Phosphorescent compound, light emitting device and display device

Abstract

The invention provides a phosphorescent compound, a light emitting device and a display device. Specifically, the light-emitting device comprises a substrate, a first micro-cavity structure layer and a second micro-cavity structure layer located on the side, away from the substrate, of the first micro-cavity structure layer. Wherein the first microcavity structure layer comprises a light-emitting layer; the materials of the light-emitting layer at least comprise a main body material, a light-emitting material and a sensitizer; wherein the luminescent material comprises a phosphorescent material; the sensitizer comprises a thermally activated delayed fluorescent material. According to the technical scheme, the spectrum of the light-emitting device can be narrowed by using the second microcavity structure layer, and the light-emitting device with the service life, the spectral characteristic and the light-emitting efficiency is obtained.

Description

Technical Field

[0001] The present disclosure relates to the field of display technologies, and particularly to a phosphorescent compound, a light-emitting device, and a display device. Background Art

[0002] In recent decades, organic light-emitting diodes (OLEDs) have played an increasingly important role in flexible displays and general solid-state lighting due to their excellent color purity, cold resistance, flexibility, and wide viewing angle. However, it is difficult for related OLEDs to balance luminous efficiency, spectral characteristics, and device lifetime. Summary of the Invention

[0003] In view of this, the purpose of the present disclosure is to provide a phosphorescent compound, a light-emitting device, and a display device.

[0004] Based on the above purpose, the present disclosure provides a phosphorescent compound, and the phosphorescent compound includes a structural general formula as shown in formula (I):

[0005]

[0006] Wherein, each A1 independently selects any one from a substituted or unsubstituted C5-C60 carbocyclic group and a substituted or unsubstituted C1-C60 heterocyclic group; the heteroatoms in the heterocyclic group are selected from one or more of O, S, and N;

[0007] B 1 selects any one from H, a halogen, a substituted or unsubstituted C1-C6 alkyl group, and a substituted or unsubstituted C1-C6 alkoxy group;

[0008] R 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R 8 and R 9 each independently selects any one from hydrogen, deuterium, a halogen group, an alkyl group, a heteroalkyl group, an aralkyl group, an alkoxy group, an aryloxy group, an amino group, a silyl group, an alkenyl group, a heteroalkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an acyl group, a carbonyl group, a carboxylic acid, an ester, a nitrile, an isonitrile, a sulfide group, a sulfinyl group, a sulfonyl group, and a phosphine group.

[0009] Based on the same inventive concept, embodiments of the present disclosure further provide a light-emitting device, including a substrate, a first microcavity structure layer, and a second microcavity structure layer located on a side of the first microcavity structure layer away from the substrate; wherein, the first microcavity structure layer includes a light-emitting layer; the material of the light-emitting layer at least includes a host material, a light-emitting material, and a sensitizer; wherein, the light-emitting material includes a phosphorescent material; the sensitizer includes a thermally activated delayed fluorescence material.

[0010] Based on the same inventive concept, embodiments of the present disclosure further provide a display device, including the light-emitting device element described in any one of the above.

[0011] As can be seen from the above, a phosphorescent compound, a light-emitting device, and a display device provided by the present disclosure add a second microcavity structure layer on the basis of a light-emitting device constructed with a thermally activated delayed fluorescence material as a sensitizer and a phosphorescent compound as a light-emitting material, and utilize the second microcavity structure layer to narrow the spectrum of the light-emitting device, so as to obtain a light-emitting device that takes into account lifespan, spectral characteristics, and luminous efficiency. Description of the Drawings

[0012] In order to more clearly illustrate the technical solutions in the present disclosure or related technologies, the following will briefly introduce the drawings required for use in the description of the embodiments or related technologies. Obviously, the drawings in the following description are only embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0013] Figure 1 A schematic structural diagram of a light-emitting device provided by an embodiment of the present disclosure is shown;

[0014] Figure 2 A schematic diagram of the principle of Fabry-Perot interference provided by an embodiment of the present disclosure is shown;

[0015] Figure 3 A schematic diagram of the pixel arrangement of a display device provided by an embodiment of the present disclosure is shown. Detailed Embodiments

[0016] To make the purpose, technical solutions, and advantages of the present disclosure clearer and more understandable, the following further details the present disclosure in conjunction with specific embodiments and with reference to the drawings. In the drawings, the thickness and shape of some layers and regions can be exaggerated for better understanding and easy description. Even if not explicitly stated, components are interpreted to include the normal error range.

[0017] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present disclosure should have the ordinary meanings understood by those of ordinary skill in the art to which the present disclosure belongs. The terms "first", "second" and similar terms used in the embodiments of the present disclosure do not denote any order, quantity or importance, but are only used to distinguish different components. Words such as "comprising" or "including" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. When terms such as "above", "on top", "below" and "next to" are used to describe the positional relationship between two components, unless these terms are used together with the term "immediately" or "directly", one or more components may be located between the two components. When an element or layer is disposed "on" another element or layer, another layer or element may be directly inserted on or between the other element.

[0018] Traditional fluorescent materials have the advantages of narrow spectra and high stability, but they can only utilize singlet excitons and cannot achieve a theoretical internal quantum efficiency (IQE) of 100%.

[0019] In order to improve the theoretical IQE, those skilled in the art found that attempting to combine thermally activated delayed fluorescence (TADF) materials and metal complex phosphorescent materials can achieve a theoretical IQE of 100%. However, its spectral width is broad, and it is difficult for the corresponding light-emitting devices to effectively utilize part of the exciton energy, resulting in a weakened device efficiency. Moreover, if it is directly used as the light-emitting center, its stability is poor, which is prone to the formation of adducts and charge traps, thereby damaging the device lifetime and efficiency. In addition, the microsecond-level triplet excitons of phosphorescent materials are prone to triplet-triplet annihilation (TTA) and triplet-polaron annihilation (TPA), which will accelerate device degradation and reduce the color saturation at high brightness. The dihedral angle distribution of the molecular thin film morphology of TADF materials is large, the sensitization efficiency is low, and the C-N bond is easily broken, which is prone to poor stability of TSF-OLEDs devices. Using phosphorescent materials as sensitizers and trace amounts of multi-resonant TADF materials as the final emitters, and incorporating both into the host material to fabricate PSF-OLEDs devices can not only achieve a 100% theoretical exciton utilization rate but also maintain a narrow-band intrinsic spectrum. However, in phosphorescent-sensitized TADF devices, due to the relatively long fluorescence lifetime of the TADF doping material, excitons tend to stay on the TADF doping material itself for a long time, resulting in an inability to improve the lifetime.

[0020] Therefore, a sensitized device with TADF sensitizing phosphorescence emerged. In this scheme, TADF is used as the sensitizer and the phosphorescent doping material is used as the light emitter, which can accept the excitons transferred by TADF and quickly consume them, reducing the amount of excitons in TADF, thereby improving the lifetime. However, for such light-emitting devices, the characteristic of the broad spectrum of phosphorescence will appear, and how to narrow the spectrum has become the key to restricting its application.

[0021] The inventors of the present disclosure noticed that a microcavity structure can generate a strong resonance phenomenon inside an electroluminescent (EL) device, and improve the efficiency of the electroluminescent device by amplifying the light intensity of a specific wavelength that satisfies a specific resonance mode, which helps to achieve high efficiency, wide color gamut, and high pixel density.

[0022] Based on this, the embodiments of the present disclosure provide a phosphorescent compound, a light-emitting device, and a display device. Multiple microcavity structures are formed in a light-emitting device constructed with a thermally activated delayed fluorescence material as the sensitizer and a phosphorescent compound as the light-emitting material, so as to narrow the spectrum of the light-emitting device by using the multiple microcavity structures without changing the electrical characteristics of the light-emitting device, and obtain a light-emitting device that takes into account the lifetime, spectral characteristics, and light-emitting efficiency.

[0023] Figure 1Schematic diagram showing the structure of a light-emitting device provided by an embodiment of the present disclosure. As Figure 1 shown, the light-emitting device 100 includes a substrate 101, and an anode 102, a hole injection layer 103, a hole transport layer 104, an electron blocking layer 105, a light-emitting layer 106, a hole blocking layer 107, an electron transport layer 108, an electron injection layer 109, a cathode 110, a microcavity layer 111, a light dimming layer 112, and a cover layer 113, which are sequentially disposed on the substrate 101.

[0024] It should be noted that the structure of the above light-emitting device is only an example and not a limitation. Those skilled in the art can selectively omit some layer structures, such as the electron blocking layer 105, the hole blocking layer 107, etc. The present disclosure does not limit this.

[0025] Combined with Figure 1 it can be seen that the light-emitting device 100 includes a first microcavity structure 114 and a second microcavity structure 115. Exemplarily, the first microcavity structure 114 may include the anode 102, the cathode 110, and a light-emitting functional layer (such as 103, 104, 105, 106, 107, etc.) between the two. Exemplarily, the second microcavity structure 115 may include the cathode 110, the light dimming layer 112, and the microcavity layer 111 between the two. Here, the first microcavity structure 114 and the second microcavity structure 115 share the cathode 110. By reusing the cathode 110, it helps to reduce the structural complexity of the light-emitting device and the process difficulty. It should be understood that the second microcavity structure 115 may be separately provided with a film layer cooperating with the light dimming layer 112 to replace the cathode 110. The present disclosure does not limit this.

[0026] Regarding the film layers in the light-emitting device 100, generally speaking, the film layers that only form the first microcavity structure 114 are usually included in the first microcavity structure layer; the film layers that only form the second microcavity structure 115 are usually included in the second microcavity structure layer; for the film layers that participate in both the first microcavity structure 114 and the second microcavity structure 115, such as the cathode 110, they may be included in the first microcavity structure layer or included in the second microcavity structure layer. The present disclosure does not limit this.

[0027] In some embodiments, the material of the substrate 101 may be glass, quartz, ceramic, plastic, etc. The substrate 101 may be flexible, stretchable, foldable, bendable, and / or curlable. The present disclosure does not limit this.

[0028] In some embodiments, the material of the anode (Anode) 102 is a high work function electrode material. For a top-emitting light-emitting device, the material of the anode 101 may be Ag / ITO, Ag / IZO, Ag / SnO 2, Ag / ZnO, Al / ITO, Al / IZO, Ag / ITO / Ag, etc. Optionally, the thickness of the metal layer (corresponding materials are Ag, Al, etc.) in the anode 102 is 80 - 100 nm, such as 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, etc.; the thickness of the oxide layer (corresponding materials can be ITO, IZO, SnO 2 , ZnO, etc.) is 5 - 20 nm, such as 5 nm, 8 nm, 10 nm, 12 nm, 15 nm, 20 nm, etc. It should be noted that the average reflectivity reference value of the anode 102 in the visible light region is 85% - 95%.

[0029] In some embodiments, the main function of the hole injection layer (Hole Inject Layer, abbreviated as HIL) 103 is to reduce the hole injection barrier and improve the hole injection efficiency. Optionally, the material of the hole injection layer 103 may include HATCN, MnO 3 , CuPc, etc. Further, the hole injection layer 103 may also include p-type doping, such as NPB:F4TCNQ, TAPC:MnO 3 , etc. Optionally, the p-type doping concentration is 0.5% - 5%, such as 0.5%, 0.8%, 1.5%, 2.5%, 4.5%, etc. Optionally, the thickness of the hole injection layer 103 is 5 nm - 20 nm, such as 5 nm, 10 nm, 15 nm, etc.

[0030] In some embodiments, the main function of the hole transport layer (Hole Transport Layer, abbreviated as HTL) 104 is to transfer holes. Optionally, the material of the hole transport layer 104 can be a carbazole-based material with a high hole mobility. By evaporating the carbazole-based material, the hole transport layer 104 can be formed.

[0031] Optionally, the thickness of the hole transport layer 104 is 10 - 100 nm, such as 10 nm, 20 nm, 25 nm, 40 nm, 50 nm, 70 nm, 96 nm, 100 nm, etc.

[0032] Based on the principle of Fabry - Perot interference, changing the thickness of the hole transport layer 104 can change the first microcavity length of the light-emitting device, thereby adjusting the wavelength of light and narrowing the spectrum.

[0033] In some embodiments, the emission material layer (EML) 106 includes a host and a guest.

[0034] The host can promote the injection and transport of carriers in the emission layer. Here, the material of the host can be a single material or a mixed material.

[0035] Exemplarily, the light-emitting layer 106 may employ a hole-transporting host material and an electron-transporting host material, and the contents of both in the light-emitting layer 106 vary with position, such that different positions in the light-emitting layer 106 have different electron and hole mobilities, and carriers mainly accumulate at the interfaces of positions with different mobilities, avoiding the efficiency decline caused by carrier accumulation quenching.

[0036] For example, the light-emitting layer 106 adopts a double-layer gradient design, including a first layer near the hole-transporting layer 104 and a second layer near the electron-transporting layer 108. Among them, the content of the electron-transporting host material in the first layer is greater than that of the hole-transporting host material; the content of the electron-transporting host material in the second layer is less than that of the hole-transporting host material.

[0037] The hole-transporting host material may include The electron-transporting host material may include

[0038] In some embodiments, the guest includes a fluorescent guest and a phosphorescent guest.

[0039] Exemplarily, the fluorescence may be a blue light TADF material, such as

[0040]

[0041] In some embodiments, the phosphorescent guest includes a phosphorescent compound. Here, the phosphorescent compound includes a structural general formula as shown in Formula (Ⅰ):

[0042]

[0043] Among them, each A1 is independently selected from any one of a substituted or unsubstituted C5-C60 carbocyclic group and a substituted or unsubstituted C1-C60 heterocyclic group; the heteroatoms in the heterocyclic group are selected from one or more of O, S, and N; optionally, each A1 is independently selected from any one of a substituted or unsubstituted C5-C40, C5-C25, C5-C20, C5-C15, C5-C10 carbocyclic group and a substituted or unsubstituted C1-C40, C1-C25, C1-C20, C1-C15, C1-C10 heterocyclic group;

[0044] B 1 is selected from any one of H, a halogen, a substituted or unsubstituted C1-C6 alkyl group, and a substituted or unsubstituted C1-C6 alkoxy group;

[0045] R 1 、R 2 、R 3 、R 4 、R5 , R 6 , R 7 , R 8 and R 9 Each independently selected from hydrogen, deuterium, halogen group, alkyl group, heteroalkyl group, aralkyl group, alkoxy group, aryloxy group, amino group, silyl group, alkenyl group, heteroalkenyl group, alkynyl group, aryl group, heteroaryl group, acyl group, carbonyl group, carboxylic acid, ester, nitrile, isonitrile, sulfhydryl group, sulfinyl group, sulfonyl group and phosphino group.

[0046] Furthermore, the heterocyclic group includes any one of

[0047] In some embodiments, the phosphorescent compound may be the following compound. It should be noted that the following compounds are only exemplary of the phosphorescent compounds provided in the embodiments of the present disclosure, rather than limiting.

[0048]

[0049] In some embodiments, the hole blocking layer (Hole Blocking Layer, abbreviated as HBL) 107 will block the holes from the anode and the excitons generated in the light-emitting layer at the interface of the device light-emitting layer, thereby increasing the probability of recombination of electrons and holes at the interface of the device light-emitting layer and increasing the light-emitting efficiency of the device.

[0050] Optionally, the thickness of the hole blocking layer 107 is 1 to 10 nm, such as 1 nm, 2 nm, 5 nm, 8 nm, 10 nm, etc.

[0051] In some embodiments, the main function of the electron transport layer (Electron Transport Layer, abbreviated as ETL) 108 is to transport electrons. The material of the electron transport layer 108 includes materials with strong electron transport ability, containing at least one of them. It should be understood that the materials containing the above groups have strong electron transport ability, which helps to realize the function of electron transport. Optionally, the electron transport layer 108 may further include a doping material, such as Exemplarily, the doping ratio is 10:1 to 1:1.

[0052] Optionally, the thickness of the electron transport layer 108 is 10 to 50 nm, such as 10 nm, 15 nm, 25 nm, 30 nm, 50 nm, etc.

[0053] In some embodiments, the main function of the electron injection layer (Electron Injection Layer, abbreviated as EIL) 109 is to inject electrons. Optionally, the material of the electron injection layer 109 may include Yb, Li, LiF, NaCl, CsF, Li 2One or more of O, BaO, and Liq. Optionally, the thickness of the electron injection layer 109 is 0.5 to 2 nm, such as 0.5 nm, 1 nm, 1.2 nm, 1.5 nm, 2 nm, etc.

[0054] In some embodiments, the material of the cathode 110 is an electrode material with a low work function. For example, Mg, Ag, Al, Al-Li, Ca, Mg:In, Mg:Ag, etc. Optionally, the thickness of the cathode 110 is 10 to 20 nm, such as 10 nm, 12 nm, 14 nm, 15 nm, 20 nm, etc.

[0055] In some embodiments, the main function of the cavity layer 111 is to create a second microcavity outside the device, without changing the electrical properties and narrowing the spectrum; especially, without changing the cavity length of the sub-pixel, it adjusts the high-order mode and balances the light emission efficiency. It should be noted that changing the thickness of the cavity layer 111 can adjust the light superposition effect to facilitate the adjustment of the high-order mode. It should be noted that the high-order mode generally refers to the transverse mode of the resonant cavity (such as the microcavity of the present disclosure) or the waveguide, excluding the fundamental mode. The modes transmitted in the optical resonant cavity and the waveguide can have different intensity cross-sections and propagation constants, and this characteristic can also be reflected in the transverse mode. The simplest mode of the intensity cross-section is called the fundamental mode, and the others are called high-order transverse modes. By modulating the high-order mode, the spectral characteristics of the light-emitting device can be controlled.

[0056] Optionally, the material of the cavity layer 111 is a high refractive index material, such as a material with a refractive index greater than 1.7 at 530 nm, such as TCTA.

[0057] In some embodiments, the dimming layer (Reflector) 112 can cooperate with the cavity layer 111 to obtain a second microcavity structure layer. Optionally, the material of the dimming layer 112 can be the same as or similar to the material of the cathode 110, such as Mg, Ag, Al, Al-Li, Ca, Mg:In, Mg:Ag, etc. Optionally, the thickness of the dimming layer 112 is 10 to 20 nm, such as 10 nm, 12 nm, 15 nm, 20 nm, etc.

[0058] In some embodiments, the main function of the capping layer (CPL) 113 is to improve the light extraction efficiency. Optionally, the material of the capping layer 113 is a high refractive index material, such as a material with a refractive index greater than 1.7 at 530 nm, such as TCTA.

[0059] Optionally, the thickness of the capping layer 113 is 50 to 100 nm, such as 50 nm, 65 nm, 70 nm, 80 nm, 85 nm, 90 nm, 100 nm, etc.

[0060] It should be noted that, in addition to the above-mentioned layer structure, the light-emitting device may also include an encapsulation layer ( Figure 1 (not shown), such as glue sealing or thin film packaging, which is not limited in the present disclosure.

[0061] The light emitting device 100 provided in the above embodiment forms a first microcavity structure and a second microcavity structure, wherein the first microcavity structure includes an anode 102 and a cathode 110 and layers therebetween, and the second microcavity structure includes a cathode 110 , a microcavity layer 111 and a dimming layer 112 .

[0062] The cooperation between the first microcavity structure and the second microcavity structure helps to improve the spectrum of the light-emitting device 100 , especially to narrow the spectrum.

[0063] The principle of improving the spectrum by the first microcavity structure and the second microcavity structure is exemplarily described as follows:

[0064] Refer to the following formula, G CAV1 =f T1_CAV1 ×f FP_CAV1 Formula (1); where G CAV1 represents the cavity gain of the first microcavity structure (abbreviated as CAV1); where f T1_CAV1 represents the double wave number interference factor, f FP_CAV1 represents the Fabry-Perot factor of the first microcavity structure.

[0065] Among them, the dual wave number interference factor is affected by many factors, and their relationship can be expressed as follows:

[0066]

[0067] The Fabry-Perot factor of the first microcavity structure can be expressed as follows:

[0068]

[0069] Among them, r 1 represents the anode 102 in CAV1, r 2 represents the cathode 110 in CAV1; |r 1 | represents the reflection coefficient of the anode 102, |r 2 | represents the reflection coefficient of cathode 110, represents the phase of the anode 102, represents the phase of cathode 110; n CAV1 represents the refractive index of CAV1, where CAV1 is the average refractive index of each layer between the anode 102 and the cathode 110; n CAV2 represents the refractive index of the second microcavity structure (abbreviated as CAV2), where the refractive index of CAV2 may be the refractive index of the microcavity layer 111; dT1 represents the thickness of the anode 102; k 0 is the wave number; d CAV1 is the microcavity length of CAV1; |t 2 | represents the transmission coefficient at the interface between the cathode 110 and the microcavity layer 111.

[0070] Furthermore, as shown in Figure 2 the Fabry - Perot factor f of the second microcavity structure is expressed as follows: FP_CAV2 as follows:

[0071]

[0072] wherein, n Air is the refractive index of air; r 3 represents the cathode 110, r 4 represents the light - modulating layer 112; |r 3 | represents the reflection coefficient of the cathode 110, |r 4 | represents the reflection coefficient of the light - modulating layer 112; represents the phase of the cathode 110, represents the phase of the light - modulating layer 112; d CAV2 is the microcavity length of CAV2; |t 4 | is the transmission coefficient at the interface between the light - modulating layer 112 and air.

[0073] It should be noted that in the above formula (4), the example is given with air on the side of the light - modulating layer 112 far from the microcavity layer 111. When other structural layers are added on the side of the light - modulating layer 112 far from the microcavity layer 111, the above formula can be adjusted adaptively, and the details are not described in this disclosure.

[0074] The cavity gain of the light - emitting device can be expressed as G D_CAV = G CAV1 × f FP_CAV2 Equation (6).

[0075] Based on the above formula, it can be clearly seen that the spectrum of the light - emitting device is directly related to the microcavity length. Changing the microcavity length (for example, adjusting the thickness of the hole - transporting layer, the thickness of the microcavity layer 111) can adjust the light superposition effect, thereby achieving technical effects such as forming high - order modes and narrowing the spectrum.

[0076] The embodiments of the present disclosure also provide a display device. Figure 3 The schematic diagram of pixel arrangement of a display device provided by the embodiments of the present disclosure is shown. As Figure 3 shown, the display device includes at least one pixel unit P, and the pixel unit P includes a first sub - pixel P 1 , a second sub - pixel P 2 and a third sub - pixel P 3Exemplarily, the first sub-pixel P 1 , the second sub-pixel P 2 and the third sub-pixel P 3 correspond to a red (R) sub-pixel, a green (G) sub-pixel, and a blue (B) sub-pixel, respectively. Among them, the blue sub-pixel may include the above-mentioned light-emitting device.

[0077] In order to objectively evaluate the technical effects of the embodiments of the present disclosure, hereinafter, the light-emitting devices provided by the embodiments of the present disclosure will be described exemplarily through specific examples.

[0078] Embodiment 1

[0079] Referring to Figure 1 , the light-emitting device includes an anode 102, a hole injection layer 103, a hole transport layer 104, an electron blocking layer 105, a light-emitting layer 106, a hole blocking layer 107, an electron transport layer 108, an electron injection layer 109, a cathode 110, a microcavity layer 111, a dimming layer 112, and a cover layer 113.

[0080] In this embodiment, the thickness of the anode 102 is 100 nm, and the material includes ITO and Al. The thickness of the hole injection layer 103 is 10 nm, and the material includes NPB:HATCN, where the doping ratio is 1.5%. The thickness of the hole transport layer 104 is 10 nm, and the material is NPB. The thickness of the electron blocking layer 105 is 15 nm, and the material is TPBi. The thickness of the light-emitting layer 106 is 35 nm. The light-emitting layer 106 adopts a double-layer gradient design. On the side close to the electron transport layer 108, the host materials include TCTA and TPBi, and the ratio of TCTA to TPBi is 75:25; on the side close to the hole transport layer, the host materials include TCTA and TPBi, and the ratio of TCTA to TPBi is 25:75. The phosphorescent guest is Ir-1, and the doping ratio is 7%, and the fluorescent guest v-DABNA is used as a sensitizer, and the doping ratio is 1%. The thickness of the hole blocking layer 107 is 5 nm, and the material is TCTA. The thickness of the electron transport layer 108 is 20 nm, and the material is Alq. The thickness of the electron injection layer 109 is 1 nm, and the material is LiF. The thickness of the cathode 110 is 15 nm, and the material is Mg:Ag, where the ratio of Mg to Ag is 1:9. The thickness of the microcavity layer 111 is 80 nm, and the material is TCTA. The thickness of the dimming layer 112 is 15 nm, and the material is Mg:Ag, where the ratio of Mg to Ag is 1:9, that is, the dimming layer 112 and the cathode 110 have the same material and thickness. The thickness of the cover layer 113 is 55 nm, and the material is TCTA.

[0081] Next, a manufacturing method of the above light-emitting device will be introduced.

[0082] 15 Ω / cm 2The ITO glass substrate was cut into a size of 40 mm × 40 mm × 0.7 mm to serve as the substrate and the anode. Next, it was ultrasonically treated with isopropyl alcohol and pure water for 5 minutes each, and then cleaned by exposure to ultraviolet light and ozone for 30 minutes. Then, the ITO glass was provided to a vacuum deposition device. Subsequently, the sample was transferred to a vacuum evaporation system, and each organic material was vacuum-evaporated and deposited. During the entire device preparation process, the organic materials were thermally deposited at a high vacuum environment of 5×10 -6 Torr at a rate of . The thermal deposition rate of the inorganic material was determined based on the material. For example, the thermal deposition rate of LiF was Al, and the thermal deposition rate of Al was s -1 .

[0083] Example 2

[0084] The difference between this example and Example 1 is that the thickness of the microcavity layer 111 is 185 nm.

[0085] Example 3

[0086] The difference between this example and Example 1 is that the thickness of the microcavity layer 111 is 310 nm.

[0087] Example 4

[0088] The difference between this example and Example 1 is that the thickness of the microcavity layer 111 is 435 nm.

[0089] Example 5

[0090] The difference between this example and Example 1 is that the thickness of the microcavity layer 111 is 560 nm.

[0091] Comparative Example 1

[0092] The difference between this comparative example and Example 1 is that the microcavity layer 111 and the light-adjusting layer 112 are omitted.

[0093] Comparative Example 2

[0094] The difference between this comparative example and Example 1 is that the light-emitting layer 106 adopts a single-layer gradient design. The host materials include TCTA and TPBi, and the ratio of TCTA to TPBi is 50:50. The phosphorescent guest is Ir-1, and the doping ratio is 7%. The fluorescent guest v-DABNA is used as a sensitizer, and the doping ratio is 1%.

[0095] Comparative Example 3

[0096] The difference between this comparative example and Example 1 is that the sensitizer is omitted from the light-emitting layer 106.

[0097] Comparative Example 4

[0098] The difference between this comparative example and Example 1 is that in the light-emitting layer 106, the phosphorescent guest is used as a sensitizer, and the doping ratio is 1%, while the doping ratio of the fluorescent guest v-DABNA is 7%.

[0099] Comparative Example 5

[0100] The difference between this comparative example and Example 1 is that the phosphorescent guest in the light-emitting layer 106 is firpic, and its structural formula is shown as follows

[0101] The performance of the light-emitting devices of the above-mentioned examples and comparative examples was tested using an IVL test device, and the test results are shown in Table 1 in detail.

[0102] Table 1

[0103] device <![CDATA[λ EL / nm]]> FWHM <![CDATA[V on / V]]> B.I. LT95@35J / h Example 1 464 25 3.5 213 561 Example 2 462 22 3.4 198 533 Example 3 461 20 3.5 192 572 Example 4 461 17 3.5 185 589 Example 5 463 13 3.5 179 521 Comparative Example 1 464 29 3.5 220 561 Comparative Example 2 464 24 3.7 209 416 Comparative Example 3 469 37 3.5 213 483 Comparative Example 4 465 19 3.6 224 381 Comparative Example 5 463 23 3.7 241 477

[0104] It should be noted that FWHM represents full width at half maximum; B.I. represents blue current efficiency / CIEy; LT95@35J represents the time when the device is continuously lit at a current density of 35 J and the brightness reaches 95% of the initial brightness.

[0105] Comparing Examples 1 to 5, it can be seen that as the thickness of the microcavity layer 111 increases, the formed high-order modes increase accordingly, and the full width at half maximum gradually narrows as the high-order modes of the microcavity layer 112 increase, but the efficiency decreases. Comparing Example 1 and Comparative Example 1, it can be seen that omitting the microcavity layer 112 will cause a significant increase in the full width at half maximum. Comparing Example 1 and Comparative Example 2, it can be seen that the single-layer gradient structure leads to exciton accumulation quenching and a significant decrease in the lifetime. Comparing Example 1 and Comparative Example 3, it can be seen that omitting the TADF sensitizer significantly increases the full width at half maximum of the light-emitting device and slightly decreases the lifetime. Comparing Example 1 and Comparative Example 4, it can be seen that the lifetime of the structure of phosphorescent sensitized TADF decreases significantly, and the possible reason is that excitons stay on TADF itself for a long time, affecting the device lifetime. Comparing Example 1 and Comparative Example 5, it can be seen that when the phosphorescent material is replaced with firpic, the efficiency of the light-emitting device increases slightly, but the lifetime decreases significantly. Thus, it can be seen that the phosphorescent compound provided by the embodiments of the present disclosure is applicable to the light-emitting device structure provided by the embodiments of the present disclosure and has better lifetime, full width at half maximum, and current efficiency.

[0106] Based on the same inventive concept, the embodiments of the present disclosure provide a phosphorescent compound, and the phosphorescent compound includes a structural general formula as shown in Formula (Ⅰ):

[0107]

[0108] Among them, each A1 is independently selected from any one of a substituted or unsubstituted C5-C60 carbocyclic group and a substituted or unsubstituted C1-C60 heterocyclic group; the heteroatoms in the heterocyclic group are selected from one or more of O, S, and N;

[0109] B 1 is selected from any one of H, a halogen, a substituted or unsubstituted C1-C6 alkyl group, and a substituted or unsubstituted C1-C6 alkoxy group;

[0110] R 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R 8 and R 9 are each independently selected from any one of hydrogen, deuterium, a halogen group, an alkyl group, a heteroalkyl group, an aralkyl group, an alkoxy group, an aryloxy group, an amino group, a silyl group, an alkenyl group, a heteroalkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an acyl group, a carbonyl group, a carboxylic acid, an ester, a nitrile, an isonitrile, a thio group, a sulfinyl group, a sulfonyl group, and a phosphino group.

[0111] In some embodiments, the phosphorescent compound includes a structural general formula as shown in Formula (II):

[0112]

[0113] The B 2 is selected from any one of hydrogen, deuterium, a halogen group, an alkyl group (such as a C1-C10 alkyl group), a heteroalkyl group, an aralkyl group (such as a C6-C20 aralkyl group, a C6-C15 aralkyl group), an alkoxy group, an aryloxy group, an amino group, a silyl group, an alkenyl group, a heteroalkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an acyl group, a carbonyl group, a carboxylic acid, an ester, a nitrile, an isonitrile, a thio group, a sulfinyl group, a sulfonyl group, a heterocyclic group, and a phosphino group.

[0114] In some embodiments, the C1-C60 heterocyclic group includes

[0115] any one of.

[0116] In some embodiments, the heterocyclic group is

[0117] In some embodiments, the phosphorescent compound includes at least one of the following compounds;

[0118]

[0119]

[0120] Based on the same inventive concept, embodiments of the present disclosure further provide a light-emitting device. As Figure 1 shown, the light-emitting device 100 includes a substrate 101, a first microcavity structure layer, and a second microcavity structure layer located on a side of the first microcavity structure layer away from the substrate 101; wherein,

[0121] The first microcavity structure layer includes a light-emitting layer 106; the material of the light-emitting layer 106 includes at least a host material, a light-emitting material, and a sensitizer; wherein, the light-emitting material includes a phosphorescent material; the sensitizer includes a thermally activated delayed fluorescence material.

[0122] In some embodiments, the doping ratio of the phosphorescent material is greater than the doping ratio of the thermally activated delayed fluorescence material.

[0123] In some embodiments, the doping ratio of the phosphorescent material is 6% to 8%; and / or the doping ratio of the thermally activated delayed fluorescence material is 0.8% to 1.2%.

[0124] In some embodiments, the phosphorescent material includes a phosphorescent compound; the phosphorescent compound includes a structural general formula such as formula (I):

[0125]

[0126] wherein, each A1 is independently selected from any one of a substituted or unsubstituted C5-C60 carbocyclic group and a substituted or unsubstituted C1-C60 heterocyclic group, such as a benzene ring; the heteroatoms in the heterocyclic group are selected from one or more of O, S, and N;

[0127] B 1 is selected from any one of H, a halogen, a substituted or unsubstituted C1-C6 alkyl group, and a substituted or unsubstituted C1-C6 alkoxy group; here, the halogen can be F, Cl, Br, etc., and the present disclosure does not limit this.

[0128] R 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R 8 and R 9 are each independently selected from any one of hydrogen, deuterium, a halogen group, an alkyl group, a heteroalkyl group, an aralkyl group, an alkoxy group, an aryloxy group, an amino group, a silyl group, an alkenyl group, a heteroalkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an acyl group, a carbonyl group, a carboxylic acid, an ester, a nitrile, an isonitrile, a sulfide group, a sulfinyl group, a sulfonyl group, and a phosphine group.

[0129] In some embodiments, the thermally activated delayed fluorescence material includes v-DABNA.

[0130] In some embodiments, the first microcavity structure layer further includes a hole transport layer 104 and an electron transport layer 108; the host material of the light-emitting layer 106 includes a hole transport type material and an electron transport type material; wherein,

[0131] On the side of the light-emitting layer 106 close to the hole transport layer 104, the content of the hole transport type material is less than that of the electron transport type material;

[0132] On the side of the light-emitting layer 106 close to the electron transport layer 108, the content of the hole transport type material is greater than that of the electron transport type material.

[0133] In some embodiments, the first microcavity structure layer further includes a first electrode (corresponding to the anode 102) and a second electrode (corresponding to the cathode 110) sequentially arranged in a direction away from the substrate; wherein, the light-emitting layer 106 is located between the first electrode and the second electrode.

[0134] In some embodiments, the second microcavity structure layer includes a microcavity layer 111 and a light modulation layer 112 sequentially stacked in a direction away from the substrate.

[0135] In some embodiments, the refractive index of the material of the microcavity layer 111 at 530 nm is greater than 1.7.

[0136] In some embodiments, the material of the microcavity layer 111 includes TCTA.

[0137] In some embodiments, the light-emitting device 100 further includes a cover layer 113; the cover layer 113 is located on the side of the light modulation layer 112 away from the substrate 101 and the refractive index of the material of the cover layer 113 at 530 nm is greater than 1.7.

[0138] In some embodiments, the materials of the second electrode 110 and the light modulation layer 112 are the same, such as a semi-transmissive semi-reflective film.

[0139] Based on the same inventive concept, an embodiment of the present disclosure further provides a display device, including the light-emitting device described in any one of the foregoing.

[0140] Those of ordinary skill in the art should understand that: the discussion of any of the above embodiments is only exemplary, and is not intended to imply that the scope of the present disclosure (including the claims) is limited to these examples; under the idea of the present disclosure, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the embodiments of the present disclosure as described above, and they are not provided in detail for the sake of brevity.

[0141] Embodiments of the present disclosure are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present disclosure shall be included within the protection scope of the present disclosure.

Claims

1. A phosphorescent compound, characterized in that The phosphorescent compound comprises a general structural formula as shown in formula (I): Wherein, A1 is independently selected from any one of a substituted or unsubstituted C5-C60 carbocyclic group and a substituted or unsubstituted C1-C60 heterocyclic group; the heteroatom in the heterocyclic group is selected from one or more of O, S and N; B1 is selected from any one of H, halogen, substituted or unsubstituted C1-C6 alkyl and substituted or unsubstituted C1-C6 alkoxy; R1, R2, R3, R4, R5, R6, R7, R8 and R9 are each independently selected from any one of hydrogen, deuterium, halide, alkyl, heteroalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, thiol, sulfinyl, sulfonyl and phosphino.

2. The phosphorescent compound according to claim 1, characterized in that The phosphorescent compound comprises a general structural formula as shown in formula (II): in, The B2 is selected from any one of hydrogen, deuterium, halide, alkyl, heteroalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, thiol, sulfinyl, sulfonyl, heterocyclic and phosphino.

3. The phosphorescent compound according to claim 1 or 2, characterized in that The C1-C60 heterocyclic group includes Any of; and / or The heterocyclic group is 4. The phosphorescent compound according to claim 1 or 2, characterized in that: The phosphorescent compound includes at least one of the following compounds; 5. A light emitting device, characterized in that: It includes a substrate, a first microcavity structure layer, and a second microcavity structure layer located on a side of the first microcavity structure layer away from the substrate; wherein, The first microcavity structure layer includes a light-emitting layer; the material of the light-emitting layer at least includes a host material, a light-emitting material and a sensitizer; wherein the light-emitting material includes a phosphorescent material; and the sensitizer includes a thermally activated delayed fluorescent material.

6. The light emitting device according to claim 5, characterized in that: The doping ratio of the phosphorescent material is greater than the doping ratio of the thermally activated delayed fluorescent material.

7. The light emitting device according to claim 6, characterized in that: The doping ratio of the phosphorescent material is 6% to 8%; and / or The doping ratio of the thermally activated delayed fluorescent material is 0.8% to 1.2%.

8. The light emitting device according to claim 5, characterized in that: The phosphorescent material includes a phosphorescent compound; the phosphorescent compound includes a general structural formula as shown in formula (I): Wherein, A1 is independently selected from any one of a substituted or unsubstituted C5-C60 carbocyclic group and a substituted or unsubstituted C1-C60 heterocyclic group; the heteroatom in the heterocyclic group is selected from one or more of O, S and N; B1 is selected from any one of H, halogen, substituted or unsubstituted C1-C6 alkyl and substituted or unsubstituted C1-C6 alkoxy; R1, R2, R3, R4, R5, R6, R7, R8 and R9 are each independently selected from any one of hydrogen, deuterium, halide, alkyl, heteroalkyl, aralkyl, alkoxy, aryloxy, amino, silanyl, alkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, isonitrile, thiol, sulfinyl, sulfonyl and phosphino.

9. The light emitting device according to claim 5, characterized in that: The thermally activated delayed fluorescent material includes v-DABNA.

10. The light emitting device according to claim 5, characterized in that: The first microcavity structure layer further includes a hole transport layer and an electron transport layer; The main material of the light-emitting layer includes hole transport material and electron transport material; wherein, On a side of the light-emitting layer close to the hole transport layer, the content of the hole transport material is less than the content of the electron transport material; On a side of the light-emitting layer close to the electron transport layer, the content of the hole transport material is greater than the content of the electron transport material.

11. The light emitting device according to claim 5, characterized in that: The first microcavity structure layer further includes a first electrode and a second electrode sequentially arranged in a direction away from the substrate; wherein the light-emitting layer is located between the first electrode and the second electrode.

12. The light emitting device according to claim 11, characterized in that: The second microcavity structure layer includes a microcavity layer and a dimming layer sequentially arranged in a direction away from the substrate; wherein the second electrode, the microcavity layer and the dimming layer form a second microcavity structure.

13. The light emitting device according to claim 12, characterized in that: The light emitting device emits blue light, and the refractive index of the material of the microcavity layer at 530 nm is greater than 1.

7.

14. The light emitting device according to claim 13, characterized in that: The light emitting device further comprises a covering layer; the covering layer is located on a side of the dimming layer away from the substrate, and a material of the covering layer has a refractive index greater than 1.7 at 530 nm.

15. The light emitting device according to claim 14, characterized in that: The material of the dimming layer and the material of the second electrode are selected from at least one of Mg, Ag, Al, Al-Li, Ca, Mg:In, and Mg:Ag.

16. A display device, characterized in that: A light-emitting device comprising any one of claims 5 to 15.

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