Environmental-friendly synthesis method of fluorescent carbon dot with up-down conversion function

Abstract

The invention belongs to the field of preparation of fluorescent carbon dots, and discloses a synthesis method of the fluorescent carbon dot with an up-down conversion function. The method comprises the following steps of: adding chilli flakes into water and evenly mixing, thereby obtaining a mixture; transferring the mixture into a hydrothermal kettle, performing a hydrothermal treatment at 120 to 200 DEG C for 2 to 10 hours, and cooling and filtering, thereby obtaining a brown liquid; centrifuging the brown liquid for 10 to 20 minutes, thereby obtaining a supernatant; dialyzing the supernatant by using a dialysis bag with the flow interception volume of 3500; and collecting a dialysate after dialyzing for 10 to 30 hours, thereby obtaining the fluorescent carbon dot. By taking a cheap raw material as a carbon source and the water as a solvent, the method for synthesizing the fluorescent carbon dot with the up-down conversion function in an environmental-friendly manner has the effects that the process is simple; the pretreatment operation is not required; the process that the synthesis is assisted by a strong acid or a surface passivator is not required; the raw material is cheap and easy to obtain; the synthesis condition is moderate and controllable; the high fluorescence quantum yield is achieved; and the carbon dot is good in fluorescent bleaching resistance and stability.

Description

technical field

[0001] The invention belongs to the field of preparation of fluorescent carbon dots, in particular to a green synthesis method of carbon dots. Background technique

[0002] As a new fluorescent nanomaterial, fluorescent carbon dots have been studied due to their good water solubility, inherent chemical inertness, simple chemical modification, high resistance to photobleaching, low toxicity and good biocompatibility. attention. In recent years, many methods, such as electrochemical oxidation, hydrothermal, acid pyrolysis, template preparation, microwave, ultrasonic, arc discharge, and laser etching, have been used to synthesize fluorescent carbon dots. The expensive synthetic equipment and materials, complex operation and non-environmental protection of by-products in most synthetic methods limit their industrial production and wide application in various fields. Among them, the hydrothermal method is recognized as the best synthetic method because of its si...

Examples

Embodiment 1

[0035] A method for preparing fluorescent carbon dots with excellent performance, including the following operation process, the synthetic route diagram is shown in figure 1 :

[0036] Edible red pepper is used as carbon source, and water is used as solvent. Add 1 g of water to 4 g of washed fresh pepper flakes, mix evenly, transfer to a 25 mL hydrothermal kettle, and heat at 180 °C for 5 h. After cooling to room temperature, large impurities were discarded to obtain a brown mixture, and the supernatant was collected after centrifugation at 13 krpm for 15 min. The supernatant was dialyzed for 24 hours with a cut-off of 3500 dialysis bags, and the dialysate was collected.

[0037] The prepared carbon dots were dispersed in deionized water to obtain fluorescent carbon dots with up- and down-conversion properties with emission wavelengths in the range of 400nm-600nm and a quantum yield of 19.2%.

[0038] figure 2 Transmission electron micrographs of the stable fluorescent c...

Embodiment 2

[0041] Ripe edible red pepper is used as carbon source, and water is used as solvent. Take 4g of washed peppers, cut them into pieces, add 1g of water, seal them in a hydrothermal kettle, and heat them at 180°C for 2h.

[0042] After the reaction, take out the still to cool to room temperature, filter out large particles, get the mixture and centrifuge at 13krpm to remove larger particles, and transfer the supernatant to a beaker. The supernatant was dialyzed for 24 hours with a cut-off of 3500 dialysis bags, and the dialysate was collected. Its fluorescence quantum yield is 14.8%.

Embodiment 3

[0044] Ripe edible red pepper is used as carbon source, and water is used as solvent. Take 4g of washed peppers, cut them into pieces, add 1g of water, seal them in a hydrothermal kettle, and heat them at 140°C for 5h.

[0045] After the reaction, take out the still to cool to room temperature, filter out large particles, get the mixture and centrifuge at 13krpm to remove larger particles, and transfer the supernatant to a beaker. The supernatant was dialyzed for 24 hours with a cut-off of 3500 dialysis bags, and the dialysate was collected. Its fluorescence quantum yield is 15.6%.

technical field

[0001] The invention belongs to the field of preparation of fluorescent carbon dots, in particular to a green synthesis method of carbon dots. Background technique

[0002] As a new fluorescent nanomaterial, fluorescent carbon dots have been studied due to their good water solubility, inherent chemical inertness, simple chemical modification, high resistance to photobleaching, low toxicity and good biocompatibility. attention. In recent years, many methods, such as electrochemical oxidation, hydrothermal, acid pyrolysis, template preparation, microwave, ultrasonic, arc discharge, and laser etching, have been used to synthesize fluorescent carbon dots. The expensive synthetic equipment and materials, complex operation and non-environmental protection of by-products in most synthetic methods limit their industrial production and wide application in various fields. Among them, the hydrothermal method is recognized as the best synthetic method because of its si...

Examples

Embodiment 1

[0035] A method for preparing fluorescent carbon dots with excellent performance, including the following operation process, the synthetic route diagram is shown in figure 1 :

[0036] Edible red pepper is used as carbon source, and water is used as solvent. Add 1 g of water to 4 g of washed fresh pepper flakes, mix evenly, transfer to a 25 mL hydrothermal kettle, and heat at 180 °C for 5 h. After cooling to room temperature, large impurities were discarded to obtain a brown mixture, and the supernatant was collected after centrifugation at 13 krpm for 15 min. The supernatant was dialyzed for 24 hours with a cut-off of 3500 dialysis bags, and the dialysate was collected.

[0037] The prepared carbon dots were dispersed in deionized water to obtain fluorescent carbon dots with up- and down-conversion properties with emission wavelengths in the range of 400nm-600nm and a quantum yield of 19.2%.

[0038] figure 2 Transmission electron micrographs of the stable fluorescent c...

Embodiment 2

[0041] Ripe edible red pepper is used as carbon source, and water is used as solvent. Take 4g of washed peppers, cut them into pieces, add 1g of water, seal them in a hydrothermal kettle, and heat them at 180°C for 2h.

[0042] After the reaction, take out the still to cool to room temperature, filter out large particles, get the mixture and centrifuge at 13krpm to remove larger particles, and transfer the supernatant to a beaker. The supernatant was dialyzed for 24 hours with a cut-off of 3500 dialysis bags, and the dialysate was collected. Its fluorescence quantum yield is 14.8%.

Embodiment 3

[0044] Ripe edible red pepper is used as carbon source, and water is used as solvent. Take 4g of washed peppers, cut them into pieces, add 1g of water, seal them in a hydrothermal kettle, and heat them at 140°C for 5h.

[0045] After the reaction, take out the still to cool to room temperature, filter out large particles, get the mixture and centrifuge at 13krpm to remove larger particles, and transfer the supernatant to a beaker. The supernatant was dialyzed for 24 hours with a cut-off of 3500 dialysis bags, and the dialysate was collected. Its fluorescence quantum yield is 15.6%.

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