Optical Property Of Au Nanocones Prepared Via Wet Chemical Synthetic Method

Gold nanomaterials are considered to be one of the most promising nanomaterials due to their unique physicochemical and plasma properties.Gold nanomaterials with tip structure attract the attention of scientists.This material is easy to form active sites,and exhibits a strong local electromagnetic field.It shows excellent electric field enhancement effect.Just like gold nanorods,it has two plasma vibration absorption peaks,and its longitudinal plasmon resonance absorption peak position can be controlled by adjusting the growth parameters of the material.It has good Raman enhancement effect and photothermal effect,and the synthesis method is simple and diverse.These advantages make it suitable for a wide range of research fields,such as biotechnology and nanomedicine,spectroscopy,optics and optoelectronics.In summary,the main content of this subject focuses on the preparation and properties of two gold nanomaterials with tip structure,respectively Au nanoshuttles（Au NSs）and Au nanobipyramids（Au NBPs）.The main works includes the following:（1）Au NSs were synthesized by wet chemical method.The regulation of LSPR was achieved by adjusting growth parameters such as AgNO₃ and HAuCl₄ solution concentration.Au NSs have excellent surface plasmon resonance properties,and the apex of Au NSs is sharper.According to the lightning rod effect,it is better for local electric field enhancement than Au NRs.The detection limit of Au nanoshuttles with arrow ends can reach 1×10^-9 M according to the sensitivity test.In addition,the effect of arrow shape on the photothermal properties of Au NSs was disscued.（2）Au NBPs with dimensional uniformity were successfully prepared.The preparation method is simpler than that of Au NSs,and the tip structure of Au NBPs is more pronounced,so it is more advantageous for local surface electric field enhancement.Raman enhancement effect was studied by using Au NBPs as SERS active substrate,and the experimental results show that Au NBPs has good Raman enhancement effect.Au NBPs have strong absorption in the near-infrared region of the tissue due to localized surface plasmon resonance,which is beneficial to obtain the best light penetration effect.When plasmon resonance is excited,it can be strongly absorbed and rapidly converted into highly localized,adjustable heat through a series of physical processes.By calculating the photothermal conversion efficiency of Au NBPs and Au NRs,it is found that Au NBPs have better photothermal effect than Au NRs and it is expected to be an effective photothermal therapy method.