A kind of preparation method of triangular silver nanosheet

Abstract

The invention belongs to the field of nanotechnology, and discloses a preparation method of triangular silver nanosheets. The triangular silver nanosheets prepared by the present invention have high purity, and have the stability of dark storage for at least 30 days under environmental conditions (the stability is measured by the displacement of the absorption peak wavelength of the ultraviolet-visible light spectrum by no more than 10nm); Thermal stability, the heat-resistant temperature can reach 95°C; it has a light-to-heat conversion efficiency of up to 42%; it has good biocompatibility, the material itself is neutral, it will not change the pH environment of the biological system, and has low biological toxicity; Under near-infrared light irradiation, a stable surface-enhanced Raman scattering signal can be generated.

Description

technical field [0001] The invention belongs to the field of nanotechnology, in particular to a method for preparing triangular silver nanosheets. Background technique [0002] Triangular silver nanosheets, as a specific two-dimensional plasmonic nanostructure, have special optical, electrical, and catalytic properties, and have shown great application value in electronics, chemical engineering, biology, and medical treatment. Compared with other shapes of nanocrystalline structures, the triangular silver nanosheets have a larger surface area, which can serve as a Raman-active substrate to provide a larger contact surface and generate a stronger surface-enhanced Raman signal. In addition, the triangular silver nanosheets themselves have extremely strong anisotropy, and the position of the plasmon resonance absorption peak can be precisely regulated by controlling the geometric size of the nanosheets. Moreover, the strong absorption peak in the near-infrared region enables i...

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Problems solved by technology

In the chemical reduction method, hydrogen peroxide is mostly used as the plasticizer, sodium citrate as the encapsulant, and sodium borohydride as the reducing agent. However, the triangular silver nanosheets synthesized by this method have poor photothermal stability and biocompatibility Flawed

For example, under near-infrared light, triangular silver nanosheets can convert light energy into thermal energy due to their strong absorption peaks in the near-infrared region, but the heat generated will cause the above-mentioned triangular silver nanosheets to transform from a large-sized triangular sheet structure Shrinking silver nanoparticles into small particle sizes leads to the disappearance of their absorption peaks in the near-infrared region, which in turn affects the stability of their surface-enhanced Raman scattering signals and photothermal conversion efficiency

In addition, a large amount of sodium citrate is attached to the surface of the above-mentioned triangular silver nanosheets, which causes the material itself to be strongly alkaline (pH is 8-10). toxicity

The shortcomings of the photothermal stability and biocompatibility of the triangular silver nanosheets synthesized by the above method greatly limit its application in surface-enhanced Raman effect and photothermal therapy.

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