Acta Phys. -Chim. Sin. ›› 2004, Vol. 20 ›› Issue (06): 647-650.doi: 10.3866/PKU.WHXB20040619

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Preparation of PyDDP-modified Gold Nanoparticles and Mechanism for Red-shift in the Surface Plasma Resonance Absorption

Gao Li-Zhen;Zhang Xing-Tang;Dai Shu-Xi;Li Yun-Cai;Huang Ya-Bin;Du Zu-Liang;Li Tie-Jin   

  1. Key Laboratory of Special Functional Materials of Henan Province, Henan University, Kaifeng 475001; Photochemistry Laboratory of Jilin University, Changchun 130021
  • Received:2003-11-21 Revised:2004-02-11 Published:2004-06-15
  • Contact: Du Zu-Liang

Abstract: Gold nanoparticles were reduced by sodium from HAuCl4 citrate and then modified by PyDDP(O,O’-Dioctadecane dithiophosphate). IR spectra indicated that PyDDP covalent bond with the surface of the gold nanoparticle. TEM results showed that nanoparticles modified by PyDDP had a similar size with that of the original nanoparticles. At the same time it had been found that the surface plasma resonance (SPR) absorbance of the PyDDP-modified gold nanoparticles had a large red shift. Furthermore, the Jellium model was used to analyze the characteristics of SPR;the dipole model and the IR spectrum were used to form a new dipole model. It can be used to explain the mechanism of the red shift.

Key words: Red shift, Surface plasma resonance, Dipole, O,O’-Dioctadecane dithiophosphate (PyDDP)