A red-light afterglow carbon dot material, its preparation method and application

Abstract

The present invention provides a red afterglow carbon dot material, a preparation method thereof and an application. The preparation method comprises the following steps: dissolving an organic dye and a nitrogen source in deionized water for hydrothermal reaction; cooling the solution after the hydrothermal reaction to room temperature, centrifuging, collecting the supernatant to obtain a seed solution; dissolving the seed solution in deionized water, then adding a nitrogen source and a silicon source, heating by oil bath until dry, naturally cooling to room temperature, and grinding to obtain the red afterglow carbon dot material, which can be used for afterglow lighting or afterglow display. The preparation method of the present invention is simple, and the prepared afterglow carbon dot luminescent material has a long emission wavelength, the emission range is red light, the photoluminescence quantum yield is close to 100%, the lifetime is up to more than 334 ms, and it has good stability.

Description

Technical Field

[0001] The present invention relates to the technical field of room temperature phosphorescent materials, and particularly to a red afterglow carbon dot material, a preparation method thereof and an application thereof. Background Art

[0002] Due to their unique afterglow luminescence properties, existing room temperature phosphorescent materials have broad application prospects in anti-counterfeiting, information encryption and other aspects. Existing room temperature phosphorescent materials are mainly divided into two categories: metal-containing room temperature phosphorescent materials and metal-free room temperature phosphorescent materials. Because metal-containing room temperature phosphorescent materials have deficiencies such as high toxicity and high cost, it is the general trend to develop metal-free room temperature phosphorescent materials with excellent performance. Afterglow carbon dot materials have gradually come into the sight of researchers. This new type of nanoscale luminescent material is considered to be the most promising new generation of luminescent materials because of its high chemical stability, simple and rapid preparation process and excellent optical properties.

[0003] However, the relatively low afterglow efficiency and lifetime (lifetime greater than 100 ms is called afterglow) seriously limit the further practical application of afterglow carbon dot luminescent materials. In addition, the existing afterglow carbon dot materials have a relatively narrow emission range distribution, concentrated in the yellow-light to blue-light (<600 nm) range, and the photoluminescence quantum yield (PLQY) has also reached almost 100%. However, it is difficult to prepare red afterglow materials with an emission wavelength greater than 600 nm and the PLQY efficiency is low (less than 60%). Summary of the Invention

[0004] The present invention provides a red afterglow carbon dot material, a preparation method thereof and an application thereof. The preparation method is simple, and the prepared afterglow carbon dot luminescent material has a long emission wavelength, the emission range is red light, the PLQY is close to 100%, the lifetime is up to more than 334 ms, and it has good stability.

[0005] The technical solution of the present invention is realized as follows: A preparation method of a red afterglow carbon dot material, comprising the following steps:

[0006] 1) Dissolve an organic dye and a nitrogen source in deionized water to form a reaction solution, stir and then carry out a hydrothermal reaction;

[0007] 2) Cool the solution after the hydrothermal reaction to room temperature, then centrifuge and collect the supernatant to obtain a seed solution;

[0008] 3) Dissolve the seed solution, the nitrogen source and the silicon source in deionized water to obtain a mixed solution. Heat the mixed solution in an oil bath until it is dry, naturally cool it to room temperature, and grind it to obtain a red afterglow carbon dot material.

[0009] Further, the nitrogen source is urea (abbreviation: urea), the silicon source is 3-aminopropyltriethoxysilane (abbreviation: APTES), and the organic dye is rhodamine B (abbreviation: RhB).

[0010] Further, in step 1), the mass ratio of the organic dye, nitrogen source and deionized water is 1:500:5000.

[0011] Further, in step 1), the hydrothermal reaction is carried out at 160 °C for 6 h.

[0012] Further, in step 3), 2 ml of the seed CDs solution, 200 mg of the nitrogen source and 125 μl of the silicon source are dissolved in 5 ml of deionized water.

[0013] Further, in step 3), the oil bath heating is carried out at 150 - 180 °C (such as 150 °C, 160 °C, 170 °C, 180 °C, etc.) for 1 - 3 h (such as 1 h, 2 h, 3 h, etc.).

[0014] The red-light persistent luminescence carbon dot material prepared by the described preparation method.

[0015] Further, the application of the red-light persistent luminescence carbon dot material in persistent luminescence illumination or persistent luminescence display.

[0016] Further, the method of the shown application is as follows: The persistent luminescence carbon dot material is fixed on the ultraviolet chip through a glue without fluorescence irradiation to obtain a persistent luminescence illumination device.

[0017] Advantages of the present invention:

[0018] The red-light persistent luminescence carbon dot material of the present invention is prepared by a simple hydrothermal method. The raw materials used are cheap, environmentally friendly and less polluting. The preparation process is simple, easy to operate and control, and suitable for continuous large-scale production.

[0019] The red-light persistent luminescence carbon dot material of the present invention realizes the persistent luminescence phenomenon with a long emission wavelength, and suppresses non-radiative recombination through the hydrogen bonds formed by urea and the construction of a three-dimensional network structure by the SiO2 matrix, etc., greatly improving the red-light luminescence efficiency. The PLQY is close to 100%, with a long persistent luminescence lifetime of more than 334 ms, and good stability and other characteristics, and can be used for afterglow illumination. Description of the drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 Transmission electron microscopy (TEM) of the seed CDs carbon dot material prepared in Example 1.

[0022] Figure 2 UV-Vis absorption spectrum of the seed CDs carbon dot material prepared in Example 1.

[0023] Figure 3 Transmission electron microscopy (TEM) and particle size diagram of the CDs@u / SiO2 carbon dot material prepared in Example 1.

[0024] Figure 4 X-ray diffraction spectrum (XRD) of the CDs@u / SiO2 carbon dot material prepared in Example 1.

[0025] Figure 5 Infrared spectrum (FT-IR) of the CDs@u / SiO2 carbon dot material prepared in Example 1.

[0026] Figure 6 X-ray photoelectron spectroscopy (XPS) of the CDs@u / SiO2 carbon dot material prepared in Example 1.

[0027] Figure 7 Afterglow lifetime time-resolved decay spectrum of the CDs@u / SiO2 carbon dot material prepared in Example 1.

[0028] Figure 8 Afterglow emission spectrum of the CDs@u / SiO2 carbon dot material prepared in Example 1.

[0029] Figure 9 Intensity and lifetime comparison diagram of the CDs@u / SiO2 carbon dot material prepared in Example 1, the CDs@u / SiO2-80 prepared in Comparative Example 2, and the RhB@u / SiO2 prepared in Comparative Example 3.

[0030] Figure 10 Photoluminescence quantum yield diagram (PLQY) of the CDs@u / SiO2 carbon dot material prepared in Example 1.

[0031] Figure 11 Afterglow illumination application diagram of the CDs@u / SiO2 carbon dot material prepared in Example 1.

[0032] Figure 12 LED stability of the CDs@u / SiO2 carbon dot material prepared in Example 1. Detailed implementation mode

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0034] Example 1

[0035] A method for preparing a red light afterglow carbon dot material comprises the following steps:

[0036] (1) Add 2 mg of RhB and 1 g of urea to 10 ml of deionized water and stir for 10 min. After thorough mixing, the reaction solution was obtained. The reaction solution was placed in a 50 ml polytetrafluoroethylene reactor, which was tightly sealed and placed in an oven at 160°C for 6 h. The reaction was then naturally cooled to room temperature. The solution after the hydrothermal reaction was centrifuged at 8000 r / min, and the supernatant was collected to obtain the seed solution (abbreviated as: seed CDs).

[0037] TEM test of the obtained seed CDs carbon dot material: Figure 1 This is a transmission electron micrograph of seed CDs taken at 50 nm, showing a typical carbon dot structure with a lattice spacing of 0.21 nm, corresponding to a graphitic carbon structure.

[0038] The obtained seed CDs carbon dot material was tested by UV-visible absorption spectrum: Figure 2 Figure 3 is the UV-visible absorption spectrum of seed CDs, and the peak at 300-400 nm can be attributed to the (π, π*) transition.

[0039] (2) Dissolve 2 ml of seed CDs solution, 200 mg of urea and 125 μl of 3-aminopropyltriethoxysilane (APTES) in 5 ml of deionized water to obtain a mixed solution. Place the mixed solution in a 20 ml glass bottle and react in an oil bath at 150 ° C for 2 h until dry to obtain CDs@u / SiO2 afterglow carbon dot material.

[0040] The CDs@u / SiO2 afterglow carbon dot material obtained in Example 1 was subjected to TEM testing: Figure 3 This is a transmission electron microscope image of CDs@u / SiO2 CDs@u / SiO2 afterglow carbon dot material taken at 50nm, which shows a typical carbon dot structure with an average particle size of 3.75nm and a lattice spacing of 0.21nm, corresponding to a graphitic carbon structure.

[0041] XRD test was carried out on the CDs@u / SiO2 afterglow carbon dot material obtained in Example 1: Figure 4 XRD photo of the CDs@u / SiO2 afterglow carbon dot material, which shows a typical SiO2 peak at 21.6°.

[0042] FT-IR test was carried out on the CDs@u / SiO2 afterglow carbon dot material obtained in Example 1: Figure 5 FT-IR spectrum of the CDs@u / SiO2 afterglow carbon dot material, which indicates that there are various functional groups on the surface of the sample.

[0043] XPS test was carried out on the CDs@u / SiO2 afterglow carbon dot material obtained in Example 1: Figure 6 XPS spectrum of the CDs@u / SiO2 afterglow carbon dot material, which indicates that there are various functional groups on the surface of the sample, verifying the results of FT-IR.

[0044] Time-resolved decay spectrum test was carried out on the CDs@u / SiO2 afterglow carbon dot material obtained in Example 1: Figure 7 Afterglow time-resolved decay curve of the CDs@u / SiO2 afterglow carbon dot material, which indicates that the sample has a long afterglow lifetime (334.2 ms).

[0045] Afterglow emission spectrum test was carried out on the CDs@u / SiO2 afterglow carbon dot material obtained in Example 1: Figure 8 Afterglow emission spectrum of the CDs@u / SiO2 afterglow carbon dot material, which indicates that the emission position of the sample is in the red light region.

[0046] PLQY test was carried out on the CDs@u / SiO2 afterglow carbon dot material obtained in Example 1: Figure 10 PLQY spectrum of the CDs@u / SiO2 afterglow carbon dot material, which indicates that the sample has an ultra-high PLQY (99.9%).

[0047] The afterglow LED application was carried out on the CDs@u / SiO2 afterglow carbon dot material obtained in Example 1. The CDs@u / SiO2 afterglow carbon dot material prepared in Example 1 was fixed on the ultraviolet chip through a glue without fluorescence irradiation, Figure 11 Afterglow illumination application diagram of the CDs@u / SiO2 afterglow carbon dot material.

[0048] LED stability test was carried out on the CDs@u / SiO2 afterglow carbon dot material obtained in Example 1: Figure 12 Stability spectrum of the CDs@u / SiO2 afterglow carbon dot material. On the premise that the brightness is 1000 cd / m 2 , under continuous excitation by a 365 nm ultraviolet lamp for ten hours, the luminous intensity remains almost unchanged.

[0049] Comparative Example 1

[0050] Add 2 mg of RhB and 1 g of urea to 10 ml of deionized water and stir for 10 minutes. After thorough mixing, the reaction solution was placed in a 50 ml polytetrafluoroethylene reactor, tightly sealed, and placed in an 80°C oven for 6 hours. The mixture was then cooled to room temperature and centrifuged at 8000 rpm. The supernatant was collected to obtain seed CDs-80.

[0051] Dissolve 2 ml of seed CDs-80 solution, 200 mg of urea and 125 μl of 3-aminopropyltriethoxysilane (APTES) in 5 ml of deionized water, place them in a 20 ml glass bottle, and react in an oil bath at 150°C for 2 h until dry to obtain CDs@u / SiO2-80 afterglow carbon dot material.

[0052] Comparative Example 2

[0053] Add 2 mg of RhB to 10 ml of deionized water and stir for 10 minutes. After thorough mixing, the reaction solution was placed in a 50 ml polytetrafluoroethylene reactor, tightly sealed, and placed in a 160°C oven for 6 hours. After cooling to room temperature, the solution was centrifuged at 8000 rpm and the supernatant collected to obtain the RhB seed solution.

[0054] 2 ml of RhB seed solution, 200 mg of urea and 125 μl of 3-aminopropyltriethoxysilane (APTES) were dissolved in 5 ml of deionized water, placed in a 20 ml glass bottle, and reacted in an oil bath at 150 ° C for 2 h until dry to obtain RhB@u / SiO2 afterglow carbon dot material.

[0055] The CDs@u / SiO2 carbon dot material obtained in Example 1 was compared with the materials prepared under the conditions of Comparative Examples 1 and 2: Figure 9 The strength and lifespan comparison of the CDs@u / SiO2 carbon dot material obtained in Example 1, the CDs@u / SiO2-80 prepared in Comparative Example 1, and the RhB@u / SiO2 prepared in Comparative Example 2 are shown in FIG. Figure 9 It can be seen that the strength of the CDs@u / SiO2 carbon dot material prepared in Example 1 increased by 131 times and the lifespan increased by 11 times.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A preparation method of a red-light afterglow carbon dot material, characterized in that, It includes the following steps: 1) Dissolve rhodamine B and urea in deionized water to form a reaction solution. After stirring, conduct a hydrothermal reaction at 160 °C for 6 h. The mass ratio of rhodamine B, urea, and deionized water for feeding is 1∶500∶5000; 2) Cool the solution after the hydrothermal reaction to room temperature, then centrifuge and collect the supernatant to obtain a seed solution; 3) Dissolve 2 ml of the seed solution, 200 mg of urea, and 125 μl of 3-aminopropyltriethoxysilane in 5 ml of deionized water to obtain a mixed solution. Heat the mixed solution in an oil bath at 150 - 180 °C for 1 - 3 h until dry. After cooling to room temperature and grinding, a red afterglow carbon dot material is obtained.

2. A red afterglow carbon dot material prepared by the preparation method described in claim 1.

3. Application of the red afterglow carbon dot material described in claim 2 in afterglow lighting.

4. The application according to claim 3, characterized in that: The method of the said application is as follows: Fix the afterglow carbon dot material on a UV chip through a glue without fluorescence irradiation to obtain an afterglow lighting device.

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