Optoelectronic properties of gold nanoparticles synthesized by using wet chemical method

We have synthesized gold nanoparticles (GNPs) with different particle sizes by using wet chemical method. The mean particle size of GNPs was calculated from Transmission Electron Microscope (TEM) images. Furthermore, UV-vis spectra are employed to study the dependence of optoelectronic properties upon the variation of particle size of GNPs. The results reveal that the surface Plasmon resonance peak (SPR) red shifted toward higher wavelength from 533 to 544 nm due to the aggregation of the GNPs. It is found that the optical energy band gap increased by the decrease of the GNPs size due to quantum confinement effects. Finally, the variation of the optical parameters; refractive index n(lambda) and extinction coefficient k(lambda) upon the Gold nanoparticle size have been presented.