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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.

The chiral perovskite has drawn intensive attention recently due to the combination of the fantastic optoelectronic properties of the perovskite and unique chiral or spin-related optical and electrical properties, which brings new insight into traditional spin-optoelectronic and spintronic applications. In this Perspective, the state-of-the-art progresses of chiral perovskite synthesis, characterization, and spin-optoelectronic and spintronic applications as well as theoretical analysis of the chiral-related property are summarized. In the end, we discussed strategies to judiciously design a perovskite with high chirality as well as challenges and opportunities for its application in spin-optoelectronic and spintronic devices.

Zero-dimensional (0D) organic metal halides have attracted significant attention because of their exceptional structure tunability and excellent optical characteristics. However, controllable synthesis of a desirable configuration of metal halide species in a rational way remains a formidable challenge, and how the unique crystal structures affect the photophysical properties are not yet well understood. Here, a reasonable metal halide structural modulation strategy is proposed to realize near-unity photoluminescence quantum efficiency (PLQE) in 0D organic antimony halides. By carefully controlling the reaction conditions, both 0D (C 12 H 28 N) 2 SbCl 5 and (C 12 H 28 N)SbCl 4 with different metal halide configurations can be prepared. (C 12 H 28 N) 2 SbCl 5 with pyramid-shaped [SbCl 5 ] 2− species exhibits yellow emission with a near-unity PLQE of 96.8%, while (C 12 H 28 N)SbCl 4 with seesaw-shaped [SbCl 4 ] − species is not emissive at room temperature. Theoretical calculations indicate that the different photophysical properties of these two crystals can be attributed to the different symmetries of their crystal structures. (C 12 H 28 N) 2 SbCl 5 adopts a triclinic structure with P-1 symmetry, while (C 12 H 28 N)SbCl 4 possesses a monoclinic structure with P2 1 /c symmetry, which has an inversion center, and thus the optical transitions between their band-edge states give a minimal dipole intensity because of their similar parity character. In addition, we also successfully synthesized (C 12 H 28 N) 2 SbCl 5 nanocrystals for the first time, which are particularly appealing for their solution processibility and excellent optical properties. Furthermore, (C 12 H 28 N) 2 SbCl 5 nanocrystals flexible composite film shows bright yellow emission under β-ray excitation, suggesting a strong potential of (C 12 H 28 N) 2 SbCl 5 for β-ray detection.

The manipulation of the dimensionality and nanostructures based on the precise control of the crystal growth kinetics boosts the flourishing development of perovskite optoelectronic materials and devices. Herein, a low‐dimensional inorganic tin halide perovskite, CsSnBrI2−x(SCN)x, with a mixed 2D and 3D structure is fabricated. A kinetic study indicates that Sn(SCN)2 and phenylethylamine hydroiodate can form a 2D perovskite structure that acts as a template for the growth of the 3D perovskite CsSnBrI2−x(SCN)x. The film shows an out‐of‐plane orientation and a large grain size, giving rise to reduced defect density, superior thermostability, and oxidation resistance. A solar cell based on this low‐dimensional film reaches a power conversion efficiency of 5.01 %, which is the highest value for CsSnBrxI3−x perovskite solar cells. Furthermore, the device shows enhanced stability in ambient air.