Preparation method of long-life room-temperature phosphorescent carbon dot and boron oxide composite material

Abstract

The invention relates to a preparation method of a long-life room-temperature phosphorescent carbon dot and boron oxide composite material, which comprises the following steps: adding trinitropyrene and boric acid into a sodium hydroxide aqueous solution, fully dissolving the trinitropyrene and the boric acid through ultrasonic treatment, and carrying out hydrothermal reaction to obtain a brown solution; and finally, calcining the brown powder in a muffle furnace to obtain the long-service-life room-temperature phosphorescent carbon dot-boron oxide composite material. The preparation method is characterized in that the long-life room-temperature phosphorescent carbon dot and boron oxide composite material is obtained by a simple preparation method, and has the advantages of simplicity and convenience in operation, high yield and the like. In addition, the prepared long-service-life room-temperature phosphorescent carbon dot and boron oxide composite material has good phosphorescence performance, and orange phosphorescence can be seen by naked eyes for 12 s after an ultraviolet lamp is turned off. The medicines used for preparation are nontoxic, harmless and low in price, the preparation is simple, and the used time is short.

Description

Technical Field

[0001] The invention belongs to the technical field of carbon dot nano material preparation, and in particular relates to a method for preparing a long-life room temperature phosphorescent carbon dot@boron oxide composite material. Background Art

[0002] Room temperature phosphorescent materials are materials that can still emit light when the external excitation light source stops. They have the advantages of large Stokes shift, long emission lifetime, high signal-to-noise ratio, and can eliminate background fluorescence and light scattering interference. They have great advantages in the fields of new generation information anti-counterfeiting, photoelectric conversion and bioimaging. However, existing room temperature phosphorescent materials are mainly traditional rare earth ion doped inorganic compounds. The complexity of the manufacturing method and the scarcity and high cost of rare earth resources limit their practical application. Therefore, it is very necessary to develop a long-life room temperature phosphorescent material that is easy to prepare, environmentally friendly and inexpensive.

[0003] Carbon dot-based room temperature phosphorescent materials have the advantages of easy preparation, tunable wavelength, non-toxicity and pollution-free, which opens up a new way to develop new room temperature phosphorescent materials that are environmentally friendly, low-cost and have stable luminescent properties. However, due to the violent vibration and rotation of the carbon dot luminescent group, it has low intersystem crossing and fast non-radiative transition, which reduces the quantum yield and phosphorescence lifetime of carbon dot-based room temperature phosphorescent materials. In order to solve these problems, researchers have embedded carbon dots in various rigid matrices or introduced polymer chains on the surface of carbon dots to limit molecular vibration and rotation, stabilize the lowest excited state, and thus reduce non-radiative decay and quenching processes. However, the preparation process and regulation methods of carbon dot-based room temperature phosphorescent materials are relatively cumbersome, which increases the complexity of the reaction. Therefore, it is of vital importance to use a simple preparation method to obtain carbon dot-based room temperature phosphorescent composite materials with long life. Summary of the invention

[0004] In order to avoid the shortcomings of the prior art, the present invention provides a method for preparing a long-life room temperature phosphorescent carbon dot@boron oxide composite material.

[0005] One of the purposes of the present invention is to provide a simple and feasible preparation method.

[0006] The second object of the present invention is to provide a long-life room temperature phosphorescent carbon dot@boron oxide composite material.

[0007] The long-life room temperature phosphorescent carbon dot@boron oxide composite material prepared by the present invention is prepared by using trinitropyrene and boric acid as raw materials in a simple and easy manner, and the preparation process includes the following specific steps: 1. First, add 10-50 mg of trinitropyrene, 1-5 g of boric acid and 0.4-1.2 g of sodium hydroxide to 10 mL of deionized water to obtain a yellow solution; 2. Place the yellow solution obtained in step 1 in a polytetrafluoroethylene reactor and react at 150-210° C. for 4-12 hours to obtain a brown solution; 3. Freeze-dry the brown solution obtained in step 2 for 12-24 hours to obtain a brown powder; 4. The brown powder obtained in step 3 is placed in a crucible with a cover, and calcined in a muffle furnace at 300-400° C. for 2-4 hours to obtain a long-life room temperature phosphorescent carbon dot@boron oxide composite material.

[0008] Beneficial effects of the present invention: 1. The present invention provides a long-life room temperature phosphorescent carbon dot@boron oxide composite material, which is characterized in that it is prepared from trinitropyrene and boric acid raw materials in a simple and easy manner, and only requires common laboratory equipment, without special equipment, and the process is simple and easy to operate; 2. The long-life room temperature phosphorescent carbon dots@boron oxide composite material obtained by this method has orange phosphorescence visible to the naked eye for up to 12 seconds after the UV light is turned off; 3. The drugs used in the present invention are non-toxic, harmless and inexpensive, and are simple to prepare and take a short time. No complicated and tedious steps are required after preparation. They are particularly suitable for batch and low-cost preparation, and are suitable for industrial-scale production and commercial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the embodiments or the description of the prior art will be briefly introduced with drawings below. However, the drawings in the following description are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0010] Figure 1 This is a transmission electron micrograph of the long-life room temperature phosphorescent carbon dot@boron oxide composite material prepared in Example 1 of the present invention.

[0011] Figure 2 This is an X-ray diffraction pattern of the long-life room temperature phosphorescent carbon dot@boron oxide composite material prepared in Example 1 of the present invention.

[0012] Figure 3 This is a phosphorescence spectrum of the long-life room temperature phosphorescent carbon dot@boron oxide composite material prepared in Example 1 of the present invention.

[0013] Figure 4 This is a phosphorescence lifetime diagram of the long-life room temperature phosphorescent carbon dot@boron oxide composite material prepared in Example 1 of the present invention.

[0014] Figure 5These are state diagrams of the long-life room temperature phosphorescent carbon dot@boron oxide composite materials prepared in Examples 1-3 under sunlight, under 365nm ultraviolet light, and after the ultraviolet light is turned off. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0016] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0017] Unless otherwise specified, the experimental methods described in the following examples are all conventional methods; the reagents and materials described are all commercially available unless otherwise specified.

[0018] Embodiment 1: First, 30 mg of trinitropyrene, 3 g of boric acid and 0.8 g of sodium hydroxide were added to 10 mL of deionized water to obtain a yellow solution; the yellow solution was placed in a polytetrafluoroethylene reactor and reacted at 180°C for 8 hours to obtain a brown solution; the brown solution was freeze-dried for 18 hours to obtain a brown powder; the brown powder was placed in a covered crucible and calcined at 350°C in a muffle furnace for 3 hours to obtain a long-life room temperature phosphorescent carbon dot@boron oxide composite material.

[0019] Embodiment 2: First, 50 mg of trinitropyrene, 1 g of boric acid and 1.2 g of sodium hydroxide were added to 10 mL of deionized water to obtain a yellow solution; the yellow solution was placed in a polytetrafluoroethylene reactor and reacted at 210°C for 4 hours to obtain a brown solution; the brown solution was freeze-dried for 12 hours to obtain a brown powder; the brown powder was placed in a covered crucible and calcined at 400°C in a muffle furnace for 2 hours to obtain a long-life room temperature phosphorescent carbon dot@boron oxide composite material.

[0020] Embodiment 3: First, 10 mg of trinitropyrene, 5 g of boric acid and 0.4 g of sodium hydroxide were added to 10 mL of deionized water to obtain a yellow solution; the yellow solution was placed in a polytetrafluoroethylene reactor and reacted at 150°C for 12 hours to obtain a brown solution; the brown solution was freeze-dried for 24 hours to obtain a brown powder; the brown powder was placed in a covered crucible and calcined at 300°C in a muffle furnace for 4 hours to obtain a long-life room temperature phosphorescent carbon dot@boron oxide composite material.

[0021] Figure 1 This is a transmission electron microscope image of the long-life room temperature phosphorescent carbon dot@boron oxide composite material prepared in Example 1. Figure 1 It can be seen that the carbon dots in the long-life room temperature phosphorescent carbon dots@boric oxide composite material are spherical particles with good dispersion.

[0022] Figure 2 This is the X-ray diffraction pattern of the long-life room temperature phosphorescent carbon dot@boron oxide composite material prepared in Example 1 after calcination. Figure 2 It can be seen that the composite material θ There are obvious characteristic diffraction peaks of boron oxide at =14.73°, 27.71° and 41.4°, indicating the formation of a boron oxide matrix.

[0023] Figure 3 This is the phosphorescence spectrum of the long-life room temperature phosphorescent carbon dot@boron oxide composite material prepared in Example 1 of the present invention. Figure 3 It can be seen that when the excitation wavelength is 365 nm, the optimal phosphorescence emission band is centered at 610 nm.

[0024] Figure 4 This is a phosphorescence lifetime decay diagram of the long-life room temperature phosphorescent carbon dot@boron oxide composite material prepared in Example 1 of the present invention. Figure 4 It can be seen that the time-resolved decay spectrum is fitted using a three-exponential function according to the following formula: τ avg =∑α i τ i 2 / ∑α i τ i The calculated phosphorescence lifetime at room temperature is 0.92 s, indicating that the prepared room temperature phosphorescent carbon dots@boron oxide composite material has a relatively excellent phosphorescence lifetime.

[0025] Figure 5 The long-life room temperature phosphorescent carbon dots@boron oxide composite materials prepared in Examples 1-3 are shown in the following states: under sunlight, under 365nm ultraviolet light, and after the light is turned off. Figure 5 It can be seen that Example 1 prepared exhibits the longest visible time to the naked eye, which is up to 12 s, while the visible time to the naked eye of the long-life room temperature phosphorescent carbon dot@boron oxide composite materials prepared in Examples 2-3 is relatively short.

[0026] Obviously, those skilled in the art can make various changes and modifications to the method for preparing a long-life room temperature phosphorescent carbon dot@boron oxide composite material described in the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing a long-life room temperature phosphorescent carbon dot@boron oxide composite material, comprising the following steps: First, 10-50 mg of trinitropyrene, 1-5 g of boric acid and 0.4-1.2 g of sodium hydroxide are added to 10 mL of deionized water to obtain a yellow solution; the yellow solution is placed in a polytetrafluoroethylene reactor and reacted at 150-210°C for 4-12 hours to obtain a brown solution; the brown solution is freeze-dried for 12-24 hours to obtain a brown powder; the powder is placed in a covered crucible and calcined in a muffle furnace at 300-400°C for 2-4 hours to obtain a long-life room temperature phosphorescent carbon dot@boron oxide composite material.

2. The method for preparing the long-life room temperature phosphorescent carbon dots@boron oxide composite material according to claim 1, characterized in that: The amount of trinitropyrene used is 30 mg, the amount of boric acid used is 3 g, and the amount of sodium hydroxide used is 0.8 g.

3. The method for preparing the long-life room temperature phosphorescent carbon dots@boron oxide composite material according to claim 1, characterized in that: The hydrothermal temperature is 180°C, the hydrothermal time is 8 hours, the calcination temperature is 350°C, and the calcination time is 3 hours.

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