A room temperature phosphorescent material and its preparation method

Abstract

This invention discloses a room-temperature phosphorescent material and its preparation method. The room-temperature phosphorescent material is a pure organic polymer containing repeating units of diacetic acid and diacetic acid copolymers, formed by esterification of diacetic acid with room-temperature phosphorescent molecules. This room-temperature phosphorescent material exhibits a long lifetime.

Description

Technical Field

[0001] This invention relates to the field of organic light-emitting materials, and more particularly to a room-temperature phosphorescent material, its preparation method, and its application. Background Technology

[0002] In recent years, room temperature phosphorescence (RTP) materials have attracted widespread attention due to their advantages such as long luminescence lifetime (ms to s), large Stokes shift (above 100 nm), high quantum yield (up to 100%), and simple detection. RTP materials are widely used in organic light-emitting diodes, bioimaging, information encryption, photothermal therapy, and photodynamic therapy. However, the use of expensive noble metals (such as platinum (II) and iridium (III)) in inorganic and organometallic phosphorescent materials limits their further development. Therefore, purely organic room temperature phosphorescent materials have garnered significant interest.

[0003] Pure organic room-temperature phosphorescent materials typically employ strategies such as emitting element embedding in a polymer matrix, host-guest recognition, covalent bonding between the emitting element and the polymer matrix, and crystal engineering to effectively control the real-time phosphorescence efficiency (RTP). The aim is to provide a rigid molecular environment for the emitting element, effectively preventing vibrational relaxation and... 3 O2 quenches phosphorescence. Summary of the Invention

[0004] One object of the present invention is to provide long-life room-temperature phosphorescent materials.

[0005] The room temperature phosphorescent material provided by this invention is a pure organic polymer, comprising a room temperature phosphorescent molecule-diyne acid copolymer repeating unit formed by esterification of diyneic acid and room temperature phosphorescent molecules.

[0006] In one embodiment, the room-temperature phosphorescent molecule is 2-(9H-carbazole-9-yl)ethanol, 2-(2-bromo-9H-carbazole-9-yl)ethanol, or 2-(2,7-dibromo-9H-carbazole-9-yl)ethanol.

[0007] In one embodiment, the diacetic acid is 10,12-pentadiacetic acid.

[0008] In one embodiment, the room-temperature phosphorescent material has an ordered molecular structure formed through self-assembly.

[0009] In one embodiment, the molar ratio of the room-temperature phosphorescent molecule-diyneic acid, formed by esterification of diyneic acid and room-temperature phosphorescent molecules in the copolymer repeating unit to the diyneic acid is 1:2.

[0010] Another method for preparing room-temperature phosphorescent materials provided by the present invention includes:

[0011] The diacetic acid monomer is formed by esterification of diacetic acid with room-temperature phosphorescent molecules.

[0012] The room-temperature phosphorescent molecule-diyneic acid monomer and the diyneic acid monomer self-assemble to form an ordered molecular structure;

[0013] Photopolymerization was performed to obtain the room-temperature phosphorescent material.

[0014] In one embodiment, the room-temperature phosphorescent molecule is 2-(9H-carbazole-9-yl)ethanol, 2-(2-bromo-9H-carbazole-9-yl)ethanol, or 2-(2,7-dibromo-9H-carbazole-9-yl)ethanol.

[0015] In one embodiment, the diacetic acid is 10,12-pentadiacetic acid.

[0016] In one embodiment, the molar ratio of the room-temperature phosphorescent molecule-diyneic acid, formed by esterification of diyneic acid and room-temperature phosphorescent molecules, to the diyneic acid is 1:2.

[0017] The room-temperature phosphorescent material of the present invention has a long lifespan. Attached Figure Description

[0018] Figure 1 The room-temperature phosphorus emission and lifetime spectra of CZEO-PCDA organic polymer and CZEO-PCDA:PCDA organic polymer are shown.

[0019] Figure 2 The room-temperature phosphorus emission and lifetime spectra of BrCZEO-PCDA organic polymer and BrCZEO-PCDA:PCDA organic polymer are shown.

[0020] Figure 3 The room-temperature phosphorus emission and lifetime spectra of Br2CZEO-PCDA organic polymer and Br2CZEO-PCDA:PCDA organic polymer are shown.

[0021] Figure 4 A schematic diagram of the synthesis strategy for the room-temperature phosphorescent material of the present invention is shown. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0023] This invention relates to room temperature phosphorescent materials that are pure organic polymers.

[0024] This invention utilizes molecular self-assembly technology to esterify diacetic acid with room-temperature phosphorescent molecules to form a room-temperature phosphorescent molecule-diacetic acid monomer. Furthermore, the molecular self-assembly technology is used to arrange the room-temperature phosphorescent molecule-diacetic acid monomer and the diacetic acid monomer together into an ordered spatial structure. Then, photopolymerization is performed under 245nm ultraviolet light irradiation, such as... Figure 4 As shown, this forms a robust conjugated framework of alternating double and triple bonds, effectively preventing vibrational relaxation. Furthermore, the ordered arrangement of room-temperature phosphorescent molecules promotes intermolecular spin-orbit coupling (SOC), increasing the rate of intersystem crossing and thus enhancing phosphorescence emission efficiency.

[0025] In one specific embodiment, the present invention utilizes common room-temperature phosphorescent molecules 2-(9H-carbazol-9-yl)ethanol (CZEO), 2-(2-bromo-9H-carbazole-9-yl)ethanol (BrCZEO), 2-(2,7-dibromo-9H-carbazole-9-yl)ethanol (Br2CZEO), and 10,12-pentadienoic acid (PCDA) to synthesize CZEO-PCDA, BrCZEO-PCDA, and Br2CZEO-PCDA monomers, respectively. These monomers are then self-assembled with the diacetic acid monomers to form ordered molecular structures. Finally, they are photopolymerized under 254 nm ultraviolet light irradiation to generate pure organic polymers.

[0026] On the one hand, the resulting polymer conjugated backbone can effectively suppress nonradiative transition processes and improve RTP emission efficiency. On the other hand, the bromine atoms substituted on the carbazole ring of the room-temperature phosphorescent molecule effectively promote intermolecular spin-orbit coupling (SOC) and enhance the rate of intersystem crossing (ISC) by utilizing the heavy atom effect.

[0027] PDA photopolymerization is a simple and rapid reaction that, compared to traditional polymerization methods, does not involve the addition of initiators, polymerization inhibitors, or other substances that would produce byproducts.

[0028] The synthetic reaction formulas for CZEO-PCDA, BrCZEO-PCDA, and Br2CZEO-PCDA monomers are as follows:

[0029]

[0030]

[0031] Synthesis of CZEO-PCDA monomers

[0032] PCDA (0.5 g, 1.3 mmol) was dissolved in dichloromethane (20 mL), and oxaloyl chloride (0.19 g, 1.5 mmol) was added under nitrogen protection. The reaction mixture was stirred for 1 h. N'N-dimethylformamide (one drop) was added to the above solution, and the mixture was stirred for another 4 h. After vacuum concentration, the residue was dissolved in dichloromethane (15 mL), and the resulting solution was added dropwise to a dichloromethane solution (15 mL) of CZEO (0.42 g, 2 mmol) and triethylamine (0.303 g, 3 mmol), and stirred overnight at room temperature. The product was purified by column chromatography using EA:PE = 1:10 eluent to obtain the CZEO-PCDA monomer.

[0033] Synthesis of BrCZEO-PCDA monomers

[0034] (a) Synthesis of BrCZEO: In a round-bottom flask, 2-bromocarbazole (0.5 g, 2 mmol), 2-bromoethanol (0.25 g, 2 mmol), K₂CO₃ (0.43 g, 3.08 mmol), and KI (0.332 g, 2 mmol) were added to 20 mL of dimethylformamide. The reaction mixture was stirred and heated overnight at 120 °C under nitrogen protection. After the reaction, the mixture was cooled, extracted with ethyl acetate, and the product was purified by column chromatography using EA:PE = 1:10 as the eluent to obtain BrCZEO.

[0035] (b) Synthesis of BRCZEO-PCDA monomer ：10,12-pentadecylene acid (0.5 g, 1.3 mmol) was dissolved in DCM (20 ml), and oxalyl chloride (0.19 g, 1.5 mmol) was added under nitrogen protection. The reaction was stirred for 1 h. One drop of DMF was added to the above solution, and the mixture was stirred for another 4 h. After vacuum concentration, the residue was dissolved in DCM (15 ml), and the resulting solution was added dropwise to a DCM solution (15 ml) of BrCZEO (0.52 g, 0.14 mmol) and triethylamine (TEA) (0.303 g, 3 mmol). The mixture was stirred overnight at room temperature. The product was purified by column chromatography using EA:PE = 1:10 as the eluent to obtain the BrCZEO-PCDA monomer.

[0036] Synthesis of Br2CZEO-PCDA monomer

[0037] (a) Synthesis of Br₂CZEO: In a round-bottom flask, 2,7-dibromocarbazole (0.5 g, 1.54 mmol), 2-bromoethanol (0.23 g, 1.85 mmol), K₂CO₃ (0.43 g, 3.08 mmol), and KI (0.26 g, 1.54 mmol) were added to 20 mL of dimethylformamide. The reaction mixture was stirred and heated overnight at 120 °C under nitrogen protection. After the reaction, the mixture was cooled, extracted with ethyl acetate, and the product was purified by column chromatography using EA:PE = 1:10 as the eluent to obtain Br₂CZEO.

[0038] (b) Synthesis of Br2CZEO-PCDA monomer: 10,12-pentadecylene acid (0.5 g, 1.3 mmol) was dissolved in DCM (20 ml), and oxalyl chloride (0.19 g, 1.5 mmol) was added under nitrogen protection. The reaction was stirred for 1 h. DMF (one drop) was added to the above solution and the mixture was stirred for another 4 h. After vacuum concentration, the residue was dissolved in DCM (15 ml), and the resulting solution was added dropwise to a DCM solution (15 ml) of CZBr2 (0.58 g, 0.15 mmol) and triethylamine (TEA) (0.303 g, 3 mmol). The mixture was stirred overnight at room temperature. The product was purified by column chromatography using EA:PE = 1:10 as the eluent to obtain the Br2CZEO-PCDA monomer.

[0039] Synthesis of CZEO-PCDA Assembly

[0040] At room temperature, 2 ml of a tetrahydrofuran solution (1 mg / ml) containing CZEO-PCDA monomer was rapidly added dropwise to 16 ml of water while stirring at 900 rpm for 2 min. The mixture was then stored at 4 °C for 24 h to form an ordered molecular self-assembled structure. Finally, the prepared self-assembled structure was dropped onto a glass plate and allowed to evaporate completely before irradiation under a 254 nm UV lamp for 90 s, yielding CZEO-PCDA with room-temperature phosphorescence properties.

[0041] like Figure 1 As shown, the phosphorescence emission peak of CZEO-PCDA is around 425nm, and the lifetime is 4.89ms.

[0042] Synthesis of CZEO-PCDA:PCDA organic polymer

[0043] At room temperature, 2 ml of a tetrahydrofuran solution (1 mg / ml) containing CZEO-PCDA monomer and PCDA monomer in a molar ratio of 1:2 was rapidly added dropwise to 16 ml of water while stirring at 900 rpm for 2 min. The mixture was then stored at 4 °C for 24 h to form an ordered molecular self-assembled structure. Finally, the prepared self-assembled structure was dropped onto a glass plate and allowed to evaporate completely before irradiation under a 254 nm UV lamp for 90 s, yielding a CZEO-PCDA:PCDA organic polymer exhibiting room-temperature phosphorescence.

[0044] like Figure 1 As shown, the phosphorescence emission peak of the CZEO-PCDA:PCDA organic polymer is around 425 nm, and the lifetime is 6.85 ms.

[0045] Synthesis of BrCZEO-PCDA assemblies

[0046] At room temperature, 2 ml of a tetrahydrofuran solution (1 mg / ml) containing BrCZEO-PCDA monomer was rapidly added dropwise to 16 ml of water while stirring at 900 rpm for 2 min. The mixture was then stored at 4 °C for 48 h to form an ordered molecular self-assembled structure. Finally, the prepared self-assembled structure was dropped onto a glass plate and allowed to evaporate completely before irradiation under a 254 nm UV lamp for 90 s, yielding BrCZEO-PCDA with room-temperature phosphorescence properties.

[0047] like Figure 2 As shown, the phosphorescence emission peak of the BrCZEO-PCDA organic polymer is around 425 nm, and the lifetime is 6.53 ms.

[0048] Synthesis of BrCZEO-PCDA:PCDA organic polymer

[0049] At room temperature, 2 ml of a tetrahydrofuran solution (1 mg / ml) containing BrCZEO-PCDA monomer and PCDA monomer in a molar ratio of 1:2 was rapidly added dropwise to 16 ml of water while stirring at 900 rpm for 2 min. The mixture was then stored at 4 °C for 48 h to form an ordered molecular self-assembled structure. Finally, the prepared self-assembled structure was dropped onto a glass plate and allowed to evaporate completely before irradiation under a 254 nm UV lamp for 90 s, yielding a BrCZEO-PCDA:PCDA organic polymer exhibiting room-temperature phosphorescence.

[0050] like Figure 2 As shown, the phosphorescence emission peak of the BrCZEO-PCDA:PCDA organic polymer is around 425 nm, and the lifetime is 7.57 ms.

[0051] Synthesis of Br2CZEO-PCDA assemblies

[0052] At room temperature, 2 ml of a tetrahydrofuran solution (1 mg / ml) containing Br2CZEO-PCDA monomer was rapidly added dropwise to 16 ml of water while stirring at 900 rpm for 2 min. The mixture was then stored at 4 °C for 28 h to form an ordered molecular self-assembled structure. Finally, the prepared self-assembled structure was dropped onto a glass plate and allowed to evaporate completely before irradiation under a 254 nm UV lamp for 90 s, yielding Br2CZEO-PCDA with room-temperature phosphorescence properties.

[0053] like Figure 3 As shown, the phosphorescence emission peak of the Br2CZEO-PCDA organic polymer is around 425 nm, and the lifetime is 5.99 ms.

[0054] Synthesis of Br2CZEO-PCDA:PCDA organic polymer

[0055] At room temperature, 2 ml of a tetrahydrofuran solution (1 mg / ml) containing Br2CZEO-PCDA monomers and PCDA monomers in a molar ratio of 1:2 was rapidly added dropwise to 16 ml of water while stirring at 900 rpm for 2 min. The mixture was then stored at 4 °C for 28 h to form an ordered molecular self-assembled structure. Finally, the prepared self-assembled structure was dropped onto a glass plate and allowed to evaporate completely before irradiation under a 254 nm UV lamp for 90 s, yielding a Br2CZEO-PCDA:PCDA organic polymer exhibiting room-temperature phosphorescence.

[0056] like Figure 3 As shown, the phosphorescence emission peak of the Br2CZEO-PCDA:PCDA organic polymer is around 425 nm, and the lifetime is 7.20 ms.

Claims

1. A room temperature phosphorescent material, characterized by, The room temperature phosphorescent material is a pure organic polymer, comprising a copolymer repeating unit of room temperature phosphorescent molecule-diacetylenic acid and diacetylenic acid formed by esterification of a room temperature phosphorescent molecule and a diacetylenic acid; The room temperature phosphorescent molecule is 2-(9H-carbazol-9-yl)ethanol, 2-(2-bromo-9H-carbazol-9-yl)ethanol or 2-(2,7-dibromo-9H-carbazol-9-yl)ethanol. The diacetylenic acid is 10,12-pentacosadiynoic acid.

2. The room temperature phosphorescent material according to claim 1, characterized in that, The room temperature phosphorescent material has an ordered molecular structure formed by self-assembly. 3.The room temperature phosphorescent material of claim 1, wherein, The molar ratio of the room temperature phosphorescent molecule-diacetylenic acid formed by esterification of a room temperature phosphorescent molecule and a diacetylenic acid to the diacetylenic acid in the copolymer repeating unit is 1:

2.

4. A method for preparing the room temperature phosphorescent material of claim 1, comprising: esterifying a diacetylenic acid and a room temperature phosphorescent molecule to form a room temperature phosphorescent molecule-diacetylenic acid monomer; self-assembling the room temperature phosphorescent molecule-diacetylenic acid monomer together with a diacetylenic acid monomer to form an ordered molecular structure; performing photopolymerization to obtain the room temperature phosphorescent material; The room temperature phosphorescent molecule is 2-(9H-carbazol-9-yl)ethanol, 2-(2-bromo-9H-carbazol-9-yl)ethanol or 2-(2,7-dibromo-9H-carbazol-9-yl)ethanol. The diacetylenic acid is 10,12-pentacosadiynoic acid.

5. The method of claim 4, wherein, The molar ratio of the room temperature phosphorescent molecule-diacetylenic acid formed by esterification of a room temperature phosphorescent molecule and a diacetylenic acid to the diacetylenic acid in the copolymer repeating unit is 1:2.

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