Multiexcitonic Emission in Zero-Dimensional Cs2ZrCl6:Sb3+ Perovskite Crystals

Metal halide perovskites are highly attractive for lighting applications, but the multiexcitonic emission processes in these crystals are largely unexplored. This study presents an investigation of Sb³⁺-doped Cs₂ZrCl₆ perovskite crystals that display double luminescence due to the intrinsic host self-trapped excitons (denoted as host STEs) and dopant-induced extrinsic self-trapped excitons (denoted as dopant STEs), respectively. Steady-state and transient-state spectroscopy reveal that the host and dopant STEs can be independently charged at specific energies. Density functional theory calculations confirm that the multiexcitonic emission stems from minimal interactions between the host and dopant STEs in the zero-dimensional crystal lattice. By selective excitation of different STEs through precise control of excitation wavelength, we further demonstrate dynamic color tuning in the Cs₂ZrCl₆:Sb³⁺ crystals. The color kinetic feature offers exciting opportunities for constructing multicolor light-emitting devices and encrypting multilevel optical codes.