No abstract

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.

Solution-grown films of CsPbBr nanocrystals imbedded in Cs PbBr are incorporated as the recombination layer in light-emitting diode (LED) structures. The kinetics at high carrier density of pure (extended) CsPbBr and the nanoinclusion composite are measured and analyzed, indicating second-order kinetics in extended and mainly first-order kinetics in the confined CsPbBr , respectively. Analysis of absorption strength of this all-perovskite, all-inorganic imbedded nanocrystal composite relative to pure CsPbBr indicates enhanced oscillator strength consistent with earlier published attribution of the sub-nanosecond exciton radiative lifetime in nanoprecipitates of CsPbBr in melt-grown CsBr host crystals and CsPbBr evaporated films.