Preparation method of white organic light-emitting device of diboron azaanthracene derivative

Abstract

The invention relates to a white organic light-emitting device of a diboron azaanthracene derivative and a preparation method of the white organic light-emitting device. The diboron azaanthracene derivative, namely BNAnti-OMe, is a diboron nitrogen doped anthracene micromolecular material, and the material has the characteristics of relatively wide band gap, relatively strong blue fluorescence emission, relatively high triplet state energy level and the like. Double light-emitting layers of the organic light-emitting device comprise an intrinsic blue fluorescent light-emitting layer of BNAL-OMe, a red phosphorescent light-emitting layer of BNAL-OMe gradient doped Ir (MDQ) 2acac, a transparent conductive ITO glass substrate, a hole injection layer HATCN and a hole transport layer TAPC, wherein the transparent conductive ITO glass substrate, the hole injection layer HATCN and the hole transport layer TAPC are located on the left side of the intrinsic blue fluorescent light-emitting layer of BNAL-OMe in sequence. And an n-type doped hole barrier layer BCP: TmPyPb, an electron transport layer TmPyPb, an electron buffer layer LiF and a metal back electrode Al are sequentially arranged on the right side of the BNAL-OMe: Ir (MDQ) 2acac light-emitting layer. According to the double-boron azaanthracene derivative light-emitting layer and the double-boron azaanthracene derivative gradient doped red phosphorescent dye light-emitting layer, white light emission is achieved through light color complementation, and the color stability and the brightness of a white light device can be effectively improved through the fluorescent / phosphorescent double-light-emitting-layer design of the double-boron azaanthracene derivative light-emitting layer and the double-boron azaanthracene derivative gradient doped red phosphorescent dye light-emitting layer.

Description

Technical Field

[0001] This invention belongs to the field of luminescent materials and devices, and relates to a method for preparing a white organic electroluminescent device based on a diboron-anthracene derivative. Background Technology

[0002] In recent years, organic light-emitting diode (OLED) technology has made remarkable progress in the fields of solid-state light sources and full-color displays due to its significant advantages such as vivid contrast, excellent flexibility, wide viewing angle, low power consumption, and fast response. OLED white light devices can be classified into single-component white light devices, complementary-color white light devices, tri-color white light devices, and tetra-color white light devices based on the composition of their luminescent materials. Among these, complementary-color white light devices have a simple composition, are easy to implement, and have high luminous efficiency, making them widely used in the field of white OLEDs.

[0003] Boron-nitrogen-doped polycyclic aromatic hydrocarbons (PAHs) have become a focus of attention in recent years. Among them, diboron-nitrogen anthracene derivatives, with an anthracene core framework, incorporate different functional groups through electron substitution with B and N electrons to adjust their molecular structure. This allows for flexible manipulation of their photoelectric properties while maintaining the basic spatial configuration of aromatic hydrocarbons. These materials exhibit a wide optical band gap and high triplet energy levels. This also provides possibilities for the thermal exciton effect of diboron-nitrogen anthracene derivatives and increases the utilization rate of singlet excitons. Summary of the Invention

[0004] The present invention aims to provide a method for preparing a white organic electroluminescent device based on a boron-nitrogen anthracene derivative. The white organic electroluminescent device comprises a BNAnt-OMe blue fluorescent emitting layer and a gradient-doped BNAnt-OMe∶Ir(MDQ)2acac red phosphorescent emitting layer. Under the drive of an electric field, it emits spectrally stable pure white light through complementary light and color.

[0005] The technical solution of the present invention:

[0006] 1. Fabrication process of white organic electroluminescent devices based on diboron-xanthracene derivatives:

[0007] The ITO glass substrate serves as the anode. HATCN, deposited on the substrate, acts as a hole injection layer. TAPC, deposited on HATCN, acts as a hole transport layer. A BNAnt-OMe film, deposited on TAPC, serves as a blue fluorescent emitting layer. A gradient-doped BNAnt-OMe:Ir(MDQ)2acac co-evaporated film, deposited on the BNAnt-OMe film, acts as a red phosphorescent emitting layer. BCP:TmPyPb, deposited on the red phosphorescent emitting layer, acts as an n-type doped hole blocking layer. TmPyPb, deposited on BCP:TmPyPb, acts as an electron transport layer. LiF, deposited on TmPyPb, acts as an electron buffer layer. Metallic Al, deposited on LiF, acts as the cathode. The diboronazanthracene derivative is BNAnt-OMe, and its molecular structure is as follows: Figure 1 As shown in (a). The chemical formula of the red phosphorescent dye is Ir(MDQ)2acac, and its molecular structure is as follows. Figure 1 As shown in (b). The device structure of the white organic electroluminescent device prepared from the diboronazanthracene derivative is as follows:

[0008] Device 1: ITO / HATCN / TAPC / BNAnt-OMe (40nm) / BNAnt-OMe:Ir(MDQ)2acac (10nm, 2%) / BNAnt-OMe:Ir(MDQ)2acac (10nm, 5%) / BNAnt-OMe:Ir(MDQ)2acac (10nm, 8%) / BCP:TmPyPb (6nm, 30%) / TmPyPb (20nm) / LiF / Al

[0009] Device 2: ITO / HATCN / TAPC / BNAnt-OMe (40nm) / BNAnt-OMe∶Ir(MDQ)2acac (30nm, 5%) / BCP∶TmPyPb (6nm, 30%) / TmPyPb (20nm) / LiF / Al

[0010] The specific fabrication steps for organic electroluminescent devices are as follows:

[0011] (1) The ITO glass substrate was ultrasonicated with acetone, isopropanol and deionized water for 15 minutes respectively, and then dried in an infrared drying oven.

[0012] (2) Place the cleaned ITO glass substrate in an ultraviolet ozone generator for surface hydrophilic treatment for 15 minutes;

[0013] (3) Vacuum evaporation was performed on a 5x10⁻¹⁰ ITO glass substrate after surface hydrophilic treatment. -5 HATCN is deposited by vapor deposition at a pressure of Pa, with a deposition rate of [value missing]. Thickness is 6nm;

[0014] (4) Vacuum evaporation was used on HATCN thin films at 5x10 -5 TAPC is deposited by vapor deposition at a pressure of Pa, with a deposition rate of [value missing]. The thickness is 40nm;

[0015] (5) Vacuum evaporation was used on TAPC films at a thickness of 5x10 mm. -5 Under a pressure of Pa, the deposition rates of diboron-nitrogen anthracene derivatives were as follows: The thickness is 40nm;

[0016] (6) Vacuum evaporation was used to deposit 5x10⁻⁶ thin films of diboronazanthracene derivatives. -5 Under a pressure of Pa, the evaporation rate of the diboronazanthracene derivative, the main material, with the diboronazanthracene derivative undergoes dual-source co-evaporation with a red phosphorescent dye is: The evaporation rate of the red phosphorescent dye in the guest material was first controlled at... A 10nm layer was deposited at a doping rate of 2%, then the evaporation rate of the host material remained constant, while the evaporation rate of the guest material was adjusted to [a specific value]. A 10nm deposition was performed at a doping rate of 5%, while maintaining the evaporation rate of the host material constant. The evaporation rate of the guest material was adjusted to a specific value. A 10nm layer was deposited at a doping rate of 8%, resulting in a final gradient-doped light-emitting layer thickness of 30nm.

[0017] (7) Vacuum evaporation was used to deposit thin films co-evaporated with diboronazanthracene derivatives and red phosphorescent dyes on 5x10 films. -5 An n-type doped hole-blocking layer BCP:TmPyPb (30%) was deposited under a pressure of Pa at a deposition rate of [value missing]. Thickness is 6nm;

[0018] (8) Vacuum evaporation was used to deposit 5x10 n-type doped hole blocking layer BCP:TmPyPb thin films on a 5x10 -5 Electron transport layer TmPyPb is deposited under a pressure of Pa, with a deposition rate of [value missing]. The thickness is 20nm;

[0019] (9) Vacuum evaporation was used to deposit 5x10 TmPyPb thin films. -5 An electron buffer layer of LiF is deposited under a pressure of Pa, with a deposition rate of [value missing]. Thickness is 1nm;

[0020] (10) Vacuum evaporation was used to deposit electron transport layer LiF thin films at a depth of 5 x 10⁻⁶. -5 Under a pressure of Pa, Al metal cathode is deposited by vapor deposition at a deposition rate of Pa. The thickness is 100nm.

[0021] 2. The white organic electroluminescent device based on a diboron-xanthracene derivative was tested and characterized using the following methods:

[0022] (1) The ultraviolet-visible absorption and photoluminescence of the bis-boron-anthracene derivative film and the red phosphorescent dye film spin-coated on the quartz glass substrate were tested using an FS5C steady-state transient spectrometer. The absorption and emission ranges of the two materials can be seen from the test results.

[0023] (2) The prepared electroluminescent device was placed on a Keithley 2450 voltage-current source and a PR-650 spectrometer to test the electroluminescence spectrum, brightness and color coordinates of the device under the applied voltage.

[0024] 3. Compared with the prior art, the present invention has the following advantages:

[0025] (1) The selected diboronazanthracene derivative has excellent photoelectric properties, suitable triplet energy level, and large conjugated plane, which is beneficial to improve hole transport efficiency and improve the light emission performance of the device.

[0026] (2) A blend of diboronazanthracene derivatives and red phosphorescent dyes as a luminescent layer can utilize both the efficient Dexter energy transfer between the host and guest components and the... The energy transfer (FRET) process together achieves efficient phosphorescence / fluorescence emission. By optimizing the recombination region of excitons in the phosphorescent emitting layer, the spectral stability of white light devices is greatly improved, thereby achieving high-quality pure white light emission.

[0027] (3) The organic electroluminescent device has a simple fabrication process, low cost, and high color stability, and can be fabricated on a flexible substrate.

[0028] (4) The method provided by the present invention is completed in a glove box for all functional layers, avoiding pollution and harm caused by organic solvents, and the preparation process is green and environmentally friendly. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the diboron-azoanthracene derivative and the red phosphorescent dye of the present invention;

[0030] Figure 2 This is a schematic diagram of the electroluminescent device structure of the present invention;

[0031] Figure 3 The UV-Vis absorption and photoluminescence spectra of diboronazanthracene derivatives and red phosphorescent dyes are shown.

[0032] Figure 4The EL spectrum of a white organic electroluminescent device 1, which is a diboronazanthracene derivative;

[0033] Figure 5 Color coordinate diagram of white organic electroluminescent device 1, a diboron-nitrogen anthracene derivative;

[0034] Figure 6 The EL spectrum of a white organic electroluminescent device 2, which is a diboronazanthracene derivative;

[0035] Figure 7 Color coordinate diagram of white organic electroluminescent device 2, a diboron-nitrogen anthracene derivative;

[0036] Figure 8 The schematic diagram of the light-emitting principle of a white organic electroluminescent device based on a diboronazanthracene derivative. Detailed Implementation

[0037] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0038] Example 1:

[0039] A schematic diagram of the structure of the white organic electroluminescent device based on the diboron-xanthracene derivative of the present invention is shown below. Figure 2 As shown in the figure, the white organic electroluminescent device of the diboronazanthracene derivative, from bottom to top, consists of: a transparent conductive substrate, a hole injection layer, a hole transport layer, a fluorescent / phosphorescent dual-emitting layer, an n-type doped hole blocking layer, an electron transport layer, an electron buffer layer, and a metal cathode. The fabricated device structure is as follows:

[0040] Device 1: ITO / HATCN / TAPC / BNAnt-OMe (40nm) / BNAnt-OMe: Ir(MDQ)2acac (10nm, 2%) / BNAnt-OMe: Ir(MDQ)2acac (10nm, 5%) / BNAnt-OMe: Ir(MDQ)2acac (10nm, 8%) / BCP: TmPyPb (6nm, 30%) / TmPyPb (20nm) / LiF / Al

[0041] A method for preparing a white organic electroluminescent device based on a diboronazanthracene derivative includes the following steps;

[0042] (1) The ITO glass substrate was ultrasonicated with acetone, isopropanol and deionized water for 15 minutes respectively, and then dried in an infrared drying oven.

[0043] (2) Place the cleaned ITO glass substrate in an ultraviolet ozone generator for surface hydrophilic treatment for 15 minutes;

[0044] (3) Vacuum evaporation was performed on a 5x10⁻¹⁰ ITO glass substrate after surface hydrophilic treatment. -5 HATCN is deposited by vapor deposition at a pressure of Pa, with a deposition rate of [value missing]. Thickness is 6nm;

[0045] (4) Vacuum evaporation was used on HATCN thin films at 5x10 -5 TAPC is deposited by vapor deposition at a pressure of Pa, with a deposition rate of [value missing]. The thickness is 40nm;

[0046] (5) Vacuum evaporation was used on TAPC films at a thickness of 5x10 mm. -5 Under a pressure of Pa, the deposition rates of diboron-nitrogen anthracene derivatives were as follows: The thickness is 40nm;

[0047] (6) Vacuum evaporation was used to deposit 5x10⁻⁶ thin films of diboronazanthracene derivatives. -5 Under a pressure of Pa, the evaporation rate of the diboronazanthracene derivative, the main material, with the diboronazanthracene derivative undergoes dual-source co-evaporation with a red phosphorescent dye is: The evaporation rate of the red phosphorescent dye in the guest material was first controlled at... A 10nm layer was deposited at a doping rate of 2%, then the evaporation rate of the host material remained constant, while the evaporation rate of the guest material was adjusted to [a specific value]. A 10nm deposition was performed at a doping rate of 5%, while maintaining the evaporation rate of the host material constant. The evaporation rate of the guest material was adjusted to a specific value. A 10nm layer was deposited at a doping rate of 8%, resulting in a final gradient-doped light-emitting layer thickness of 30nm.

[0048] (7) Vacuum evaporation was used to deposit thin films co-evaporated with diboronazanthracene derivatives and red phosphorescent dyes on 5x10 films. -5 An n-type doped hole-blocking layer BCP:TmPyPb (30%) was deposited under a pressure of Pa at a deposition rate of [value missing]. Thickness is 6nm;

[0049] (8) Vacuum evaporation was used on an n-type doped hole-blocking layer BCP:TmPyPb at a depth of 5x10. -5 Electron transport layer TmPyPb is deposited under a pressure of Pa, with a deposition rate of [value missing]. The thickness is 20nm;

[0050] (9) Vacuum evaporation was used to deposit 5x10 TmPyPb thin films. -5 An electron buffer layer of LiF is deposited under a pressure of Pa, with a deposition rate of [value missing]. Thickness is 1nm;

[0051] (10) Vacuum evaporation was used to deposit electron transport layer LiF thin films at a depth of 5 x 10⁻⁶. -5 Under a pressure of Pa, Al metal cathode is deposited by vapor deposition at a deposition rate of Pa. The thickness is 100nm.

[0052] Example 2:

[0053] The ultraviolet-visible absorption and photoluminescence of the diboron-adenothane derivative and the red phosphorescent dye films spin-coated on the quartz substrate were measured. Figure 3 The UV-Vis absorption and photoluminescence spectra of the diboronazanthracene derivative and the red phosphorescent dye are shown. The figures show that the absorption and emission peaks of the diboronazanthracene derivative are at 377 nm and 436 nm, respectively, while the absorption and emission peaks of the red phosphorescent dye are at 364 nm and 616 nm, respectively.

[0054] Example 3:

[0055] Performance testing was performed on OLED device 1.

[0056] like Figure 4 The image shows the EL spectrum of the OLED device 1 of the present invention under different voltages. The two EL peaks of the device 1 are at 436 and 600 nm.

[0057] like Figure 5 The figure shown is a color coordinate diagram of the OLED device 1 of the present invention under different voltages.

[0058] like Figure 6 The figure shows the EL spectra of the OLED device 2 of the present invention at different voltages.

[0059] like Figure 7 The figure shown is a color coordinate diagram of the OLED device 2 of the present invention under different voltages.

[0060] like Figure 8 The diagram shows the light-emitting principle of the white OLED device of the present invention.

[0061] Comparative Example 1:

[0062] In the specific implementation, except that the red phosphorescent emitting layer is not gradient-doped, the other contents are the same as in Example 1.

[0063] The structure of the comparison device is as follows:

[0064] Device 2: ITO / HATCN / TAPC / BNAnt-OMe (40nm) / BNAnt-OMe∶Ir(MIDQ)2acac (30nm, 5%) / BCP∶TmPyPb (6nm, 30%) / TmPyPb (20nm) / LiF / Al

[0065] Comparison of the EL spectrum and color coordinates with device 2 revealed that the color coordinate stability of device 1, with its gradient-doped BNAnt-OMe:Ir(MDQ)2acac as the emitting layer, is higher than that of the single-doped device. Due to its single doping concentration, device 2 exhibits a higher intensity of the red phosphorescence emission peak than the intrinsic blue emission peak with increasing voltage, resulting in a color coordinate that leans more towards warm white light. In contrast, the gradient-doped emitting layer design in device 1 causes the exciton recombination region to initially approach the high-doping region of the metal cathode at low voltages, shifting towards the low-doping region of the anode as the voltage increases. This maintains a consistent ratio of intensity increase between the red and blue phosphorescence emission peaks, resulting in a very stable EL spectrum with minimal color coordinate variation across different voltages. The results are shown in Table 1. Table 1 Color coordinates / luminance of Device 1 and Device 2

[0066] In-depth analysis of the energy level structure of OLED devices revealed that the HLCT effect of the host material, a diboronazanthracene derivative, significantly improves the utilization rate of singlet excitons. Because the diboronazanthracene derivative possesses a high LUMO level (1.9 eV) and a triplet T1 level (2.4 eV), it matches well with the T1 (2.2 eV) level of Ir(MDQ)₂acac. Furthermore, under the influence of the thermal exciton channel, the higher triplet level transitions to the singlet level, improving exciton utilization and enhancing the FRET process, thereby achieving more efficient red phosphorescence emission, such as… Figure 8 As shown. By combining the intrinsic blue fluorescence emission of the diboronazanthracene derivative, the spectral stability of the light-emitting device can be improved by optimizing different evaporation rates, thereby achieving high-quality white light emission.

[0067] This invention fabricates a highly efficient complementary-color white light device by rationally selecting luminescent materials and appropriately controlling the deposition rate and doping ratio. Diboronazanthracene derivatives can serve as both highly efficient intrinsic luminescent materials and the main material for gradient-doped red phosphorescent materials. Considering energy level matching and carrier transport balance, this fluorescent / phosphorescent dual-emitting-layer design is employed, achieving gradient doping of the luminescent layer components, thereby effectively improving the color stability and brightness of the white light device.

Claims

1. A white organic electroluminescent device based on a diboronazanthracene derivative, characterized in that: The white organic light-emitting device of the bis-boron-anthracene derivative includes an intrinsic blue fluorescent light-emitting layer of BNAnt-OMe and a red phosphorescent light-emitting layer of BNAnt-OMe gradient-doped Ir(MDQ)2acac. To the left of the intrinsic light-emitting layer of BNAnt-OMe are a hole transport layer and a hole injection layer, respectively. A transparent conductive substrate is provided on the side of the hole injection layer opposite to the intrinsic light-emitting layer of BNAnt-OMe. An n-type doped hole blocking layer, an electron transport layer, an electron buffer layer, and a metal electrode are provided on the side of the co-evaporated film of BNAnt-OMe and Ir(MDQ)2acac opposite to the hole transport layer.

2. The white organic electroluminescent device based on a diboronazanthracene derivative according to claim 1, characterized in that... The transparent substrate is ITO glass, with ITO as the conductive anode and a sheet resistance of 10-15Ω. The required ITO glass substrate is cleaned, dried, and pretreated.

3. The hole injection layer according to claim 1 is a HATCN thin film, which is deposited on an ITO glass substrate by vacuum evaporation and has a film thickness of 6 nm.

4. The hole transport layer according to claim 1 is a TAPC thin film, which is deposited on a HATCN thin film by vacuum evaporation, and the film thickness is 40 nm.

5. A white organic electroluminescent device based on a diboronazanthracene derivative according to claim 1, characterized in that... The intrinsic blue light-emitting layer of the boron-nitrogen anthracene derivative BNAnt-OMe was deposited on a TAPC thin film using a vacuum evaporation method, with a film thickness of 40 nm.

6. A white organic electroluminescent device based on a diboronazanthracene derivative according to claim 1, characterized in that... A gradient-doped red luminescent layer was obtained by co-distillation of the diboron-nitrogen anthracene derivative BNAnt-OMe with the red phosphorescent dye Ir(MDQ)2acac.

7. A white organic electroluminescent device based on a diboronazanthracene derivative according to claim 1, characterized in that... First The evaporation rate was [value missing], and the intrinsic blue luminescent layer was deposited, resulting in a final film thickness of 40 nm. The diboronazanthracene derivative and the red phosphorescent dye were co-evaporated using a dual-source method, with the evaporation rate of the diboronazanthracene derivative as the main material being [value missing]. The evaporation rate of the red phosphorescent dye in the guest material was first controlled at... A 10nm layer was deposited at a doping rate of 2%, then the evaporation rate of the host material remained constant, while the evaporation rate of the guest material was adjusted to [a specific value]. A 10nm deposition was performed at a doping rate of 5%, while maintaining the evaporation rate of the host material constant. The evaporation rate of the guest material was adjusted to a specific value. A 10nm layer was deposited at a doping rate of 8%, resulting in a final gradient-doped phosphorescent layer thickness of 30nm.

8. A white organic electroluminescent device based on a diboronazanthracene derivative according to claim 1, characterized in that... The aforementioned n-type doped hole blocking layer, BCP:TmPyPb (mass doping ratio of 30%), has a film thickness of 6 nm; the electron transport layer is TmPyPb with a film thickness of 20 nm; and the electron buffer layer adjacent to the electron transport layer is LiF with a film thickness of 1 nm. All three films were prepared by vacuum thermal evaporation.

9. The metal back electrode according to claim 1 is an Al thin film, which is vapor-deposited on LiF after being shielded by a mask, and the film thickness is 100 nm.

10. A white organic electroluminescent device based on a diboronazanthracene derivative according to claims 1-9, characterized in that... The preparation process includes the following steps: (1) A hole injection layer and a hole transport layer are prepared on a transparent conductive substrate. (2) The surface of the hole transport layer obtained in step (1) is vapor-deposited with a boron-azoanthracene derivative and a red phosphorescent dye film with a gradient doped boron-azoanthracene derivative and a red phosphorescent dye film. (3) An n-type doped hole blocking layer and an electron transport layer are vapor deposited on the thin film of the diboron-azoanthracene derivative and red phosphorescent dye obtained in step (2). (4) An electron buffer layer and a cathode are sequentially deposited on the electron transport layer obtained in step (3).

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