[14a-B9-1~13] 3.1 Basic optics and frontier of optics

[14a-B9-10] Structural Evaluation of Polyethyleneimine Capping Pt Nanoclusters by Fluorescence Correlation Spectroscopy

〇Hidekazu Ishitobi^1,2, Mana Hosokawa², Xin Huang¹, Yasushi Inouye^1,2 (1.FBS, Osaka Univ., 2.Eng., Osaka Univ.)

Keywords:Nano clusters, Fluorescent probe, Fluorescence correlation spectroscopy

We evaluated the structure of yellow emitting Pt nano clusters, which is synthesized by using hyper branched polymer of Polyethyleneimine (PEI) as template molecules. The Pt nano clusters were synthesized by mixing solutions of hexachloroplatinic acid and PEI, then reduced by L-ascorbic acid after forming complexes via amines of PEI. The diffusion constant and hydrodynamic diameter of the synthesized Pt nano clusters were measured by fluorescence correlation spectroscopy. As a result, we found that the diffusion constant and hydro-dynamical diameter were (0.95±0.54)×10^-10 m²/s and 6.3±2.8 nm, respectively. Judging from the fact that the diameter of the synthesized Pt nano clusters was 1.4±0.4 nm by transmission electron microscopic observation, it is suggested that the Pt nano clusters were synthesized inside not a single PEI molecule but a cavity surrounded by several PEI molecules.