  Excitonic 0D and 2D lead-halide perovskites have been recently developed and
investigated as new materials for light generation. Here we report broadband (>
1 eV) emission from newly synthesised zero-dimensional (0D) lead-free colloidal
Cs3Bi2I9 nanocrystals. We investigate the nature of their emissive states as
well as the relative dynamics which are currently hotly debated. In particular,
we find that the broadband emission is made by the coexistence of emissive
excitons and sub-bandgap emissive trap-states. Remarkably, we observe evidence
of enhanced Raman scattering from the ligands when attached to the nanocrystals
surface, an effect that we preliminary attribute to strong exciton-ligands
electronic coupling in these systems.
