A method for preparing a high brightness hybrid fluorescent-phosphorescent white light emitting ipa material

Abstract

The application relates to a method for preparing a high-brightness mixed fluorescent and phosphorescent white light-emitting IPA material, and belongs to the technical field of white light-emitting organic material preparation. The method comprises the following steps: taking a blue fluorescent emission dominated IPA as an initial material; pressurizing the initial sample to 16.0-23 GPa through a diamond anvil cell; and then discharging the diamond anvil cell to normal pressure to obtain a bright mixed fluorescent and phosphorescent white light-emitting IPA material. The IPA sample prepared through pressure engineering has high-brightness white light emission based on fluorescent and phosphorescent mixing, and the initial fluorescent and phosphorescent components of the IPA material are uneven. The preparation process is simple, the synthesis is at room temperature, the method is green and environment-friendly, and the method has high repeatability. The method greatly expands the selection range of the design of high-brightness white light-emitting materials.

Description

Technical Field

[0001] This invention belongs to the technical field of white luminescent organic material preparation, and particularly relates to a method for obtaining high-brightness mixed fluorescent phosphorescent white luminescent isophthalic acid material. Background Technology

[0002] White organic light-emitting materials (OLEDs) have shown great application potential in display, lighting, and probe fields, attracting widespread attention from academia and industry. Compared to multi-component composite OLEDs, single-component OLEDs offer advantages such as no phase separation, no color decay, good stability and reproducibility, and simple device fabrication processes, creating new possibilities for the development of low-cost, high-efficiency devices. Among them, single-component mixed fluorescent-phosphorescent dual-emission OLEDs possess characteristics such as long lifetime, large Stokes shift, and high exciton utilization, showing promising application prospects in data encryption, bioimaging, information storage, and optoelectronic applications, and are currently one of the research hotspots in the field of luminescent materials. However, pure organic (metal-free) phosphors are relatively scarce, and long-lived triplet excitons are easily quenched. The inherent unbalanced distribution of singlet and triplet excitons greatly limits the design and development of mixed fluorescent-phosphorescent dual-emission OLEDs. Therefore, it is necessary to accelerate the intersystem crossing process from singlet to triplet and suppress the nonradiative loss of triplet excitons in order to improve phosphorescence emission efficiency, thereby preparing isophthalic acid (IPA) materials with balanced distribution of singlet and triplet excitons and mixed fluorescence phosphorescence white emission. Summary of the Invention

[0003] The technical problem to be solved by this invention is to overcome the problem of uneven distribution of fluorescent and phosphorescent components in IPA materials, and to provide a method for preparing high-brightness mixed fluorescent and phosphorescent white luminescent IPA materials through pressure treatment engineering.

[0004] This invention uses weakly blue luminescent IPA as the initial research object and employs a pressure treatment method to obtain high-brightness mixed fluorescent phosphorescent white luminescent material. The specific technical solution is as follows.

[0005] A method for preparing a high-brightness mixed-fluorescent phosphorescent white luminescent IPA material involves using a T301 stainless steel sheet as a gasket, with a pre-pressed groove thickness of 40-60 μm. A sample cavity with a diameter of 150 μm is created using laser drilling. A blue luminescent IPA solid sample is placed in the sample cavity, and silicone oil is added as a pressure transmitting medium to ensure uniform pressure distribution during the pressurization process. A spherical ruby ​​is placed in the sample cavity, and the pressure is calibrated using the ruby ​​fluorescence pressure calibration method. A metal gasket is then placed between two diamond anvils, and the sample is manually pressurized to 16.0 GPa to 23.0 GPa. The press is then depressurized to atmospheric pressure to obtain a high-brightness mixed-fluorescent phosphorescent white luminescent IPA material. The IPA is isophthalic acid.

[0006] Preferably, the pressurization treatment of the sample is performed by gradually increasing the pressure to 16.0 GPa.

[0007] Beneficial effects:

[0008] The advantages of this invention in preparing high-brightness mixed-fluorescence phosphorescent white-emitting IPA materials via pressure processing engineering are: the process is simple, highly reproducible, clean, and environmentally friendly, with the potential for large-scale material production. The preparation method of this invention is based on an initial weakly blue-emitting IPA material with predominantly fluorescence emission. The obtained IPA has a framework structure essentially identical to the initial weakly blue-emitting IPA and possesses high-brightness mixed-fluorescence phosphorescent white-emitting properties. The successful preparation of high-brightness mixed-fluorescence phosphorescent white-emitting IPA materials expands the range of initial materials that can be selected for preparing such materials. Attached Figure Description

[0009] Figure 1 These are the photoluminescence spectra of IPA before and after 5GPa pressure treatment.

[0010] Figure 2 These are the photoluminescence spectra of IPA before and after 10 GPa pressure treatment.

[0011] Figure 3 These are the photoluminescence spectra of IPA before and after 16 GPa pressure treatment.

[0012] Figure 4 These are the photoluminescence spectra of IPA before and after treatment with 23 GPa pressure.

[0013] Figure 5 It is the chromaticity coordinate diagram of a weak blue luminescent IPA that has not undergone pressure treatment.

[0014] Figure 6 This is the chromaticity coordinate diagram of a white luminescent IPA after treatment with 16 GPa pressure.

[0015] Figure 7 This is the photoluminescence spectrum of a weak blue emitting IPA that has not undergone pressure treatment.

[0016] Figure 8 The time-resolved fluorescence decay curve at 402 nm of the weak blue luminescent IPA without pressure treatment is shown.

[0017] Figure 9 The time-resolved fluorescence decay curve at 530 nm of the weak blue emitting IPA without pressure treatment is shown.

[0018] Figure 10 This is the photoluminescence spectrum of a bright white luminescent IPA after treatment with 16 GPa pressure.

[0019] Figure 11 It is the time-resolved fluorescence decay curve at 481nm of the bright white luminescent IPA after pressure treatment.

[0020] Figure 12 It is the time-resolved fluorescence decay curve at 573nm of the bright white luminescent IPA after pressure treatment.

[0021] Figure 13 This is the in-situ synchrotron radiation XRD spectrum of the IPA sample before pressure treatment.

[0022] Figure 14 This is the in-situ synchrotron radiation XRD spectrum of the IPA sample after being treated with 16 GPa pressure.

[0023] Figure 15 This is the in-situ high-pressure infrared absorption spectrum of the IPA sample before pressure treatment.

[0024] Figure 16 This is the in-situ high-pressure infrared absorption spectrum of the IPA sample after treatment with 16 GPa pressure. Detailed Implementation

[0025] The present invention will now be described in more detail with reference to the following embodiments. Unless otherwise specified, all reagents used are commercially available products and have not been further purified before use.

[0026] Example 1: High-pressure preparation of high-brightness mixed fluorescent phosphorescent white luminescent IPA material

[0027] The sample IPA was a commercially available product and was not further purified before use.

[0028] High pressure was generated using a diamond anvil cell (PAC) with a 400 μm diameter anvil. A 45 μm thick indentation was pre-pressed into the center of a T301 stainless steel washer, and a 150 μm diameter hole was drilled in the center of the indentation to hold the sample. A ruby ​​sphere was then placed in the sample chamber to determine the actual pressure. Pressure calibration was performed using standard ruby ​​fluorescence. In-situ high-pressure fluorescence experiments were conducted using a 10 mW 355 nm laser excitation line. The diamond anvil cell was pressurized to 5.0 GPa, 10.0 GPa, 16.0 GPa, and 23.0 GPa, respectively, and then depressurized to atmospheric pressure, yielding high-brightness blue and white luminescent IPA materials.

[0029] The emission spectra of IPA samples before and after pressure treatment at 5.0 GPa, 10.0 GPa, 16.0 GPa and 23.0 GPa were collected under the same test conditions. Figure 1 These are the photoluminescence spectra of the IPA samples before and after treatment with 5.0 GPa pressure. Figure 2 These are the photoluminescence spectra of the IPA samples before and after treatment with 10.0 GPa pressure. Figure 3 These are the photoluminescence spectra of the IPA samples before and after treatment with 16.0 GPa pressure. Figure 4 These are the photoluminescence spectra of IPA samples before and after pressure treatment at 23.0 GPa. Before pressure treatment, the samples exhibited weak blue light emission, with chromaticity coordinates of (0.22, 0.22). Figure 5 As shown, enhanced blue light emission is observed after pressure treatment at 5.0 GPa and 10.0 GPa; bright white light emission is observed after pressure treatment at 16.0 GPa and 23.0 GPa. 16 GPa is the optimal pressure point for IPA material to achieve the best white light performance, with chromaticity coordinates of (0.28, 0.36). Figure 6 As shown.

[0030] Example 2: Fluorescence and phosphorescence composition analysis of IPA samples before and after 16.0 GPa pressure treatment

[0031] Figure 7 This is a peak-splitting of the photoluminescence spectrum of the IPA sample before pressure treatment. The figure shows that the initial photoluminescence spectrum can be characterized as a combination of two peaks with emission wavelengths of 402 nm and 530 nm. Figure 8 The time-resolved fluorescence decay curve at a wavelength of 402 nm was fitted, and its lifetime was found to be 6.81 ns, indicating that the component emits fluorescence. Figure 9 The time-resolved fluorescence decay curve at a wavelength of 530 nm was fitted, and its lifetime was found to be 888.6 ms, indicating that the component emits phosphorescence. Figure 10This is a peak-splitting analysis of the photoluminescence spectrum of the IPA sample after treatment with 16.0 GPa pressure. The figure shows that the photoluminescence spectrum can be characterized as a combination of emission wavelengths of 481 nm and 573 nm. Figure 11 The time-resolved fluorescence decay curve at a wavelength of 481 nm was fitted, and its lifetime was found to be 6.83 ns, indicating that the component emits fluorescence. Figure 12 The time-resolved fluorescence decay curve at a wavelength of 573 nm was fitted, and its lifetime was found to be 900.2 ms, indicating that the component emits phosphorescence.

[0032] Example 3: Structural characterization of IPA samples before and after 16.0 GPa pressure treatment

[0033] In-situ synchrotron radiation XRD and in-situ high-pressure infrared absorption spectroscopy were performed on the IPA samples after pressure treatment at 16.0 GPa.

[0034] Figure 13 This is the synchrotron radiation XRD spectrum of the IPA sample before pressure treatment. Figure 14 This is the synchrotron radiation XRD spectrum of the IPA sample after treatment with 16.0 GPa pressure. Figure 15 This is the in-situ high-pressure infrared absorption spectrum of an IPA sample that has not undergone pressure treatment. Figure 16 This is the in-situ high-pressure infrared absorption spectrum of the IPA sample after treatment with 16.0 GPa pressure. Structural characterization shows that the IPA before and after the 16.0 GPa pressure treatment has a basically consistent framework structure.

Claims

1. A method for preparing a high-brightness mixed fluorescent phosphorescent white luminescent IPA material, comprising: using a T301 stainless steel sheet as a gasket; pre-pressing groove thickness of 40-60 μm; creating a sample cavity with a diameter of 150 μm using laser drilling; placing a blue luminescent IPA solid sample in the sample cavity; adding silicone oil as a pressure transmitting medium to ensure uniform pressure distribution during the pressurization process; placing a spherical ruby ​​in the sample cavity; calibrating the pressure using the ruby ​​fluorescence pressure calibration method; then placing a metal gasket between two diamond anvils; manually pressurizing the sample to 16.0 GPa to 23.0 GPa; and then depressurizing the press to atmospheric pressure to obtain a high-brightness mixed fluorescent phosphorescent white luminescent IPA material; wherein the IPA is isophthalic acid.

2. The method for preparing a high-brightness hybrid fluorescent phosphorescent white luminescent IPA material according to claim 1, characterized in that, The pressurization treatment of the sample involves gradually increasing the pressure to 16.0 GPa.

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