Shape change and color gamut in gold nanorods, dumbbells, and dog bones

It is shown here that deviations from a prolate ellipsoidal shape have a significant effect on the optical properties of gold nanorods. Transitions from rods to 'dumbbell'- or 'phi'-shaped particles lead to a shift in the longitudinal plasmon peak in the blue and red directions, respectively. Development of 'dog-bone' shapes leads to a red-shift and to the development of a third peak. A broad and flexible color gamut can be obtained.