A deep blue light OLED device and preparation method thereof

Abstract

The present invention relates to the field of organic light-emitting semiconductor technology, and provides a deep blue light OLED device, comprising a substrate, an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer and a cathode arranged in sequence; the light-emitting layer comprises three JBD‑1 layers and TCTA:TPBi layers spaced between the JBD‑1 layers. The present invention provides a TCTA:TPBi layer in the light-emitting layer as an isolation layer for the deep blue light JBD‑1 layer, and the isolation layer can provide a good electron transmission channel and balance the carrier flow in the emission layer, thereby improving the electronic performance of the deep blue light OLED device. Experimental results show that the maximum current efficiency of the deep blue light OLED device provided by the present invention can reach 15.8 cdA ‑1 , Maximum power efficiency can reach 10.8lmW ‑1 And the maximum external quantum efficiency can reach 6.8%.

Description

Technical Field

[0001] The present invention relates to the technical field of organic light-emitting semiconductors, and in particular to a deep blue light OLED device and a preparation method thereof. Background Art

[0002] OLED is a current-type organic light-emitting device, and its structure consists of a substrate, an anode, a hole injection layer (HIL), a hole transport layer (HTL), an emitting layer (EML), an electron transport layer (ETL) and a cathode arranged in sequence. When the emitting layer contains a JBD-1 (4,9-Diisopropyl-N,N,N',N'-tetrakis-(4-methyl-biphenyl-3-yl)-pyrene-1,6-diamine Chinese name 4,9-diisopropyl-N,N,N,N-tetrakis-(4-methyl-biphenyl-3-yl)-1.6-diaminopyrene) layer, the OLED device emits deep blue light.

[0003] In the prior art, specific organic substances are usually doped in the light-emitting layer to improve the electron transmission rate, thereby improving the electrical performance of deep blue OLED devices, such as maximum current efficiency, maximum power efficiency, and maximum external quantum efficiency. How to achieve the above-mentioned improvement of electrical performance of deep blue OLED devices without doping has become a technical difficulty that needs to be solved in this field. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a substrate, an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer and a cathode arranged in sequence;

[0005] The light-emitting layer includes three JBD-1 layers and a TCTA:TPBi layer spaced between the JBD-1 layers.

[0006] Preferably, the hole injection layer is made of NPB:MoO x , the thickness of the hole injection layer is 40 nm.

[0007] Preferably, the material of the hole transport layer is TCTA, and the thickness of the hole transport layer is 10 nm.

[0008] Preferably, the thickness of the TCTA:TPBi layer is 5 nm.

[0009] Preferably, the JBD-1 layer is doped or undoped with Ga(pyimd)3.

[0010] Preferably, the JBD-1 layer is not doped with Ga(pyimd)3, and the thickness of the JBD-1 layer is 0.2 nm.

[0011] Preferably, the JBD-1 layer is doped with Ga(pyimd)3, the mass of JBD-1 in the JBD-1 layer is 20% of the total mass of JBD-1 and Ga(pyimd)3, and the thickness of the JBD-1 layer is 1nm; or, the mass of JBD-1 in the JBD-1 layer is 40% of the total mass of JBD-1 and Ga(pyimd)3, and the thickness of the JBD-1 layer is 0.5nm.

[0012] Preferably, the material of the electron transport layer is TPBi, and the thickness of the electron transport layer is 40 nm.

[0013] Preferably, the electron injection layer is made of Liq, and the thickness of the electron injection layer is 1 nm.

[0014] The present invention provides a method for preparing the deep blue light OLED device described in the above scheme, comprising: sequentially evaporating an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer and a cathode on a substrate.

[0015] The present invention provides a deep blue light OLED device. By setting a TCTA:TPBi layer in the light-emitting layer as an isolation layer for the deep blue light JBD-1 layer, the isolation layer can provide a good electron transmission channel and balance the carrier flow in the emission layer, thereby improving the electronic performance of the deep blue light OLED device. Experimental results show that the maximum current efficiency of the deep blue light OLED device provided by the present invention can reach 15.8cdA -1 , Maximum power efficiency can reach 10.8lmW -1 And the maximum external quantum efficiency can reach 6.8%. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The overall structure of the deep blue light OLED device provided by the present invention;

[0017] Figure 2 The EML layer of the device A1 provided in Comparative Example 1 of the present invention;

[0018] Figure 3 The EML layer of the device A2 provided in Example 1 of the present invention;

[0019] Figure 4 The EML layer of the device B1 provided in Example 2 of the present invention;

[0020] Figure 5 This is the EML layer of the device B2 provided in Example 3 of the present invention. DETAILED DESCRIPTION

[0021] The present invention provides a deep blue light OLED device, comprising a substrate, an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer and a cathode arranged in sequence; the light-emitting layer comprises three JBD-1 layers and a TCTA:TPBi layer spaced between the JBD-1 layers.

[0022] In the present invention, the deep blue light OLED device includes a substrate. In the present invention, the material of the substrate is preferably glass. The present invention has no special provisions on the thickness of the substrate, and it can be selected according to actual needs. The present invention has no special provisions on the source of the glass, and commercial products well known to those skilled in the art can be used. In the present invention, the substrate serves as a support for the deep blue light OLED device.

[0023] In the present invention, the deep blue light OLED device includes an anode disposed on the upper surface of the substrate. In the present invention, the material of the anode is preferably ITO. In the present invention, the thickness of the anode is preferably 150nm. The present invention has no special limitation on the source of the ITO, and commercially available products known to those skilled in the art can be used.

[0024] In the present invention, the deep blue OLED device further comprises a hole injection layer disposed on the upper surface of the anode. In the present invention, the material of the hole injection layer is preferably NPB and MoO x In the present invention, NPB represents N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine. In the present invention, MoO x Represents molybdenum oxide. In the embodiment of the present invention, the MoO x Preferably, MoO3. In the present invention, the MoO x The amount of substance is preferably NPB and MoO x The present invention relates to the NPB and MoO x The source of is not particularly limited, and commercial products known to those skilled in the art can be used. In the present invention, the thickness of the hole injection layer is preferably 40 nm. x As a hole injection layer, the thickness of the hole injection layer is limited to 40nm, which increases the conductivity of the hole injection layer and reduces the hole injection barrier, thereby improving the electronic performance of the deep blue light OLED device.

[0025] In the present invention, the deep blue OLED device further comprises a hole transport layer disposed on the upper surface of the hole injection layer. In the present invention, the material of the hole transport layer is preferably TCTA. In the present invention, the TCTA represents 4,4',4"-tri(carbazole-9-yl)triphenylamine. In the present invention, the thickness of the hole transport layer is preferably 10 nm. In the present invention, TCTA is selected as the hole transport layer, and NPB and MoO x When used in conjunction with a hole injection layer, hole injection can be enhanced, thereby improving the electronic performance of deep blue light OLED devices.

[0026] In the present invention, the deep blue light OLED device further comprises a light-emitting layer disposed on the upper surface of the hole transport layer. In the present invention, the light-emitting layer comprises three JBD-1 layers and TCTA:TPBi layers spaced between the JBD-1 layers. In the present invention, the TPBi represents 1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl. In the present invention, the JBD-1 represents 4,9-diisopropyl-N,N,N,N-tetrakis(4-methyl-biphenyl-3-yl)-1.6-diaminopyrene, whose English name is 4,9-Diisopropyl-N,N,N',N'-tetrakis-(4-methyl-biphenyl-3-yl)-pyrene-1,6-diamine. The present invention provides a TCTA:TPBi layer in the light-emitting layer as an isolation layer for the deep blue light JBD-1 layer. The isolation layer can provide a good electron transmission channel and balance the carrier flow in the emission layer, thereby improving the electronic performance of the deep blue light OLED device.

[0027] In the present invention, the thickness of each TCTA:TPBi layer is preferably 5 nm. The present invention optimizes the electronic performance of the deep blue OLED device by limiting the thickness of the TCTA:TPBi layer to 5 nm.

[0028] In the present invention, the JBD-1 layer is preferably doped or undoped with Ga(pyimd)3. In the present invention, the Ga(pyimd)3 represents tris[2-(2-pyridyl)imidazole]gallium(III).

[0029] In the present invention, when Ga(pyimd)3 is not doped in the JBD-1 layer, the thickness of each JBD-1 layer is preferably 0.2nm. In the present invention, when Ga(pyimd)3 is doped in the JBD-1 layer, the mass of JBD-1 in the JBD-1 layer is 20% of the total mass of JBD-1 and Ga(pyimd)3, and the thickness of each JBD-1 layer is preferably 1nm; or, the mass of JBD-1 in the JBD-1 layer is 40% of the total mass of JBD-1 and Ga(pyimd)3, and the thickness of each JBD-1 layer is preferably 0.5nm. In the present invention, whether Ga(pyimd)3 is doped in the JBD-1 layer or not, by setting a TCTA:TPBi layer in the light-emitting layer as an isolation layer of the deep blue light JBD-1 layer, the isolation layer can provide a good electron transmission channel, thereby balancing the carrier flow in the emission layer, thereby achieving the maximum current efficiency, maximum power efficiency and maximum external quantum efficiency of the obtained deep blue light OLED device compared to the deep blue light OLED device without an isolation layer.

[0030] In the present invention, the deep blue light OLED device further comprises an electron transport layer disposed on the upper surface of the light emitting layer. In the present invention, the material of the electron transport layer is preferably TPBi. In the present invention, the TPBi represents 1,3,5-tri(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl. In the present invention, the thickness of the electron transport layer is 40nm. The present invention does not specifically limit the source of the TPBi, and commercially available products familiar to those skilled in the art may be used. The present invention selects TPBi as the electron transport layer, limits its thickness to the above range, and cooperates with the selection of materials for other layers and the thickness limitation, so that the electronic performance of the obtained deep blue light OLED device is better.

[0031] In the present invention, the deep blue light OLED device further comprises an electron injection layer disposed on the upper surface of the electron transport layer. In the present invention, the material of the electron injection layer is preferably Liq. In the present invention, the Liq represents 8-hydroxyquinoline-lithium. In the present invention, the thickness of the electron injection layer is preferably 1 nm. The present invention selects Liq as the injection layer and limits its thickness to the above range, and cooperates with the selection of materials of other layers and the thickness limit, so that the electronic performance of the obtained deep blue light OLED device is better.

[0032] In the present invention, the deep blue light OLED device further comprises a cathode disposed on the upper surface of the electron injection layer. In the present invention, the cathode is preferably aluminum. In the present invention, the thickness of the cathode is preferably 120 nm. The present invention selects aluminum as the cathode and limits its thickness to the above range, and cooperates with the selection of other layer materials and thickness limits, so that the electronic performance of the obtained deep blue light OLED device is better.

[0033] The present invention provides a deep blue light OLED device. By setting a TCTA:TPBi layer in the light-emitting layer as an isolation layer for the deep blue light JBD-1 layer, the isolation layer can provide a good electron transmission channel and balance the carrier flow in the emission layer, thereby improving the electronic performance of the deep blue light OLED device. Experimental results show that the maximum current efficiency of the deep blue light OLED device provided by the present invention can reach 15.8cdA -1 , Maximum power efficiency can reach 10.8lmW -1 And the maximum external quantum efficiency can reach 6.8%.

[0034] The present invention also provides a method for preparing the deep blue light OLED device described in the above scheme, comprising: sequentially evaporating an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer and a cathode on a substrate. The present invention has no special provisions for the evaporation method of the anode, hole injection layer, hole transport layer, light emitting layer, electron transport layer, electron injection layer and cathode. The evaporation method of OLED devices well known to those skilled in the art is adopted to sequentially evaporating an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer and a cathode on a substrate.

[0035] The preparation method provided by the invention has simple process, strong operability and broad application prospects.

[0036] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

[0037] The overall structure of the deep blue light OLED device provided by the present invention is: Glass (0.7 mm) / ITO (150 nm ) / NPB:15%MoO X (40nm) / NPB(10nm) / TCTA(10nm) / EML / TPBi(40nm) / Liq(1nm) / Al(120nm), the above structure is attached Figure 1 , structural design of the EML light-emitting layer.

[0038] Example 1

[0039] Device A2 structure:

[0040] Glass (0.7mm) / ITO (150nm) / NPB:15%MoO3 (40nm) / NPB (10nm) / TCTA (10nm) / JBD-1 (0.2nm) / TCTA:TPBi (1:1) (5nm) / JBD-1 (0.2nm) / TCTA:TPBi (1:1) (5nm) / JBD-1 (0.2nm) / TPBi (40nm) / Liq (1nm) / Al (120nm). The EML layer structure of device A2 is shown in the attached figure. Figure 3 .

[0041] Preparation method: ITO, NPB:15% MoO3, NPB, TCTA, JBD-1, TCTA:TPBi (1:1), JBD-1, TCTA:TPBi (1:1), JBD-1, TPBi, Liq and Al are sequentially deposited on a glass substrate to obtain a deep blue OLED device A2. NPB:15% MoO3 refers to a vapor deposition material obtained by mixing NPB and MoO3, wherein the amount of MoO3 is NPB and MoO x 15% of the total mass; TCTA:TPBi (1:1) represents the evaporation material obtained by mixing TCTA:TPBi, wherein the mass ratio of TCTA and TPBi is 1:1; the thickness of the evaporation layer containing NPB and 15% MoO3 is controlled to be 40nm; the thickness of the NPB evaporation layer is 10nm; the thickness of the TCTA evaporation layer is 10nm; the thickness of the JBD-1 evaporation layer is 0.2nm; the thickness of the evaporation layer containing TCTA and TPBi is 5nm; the thickness of the TPBi evaporation layer is 40nm; the thickness of the Liq evaporation layer is 1nm; and the thickness of the Al evaporation layer is 120nm. The electroluminescent performance test results of the obtained device A2 are shown in Table 1.

[0042] Example 2

[0043] Device B1 structure:

[0044] Glass(0.7mm) / ITO(150nm) / NPB:15%MoO3(40nm) / NPB(10nm) / TCTA(10nm) / Ga(pyimd)3:20wt%JBD-1(1nm) / TCTA:TPBi(1:1)(5n m) / Ga(pyimd)3:20wt%JBD-1(1nm) / TCTA:TPBi(1:1)(5nm) / Ga(pyimd)3:20wt%JBD-1(1nm) / TPBi(40nm) / Liq(1nm) / Al(120nm).

[0045] The EML layer structure of device B1 is attached. Figure 4 .

[0046] Preparation method: ITO, NPB: 15% MoO3, NPB, TCTA, Ga(pyimd)3: 20wt% JBD-1, TCTA: TPBi (1: 1), Ga(pyimd)3: 20wt% JBD-1, TCTA: TPBi (1: 1), Ga(pyimd)3: 20wt% JBD-1, TPBi, Liq and Al are sequentially deposited on a glass substrate to obtain a deep blue light OLED device B1. Wherein NPB: 15% MoO3 represents a vapor deposition material obtained by mixing NPB and MoO3, wherein the amount of MoO3 is NPB and MoO x 15% of the total mass; Ga(pyimd)3:20wt% JBD-1 represents the evaporation material obtained by mixing Ga(pyimd)3 and JBD-1, wherein the mass of JBD-1 is 20% of the total mass of Ga(pyimd)3 and JBD-1; TCTA:TPBi(1:1) represents the evaporation material obtained by mixing TCTA:TPBi, wherein the mass ratio of TCTA and TPBi is 1:1; the thickness of the evaporation layer containing NPB and 15% MoO3 is controlled to be 40nm; the thickness of the NPB evaporation layer is 10nm; the thickness of the TCTA evaporation layer is 10nm; the thickness of the evaporation layer containing Ga(pyimd)3 and JBD-1 is 1nm; the thickness of the evaporation layer containing TCTA and TPBi is 5nm; the thickness of the TPBi evaporation layer is 40nm; the thickness of the Liq evaporation layer is 1nm; the thickness of the Al evaporation layer is 120nm. The electroluminescent performance test results of the obtained device B1 are shown in Table 1.

[0047] Example 3

[0048] Device B2 structure:

[0049] Glass (0.7mm) / ITO (150nm) / NPB: 15% MoO3 (40nm) / NPB (10nm) / TCTA (10nm) / Ga (pyimd) 3: 40wt% JBD-1 (0.5nm) / TCTA: TPBi (1:1) (5nm) / Ga (pyimd) 3: 40wt% JBD-1 (0.5nm) / TCTA: TPBi (1:1) (5nm) / Ga (pyimd) 3: 40wt% JBD-1 (0.5nm) / TPBi (40nm) / Liq (1nm) / Al (120nm). The EML layer structure of device B2 is shown in the attached figure. Figure 5 .

[0050] Preparation method: ITO, NPB: 15% MoO3, NPB, TCTA, Ga(pyimd)3: 40wt% JBD-1, TCTA: TPBi (1: 1), Ga(pyimd)3: 40wt% JBD-1, TCTA: TPBi (1: 1), Ga(pyimd)3: 40wt% JBD-1, TPBi, Liq and Al are sequentially deposited on a glass substrate to obtain a deep blue light OLED device B2. Wherein NPB: 15% MoO3 represents a vapor deposition material obtained by mixing NPB and MoO3, wherein the amount of MoO3 is NPB and MoO x 15% of the total mass; Ga(pyimd)3:40wt% JBD-1 represents the evaporation material obtained by mixing Ga(pyimd)3 and JBD-1, wherein the mass of JBD-1 is 40% of the total mass of Ga(pyimd)3 and JBD-1; TCTA:TPBi(1:1) represents the evaporation material obtained by mixing TCTA:TPBi, wherein the mass ratio of TCTA and TPBi is 1:1; the thickness of the evaporation layer containing NPB and 15% MoO3 is controlled to be 40nm; the thickness of the NPB evaporation layer is 10nm; the thickness of the TCTA evaporation layer is 10nm; the thickness of the evaporation layer containing Ga(pyimd)3 and JBD-1 is 0.5nm; the thickness of the evaporation layer containing TCTA and TPBi is 5nm; the thickness of the TPBi evaporation layer is 40nm; the thickness of the Liq evaporation layer is 1nm; the thickness of the Al evaporation layer is 120nm. The electroluminescent performance test results of the obtained device B2 are shown in Table 1.

[0051] Comparative Example 1

[0052] Device A1 structure:

[0053] Glass (0.7mm) / ITO (150nm) / NPB: 15% MoO3 (40nm) / NPB (10nm) / TCTA (10nm) / JBD-1 (0.2nm) / TPBi (40nm) / Liq (1nm) / Al (120nm). The EML layer structure of device A1 is shown in the attached figure. Figure 2 .

[0054] Preparation method: ITO, NPB:15% MoO3, NPB, TCTA, JBD-1, TPBi, Liq and Al are sequentially deposited on a glass substrate to obtain a deep blue OLED device. NPB:15% MoO3 refers to a material obtained by mixing NPB and MoO3, wherein the amount of MoO3 is the amount of NPB and MoO xThe total mass is 15%; the thickness of the evaporated layer containing NPB and 15% MoO3 is controlled to be 40nm; the thickness of the evaporated layer of NPB is 10nm; the thickness of the evaporated layer of TCTA is 10nm; the thickness of the evaporated layer of JBD-1 is 0.2nm; the thickness of the evaporated layer of TPBi is 40nm; the thickness of the evaporated layer of Liq is 1nm; the thickness of the evaporated layer of Al is 120nm. The electroluminescent performance test results of the obtained device A1 are shown in Table 1.

[0055] Table 1 Electroluminescent performance test results of deep blue OLED devices prepared in Examples 1 to 3 and Comparative Example 1

[0056]

[0057] Device a) Represents different device structures; Thickness b) Represents the thickness of the emission layer; Dopant conc. c) represents the doping rate of the guest material JBD-1 in the emitter; V on d) Represents a brightness of 1cdm -2 Working voltage at e) Represents maximum brightness; CE f) Represents the maximum current efficiency; PE g) Stands for maximum power efficiency; EQE h) Stands for maximum external quantum efficiency; EL i) Represents the EL emission wavelength at maximum intensity.

[0058] It can be seen from Table 1 that in device A2, the mixed TCTA:TPBi (1:1) is inserted into the multi-UEML structure as a spacer layer, and the high exciton concentration at the TCTA / TPBi interface leads to severe annihilation, which is manifested as a significant reduction in the efficiency and brightness of device A1. However, in the A2 device, the multi-UEML structure with the isolation layer is located at the emitter interface of the exciton concentration, resulting in the accumulation of low-concentration excitons with increasing current density, while the quenching of radiative excitons is negligible. When Ga(Pyimd)3 is doped in JBD-1, the thicker the layer containing Ga(Pyimd)3 and JBD-1, the higher the luminescence brightness and the larger the injection current density; this indicates that the thickness of the emission layer and the doping rate have a significant effect on the charge transport characteristics of the device; if the thickness of JBD-1 is reduced, the excess luminescent sites will become trap states of excitons, so carrier quenching also plays a dominant role in the emission mechanism. By comparing with device A1, it can be seen that regardless of whether Ga(pyimd)3 is doped in the JBD-1 layer, by setting a TCTA:TPBi layer in the light-emitting layer as an isolation layer for the deep blue light JBD-1 layer, the isolation layer can provide a good electron transmission channel, thereby balancing the carrier flow in the emission layer, thereby achieving the maximum current efficiency, maximum power efficiency and maximum external quantum efficiency of the obtained deep blue light OLED device compared to the deep blue light OLED device without an isolation layer.

[0059] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A deep blue light OLED device, comprising a substrate, an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer and a cathode arranged in sequence; The light-emitting layer includes three JBD-1 layers and TCTA:TPBi layers spaced between the JBD-1 layers, the thickness of each TCTA:TPBi layer is 5 nm; the mass ratio of TCTA to TPBi is 1:1; The substrate is made of glass; The material of the anode is ITO, and the thickness of the anode is 150nm; The material of the hole injection layer is NPB:MoO x The thickness of the hole injection layer is 40 nm, and the MoO x The amount of substance for NPB and MoO x 15% of the total mass; The material of the hole transport layer is TCTA, and the thickness of the hole transport layer is 10 nm; The material of the electron transport layer is TPBi, and the thickness of the electron transport layer is 40 nm; The material of the electron injection layer is Liq, and the thickness of the electron injection layer is 1 nm; The cathode is aluminum, and the thickness of the cathode is 120 nm.

2. The deep blue light OLED device according to claim 1, characterized in that: The JBD-1 layer is doped or undoped with Ga(pyimd)3.

3. The deep blue OLED device according to claim 2, characterized in that: The JBD-1 layer is not doped with Ga(pyimd)3, and the thickness of the JBD-1 layer is 0.2 nm.

4. The deep blue light OLED device according to claim 2, characterized in that: The JBD-1 layer is doped with Ga(pyimd)3, the mass of JBD-1 in the JBD-1 layer is 20% of the total mass of JBD-1 and Ga(pyimd)3, and the thickness of the JBD-1 layer is 1nm; or, the mass of JBD-1 in the JBD-1 layer is 40% of the total mass of JBD-1 and Ga(pyimd)3, and the thickness of the JBD-1 layer is 0.5nm.

5. The method for preparing the deep blue light OLED device according to any one of claims 1 to 4, comprising: An anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer and a cathode are sequentially deposited on a substrate.

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