@article {1171,
	title = {Gold nanoparticle formation from photochemical reduction of Au3+ by continuous excitation in colloidal solutions. A proposed molecular mechanism},
	journal = {Journal of Physical Chemistry B},
	volume = {109},
	number = {11},
	year = {2005},
	note = {Eustis, S Hsu, HY El-Sayed, MA},
	month = {Mar},
	pages = {4811-4815},
	abstract = {A photochemical reduction of Au3+ with continuous 250-400 nm excitation is studied in ethylene Zalycol, and poly (vinylpyrrolidone) (PVP) is used as a capping material. After the absorption of Au3+ disappears, excitation is stopped. The surface plasmon absorption of gold as well as the thermal reappearance of the Au3+ absorption are found to increase as a function of time. The rates of these changes are studied as a function of the mole fraction of ethylene glycol in water. Experimental results show that a small amount of ethylene glycol increases the formation of gold nanoparticles and decreases the reformation of the Au3+ absorption after irradiation. Increasing the glycol concentration first increases the rate of formation of gold nanoparticles to a maximum at a mole fraction 0.40. As the glycol concentration is further increased, the rate of formation of the gold nanoparticles and the rate of re-formation of Au3+ decrease. A mechanism is proposed that involves the reduction of the excited Au3+ to Au2+ by ethylene glycol. This is followed by the disproportionation of Au2+ to Au3+ and Au1+. Both the reduction of Au1+ by ethylene glycol and its disproportionation lead to the formation of Au-0, which upon nucleation and growth form An nanoparticles.},
	isbn = {1520-6106},
	doi = {10.1021/jp0441588},
	author = {Eustis, Susie and Hsu, H. Y. and El-Sayed, Mostafa A}
}
