With high photoluminescence efficiency and a simple solution synthesis method, lead halide perovskites are expected to be a promising material for display and illumination. However, the toxicity and environmental sensitivity of lead hinder its potential applications. Here, we introduced Sb 3+ ions into the lead-free perovskites derivative (NH 4 ) 2 SnCl 6 via a doping strategy. For the first time we synthesis the excitation-dependent perovskite with dynamically tunable fluorescence from yellow to near-infrared (NIR) emission by varying the UV excitation from 360 to 390 nm at room temperature. The DFT calculations are highly consistent no matter whether the coordination number of Sb 3+ is 5 or 6. In contrasting to the early report of Sb triplet emission in the Sb doped perovskite, this material give a mixed self-trapped exciton (STE) emission. The 590 nm emission band is derived from the STE of SbCl 5 , and the 734 nm NIR emission band is attributed to the Sb−Sn mixed STE, which is supported by DFT calculations and spectral results. This study provides guidance for the design of perovskite phosphors with high efficiency and excitation-dependent properties.

In recent years, low-dimensional lead-free metal halides have captured wide interest in the application of fluorescence anticounterfeiting due to their unique optical properties, low toxicity, and excellent environmental stability. Herein, we report an effective multimode photoluminescent material of Cu + @Sb 3+ -codoped Cs 2 ZnCl 4 microcrystals via a facile solution synthesis method. Upon a 365 nm ultraviolet (UV) excitation, Cu + @Sb 3+ -codoped Cs 2 ZnCl 4 shines a highly efficient broad red emission band at 714 nm. Under a 254 nm UV irradiation, this codoped compound exhibits a dual-band emission with an additional high-intensity emission band at 492 nm, enabling a bright sky-blue emission to be observed. The study of the photophysical mechanism reveals that the observed dualemission bands at 492 and 714 nm in this compound stem from the self-trapped exciton emission of [CuCl 4 ] 3− and [SbCl 4 ] − clusters, respectively. In addition, inspired by the obvious excitation-wavelength-dependent emission characteristics and excellent stabilities of Cu + @Sb 3+ -codoped Cs 2 ZnCl 4 , we successfully applied this compound to fluorescent anticounterfeiting and information encryption−decryption applications.

Environment-friendly lead-free double perovskite with good stability can solve the toxicity and instability problems of lead halide perovskite as a powerful substitute for them. In this paper, a simple...

All-inorganic metal halide perovskite semiconductors have great potentials in lighting applications, but the effect of excitonic magnetic polarons (EMPs) in the transition metal (TM) ion-doped halide perovskites on their luminescence processes has not been extensively understood. Here, we have synthesized Mn 2+doped Rb 3 Cd 2 Cl 7 perovskite powders with different doping amounts by a hydrothermal method. After Mn(II) is doped, Rb 3 Cd 2 Cl 7 gives strong emission, though the Rb 3 Cd 2 Cl 7 powder itself does not emit light. This emission originates from the intrinsic self-trapped exciton (STE) formation enhanced by the ferromagnetic Mn−Mn pair with spin−spin coupling, that is, the magnetic polaron whose astonishing luminescence at 587 nm has a quantum yield up to 147%. Some shallow trapped centers below the conduction band out of high d levels by localized EMPs after photoexcitation are proven to add to this luminescence process. The thermoluminescence phenomenon with rising temperature proves that these shallow trapped carriers are present with phonon and multiphonon notation, and their efficient transfer to the conduction band and the STE state occurs via the electron−phonon coupling during photoexcitation. This compound provides a new way for TM-doped perovskite material design and applications for magneto-optical and display technology.

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