Size-dependent optical and electrochemical properties of gold nanoparticles to L-cysteine

A series of gold nanoparticles were synthesized by stepwise growth method under the condition of citrate as a reducing agent and stabilizer. The optical properties with the maximum absorption wavelength (λ_max) and electrochemical properties of the oxidation potential (E_p) dependence on the particle size were analyzed. The method of calculating the particle size from the UV-visible spectrum and the electrochemical oxidation peak was deduced, following the theoretical prediction trend and consistent with previous observations. Furthermore, we investigated the application performance based on the electrochemical catalytic activity and the aggregation of the spherical gold nanoparticles using L-cysteine as a target. The results indicated that the optical and electrochemical properties of the gold nanoparticles to L-cysteine were closely related to the particle size of gold nanoparticles. With the increased size of the nanoparticles, the full width at half maximum in the UV-visible absorption spectrum increased and the electrochemical oxidation potential was positively shifted.