Thin to Thick, Short to Long: Spectral Properties of Gold Nanorods by Theoretical Modeling

Recent advances in gold nanorod colloidal synthesis demand a theoretical model capable of predicting the spectral characteristics of gold nanorods with dimensions outside the realm of consideration of previous models. We employ the discrete dipole approximation to calculate the spectra and extinction intensities of a series of gold nanorods in water, with sizes ranging from 3 × 6 to 15 × 90 nm. We then present models to relate the plasmon resonant wavelength and extinction intensity to the nanoparticle aspect ratio and volume, respectively. These relationships will allow for facile determination of the dimensions necessary to generate the desired characteristics for applications of gold nanorods in medicine and energy.