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CN-121991689-A - Dual-template-regulated high-quantum-yield fluorescent powder with calcium carbonate coated carbon dots, and preparation method and application thereof

CN121991689ACN 121991689 ACN121991689 ACN 121991689ACN-121991689-A

Abstract

The invention belongs to the technical field of nanometer luminescent materials. A method for preparing the fluorescent powder with high quantum yield by coating carbon dots with dual-template regulated calcium carbonate includes such steps as preparing the solution of carbon dots, adding template agent and anhydrous calcium chloride to the solution of carbon dots to obtain mixed solution A, dissolving anhydrous sodium carbonate in glycol to obtain mixed solution B, slowly dropping the mixed solution B in the mixed solution A while stirring, ageing at room temp, centrifugal collecting the deposit, washing and drying. The invention accurately regulates and controls the crystal form through the double templates, adopts an adaptive purification strategy, effectively overcomes the limitation of a single process, can be widely applied to carbon points with different surface properties, and has high solid state fluorescence quantum yield and good stability of the obtained composite material, and important application value in the fields of solid state luminescence, fluorescence anti-counterfeiting, biological imaging and the like.

Inventors

  • SUN XIAOBO
  • ZHANG WEI
  • WANG JINPING
  • PAN WEI

Assignees

  • 青岛农业大学

Dates

Publication Date
20260508
Application Date
20260313

Claims (10)

  1. 1. The preparation method of the dual-template regulated and controlled calcium carbonate coated carbon dot high quantum yield fluorescent powder is characterized by comprising the following steps of: (1) Preparing a carbon dot solution, namely adding carbon dots into ethylene glycol, and adjusting the carbon dots to a certain absorbance to obtain the carbon dot solution; (2) Adding a certain amount of template agent and anhydrous calcium chloride into the carbon dot solution in the step (1) to obtain a mixed solution A; (3) Dissolving anhydrous sodium carbonate into ethylene glycol to obtain a mixed solution B; (4) Slowly dripping the mixed solution B in the step (3) into the mixed solution A in the step (2) under stirring, stirring for a period of time after dripping is completed to fully react, aging the reaction solution at room temperature to obtain a composite product, centrifugally collecting the precipitate of the composite product, washing the precipitate with a washing solvent, and drying to obtain the fluorescent powder with high quantum yield.
  2. 2. The method for preparing the dual-template controlled calcium carbonate coated carbon dot high quantum yield fluorescent powder according to claim 1, wherein the carbon dot in the step (1) is any one of blue light carbon dot, green light carbon dot and orange light carbon dot.
  3. 3. The method for preparing the dual-template controlled calcium carbonate coated carbon dot fluorescent powder with high quantum yield according to claim 1, wherein in the step (1), absorbance of a carbon dot solution is adjusted to 1.8-2.5.
  4. 4. The method for preparing the dual-template controlled calcium carbonate coated carbon dot fluorescent powder with high quantum yield according to claim 1, wherein in the step (2), the template agent is any one or two of polyethylene glycol 400, polyethylene glycol 2000, polyethylene glycol 10000, polyacrylic acid, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, sodium stearate and sodium oleate.
  5. 5. The method for preparing the dual-template controlled calcium carbonate coated carbon dot high quantum yield phosphor according to claim 4, wherein in the step (2), the template agent is a mixture of polyethylene glycol 2000 and sodium dodecyl sulfate.
  6. 6. The method for preparing the dual-template controlled calcium carbonate coated carbon dot high quantum yield fluorescent powder according to claim 1, wherein the volume ratio of the mixed solution A to the mixed solution B in the step (4) is (2-3): 1.
  7. 7. The method for preparing the dual-template controlled calcium carbonate coated carbon dot high quantum yield phosphor according to claim 1, wherein the centrifugation condition in the step (4) is 10,000 rpm min.
  8. 8. The fluorescent powder is characterized in that the fluorescent powder is prepared by the preparation method of the dual-template regulated and controlled calcium carbonate coated carbon dot high quantum yield fluorescent powder according to any one of claims 1-7.
  9. 9. The phosphor according to claim 8, wherein the phosphor is a blue phosphor having an emission peak wavelength of 410 to 500nm in an excitation wavelength range of 305 to 400nm, or a green phosphor having an emission peak wavelength range of 520 to 550nm in an excitation wavelength range of 480 to 515nm, or an orange phosphor having an emission peak wavelength of 570 to 600nm in an excitation wavelength range of 515 to 570 nm.
  10. 10. The phosphor prepared by the preparation method according to any one of claims 1 to 7 or the use of the phosphor according to any one of claims 8 to 9, wherein the phosphor is used for preparing an LED device, a display device, a laser illumination or a luminescent material.

Description

Dual-template-regulated high-quantum-yield fluorescent powder with calcium carbonate coated carbon dots, and preparation method and application thereof Technical Field The invention relates to the technical field of nano luminescent materials, in particular to a high quantum yield fluorescent powder with a double-template regulated calcium carbonate coated carbon dot, and a preparation method and application thereof. Background Carbon Dots (CDs) as an emerging zero-dimensional Carbon nanomaterial have demonstrated great potential for applications in the fields of bioimaging, photocatalysis, light Emitting Diodes (LEDs), etc., due to their unique optical properties, excellent water solubility, low toxicity, and tunable fluorescence emission wavelength. Particularly, with the progress of synthesis technology, high quantum yield carbon dots covering the full spectrum of blue light to red light can be prepared through simple and convenient approaches such as a hydrothermal method, a solvothermal method and the like at present. However, carbon dots face severe "aggregation-induced quenching" (ACQ) problems in practical applications, particularly when used as solid state light emitting devices (e.g., WLED phosphors). In the solution state, the dispersibility of carbon dots is good, and the fluorescence intensity is high, but when the solid powder is dried, the fluorescence quantum yield is drastically reduced or even completely quenched due to the fact that the distance between the carbon dots is drastically reduced and a strong pi-pi stacking interaction occurs, so that non-radiative transition is increased. To solve this problem, researchers have generally employed methods of dispersing carbon dots in solid matrices (e.g., polymers, silica, salt crystals, etc.), using steric isolation of the matrix to block aggregation quenching. Among many matrix materials, polymer matrices have the problems of poor thermal stability and easy aging and yellowing after long-term use, and silica matrices are complex in preparation process, generally involve a sol-gel process, and are long in time consumption and high in cost. In contrast, calcium carbonate (CaCO 3) has the advantages of good biocompatibility, low-cost and easily available raw materials, environmental friendliness and the like, and is an ideal carbon dot solid carrier. However, the existing calcium carbonate coated carbon dot technology still has the following significant drawbacks: First, the crystal form is difficult to regulate and control and has poor matching property with carbon dots. Calcium carbonate exists mainly in three crystalline forms, calcite (Calcite), aragonite (Aragonite) and vaterite (Vaterite). The aragonite has a porous spherical structure, large specific surface area and is most suitable for adsorbing and coating carbon points, but is extremely unstable in an aqueous phase system, and is easily converted into calcite through dissolution and recrystallization processes, so that the originally coated carbon points are expelled out of a lattice, and the loading efficiency is greatly reduced. More importantly, the carbon dots obtained by different luminescent colors and different preparation methods have obvious differences between surface functional groups and surface states, and have quite different induction effects on calcium carbonate nucleation and crystal form conversion. The prior art often lacks effective template control means to stabilize the corresponding crystalline phases according to the characteristics of the carbon dots. Second, there is a lack of post-treatment processes that compromise both crystal form stability and luminous efficiency. This is the biggest technical bottleneck faced by preparing full spectrum solid carbon point fluorescent powder at present. How to remove the reaction byproducts and simultaneously consider the stability of the calcium carbonate crystal form and the efficient retention of carbon points, and no universal solution aiming at the characteristics of different carbon points exists at present. In addition, the Chinese patent CN202010499499.0 of the inventor discloses a microwave preparation method of colorful fluorescent powder, wherein saturated salt solution is adopted to disperse fluorescent substances, and the solid fluorescent powder is obtained through microwave reaction, and the Chinese patent CN202411217456.3 of the inventor discloses colorful fluorescent powder and a spray drying preparation method thereof, wherein colorful carbon dot solution and carrier solution are mixed, and the solid fluorescent powder is obtained through spray drying. The two preparation methods can obtain solid fluorescent powder with good color rendering property and high yield, however, the microwave method has high heating speed and can cause local overheating, and the spray drying also needs to set a certain outlet temperature. Both of the above schemes produce an effect of high temperature on the carbon dots or p