SiO2 coated upconverting nanoparticles(Purpleblue)

Product Name

Name: SiO2 coated upconverting nanoparticles（Purple and blue light:/span>

^{Product Overview}

Upconversion nanoparticles (UCNPs) are nanomaterials that can convert low-energy light into high-energy light. They are composed of inorganic nanocrystals doped with rare earth ions and have unique upconversion luminescence properties. Rare earth upconversion luminescence is based on the 4f electron transition of lanthanide rare earth ions. Currently, the common upconversion luminescence mechanisms can be summarized into three types: excited state absorption, energy transfer upconversion, and photon avalanche.

The preparation methods of upconversion nanoparticles mainly include coprecipitation method, high-temperature pyrolysis method, hydrothermal method, solvothermal method, sol gel method, etc. In order to widely apply UCNPs in the biomedical field, in addition to improving luminescence efficiency, it is also necessary to functionalize their surfaces to enhance water solubility and biocompatibility, and achieve multifunctionality. The main surface modification methods include ligand exchange (PEG, PEI, etc. with - COOH, - NH2 groups), ligand oxidation, ligand adsorption, layer by layer self-assembly, and silica coating.

Most of the rare earth doped ions in the nuclear nanoparticles are exposed on the crystal surface, which is prone to non radiative energy transfer with the external environment, leading to fluorescence quenching and thus reducing the upconversion luminescence efficiency. The most commonly used method to reduce this quenching process is to wrap an inert shell layer on the surface of doped nanocrystals to form a core-shell structure, which confines the luminescent ions in the internal core. The shell layer increases the distance between the luminescent center ion and the external environment, effectively reducing energy transfer and thus increasing the luminescence efficiency. At present, the most commonly used method is to modify the shell layer in the previously synthesized nuclear layer structure that is the same as the matrix material, such as NaYF: Yb, Er@NaYF4 NaYF4: Yb, Tm@NaYF4.

^{Technical Parameter}

Emission wavelength: 365/475nm

Excitation wavelength: 975-980nm

Particle diameter:50+/-10nm  Subject to actual measurement

Main components: NaYREF4 (RE:Yb, Tm) 

^{Product Features}

Colorful luminescence: By changing the type and concentration of rare earth ions doped, multi-color luminescence from visible light to near-infrared light can be achieved.

Stokes shift is large: Stokes shift refers to the difference between the emission wavelength and the excitation wavelength. The Stokes shift of upconversion nanoparticles is relatively large, which can effectively reduce self absorption and background interference, improve luminescence efficiency and detection sensitivity.

Good photostability: Upconversion nanoparticles have good photostability and can maintain stable luminescence performance under long-term illumination.

Good biocompatibility: Through surface modification, upconversion nanoparticles can be coupled with biomolecules (such as proteins, antibodies, etc.) to achieve biological labeling and detection.

Non damaging to biological tissues: Its excitation light source near-infrared light (980nm or 808nm) has strong light penetration, almost no damage to biological tissues, and no background fluorescence.

Application Fields

Biomedical: Upconversion nanoparticles can serve as biomarkers for cell imaging, biological detection, drug delivery, and other applications. For example, coupling upconversion nanoparticles with antibodies or biomolecules can achieve targeted labeling and detection of specific cells or biomolecules.

Optical imaging: Upconversion nanoparticles can be used for deep tissue imaging, such as in vivo animal imaging. Due to its longer emission wavelength, it can penetrate deeper biological tissues, reduce tissue scattering and self fluorescence interference, and improve imaging clarity and contrast.

Photocatalysis: Upconversion nanoparticles can convert visible light into ultraviolet or near-infrared light, thereby broadening the spectral response range of photocatalytic materials and improving photocatalytic efficiency.

Solar cells: Upconversion nanoparticles can be used to improve the efficiency of solar cells. By combining upconversion nanoparticles with solar cell materials, low-energy photons can be converted into high-energy photons, increasing the absorption and utilization of solar light by the cell.

^{Related Information}

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