Ag@zinc-tetraphenylporphyrin core-shell nanostructures with unusual thickness-tunable fluorescence.

Ag@zinc-tetraphenylporphyrin (Ag@ZnTPP) core-shell nanostructures have been fabricated by in situ chemical deposition. Unusual thickness-dependent fluorescence allowed their colour to be tuned from blue to red by simply increasing the shell thickness from ~2 nm to ~9 nm. The competition between metal enhancement and the self-absorption effect of ZnTPP has been shown to be the main reason for this variation.