Pd nanocrystals with single-, double-, and triple-cavities: facile synthesis and tunable plasmonic properties

The surface plasmon resonance (SPR) of palladium (Pd) nanocrystals is of potential importance due to their catalytic properties and surface stability. Pd nanocrystals with single-, double-, and triple-cavities were produced using a one-pot aqueous approach, where micelles formed by PVP dictate the cavity formation. The cavity number and cavity size were further regulated by systematically changing the experimental parameters. The SPR of the as-prepared hollow Pd can be tuned from 355 nm to 702 nm to cover the entire visible spectral region. The plasmonic nature of the hollow Pd was investigated by finite-difference-time-domain simulation, which indicated that the SPR shift was mainly attributed to the size variations of the monomer cavity.