Preparation method of graphene-coated fluorescent material for LED

Abstract

The invention relates to a preparation method of a graphene-coated fluorescent material for an LED (light-emitting diode), which mainly comprises the following steps: placing fluorescent powder in a reaction furnace, vacuumizing to below 1Pa, heating to 300-500 DEG C, introducing methane and hydrogen into the furnace, simultaneously exciting microwave plasma, and finally naturally cooling to room temperature. Particularly, the method disclosed by the invention also uses barium disilicate fluorescent powder, and the novel fluorescent powder with excellent optical performance can be obtained by adding proper elements; and the single-layer graphene is used as a carrier for preparation, so that the dispersion supporting and protection effects of the fluorescent powder can be improved. In addition, by adjusting the flow of methane and hydrogen, the concentration of plasma can be accurately controlled, then the coverage rate of graphene is affected, and accurate regulation and control of the performance of the fluorescent powder are achieved. The preparation method is simple and efficient, the obtained fluorescent powder is excellent in performance, and the LED lighting performance can be remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor lighting, and in particular to a method for preparing a graphene-coated fluorescent material for LEDs. Background Art

[0002] Phosphor is a substance that can absorb light and re-emit light, also known as fluorescent material. Phosphor is widely used in LED lights, high-brightness display screens, phosphor coatings and other fields. However, in actual use, high temperature will cause the surface of the LED to expand and contract, thereby promoting micro cracks and causing the LED phosphor to come into contact with the air. Under the action of high temperature, the phosphor reacts with the air and degrades, thus affecting the luminous performance of the diode.

[0003] There are two main methods for increasing the life of phosphors in the prior art:

[0004] (1) Improve the thermal conductivity and heat dissipation performance of LED to reduce the junction temperature.

[0005] (2) Use ceramic-based phosphor materials to improve the chemical stability of the phosphor.

[0006] Of the above two solutions, solution (1) will increase the unnecessary heat dissipation cost; solution (2) has a low fluorescence conversion efficiency. Therefore, it is of great significance to study a new type of phosphor that can improve the high temperature stability of the phosphor and thus improve the performance of LED lighting. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a method for preparing a graphene-coated fluorescent material for LEDs, by using plasma enhanced chemical vapor deposition technology to coat a layer of graphene material on the surface of an existing low-cost fluorescent powder. The graphene material can effectively isolate water vapor and has excellent thermal stability, which can improve the high-temperature stability of the fluorescent powder.

[0008] The specific plan is as follows:

[0009] A method for preparing a graphene-coated fluorescent material for LEDs comprises the following steps:

[0010] (1) Place the phosphor in a reaction furnace and use a mechanical pump to evacuate the furnace until the vacuum degree reaches below 1 Pa;

[0011] (2) Raise the temperature in the furnace to 300-500°C and keep the temperature constant at 300-500°C for 5-10 minutes;

[0012] (3) When the temperature is 300-500°C, methane and hydrogen are introduced into the furnace, and microwave plasma is excited at the same time, and maintained for 10-30 minutes;

[0013] (4) After the heat preservation is completed, the temperature is naturally cooled to room temperature to obtain the graphene-coated phosphor.

[0014] Furthermore, the phosphor in step (1) is barium disilicate.

[0015] Furthermore, in step (3), the methane flow rate is 10-20 sccm, and the hydrogen flow rate is 10-40 sccm.

[0016] Furthermore, the graphene is single-layer graphene.

[0017] Beneficial effects:

[0018] 1. A new method for preparing graphene-coated fluorescent materials for LEDs is provided, which has high light efficiency and stability.

[0019] 2. The graphene-coated fluorescent material is grown by chemical vapor deposition, which can achieve efficient preparation and high-precision control of the coating material, thereby improving the performance and reliability of the product.

[0020] 3. The graphene material is a single-layer graphene, which can effectively reduce the cost of the material while ensuring the stability and efficiency of the coating material. DETAILED DESCRIPTION

[0021] The present invention will now be further described in conjunction with specific implementation methods.

[0022] The purpose of the present invention is to provide a method for preparing a graphene-coated fluorescent material for LEDs, the method having the advantages of simple preparation process, high efficiency, excellent performance of the obtained fluorescent powder, etc.

[0023] The preparation method of the present invention comprises the following steps:

[0024] (1) Place the phosphor in a reaction furnace and use a mechanical pump to evacuate the furnace until the vacuum degree reaches below 1 Pa;

[0025] As a preferred embodiment of the present invention, the phosphor is barium silicate. On the basis of barium silicate, by adding appropriate elements, a phosphor with excellent optical properties can be prepared.

[0026] (2) Raise the furnace temperature to 300-500°C;

[0027] (3) When the temperature is 300-500°C, methane and hydrogen are introduced into the furnace, and microwave plasma is excited at the same time, and maintained for 10-30 minutes;

[0028] As a preferred embodiment of the present invention, the methane flow rate is 10-20 sccm, and the hydrogen flow rate is 10-40 sccm. By adjusting the flow rates of methane and hydrogen, the concentration of plasma can be controlled, thereby affecting the coverage of graphene, thereby achieving control of the performance of the phosphor.

[0029] (4) After the heat preservation is completed, the temperature is naturally cooled to room temperature to obtain the graphene-coated phosphor.

[0030] In addition, the graphene of the present invention is a single-layer graphene. The single-layer graphene has good electrical conductivity and thermal conductivity, and can provide good dispersion support and protection for the phosphor.

[0031] Through the above implementation, the preparation method of the present invention has the advantages of simple preparation process, high efficiency, excellent performance of the obtained phosphor, etc., and can effectively improve the performance of LED lighting.

[0032] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, it should be understood by those skilled in the art that various changes may be made to the present invention in form and details without departing from the spirit and scope of the present invention as defined by the appended claims, all of which are within the scope of protection of the present invention.

Claims

1. A method for preparing a graphene-coated fluorescent material for LED, characterized in that: The following steps are involved: (1) Place the phosphor in a reaction furnace and use a mechanical pump to evacuate the furnace until the vacuum degree reaches below 1 Pa; (2) Raise the temperature in the furnace to 300-500°C and keep the temperature constant at 300-500°C for 5-10 minutes; (3) When the temperature is 300-500°C, methane and hydrogen are introduced into the furnace, and microwave plasma is excited at the same time, and maintained for 10-30 minutes; (4) After the heat preservation is completed, the temperature is naturally cooled to room temperature to obtain the graphene-coated phosphor.

2. The preparation method according to claim 1, characterized in that: The fluorescent powder in step (1) is barium disilicate.

3. The preparation method according to claim 1, characterized in that: In step (3), the methane flow rate is 10-20 sccm, and the hydrogen flow rate is 10-40 sccm.

4. The preparation method according to claim 1, characterized in that: The graphene is single-layer graphene.