A preparation method of chiral phosphorescent carbon dots and directional control of their circularly polarized phosphorescence color

Abstract

This invention discloses a method for preparing chiral phosphorescent carbon dots and the directional control of their circularly polarized phosphorescence color. The invention prepares chiral phosphorescent carbon dots using polymers and amino acids as precursors. By co-assembling the carbon dots, dye molecules, and polyvinyl alcohol, the directional control of the circularly polarized phosphorescence color of the carbon dots is achieved, resulting in a multicolor circularly polarized luminescent material based on the carbon dots.

Description

Technical Field

[0001] The invention relates to a preparation method of chiral phosphorescent carbon dots and directional control of circularly polarized phosphorescent color thereof, and belongs to the field of new materials. Background Art

[0002] Circularly polarized luminescence (CPL) refers to the phenomenon in which chiral materials emit differentially left-handed and right-handed circularly polarized light. It has potential applications in 3D displays, bioimaging, optoelectronic devices, anti-counterfeiting materials, and asymmetric photocatalysis. Among the diverse array of circularly polarized luminescent materials, circularly polarized phosphorescent materials with long-lived circularly polarized emission have emerged as a new frontier research topic, offering even more exciting application potential. Currently reported CPL materials are based on noble metal complexes or organic compounds, which face challenges such as high cost, demanding preparation conditions, and difficulty in controlling optical properties, limiting their practical applications.

[0003] Carbon dots are a type of carbon-based nanomaterial with a size of less than 10 nm. They have the advantages of simple synthesis, low cost, and easy control of optical properties. They have shown unique advantages in bioimaging, catalysis, sensors, and energy storage and conversion. Chirality and phosphorescence are the two basic units for constructing circularly polarized phosphorescent materials. At present, carbon dot-based circularly polarized phosphorescent materials are mainly composed of complexes constructed by phosphorescent carbon dots and chiral molecules ( ACS Nano 2020, 14, 11130-11139; ACS Nano 2023,17, 6912-6921), carbon dots with circularly polarized phosphorescence properties have not yet been reported. Adjustable emission color is the key to expanding the application of circularly polarized phosphorescent materials. Currently, the emission of phosphorescent carbon dots is usually in the blue-green region ( Small 2023,2301240), which to some extent limits the application of carbon dot-based circularly polarized phosphorescent materials. Therefore, it is of great research significance to synthesize carbon dots with inherent circularly polarized phosphorescent properties through rational molecular design and achieve directional control of emission color. Summary of the Invention

[0004] The present invention provides a method for preparing chiral phosphorescent carbon dots. Furthermore, given that phosphorescent carbon dots typically emit light in the blue-green region, the present invention provides an effective method for directional control of the color of circularly polarized phosphorescence.

[0005] The technical solutions of the present invention are as follows:

[0006] (1) A method for preparing chiral phosphorescent carbon dots, comprising the following steps:

[0007] 1. Dissolve the polymer and amino acid in a certain amount of distilled water respectively and stir to dissolve.

[0008] 2. Transfer the dissolved solution to the reactor in sequence, place the reactor in a forced air drying oven at 80-160°C for 8-12 hours, and remove the reacted solution after cooling to room temperature.

[0009] 3. The reaction solution is dialyzed using a 500-3500 Da dialysis bag for 12-48 hours, and then freeze-dried to remove residual water to obtain chiral phosphorescent carbon dots.

[0010] According to the present invention, the polymer in step 1 is sodium alginate or polyacrylic acid, but is not limited to these two polymers. Other polymers such as polyacrylamide and polyethyleneimine may also be used.

[0011] According to the present invention, the amino acids in step 1 are L- / D-arginine and L- / D-lysine.

[0012] According to the present invention, the mass ratio of the polymer to the amino acid in step 1 is 8:1 to 1:8.

[0013] (2) Directional control of circularly polarized phosphorescence color, including the following steps:

[0014] 4. Dissolve a certain amount of carbon dots obtained in step 3 in a polyvinyl alcohol aqueous solution and stir for 0.5-3 hours to fully dissolve them. The concentration of carbon dots in the polyvinyl alcohol aqueous solution is 1-10 mg / mL.

[0015] 5. Add a certain amount of dye molecules to the solution in step 4 and stir for 0.5 to 3 hours to fully mix them. The concentration of the dye molecules in the polyvinyl alcohol aqueous solution is 0.001 to 1 mg / mL.

[0016] 6. Pour the mixed solution into a mold and heat it in an oven at 50-120 °C for 0.5-4 hours to obtain a multicolor circularly polarized phosphorescent material.

[0017] According to the present invention, the dye molecules in step 5 are rhodamine 6G, rhodamine B, and sulfadiazine 101.

[0018] The technical key points of the present invention are as follows: (1) preparation of chiral phosphorescent carbon dots; (2) directional control of circularly polarized phosphorescence color.

[0019] The outstanding features of the present invention are: 1) the preparation method is simple and feasible, highly designable, and easy to scale up; 2) it provides a method for preparing chiral phosphorescent carbon dots; 3) it provides an effective strategy for directionally controlling the color of circularly polarized phosphorescence.

[0020] The advantages of the present invention are: 1) no external chiral molecules are required to construct carbon dots with circularly polarized phosphorescence properties; 2) directional control of the carbon dot-based circularly polarized phosphorescence color is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a high-resolution transmission electron microscope photograph of the carbon dots obtained in Example 2.

[0022] Figure 2 is the X-ray diffraction spectrum of the carbon dots obtained in Example 2.

[0023] Figure 3 This is the phosphorescence spectrum of the carbon dots obtained in Example 2.

[0024] Figure 4 This is the circularly polarized phosphorescence spectrum of the carbon dots obtained in Example 2.

[0025] Figure 5 4 is the circularly polarized phosphorescence spectrum of the carbon dots obtained in Example 4.

[0026] Figure 6 This is the circularly polarized phosphorescence spectrum of the material obtained in Example 28.

[0027] Figure 7 This is the circularly polarized phosphorescence spectrum of the material obtained in Example 29.

[0028] Figure 8 This is the circularly polarized phosphorescence spectrum of the material obtained in Example 30. Implementation Method

[0029] 1. Preparation of Chiral Phosphorescent Carbon Dots Example 1

[0030] Weigh 0.8 g of sodium alginate and dissolve it in 4 mL of distilled water, stirring until fully dissolved. Weigh 0.8 g of L-arginine and dissolve it in 4 mL of distilled water, stirring until fully dissolved. Transfer the sodium alginate solution and the L-arginine solution to a reaction vessel in sequence. Place the reaction vessel in a forced air drying oven at 120°C and react for 10 hours. After the reaction is complete, allow the reaction vessel to cool naturally to room temperature. Transfer the reaction solution to a 1000 Da dialysis bag and dialyze it for 24 hours, changing the water once during dialysis. After dialysis, freeze-dry the solution in the dialysis bag to remove any residual water, thereby obtaining chiral phosphorescent carbon dots. Example 2

[0031] The same method as described in Example 1, except that the mass of L-arginine was 3.2 g, and other conditions remained unchanged.

[0032] The high-resolution transmission electron microscopy of the carbon dots prepared in this example is as follows Figure 1 As shown, from Figure 1It can be seen that the obtained carbon dots are spherical structures.

[0033] The X-ray diffraction spectrum of the carbon dots prepared in this example is shown in FIG. Figure 2 As shown, from Figure 2 It can be seen that the internal structure of the obtained carbon dots is amorphous, which is consistent with the characteristics of carbonized polymer dots.

[0034] The phosphorescence spectrum of the carbon dots prepared in this example is shown in FIG. Figure 3 As shown, from Figure 3 It can be seen that the prepared carbon dots phosphorescence emission range is between 400 and 800 nm, and the peak with the highest intensity is in the green light range.

[0035] The circularly polarized phosphorescence spectrum of the carbon dots prepared in this example is shown in FIG. Figure 4 As shown, from Figure 4 It can be seen that the circularly polarized phosphorescence spectrum of the prepared carbon dots is similar to Figure 3 The emission peaks of the phosphorescence spectra are consistent. Example 3

[0036] The same method as described in Example 1, except that the mass of L-arginine was 0.2 g, and other conditions remained unchanged. Example 4

[0037] As described in Example 1, except that L-arginine was replaced by D-arginine, and other conditions remained unchanged.

[0038] The circularly polarized phosphorescence spectrum of the carbon dots prepared in this example is shown in FIG. Figure 5 shown. Example 5

[0039] The same process as in Example 1 was carried out except that the reaction temperature was 100°C and the other conditions remained unchanged. Example 6

[0040] The same process as in Example 1 was carried out except that the reaction temperature was 140°C and the other conditions remained unchanged. Example 7

[0041] The same process as in Example 1 was carried out except that the reaction temperature was 160°C and the other conditions remained unchanged. Example 8

[0042] The same process as in Example 1 was carried out except that the reaction temperature was 180°C and the other conditions remained unchanged. Example 9

[0043] As described in Example 1, except that L-arginine was replaced by L-lysine, and other conditions remained unchanged. Example 10

[0044] As described in Example 2, except that L-arginine was replaced by L-lysine, and other conditions remained unchanged. Example 11

[0045] As described in Example 3, except that L-arginine was replaced by L-lysine, and other conditions remained unchanged. Example 12

[0046] As described in Example 4, except that D-arginine was replaced by D-lysine, and other conditions remained unchanged. Example 13

[0047] Weigh 0.6 g of L-lysine and dissolve it in 6 mL of distilled water. Stir to dissolve thoroughly. Weigh 0.4 g of a 50% aqueous solution of polyacrylic acid (50 wt.%) and add it to the dissolved lysine solution. Transfer the mixed solution to a reactor. Place the reactor in a forced-air drying oven at 100°C and react for 10 hours. After the reaction is complete, allow the reactor to cool naturally to room temperature. Transfer the reaction solution to a 3500 Da dialysis bag and dialyze it for 24 hours, changing the water once. After dialysis, freeze-dry the solution in the bag to remove any residual water, thereby obtaining chiral phosphorescent carbon dots. Example 14

[0048] The reaction was carried out as described in Example 13, except that the reaction temperature was 120°C and the other conditions remained unchanged. Example 15

[0049] The reaction was carried out as described in Example 13, except that the reaction temperature was 140°C and the other conditions remained unchanged. Example 16

[0050] The reaction was carried out as described in Example 13, except that the reaction temperature was 160°C and the other conditions remained unchanged. Example 17

[0051] The reaction was carried out as described in Example 13, except that the reaction temperature was 180°C and the other conditions remained unchanged. Example 18

[0052] As described in Example 13, except that L-lysine was replaced by D-lysine, and other conditions remained unchanged. Example 19

[0053] As described in Example 13, except that L-lysine was replaced by L-arginine, and other conditions remained unchanged. Example 20

[0054] As described in Example 13, except that L-lysine was replaced by D-arginine, and other conditions remained unchanged.

[0055] 2. Directional Control of the Circularly Polarized Phosphorescence Color of Carbon Dots Example 21

[0056] Weigh 10 mg of carbon dots and dissolve them in 2 mL of polyvinyl alcohol (PVA) solution. Stir for 2 hours to fully dissolve. Prepare a Rhodamine 6G stock solution by weighing 5 mg of Rhodamine 6G and dissolving it in 1 mL of distilled water. Pipette 2 μL of the Rhodamine 6G stock solution into the PVA solution of carbon dots and stir for 2 hours to thoroughly mix. Pour the resulting solution into a mold and heat it in an oven at 80°C for 3 hours to obtain a yellow circularly polarized phosphorescent material. Example 22

[0057] The same method as described in Example 18 was used, except that the volume of the Rhodamine 6G stock solution transferred was 2.5 μL, and other conditions remained unchanged. Example 23

[0058] The same method as described in Example 18 was used, except that the volume of the Rhodamine 6G stock solution transferred was 5 μL, and other conditions remained unchanged. Example 24

[0059] The same method as described in Example 18 was used, except that the volume of the Rhodamine 6G stock solution transferred was 10 μL, and other conditions remained unchanged. Example 25

[0060] The same method as described in Example 18 was used, except that the volume of the Rhodamine 6G stock solution transferred was 20 μL, and other conditions remained unchanged. Example 26

[0061] The same method as described in Example 18 was used, except that the volume of the Rhodamine 6G stock solution transferred was 40 μL, and other conditions remained unchanged. Example 27

[0062] The same method as described in Example 18 was used, except that the volume of the Rhodamine 6G stock solution transferred was 100 μL, and other conditions remained unchanged. Example 28

[0063] The same method as in Example 18 was used, except that the volume of the Rhodamine 6G mother solution was 200 μL, and other conditions remained unchanged. The circularly polarized phosphorescence spectrum of the obtained material is shown in FIG. Figure 6 shown. Example 29

[0064] The same method as in Example 28 was used except that the dye Rhodamine 6G was replaced with Rhodamine B. Other conditions remained unchanged. The circularly polarized phosphorescence spectrum of the obtained material is shown in FIG. Figure 7 shown. Example 30

[0065] The same method as in Example 28 was used except that the dye Rhodamine 6G was replaced with Sulfabutin 101. Other conditions remained unchanged. The circularly polarized phosphorescence spectrum of the obtained material is shown in FIG. Figure 8 shown.

Claims

1. A method for preparing carbon dots with circularly polarized phosphorescent properties, characterized in that The specific steps are: (1) Dissolve the polymer and amino acid in a certain amount of distilled water, stirring to dissolve, wherein the polymer is sodium alginate, polyacrylic acid, polyacrylamide, or polyethyleneimine, and the amino acid is L-arginine, D-arginine, L-lysine, or D-lysine, and the mass ratio of the polymer to the amino acid is 8:1 to 1:8; (2) The dissolved solution was transferred to the reactor in sequence, and the reactor was placed in a forced air drying oven at 80-160 °C for 8-12 hours. After cooling to room temperature, the reaction solution was taken out; (3) The reaction solution is dialyzed using a 500-3500 Da dialysis bag for 12-48 hours, and then freeze-dried to remove residual water to obtain circularly polarized phosphorescent carbon dots.

2. A method for directional control of circularly polarized phosphorescence color, characterized in that The specific steps are: (1) dissolving a certain amount of carbon dots obtained by the preparation method of claim 1 and a certain amount of dye molecules in a polyvinyl alcohol aqueous solution and stirring for 0.5 to 3 hours to fully dissolve them, wherein the concentration of the carbon dots in the polyvinyl alcohol aqueous solution is 1 to 10 mg / mL, and the concentration of the dye molecules in the polyvinyl alcohol aqueous solution is 0.001 to 1 mg / mL, and the dye molecules are rhodamine 6G, rhodamine B, or sulfadiazine 101; (2) Pour the mixed solution into a mold and heat it in an oven at 50-120 °C for 0.5-4 hours to obtain a multicolor circularly polarized phosphorescent material.

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