Confinement-enhanced stimulated emission in microcrystalline CsPbCl3 films grown from the amorphous phase

Highly excited photoluminescence in microcrystalline CsPbCl3 films grown from the amorphous phase is very different in character from that of bulk single crystals, exhibiting very simple and prominent spectral structures composed of three emission bands related to free excitons, compared to complicated structures for the latter. The lowest-energy emission band is characterized by strong stimulated emission originating from free exciton inelastic collisions, in great contrast to the case for bulk single crystals. The threshold of the excitation fluence for the stimulated emission decreases with decreasing microcrystallite size and increasing film thickness.