured into 800 mL of deionized water, extracted with dichloromethane, and the organic phase was collected, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. Subsequently, toluene was used as the eluent, and the mixture was purified by silica gel column chromatography to remove inorganic salts and excess catalyst impurities. The crude product was then concentrated by rotary evaporation. The crude product was recrystallized from n-heptane / dichloromethane to finally obtain compound G of the present invention (yield 63.16%).

[0106] The compound G prepared in this invention was analyzed. Figure 7 The hydrogen spectrum in the image is interpreted as follows: 1 H NMR(500MHz,Chloroform-d)δ8.37–8.31(m,1H),8.30–8.27(m,1H),8.23–8.13(m,2H) ,8.01(d,J=7.3Hz,1H),7.80(t,J=2.2Hz,1H),7.68–7.42(m,14H),7.42–7.25(m,14H). Figure 8The carbon spectrum in the image is resolved as follows: 13C NMR (125MHz, Common NMR) Solvents)δ150.06,139.63,139.36,137.66,136.85,135.98,134.10,132 .85,132.83,132.64,130.62,129.92,129.89,129.40,128..64,128.22,12 8.01,127.44,127.27,127.09,126.04,124.85,124.62,124.56,123..59, 123.04,122.83,121.53,120.27,117.87,116.90,116.52,112.89,107.00. Spectral analysis confirmed that the final compound prepared was the desired compound G.

[0107] Preparation of the compound having structural formula 77 according to the present invention:

[0108]

[0109] Under a nitrogen atmosphere, substances A1 (105.23 mmol) and B1 (105.23 mmol), tripotassium phosphate (94.59 mol), cuprous iodide (51.32 mmol), dimethyl sulfoxide (200 mL), and 8-hydroxyquinoline (56.02 mmol) were added sequentially to a 500 mL three-necked flask. The mixture was heated to 60 °C and refluxed for 10 h. After the system temperature cooled to room temperature, the reaction solution was poured into 1000 mL of deionized water, extracted with dichloromethane, and the organic phase was collected, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. Subsequently, toluene was used as the eluent, and the mixture was filtered through a silica gel column to remove inorganic salts and excess catalyst impurities. The crude product was then concentrated by rotary evaporation. The crude product was recrystallized from n-heptane / dichloromethane to finally obtain substance C0 (yield 62.23%).

[0110]

[0111] Under a nitrogen atmosphere, substances C0 (86.53 mmol), D1 (96.54 mmol), cesium carbonate (70.64 mmol), and dimethyl sulfoxide (200 mL) were added sequentially to a 500 mL three-necked flask. The mixture was heated to 100 °C, extracted with dichloromethane, and the organic phase was collected, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. The reaction mixture was refluxed for 10 h. After the system temperature cooled to room temperature, the reaction solution was poured into 1000 mL of deionized water. Subsequently, toluene was used as the eluent, and the mixture was filtered through a silica gel column to remove inorganic salts and excess catalyst and other impurities. The crude product was concentrated by rotary evaporation. The crude product was recrystallized from n-heptane / dichloromethane to finally obtain solid C1 (yield 64.55%).

[0112]

[0113] Under a nitrogen atmosphere, C1 (105.24 mmol), stannous chloride (189.35 mmol), and ethanol (900 ml) were added sequentially to a 500 ml three-necked flask. The mixture was heated to 85 °C and refluxed for 8 h. After the system temperature cooled to room temperature, the reaction solution was poured into 1200 mL of deionized water, extracted with dichloromethane, and the organic phase was collected, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. Subsequently, toluene was used as the eluent, and the mixture was purified by silica gel column chromatography to remove inorganic salts and excess catalyst impurities. The crude product was then concentrated by rotary evaporation. The crude product was recrystallized from n-heptane / dichloromethane to finally obtain solid C2 (yield 64.42%).

[0114]

[0115] Under a nitrogen atmosphere, substances C2 (95.53 mmol) and E1 (99.24 mmol), along with pd2(dba)3, X-Phos, t-BuONa, and toluene, were added sequentially to a 500 mL three-necked flask. The mixture was heated to 65 °C and refluxed for 7 h. After the system temperature cooled to room temperature, the reaction solution was poured into 1000 mL of deionized water, extracted with dichloromethane, and the organic phase was collected, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. Subsequently, toluene was used as the eluent, and the mixture was purified by silica gel column chromatography to remove inorganic salts and excess catalyst impurities. The crude product was then concentrated by rotary evaporation. The crude product was recrystallized from the crude product using n-heptane / dichloromethane to finally obtain substance C3 (yield 68.95%).

[0116]

[0117] Under a nitrogen atmosphere, substances C3 (86.53 mmol) (79.54 mmol), Pd(Oac)2, K3PO4, and DMA (dimethyl adipate) were added sequentially to a 500 mL three-necked flask. The mixture was then heated to 110 °C and refluxed for 12 h. After the system temperature cooled to room temperature, the reaction solution was poured into 800 mL of deionized water, extracted with dichloromethane, and the organic phase was collected, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. Subsequently, toluene was used as the eluent, and the mixture was purified by silica gel column chromatography to remove inorganic salts and excess catalyst impurities. The crude product was then concentrated by rotary evaporation. The crude product was recrystallized from the crude product using n-heptane / dichloromethane to finally obtain substance C4 (yield 59.65%).

[0118]

[0119] Under a nitrogen atmosphere, E (95.23 mmol) and FO (98.14 mmol), along with Pd2(dba)3, S-phos (2-bicyclohexylphosphine-2',6'-dimethoxy-1,1'-diphenyl), t-BuONa, and toluene, were added sequentially to a 500 mL three-necked flask. The mixture was then heated to 65 °C and refluxed for 9 h. After the system temperature cooled to room temperature, the reaction solution was poured into 800 mL of deionized water, extracted with dichloromethane, and the organic phase was collected, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. Subsequently, toluene was used as the eluent, and the mixture was purified by silica gel column chromatography to remove inorganic salts and excess catalyst impurities. The crude product was then concentrated by rotary evaporation. The crude product was recrystallized from n-heptane / dichloromethane to finally obtain the compound of the present invention with structural formula 77 (yield 63.16%).

[0120] The compound of structural formula 77 prepared in this invention was analyzed. Figure 9 The hydrogen spectrum was resolved as follows: 1H NMR (500MHz, Chloroform-d) δ 8.37–8.30 (m, 2H), 8.21 (d, J = 7.3Hz, 1H), 8.17–8.10 (m, 1H), 7.99 (d, J = 7.3Hz, 1H), 7.69–7.62 (m, 1H), 7.50–7.41 (m, 2H), 7.38–7.30 (m, 2H), 7.27–7.12 (m, 3H), 7.06 (d, J = 8.1Hz, 2H), 2.23 (d, J = 0.6Hz, 2H), 2.16 (s, 5H). Figure 10 The carbon spectrum resolution is as follows: 13C NMR (125MHz, Common NMR Solvents) δ 148.94, 142.15, 136.70, 134.19, 133.64, 133.02, 132.86, 130.29, 129.22, 128.66, 128.65, 128.38, 128.36, 126.89, 125.84, 124.82, 124.62, 123.65, 123.32, 121.35, 119.88, 117.68, 116.93, 116.53, 111.71, 107.07, 18.01, 17.31, 17.28. Spectral analysis confirmed that the final compound was the desired structural formula 77.

[0121] Preparation of the compound having structural formula 79 according to the present invention:

[0122] The first five steps are the same as those used in the preparation of compound G in this invention to prepare compound E, and the steps described above can be referred to. The final step is as follows:

[0123]

[0124] Under a nitrogen atmosphere, substances E (95.23 mmol) and F1 (98.14 mmol), along with Pd2(dba)3, S-phos (2-bicyclohexylphosphine-2',6'-dimethoxy-1,1'-diphenyl), t-BuONa, and toluene, were added sequentially to a 500 mL three-necked flask. The mixture was then heated to 70 °C and refluxed for 10 h. After the system temperature cooled to room temperature, the reaction solution was poured into 800 mL of deionized water, extracted with dichloromethane, and the organic phase was collected, dried over anhydrous sodium sulfate, and concentrated to obtain the crude product. Subsequently, toluene was used as the eluent, and the mixture was purified by silica gel column chromatography to remove inorganic salts and excess catalyst impurities. The crude product was then concentrated by rotary evaporation. The crude product was recrystallized from n-heptane / dichloromethane to finally obtain the compound of the present invention with structural formula 79 (yield 65.16%).

[0125] The compound of structural formula 79 prepared in this invention was analyzed. Figure 11 The hydrogen spectrum was resolved as follows: 1H NMR (500MHz, Chloroform-d) δ 8.37–8.30 (m, 1H), 8.33–8.25 (m, 1H), 8.20 (d, J = 7.3Hz, 1H), 8.21–8.12 (m, 3H), 8.00 (d, J = 7.3Hz, 1H), 7.81 (dd, J = 4.2, 2.8Hz, 1H), 7.70 (dd, J = 4.1, 2.8Hz, 1H), 7.62 (ddd, J = 7.7, 5.5, 2.6Hz, 3H), 7.53–7.28 (m, 15H). Figure 12 The carbon spectrum resolution is as follows: 13C NMR (125MHz, Common NMR Solvents) δ 150.06, 140.34, 140.11, 135.98, 134.79, 134.74, 132.80, 129.89, 129.85, 129.37, 128.64, 128.17, 127.73, 127.29, 127.09, 124.85, 124.6 2,124.56,124.53,123.59,123.51,123.36,122.83,122.71,121.44,121.38,121.27,120.78,119.79,117.43,116.90,116.52,113.05,112.22,106.97. Spectral analysis confirmed that the final compound obtained was of the desired structural formula 79.

[0126] The compounds of this invention can achieve energy levels above 3.0 eV based on quantum computing T1, with HOMO energy levels in the range of 4.8–5.2 eV, demonstrating improved hole injection compared to existing host materials. HOMO represents the highest occupied molecular orbital, and LOMO represents the lowest occupied molecular orbital.

[0127] The HOMO and LOMO energy level values ​​of existing OLED materials are shown in Table 1.

[0128] Table 1. HOMO and LOMO energy levels of existing OLED materials.

[0129] Name HOMO (eV) LOMO (eV) HIL 4.51 1.19 HTL 4.76 0.87 Bprime 4.95 1.21 Bhost 5.14 1.64 Gprime 4.80 0.99 Ghptype 5.10 1.05 Ghntype 5.26 1.95 Rprime 4.87 1.18 Rhost 4.97 2.15 HBL 5.57 1.86 ETL 5.72 1.92

[0130] Wherein, HIL: hole injection layer, HTL: hole transport layer, Bprime: blue luminescent functional material, Bhost: blue luminescent host material, Gprime: green luminescent functional material, Ghptype: green hole injection type luminescent host material, Ghntype: green electron injection type luminescent host material, Rprime: red luminescent functional material, Rhost: red luminescent host material, HBL: hole blocking layer, ETL: electron transport layer.

[0131] The HOMO, LOMO, and T1 energy level values ​​of the material compounds and mCP and dmCBP materials in this invention are shown in Table 2.

[0132] Table 2. HOMO, LOMO, and T1 energy level values ​​of the materials in this invention and mCP and dmCBP materials.

[0133]

[0134] Wherein, mCP represents 1,3-di-9-carbazolebenzene, and dmCBP represents 4-4'-bis(9-carbazole)-2,2'-dimethyl-biphenyl.

[0135] In order for holes to be successfully injected through the blue phosphorescent host material, the HOMO value needs to be between 4.9 and 5.2 eV according to quantum computing. However, the existing blue phosphorescent host material has the same HOMO value as the compound in Example 1. Another problem with the blue phosphorescent host material is insufficient molecular stereochemistry. Due to the characteristics of the dopant molecular structure, the molecules overlap with each other, which easily leads to the formation of excitocomplexes. Therefore, the T1 energy level decreases, resulting in a redshift of the emission wavelength or a decrease in luminescence efficiency.

[0136] Light-emitting devices were prepared using compounds F and G. Compounds F and G were added to the light-emitting layer of the light-emitting devices. The performance of the devices prepared using compounds F and G was compared, as shown in Table 3.

[0137] In Example 1 of this application, the structure of the organic electroluminescent device can be: ITO / HIL (HTL: P-Dopant) (10nm, film thickness ratio 98%:2%) / HTL (110nm) / EBL (5nm) / EML: (compound G: SiTrzCz2: Ptdopant) (30nm, film thickness ratio 7:3:10%) / HBL (5nm) / ETL:LIQ (35nm, film thickness ratio 1:1) / YB (1nm) / Mg:Ag (11nm, mass ratio 2:8) / CPL (70nm). Among them, "film thickness ratio 98%:2%" means that the film thickness ratio of HTL to P-Dopant is 98%:2%; "film thickness ratio 7:3:10%" means that the vapor-deposited film thickness of Pt dopant accounts for 10% of the total thickness of the light-emitting layer, the sum of the vapor-deposited film thicknesses of compound G and SiTrzCz2 accounts for 90% of the total thickness of the light-emitting layer, and the vapor-deposited film thickness ratio of compound G to SiTrzCz2 is 7:3.

[0138] The difference between Comparative Example 1 and Implementation Example 1 is that compound G is replaced by compound F.

[0139]

[0140]

[0141] The difference between Implementation Example 2 and Implementation Example 1 is:

[0142] Replace compound G with a compound having structural formula 77;

[0143] The difference between Implementation Example 3 and Implementation Example 1 is:

[0144] Replace compound G with a compound having structural formula 79.

[0145] Table 3 compares the performance of light-emitting devices prepared from different compounds in the examples and implementation examples.

[0146] Name Efficiency (Cd / A / y) CIE y Lifetime (hr @ LT90) Comparative Example 1 100％ 0.061 100％ Example 1 238％ 0.059 2000％ Example 2 252％ 0.056 1280％ Example 3 244％ 0.058 2560％

[0147] As shown in Table 3, the light-emitting device prepared by compound F in Comparative Example 1 has lower efficiency and shorter lifespan; the light-emitting devices prepared by the compounds in Examples 1-3 have higher efficiency and longer lifespan. The compounds in this invention have higher luminous efficiency and longer lifespan than the light-emitting device prepared by compound F in Comparative Example 1.

[0148] like Figures 1 to 3 As shown, in Figure 1In the diagram, curve m1 represents the spectrum of compound F in Comparative Example 1, curve m2 represents the spectrum of compound F in Comparative Example 1 mixed with the N-type host material, and curve m3 represents the spectrum of the blue phosphorescent dopant material; Figure 2 In the diagram, curve n1 represents the spectrum of compound G in Example 1, curve n2 represents the spectrum of compound G mixed with the N-type host material in Example 1, and curve n3 represents the spectrum of the blue phosphorescent dopant material. In contrast, in Example 1, compound F forms a thin film with the host material. The spectral wavelength of this film is longer than that of the blue phosphorescent dopant material. The T1 energy level of the host material is lower, resulting in the transfer of some excitons originally belonging to the dopant material, hindering luminescence and reducing luminescence efficiency. However, when compound G is mixed with the host material, the spectrum is almost within the same wavelength range as the dopant material, so energy transfer can proceed normally.

[0149] With its relatively planar molecular structure, compound F in Example 1, while exhibiting a high T1 value in its thin film state, forms an exciton complex when deposited together with the N-type host material. This causes the PL (photoluminescence) spectrum to shift towards longer wavelengths. Therefore, compared to the blue light-doped material, the host material has a lower T1 energy level, transferring some of the exciton complex that originally belonged to the dopant material, hindering luminescence and reducing luminous efficiency by 60%. Compound G in Example 1 possesses a high T1 energy level, an appropriate HOMO energy level, and a stereolithographic material structure. Its properties were compared by fabricating it into a top-mounted light-emitting device on a development device.

[0150]

[0151] Compound H was used to prepare a device as Comparative Example 2, and compound G was used to prepare a device as Implemented Example 1. The difference between Comparative Example 2 and Implemented Example 1 is that compound G was replaced by compound H.

[0152] The specific test results of compound H in Comparative Example 2 and compound G in Example 1, as well as the prepared light-emitting devices, are shown in Table 4.

[0153] Table 4 compares the specific test results of compound H in Example 2 with those of the compound in the implementation example and the prepared light-emitting device.

[0154]

[0155] As shown in Table 4, the devices prepared by the compounds in this invention have low driving voltage and long service life.

[0156] like Figures 4 to 6 As shown, Figure 4 Represents the JV curve. Figure 5 Represents the Roll-off curve. Figure 6Represents the lifespan curve. For example... Figure 4 As shown in the figure, the JV curve in Example 1 is more skewed to the left, indicating a lower driving voltage and superior hole injection capability compared to the comparative compound H. Figure 5 As shown in the figure, the roll-off curves have a basically consistent slope, indicating that the efficiency levels are comparable. Figure 6 As shown in the lifetime curves, it can be seen that under the same test conditions (1000 nits @ 25°C), the lifetime performance of Example 1 is better than that of the device using the comparative compound H.

[0157] It is difficult for blue phosphorescent host materials to simultaneously possess both high T1 and shallow HOMO characteristics. This molecular structure is the p-type host material with the shallowest HOMO level among existing blue phosphorescent host materials. Furthermore, to prevent the formation of exciton complexes between host materials or between the host material and dopants, which would lead to a decrease in luminescence efficiency, it is necessary to include a molecular structure that enhances stereochemistry.

[0158] Table 5 shows the quantum calculation results for some compound molecules, whose molecular structures cannot meet the standard of T1>3.0ev.

[0159] Table 5. Quantum calculation results for some compound molecules.

[0160]

[0161]

[0162] As shown in Table 5, the quantum calculation results of some of the above-mentioned compound molecules show that their molecular structures cannot meet the standard of T1 > 3.0 eV. The T1 energy level of the compound in Example 1 of this invention is 3.11 eV, which is relatively high. The test results of the above examples show that the compound in this invention can solve the problem of difficulty in improving hole injection while balancing a high T1 energy level and a shallow HOMO, making the HOMO and LOMO energy levels more matched, possessing a high T1 energy level and a shallow HOMO energy level, suppressing the formation of exciton complexes, and allowing holes and electrons to be injected more smoothly into the luminescent layer.

[0163] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

Claims

1. A luminescent material, characterized by, The application relates to a luminescent material, a luminescent device and a display panel. The luminescent compound has a structural formula comprising a host structure and a group structure connected to the host structure, wherein the host structure is selected from the following structural formulas: X1, X2, X3 are selected from C or Si, and R1, R2, R3 are independently selected from aryl, arylene and heteroaryl; The wavy line represents the connection position of the group structure on the host structure; The structural formula of the group structure is selected from the following structural formulas a1 to a24: In the structural formulas a1 to a24, the dotted arc represents an aromatic ring or a heteroaromatic ring connected to the benzene ring.

2. The light emitting material of claim 1, wherein, The structural formula of the group structure is selected from the following structural formulas a25 to a72:

3. The light emitting material of claim 1, wherein, The structural formula of the luminescent compound is selected from the following structural formulas a73 to a88:

4. The light emitting material of claim 1, wherein, The T1 energy level of the luminescent material is greater than 3.0 eV.

5. The light emitting material of claim 1, wherein, The HOMO energy level of the luminescent material is 4.8-5.2 eV.

6. A light-emitting device, characterized in that, The application relates to a luminescent material, a luminescent device and a display panel. The luminescent material is selected from the following structural formulas 1 to 5:

7. The light emitting device of claim 6, wherein the first and second light emitting devices are arranged in a vertical stack. The luminescent device comprises: A luminescent layer comprising the luminescent material.

8. The light emitting device of claim 7, wherein, The luminescent layer comprises a host material and a guest material, and the host material is the luminescent material.

9. A display panel, characterized by, The application relates to a luminescent material, a luminescent device and a display panel. The luminescent device is selected from the following structural formulas 6 to 8:

10. A display device, characterized by comprising: The display panel is selected from the following structural formula 9: ​

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