Light emitting device containing carbocation compound

Abstract

The invention relates to a light-emitting device containing a carbocation type compound, and belongs to the technical field of organic electroluminescence. The technical problem that the color purity is poor due to the fact that the light-emitting spectrum of an existing organic light-emitting device is too wide is solved. According to the light-emitting device, a carbocation type compound is adopted as a light-emitting material, a wide-band gap material is added to serve as a main body material, and narrow-band light emitting is achieved. The host material can effectively dilute the exciton concentration of the carbocation type compound, reduce triplet-triplet and triplet-polaron annihilation, and enhance the stability of the device; a TADF material can also be doped as an auxiliary main body material to sensitize a carbocation type compound to emit light, so that the luminous efficiency of the device is improved, and the efficiency roll-off caused by overlong triplet service life under high brightness is reduced; and by doping an auxiliary ionic compound, the conductivity of the light-emitting layer can be improved, and the efficiency of the device can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of organic electroluminescence, and in particular relates to a light-emitting device containing a carbon cation type compound. Background Art

[0002] Organic electroluminescent devices are devices that emit light by being driven by electric current. Their main characteristics come from the organic light-emitting layer, which specifically refers to the technology that organic light-emitting materials emit light by carrier injection and recombination under the drive of electric field. Compared with inorganic semiconductor materials, organic semiconductor materials have the advantages of low cost, flexibility, solution processing and adjustable functions. They have attracted extensive attention from researchers and the business community and have great application potential. At present, the light-emitting layer is composed of a main material and a doped dye, and the dye is mostly selected from traditional fluorescent materials and phosphorescent materials. Traditional fluorescent materials cannot utilize the defects of triplet excitons. Although traditional metal phosphorescent materials achieve 100% energy utilization, metals such as iridium or platinum are precious metals, which are expensive and easily cause environmental pollution, which also limits its large-scale commercial application.

[0003] Thermally activated delayed fluorescence (TADF) materials, compared with traditional fluorescent materials, can achieve reverse intersystem crossing of triplet excitons to singlet states by absorbing ambient heat, and then emit fluorescence from the singlet state, achieving 100% utilization of excitons without the need for heavy metals. However, most current TADF materials also have certain defects, such as poor color purity due to the wide emission spectrum. Summary of the invention

[0004] The present invention aims to solve the technical problem in the prior art that TADF materials used in organic electroluminescent devices have poor color purity due to their overly wide luminescent spectrum, and provides a light-emitting device containing a carbon cation compound.

[0005] In order to solve the above technical problems, the technical solutions of the present invention are as follows:

[0006] A light-emitting device containing a carbon cation type compound comprises a first electrode and a second electrode arranged opposite to each other, an organic material layer is arranged between the first electrode and the second electrode, and the organic material layer comprises a light-emitting layer;

[0007] It is characterized in that

[0008] The light-emitting layer comprises a carbon cation compound and a host material;

[0009] Or the light-emitting layer comprises a carbon cation compound, a host material and a sensitizer material;

[0010] Alternatively, the light-emitting layer contains a carbocationic compound, a host material, and an auxiliary ionic compound;

[0011] Alternatively, the light-emitting layer contains a carbocationic compound, a host material, a sensitizer, and an auxiliary ionic compound;

[0012] The carbocationic compound has a structure represented by general formula (i), (ii), (iii), or (iv):

[0013]

[0014] wherein, X 1 -X 3 independently selects one from O, S, Se, or NR 4 ; R 1 ~R 3 each independently selects from H, D, F, Cl, Br, I, -CN, -NO 2 , -CF 3 , -OH, -SH, -NR 5 R 6 , a linear hydrocarbon group having 1 to 30 carbon atoms, a branched hydrocarbon group having 3 to 30 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, an alkoxy group having 1 to 30 carbon atoms, an alkylthio group having 1 to 30 carbon atoms, an aryl group having 6 to 60 carbon atoms, an aryl ether group having 6 to 60 carbon atoms, a heteroaryl group having 3 to 60 carbon atoms, or a heteroaryl ether group having 3 to 60 carbon atoms;

[0015] wherein, R 4 selects from H, a linear hydrocarbon group having 1 to 30 carbon atoms, a branched hydrocarbon group having 3 to 30 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, an aryl group having 6 to 60 carbon atoms, or a heteroaryl group having 3 to 60 carbon atoms, and the heteroatoms of the heteroaromatic groups independently select from Si, Ge, N, P, O, S, or Se; R 5 , R 6 independently select from H, a linear hydrocarbon group having 1 to 30 carbon atoms, a branched hydrocarbon group having 3 to 30 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, an alkoxy group having 1 to 30 carbon atoms, an alkylthio group having 1 to 30 carbon atoms, and the heteroatoms of the heteroaromatic groups independently select from Si, Ge, N, P, O, S, or Se;

[0016] A 1 - is a monovalent anion, and selects from F - , Cl - , Br - , I - , ClO 4 - , BF 4 - , FeCl 4- , GaCl 4 - , PF 6 - , SbCl 6 - or one of the following monovalent anions:

[0017]

[0018] A 2 - is a monovalent anion selected from -CO 2 - or -SO 3 - ;

[0019] a, b, and c respectively represent the numbers of R 1 , R 2 , R 3 connected to the benzene ring. In formulas (i) and (iii), a, b, and c are selected from any integers between 1 and 3. In formulas (ii) and (iv), a is selected from any integer between 1 and 3, and b and c are selected from any integers between 1 and 4;

[0020] The host material is a compound containing at least one group selected from a carbazolyl group, a dibenzothiophenyl group, a carbazolyl group, a fluorene group, a spirofluorene group, a spirosilfluorene group, and a phosphine oxide group;

[0021] The sensitizer material is selected from thermally activated delayed fluorescence materials containing an electron-donating group and an electron-accepting group; the electron-donating group is selected from at least one of a carbazolyl group, a phenothiazinyl group, a phenoxazinyl group, an indolocarbazolyl group, a diphenylamino group, a triphenylamino group, and an acridinyl group; the electron-accepting group is selected from at least one of a pyridyl group, a pyrazinyl group, a pyrimidinyl group, a triazinyl group, a sulfonyl group, a thiazolyl group, an oxazolyl group, an oxadiazolyl group, a thiadiazolyl group, a triazolyl group, a phenazinyl group, a boron group, a carbonyl group, a cyano group, and an imide group.

[0022] Furthermore, the carbocationic compound is selected from one of the following structures:

[0023]

[0024]

[0025]

[0026]

[0027]

[0028] Furthermore, the host material is selected from one of the following structures:

[0029]

[0030] Furthermore, the electron-donating group of the sensitizer material is selected from at least one of the following groups:

[0031] and / or the electron-accepting group is selected from at least one of the following groups:

[0032]

[0033] Furthermore, the sensitizer material has one of the following structures:

[0034]

[0035] Furthermore, the auxiliary ionic compound is selected from one of the compounds having the following structures:

[0036]

[0037] Furthermore, the organic material layer further includes one or more structures of a hole injection layer, a hole transport layer, an electron blocking layer, an electron transport layer, and an electron injection layer. Preferably, the light-emitting device is sequentially provided with the second electrode, the hole injection layer, the hole transport layer, the electron blocking layer, the light-emitting layer, the electron transport layer, the electron injection layer, and the first electrode from the height direction.

[0038] Furthermore, when the light-emitting layer contains a carbocationic compound and a host material, the mass ratio of the carbocationic compound in the light-emitting layer is 1 wt% - 90 wt%;

[0039] When the light-emitting layer contains a carbocationic compound, a host material, and a sensitizer material, the mass ratio of the carbocationic compound in the light-emitting layer is 1 wt% - 25 wt%, and the mass ratio of the sensitizer material in the light-emitting layer is 5 wt% - 50 wt%;

[0040] When the light-emitting layer contains a carbocationic compound, a host material, and an auxiliary ionic compound, the mass ratio of the carbocationic compound in the light-emitting layer is 1 wt% - 50 wt%, and the mass ratio of the auxiliary ionic compound in the light-emitting layer is 1 wt% - 50 wt%;

[0041] When the light-emitting layer contains a carbocationic compound, a host material, a sensitizer, and an auxiliary ionic compound, the mass ratio of the carbocationic compound in the light-emitting layer is 1 wt% - 50 wt%, the mass ratio of the sensitizer material in the light-emitting layer is 5 wt% - 50 wt%; the mass ratio of the auxiliary ionic compound in the light-emitting layer is 1 wt% - 50 wt%.

[0042] A display device includes the light-emitting device described in the present invention.

[0043] The beneficial effects of the present invention are as follows:

[0044] The light-emitting device of the present invention uses a carbocationic compound as a light-emitting material, and at the same time adds a wide-bandgap material as a host material to achieve narrow-band emission. The host material can effectively dilute the exciton concentration of the carbocationic compound, reduce triplet-triplet (TTA) and triplet-polaron annihilation (TPA), and enhance the stability of the device; it can also sensitize the emission of the carbocationic compound by doping a TADF material as an auxiliary host material, improve the luminous efficiency of the light-emitting device of the present invention, and also reduce the efficiency roll-off caused by the too long triplet lifetime at high brightness; it can also improve the conductivity of the light-emitting layer by doping an auxiliary ionic compound. The carbocationic compound used in the light-emitting layer of the light-emitting device of the present invention does not have obvious intramolecular charge transfer, so it is beneficial to achieve narrow-band emission and improve the color purity of the device. The light-emitting layer prepared by solution processing in the present invention can also overcome the disadvantage of the wide emission spectrum of traditional TADF materials. Description of the Drawings

[0045] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0046] Figure 1 It is a schematic structural diagram of a light-emitting device containing a carbocationic compound of the present invention.

[0047] The reference numerals in the figure are represented as:

[0048] 101 - Substrate, 102 - Anode, 103 - Hole transport region, 104 - Light-emitting layer, 105 - Electron transport region, 106 - Cathode. Specific Embodiments

[0049] The present invention provides a light-emitting device and a display device containing a carbocationic compound. The light-emitting layer of the light-emitting device contains a carbocationic compound and a host material as light-emitting materials, and overcomes the defect of wide spectrum caused by using traditional TADF materials at the present stage by adding a TADF material as a sensitizer and / or an auxiliary ionic compound to assist the device in emitting light. Specifically, the present invention provides a light-emitting device containing a carbocationic compound, including a first electrode and a second electrode arranged opposite to each other, an organic material layer is arranged between the first electrode and the second electrode, and a light-emitting layer is included in the organic material layer; the organic light-emitting layer mainly contains a carbocationic compound and a host material, and a sensitizer material and / or an auxiliary ionic compound can also be added to assist in emitting light. The host material is a wide-bandgap material; the sensitizer material is a thermally activated delayed fluorescence material.

[0050] Among them, the carbocationic compound has a structure represented by general formula (i), (ii), (iii) or (iv):

[0051]

[0052] Among them, X 1 -X 3 is independently selected from one of O, S, Se or NR 4 ; R 1 ~R 3 are each independently selected from H, D, F, Cl, Br, I, -CN, -NO 2 , -CF 3 , -OH, -SH, -NR 5 R 6 , a straight-chain hydrocarbon group with 1 to 30 carbon atoms, a branched-chain hydrocarbon group with 3 to 30 carbon atoms, a cycloalkyl group with 3 to 30 carbon atoms, an alkoxy group with 1 to 30 carbon atoms, an alkylthio group with 1 to 30 carbon atoms, an aryl group with 6 to 60 carbon atoms, an aryl ether group with 6 to 60 carbon atoms, a heteroaryl group with 3 to 60 carbon atoms or a heteroaryl ether group with 3 to 60 carbon atoms;

[0053] Among them, R 4 is selected from H, a straight-chain hydrocarbon group with 1 to 30 carbon atoms, a branched-chain hydrocarbon group with 3 to 30 carbon atoms, a cycloalkyl group with 3 to 30 carbon atoms, an aryl group with 6 to 60 carbon atoms or a heteroaryl group with 3 to 60 carbon atoms, and the heteroatoms of the heteroaromatic groups are independently selected from Si, Ge, N, P, O, S or Se; R 5 , R 6 are independently selected from H, a straight-chain hydrocarbon group with 1 to 30 carbon atoms, a branched-chain hydrocarbon group with 3 to 30 carbon atoms, a cycloalkyl group with 3 to 30 carbon atoms, an alkoxy group with 1 to 30 carbon atoms, an alkylthio group with 1 to 30 carbon atoms, and the heteroatoms of the heteroaromatic groups are independently selected from Si, Ge, N, P, O, S or Se;

[0054] A 1 - is a monovalent anion, selected from F - , Cl - , Br - , I - , ClO 4 - , BF 4 - , FeCl 4 - , GaCl 4 - , PF 6 - , SbCl 6 -or one of the following monovalent anions:

[0055]

[0056] A 2 - is a monovalent anion, selected from but not limited to -CO 2 - or -SO 3 - ;

[0057] a, b, and c respectively represent the numbers of R 1 , R 2 , R 3 connected to the benzene ring. In formulas (i) and (iii), a, b, and c are selected from any integers between 1 and 3. In formulas (ii) and (iv), a is selected from any integer between 1 and 3, and b and c are selected from any integers between 1 and 4.

[0058] Optionally, the carbocationic compound is a compound having one of (M1)-(M163) of the present invention.

[0059] Optionally, the host material is a compound containing at least one group selected from a carbazolyl group, a dibenzothiophenyl group, a carbazolyl group, a fluorenyl group, a spirofluorenyl group, a spirosilylfluorenyl group, and a phosphonyloxy group, and is optionally a compound selected from one of (H1)-(H24).

[0060] Optionally, the sensitizer material is a compound including an electron-donating group and an electron-accepting group; the electron-donating group includes but is not limited to at least one of a carbazolyl group, a phenothiazinyl group, a phenoxazinyl group, an indolocarbazolyl group, a diphenylamino group, a triphenylamino group, and an acridinyl group, and is preferably a group selected from one of (D1)-(D18); the electron-accepting group includes but is not limited to at least one of a pyridyl group, a pyrazinyl group, a pyrimidinyl group, a triazinyl group, a sulfonyl group, a thiazolyl group, an oxazolyl group, an oxadiazolyl group, a thiadiazolyl group, a triazolyl group, a phenazinyl group, a boron group, a carbonyl group, a cyano group, and an imide group, and is preferably a group selected from one of (A1)-(A29), and more preferably a thermally activated delayed fluorescence material having a structure of (T1)-(T29); the auxiliary ionic compound can preferably be selected from one of the compounds having a structure of (I1)-(I12).

[0061] Optionally, when the light-emitting layer contains a carbocationic compound and a host material, the mass ratio of the carbocationic compound in the light-emitting layer is 1 wt% - 90 wt%; when the light-emitting layer contains a carbocationic compound, a host material and a sensitizer material, the mass ratio of the carbocationic compound in the light-emitting layer is 1 wt% - 25 wt%, and the mass ratio of the sensitizer material in the light-emitting layer is 5 wt% - 50 wt%; when the light-emitting layer contains a carbocationic compound, a host material and an auxiliary ionic compound, the mass ratio of the carbocationic compound in the light-emitting layer is 1 wt% - 50 wt%, and the mass ratio of the auxiliary ionic compound in the light-emitting layer is 1 wt% - 50 wt%; when the light-emitting layer contains a carbocationic compound, a host material, a sensitizer and an auxiliary ionic compound, the mass ratio of the carbocationic compound in the light-emitting layer is 1 wt% - 50 wt%, the mass ratio of the sensitizer material in the light-emitting layer is 5 wt% - 50 wt%; the mass ratio of the auxiliary ionic compound in the light-emitting layer is 1 wt% - 50 wt%.

[0062] Furthermore, the organic material layer further includes one or more layers of a hole injection layer, a hole transport layer, an electron blocking layer, an electron transport layer, and an electron injection layer. Preferably, the light-emitting device sequentially includes the second electrode, the hole injection layer, the hole transport layer, the electron blocking layer, the light-emitting layer, the electron transport layer, the electron injection layer, and the first electrode in the height direction.

[0063] The present invention also provides a display device including the light-emitting device described in any one of the above.

[0064] Next, in conjunction with Figure 1 , a structural schematic diagram of the light-emitting device of the present invention will be specifically described. As shown in Figure 1 , the light-emitting device of the present invention includes an anode 102, a hole transport region 103, a light-emitting layer 104, an electron transport region 105, and a cathode 106 sequentially deposited on a substrate 101. Specifically, the substrate 101 can be made of glass or polymer with excellent transparency, high mechanical strength, good thermal stability, and good waterproofness. In addition, thin-film transistors may also be provided on the substrate 101 for display use. The hole transport region 103 and the electron transport region 105 can be selectively used or not used.

[0065] The anode 102 can be formed by sputtering or depositing an anode material on the substrate. Among them, the anode material can be indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), tin dioxide (SnO 2) Oxide transparent conductive materials and any combination thereof; the cathode 106 can be made of metals or alloys such as silver (Ag), aluminum (Al), magnesium (Mg), calcium (Ca), aluminum-lithium (Al-Li), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), etc., and any combination thereof. The organic material layers of the hole transport region 103, the light-emitting layer 104, and the electron transport region 105 can be sequentially prepared on the anode 102 by methods such as vacuum thermal evaporation, spin coating, printing, etc. Among them, the compounds used as organic material layers can be organic small molecules, organic macromolecules, and polymers, as well as combinations thereof.

[0066] For the light-emitting layer 104, traditional TADF materials generally adopt a donor-acceptor structure, which will cause disadvantages such as too wide emission spectrum and low color purity. The light-emitting layer 104 of the light-emitting device of the present invention contains a carbocationic compound with a resonance-type rigid skeleton, which can achieve narrow-band emission; at the same time, the light-emitting layer 104 also contains a host material with a wide band gap, which can dilute the concentration of the carbocationic compound, inhibit and reduce triplet-triplet (TTA) and triplet-polaron annihilation (TPA), and enhance the stability of the device. The light-emitting layer 104 can also be doped with a TADF material as an auxiliary host material to sensitize the emission of the carbocationic compound, improve the emission efficiency of the light-emitting device of the present invention, and also reduce the efficiency roll-off caused by the too long triplet lifetime at high brightness. The carbocationic compound used in the light-emitting layer 104 of the present invention does not have obvious intramolecular charge transfer, so it is beneficial to achieve narrow-band emission and improve the color purity of the device. The present invention can not only achieve narrow-band emission, improve the lifetime of organic electroluminescent devices, and reduce roll-off, but also has very important significance for the commercial application of OLEDs.

[0067] The hole transport region 103, electron transport region 105, and cathode 106 of the invention are introduced. The hole transport region 103 is located between the anode 102 and the light-emitting layer 104. The hole transport region 103 can be a single-layer hole transport layer (HTL), including a single-layer hole transport layer containing only one compound and a single-layer hole transport layer containing multiple compounds. The hole transport region 103 can also include a multi-layer structure of at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL). The materials of the hole transport region 103 (including HIL, THL, and EBL) can be selected from, but are not limited to, phthalocyanine derivatives such as CuPc, conductive polymers, or polymers containing conductive dopants such as poly(phenylene vinylene), polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CAS), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), aromatic amine derivatives, etc. If the material of the hole transport region 103 is an aromatic amine derivative, it can be selected from one or more of the compounds shown in HT1 to HT33, but is not limited to them.

[0068]

[0069] The hole injection layer is located between the anode 102 and the hole transport region 103. The hole injection layer can be a single compound material or a combination of multiple compounds. The hole injection layer can be selected from one or more of the compounds HT1 to HT33, or one or more of the following compounds HI1 - HI3 can be used; one or more of the compounds HT1 to HT33 can also be doped with one or more of the compounds HI1 - HI3.

[0070]

[0071] The electron transport region 105 can be a single-layer electron transport layer (ETL), including a single-layer electron transport layer containing only one compound and a single-layer electron transport layer containing multiple compounds. The electron transport region 105 can also be a multi-layer structure including at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL). In one aspect of the invention, the materials of the electron transport region 105 can be selected from one or more combinations of ET1 to ET33 listed below, but are not limited to them.

[0072]

[0073] The structure of the light-emitting device of the present invention may further include an electron injection layer located between the electron transport region 105 and the cathode 106. The materials of the electron injection layer include, but are not limited to, one or more combinations of the following: LiF, NaCl, CsF, Li 2 O, Cs 2 CO 3 , BaO, Na, Li, and Ca.

[0074] The thicknesses of the above-mentioned layers can adopt the conventional thicknesses of these layers in the art.

[0075] The preparation method of the light-emitting device of the present invention, taking Figure 1 as an example, includes depositing the anode 102, the hole transport region 103, the light-emitting layer 104, the electron transport region 105, and the cathode 106 on the substrate 101 in sequence, and then encapsulating. Among them, when preparing the light-emitting layer 104, a wide-bandgap host material and a carbocationic compound, and a sensitizer material or an auxiliary ionic compound may also be added, and the light-emitting layer 104 is formed by a co-solution processing method.

[0076] Specifically, the preparation method of the light-emitting device of the present invention includes the following steps:

[0077] 1. Ultrasonically clean the glass plate 101 prefabricated with the anode 102 material in a commercial cleaning agent, clean it in deionized water, ultrasonically degrease it in a mixed solvent of acetone / ethanol, bake it until all moisture is removed, and clean it with an ultraviolet lamp and ozone.

[0078] 2. Spin-coat a hole injection layer on the glass plate 101 with the anode 102 material thereon, and perform thermal annealing treatment.

[0079] 3. Vacuum-evaporate the hole transport region 103 on the hole injection layer at a deposition rate of 0.1-0.5 nm / s.

[0080] 4. Spin-coat the light-emitting layer 104 on the hole transport region 103. The light-emitting layer 104 includes a host material and a carbocationic compound, and a sensitizer material or an auxiliary ionic compound may also be added, and the doping ratios of the carbocationic compound, the sensitizer material, and the auxiliary ionic compound in the host material are adjusted.

[0081] 5. Vacuum-evaporate the electron transport region 105 material on the light-emitting layer 104 at a deposition rate of 0.1-0.5 nm / s.

[0082] 6. Vacuum-evaporate LiF or Liq as the electron injection layer on the electron transport region 105 at a rate of 0.1-0.5 nm / s.

[0083] 7. Vacuum-evaporate Al as the cathode 106 of the device on the electron injection layer at a rate of 0.5-1 nm / s.

[0084] The present invention also provides a display device, which includes the electroluminescent device provided above. The display device may specifically be display devices such as OLED and OLEC displays, as well as any product or component with a display function including such display devices, such as a television, a mobile phone, a tablet computer, a digital camera, etc.

[0085] The structure of the electroluminescent device of the present invention will be introduced in detail through specific embodiments below. There is no special limitation on the preparation method, and the preparation methods commonly used in the art can be adopted. The following embodiments are prepared using the preparation method of the light-emitting device in the specific implementation part of the present invention.

[0086] The carbocation-type compounds described in the present invention and the carbocation-type compounds used in the following embodiments are all obtained by referring to the synthesis methods disclosed in the prior art, and the specific preparation processes of the carbocation-type compounds will not be given in the embodiment part of the present invention. For example, the methods in the following documents can be referred to for synthesis:

[0087] Document 1. J. Am. Chem. Soc. 1998, 120, 12255 - 12263, 2,6,10-Tris(dialkylamino)trioxatriang ulenium Ions. Synthesis, Structure, and Properties of Exceptionally Stable Carbenium Ions;

[0088] Document 2. J. Org. Chem. 2010, 75, 6182–6190, Synthesis and Optical Properties of Trioxa triangulenium Dyes with One and Two Peripheral Amino Substituents.

[0089] Example 1

[0090] The device structure of this example is:

[0091] ITO / HI-3(10 nm) / HT1(40 nm) / H2: 5 wt% M6(30 nm) / ET1(30 nm) / LiF(1 nm) / Al(150 nm); On a glass substrate coated with an anode ITO, a 10-nm hole injection layer material HT1 and a 40-nm hole transport layer material HT1 are vacuum-evaporated; A blend solution of a carbocationic compound M6 (5 wt%) and a host material H2 is prepared and spin-coated onto the hole transport layer with a thickness of 30 nm; Then, a 30-nm electron transport layer material ET1 is evaporated on it, a 1-nm electron injection layer LiF is selected, and a 100-nm cathode material aluminum is evaporated to complete the device fabrication.

[0092] Example 2

[0093] Differing from Example 1, the structure of the device in this example is:

[0094] ITO / HI-3(10 nm) / HT1(40 nm) / H2: 5 wt% M9(30 nm) / ET1(15 nm) / LiF(1 nm) / Al(100 nm).

[0095] Example 3

[0096] Differing from Example 1, the structure of the device in this example is:

[0097] ITO / PEDOT:PSS(30 nm) / H16: 35 wt% M45(30 nm) / ET1(15 nm) / LiF(1 nm) / Al(100 nm).

[0098] Example 4

[0099] Differing from Example 1, the structure of the device in this example is:

[0100] ITO / PEDOT:PSS(30 nm) / H16: 40 wt% M60(30 nm) / ET1(15 nm) / LiF(1 nm) / Al(100 nm).

[0101] Example 5

[0102] Differing from Example 1, the structure of the device in this example is:

[0103] ITO / PEDOT:PSS(30 nm) / H16: 10 wt% M66(30 nm) / ET1(15 nm) / LiF(1 nm) / Al(100 nm).

[0104] Example 6

[0105] Different from Example 1, the structure of the device in this example is as follows:

[0106] ITO / PEDOT:PSS(30nm) / HT1(40nm) / H2:25wt%M74(30nm) / ET1(15nm) / LiF(1nm) / Al(100nm).

[0107] Example 7

[0108] Different from Example 1, the structure of the device in this example is as follows:

[0109] ITO / HI-3(10nm) / HT1(40nm) / H2:2wt%M110(30nm) / ET1(15nm) / LiF(1nm) / Al(100nm).

[0110] Example 8

[0111] Different from Example 1, the structure of the device in this example is as follows:

[0112] ITO / HI-3(10nm) / HT1(40nm) / H2:2wt%M122(30nm) / ET1(15nm) / LiF(1nm) / Al(100nm).

[0113] Example 9

[0114] Different from Example 1, the structure of the device in this example is as follows:

[0115] ITO / HI-3(10nm) / HT1(40nm) / H2:2wt%M136(30nm) / ET1(15nm) / LiF(1nm) / Al(100nm).

[0116] Example 10

[0117] Different from Example 1, the structure of the device in this example is as follows:

[0118] ITO / PEDOT:PSS(30nm) / H16:5wt%M45(30nm) / LiF(1nm) / Al(100nm).

[0119] Example 11

[0120] Different from Example 1, the structure of the device in this example is as follows:

[0121] ITO / PEDOT:PSS(30nm) / H16:3wt%M60(30nm) / LiF(1nm) / Al(100nm).

[0122] Example 12

[0123] Different from Example 1, the structure of the device in this example is as follows:

[0124] ITO / PEDOT:PSS(30nm) / H16:15wt%T7:10wt%M66(30nm) / ET1(15nm) / LiF(1nm) / Al(100nm).

[0125] Example 13

[0126] Different from Example 1, the structure of the device in this example is as follows:

[0127] ITO / PEDOT:PSS(30nm) / HT1(30nm) / H2:15wt%T7:25wt%M74(30nm) / ET1(15nm) / LiF(1nm) / Al(100nm).

[0128] Example 14

[0129] Different from Example 1, the structure of the device in this example is as follows:

[0130] ITO / HI-3(10nm) / HT1(30nm) / H2:10wt%T9:2wt%M110(30nm) / ET1(15nm) / LiF(1nm) / Al(100nm).

[0131] Example 15

[0132] Different from Example 1, the structure of the device in this example is as follows:

[0133] ITO / HI-3(10nm) / HT1(30nm) / H2:8wt%T9:2wt%M122(30nm) / ET1(15nm) / LiF(1nm) / Al(100nm).

[0134] Example 16

[0135] Different from Example 1, the structure of the device in this example is as follows:

[0136] ITO / HI-3(10nm) / HT1(40nm) / H2:12wt%T10:2wt%M136(30nm) / ET1(15nm) / LiF(1nm) / Al(100nm).

[0137] Example 17

[0138] ITO / PEDOT:PSS (30 nm) / H2: 10 wt% M45: 1 wt% I9 (30 nm) / Al (100 nm).

[0139] Example 18

[0140] Differing from Example 1, the structure of the device in this example is:

[0141] ITO / PEDOT:PSS (30 nm) / H16: 10 wt% M60: 5 wt% I9 (30 nm) / Al (100 nm).

[0142] Example 19

[0143] Differing from Example 1, the structure of the device in this example is:

[0144] ITO / PEDOT:PSS (30 nm) / H2: 10 wt% T9: 10 wt% M45: 1 wt% I9 (30 nm) / Al (100 nm).

[0145] Example 20

[0146] Differing from Example 1, the structure of the device in this example is:

[0147] ITO / PEDOT:PSS (30 nm) / H16: 15 wt% T9: 10 wt% M60: 5 wt% I9 (30 nm) / Al (100 nm).

[0148] Test Example: The following performance measurements were carried out on the organic electroluminescent devices prepared by the above process (Examples 1 - 20, where the devices prepared in Examples 1 - 16 are OLED devices and Examples 17 - 20 are OLEC devices): The characteristics such as current, voltage, luminance, emission spectrum, current efficiency, and external quantum efficiency of the prepared devices were synchronously measured using a PR655 spectral scanning luminance meter and a Keithley K2450 digital source meter system.

[0149] The test results are shown in Table 1.

[0150] Table 1

[0151]

[0152]

[0153] In summary, the light-emitting device of the present invention uses a carbocationic compound as a light-emitting material, and at the same time adds a wide-bandgap material as a host material to achieve narrow-band emission. The host material can effectively dilute the exciton concentration of the carbocationic compound, reduce triplet-triplet (TTA) and triplet-polaron annihilation (TPA), and enhance the stability of the device; it can also sensitize the emission of the carbocationic compound by doping a TADF material as an auxiliary host material, improve the luminous efficiency of the light-emitting device of the present invention, and also reduce the efficiency roll-off caused by the too long triplet lifetime at high brightness; it can also improve the conductivity of the light-emitting layer by doping an auxiliary ionic compound, and finally improve the device performance. The carbocationic compound used in the light-emitting layer of the light-emitting device of the present invention does not have obvious intramolecular charge transfer, so it is beneficial to achieve narrow-band emission and improve the color purity of the device. The light-emitting layer prepared by solution processing in the present invention can also overcome the disadvantage of the wide emission spectrum of traditional TADF materials.

[0154] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. A light-emitting device containing a carbocationic compound, comprising a first electrode and a second electrode arranged opposite to each other, an organic material layer is arranged between the first electrode and the second electrode, and a light-emitting layer is included in the organic material layer; Characterized in that, the light-emitting layer contains a carbocationic compound and a host material; or the light-emitting layer contains a carbocationic compound, a host material and a sensitizer material; or the light-emitting layer contains a carbocationic compound, a host material and an auxiliary ionic compound; or the light-emitting layer contains a carbocationic compound, a host material, a sensitizer material and an auxiliary ionic compound; the carbocationic compound has a structure shown by general formula (i), (ii), (iii) or (iv): Among them, X 1 -X 3 is independently selected from one of O, S, Se or NR 4 ; R 1 ~R 3 are each independently selected from H, D, F, Cl, Br, I, -CN, -NO 2 , -CF 3 , -OH, -SH, -NR 5 R 6 , a linear hydrocarbon group having 1 to 30 carbon atoms, a branched hydrocarbon group having 3 to 30 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, an alkoxy group having 1 to 30 carbon atoms, an alkylthio group having 1 to 30 carbon atoms, an aryl group having 6 to 60 carbon atoms, an aryl ether group having 6 to 60 carbon atoms, a heteroaryl group having 3 to 60 carbon atoms or a heteroaryl ether group having 3 to 60 carbon atoms; Among them, R 4 is selected from H, a linear hydrocarbon group having 1 to 30 carbon atoms, a branched hydrocarbon group having 3 to 30 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, an aryl group having 6 to 60 carbon atoms, or a heteroaryl group having 3 to 60 carbon atoms, and the heteroatoms of the heteroaromatic groups are independently selected from Si, Ge, N, P, O, S or Se; R 5 , R 6 are independently selected from H, a linear hydrocarbon group having 1 to 30 carbon atoms, a branched hydrocarbon group having 3 to 30 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, an alkoxy group having 1 to 30 carbon atoms, an alkylthio group having 1 to 30 carbon atoms, and the heteroatoms of the heteroaromatic groups are independently selected from Si, Ge, N, P, O, S or Se; A 1 - is a monovalent anion selected from F - , Cl - , Br - , I - , ClO 4 - , BF 4 - , FeCl 4 - , GaCl 4 - , PF 6 - , SbCl 6 - or one of the following monovalent anions: A 2 - is a monovalent anion selected from -CO 2 - or -SO 3 - ; a, b, and c respectively represent the number of R 1 , R 2 , R 3 , and in formulas (i) and (iii), a, b, and c are selected from any integer between 1 and 3, and in formulas (ii) and (iv), a is selected from any integer between 1 and 3, and b and c are selected from any integer between 1 and 4; the host material is a compound containing at least one group among a carbazolyl group, a dibenzothiophenyl group, a carbazolyl group, a fluorenyl group, a spirofluorene group, a spirosilfluorene group, a phosphine oxide group; the sensitizer material is selected from thermally activated delayed fluorescence materials containing an electron-donating group and an electron-accepting group; the electron-donating group is selected from at least one of a carbazolyl group, a phenothiazinyl group, a phenoxazinyl group, an indolocarbazolyl group, a diphenylamino group, a triphenylamino group, an acridinyl group; the electron-accepting group is selected from at least one of a pyridyl group, a pyrazinyl group, a pyrimidinyl group, a triazinyl group, a sulfonyl group, a thiazolyl group, an oxazolyl group, an oxadiazolyl group, a thiadiazolyl group, a triazolyl group, a phenazinyl group, a boron group, a carbonyl group, a cyano group, an imide group.

2. The light-emitting device according to claim 1, Characterized in that, the carbocationic compound is selected from one of the following structures:

3. The light-emitting device according to claim 1, Characterized in that, the host material is selected from one of the following structures:

4. The light-emitting device according to claim 1, Characterized in that, the electron-donating group of the sensitizer material is selected from at least one of the following groups: and / or the electron-accepting group is selected from at least one of the following groups:

5. The light-emitting device according to claim 1, Characterized in that, the sensitizer material has one of the following structures:

6. The light-emitting device according to claim 1, Characterized in that, the auxiliary ionic compound is selected from one of the compounds with the following structures:

7. The light-emitting device according to claim 1, Characterized in that, the organic material layer further includes one or more structures of a hole injection layer, a hole transport layer, an electron blocking layer, an electron transport layer and an electron injection layer.

8. The light-emitting device according to claim 1, Characterized in that, when the light-emitting layer contains a carbocationic compound and a host material, the mass ratio of the carbocationic compound in the light-emitting layer is 1wt% - 90wt%; when the light-emitting layer contains a carbocationic compound, a host material and a sensitizer material, the mass ratio of the carbocationic compound in the light-emitting layer is 1wt% - 25wt%, and the mass ratio of the sensitizer material in the light-emitting layer is 5wt% - 50wt%; When the light-emitting layer contains a carbocationic compound, a host material, and an auxiliary ionic compound, the mass ratio of the carbocationic compound in the light-emitting layer is 1 wt% - 50 wt%, and the mass ratio of the auxiliary ionic compound in the light-emitting layer is 1 wt% - 50 wt%. When the light-emitting layer contains a carbocationic compound, a host material, a sensitizer, and an auxiliary ionic compound, the mass ratio of the carbocationic compound in the light-emitting layer is 1 wt% - 50 wt%, the mass ratio of the sensitizer material in the light-emitting layer is 5 wt% - 50 wt%; the mass ratio of the auxiliary ionic compound in the light-emitting layer is 1 wt% - 50 wt%.

9. A display device Characterized in that It includes the light-emitting device according to any one of claims 1-8.

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