Multimodal Luminescent Low-Dimension Cs₂ZrCl₆: x Sb³⁺ Crystals for White Light-Emitting Diodes and Information Encryption

Low-dimension perovskite materials have attracted wide attention due to their excellent optical properties and stability. Herein, Sb³⁺-doped Cs₂ZrCl₆ crystals are synthesized by a coprecipitation method in which Sb³⁺ ions partially replace Zr⁴⁺ ions. The Cs₂ZrCl₆:xSb³⁺ powder shows blue and orange-red emissions under a 254 and 365 nm light, respectively, due to the [ZrCl₆]^2- octahedron and [SbCl₆]^3- octahedron. The photoluminescence quantum yield (PLQY) of Cs₂ZrCl₆:xSb³⁺ (x = 0.1) crystals is up to 52.5%. According to experimental and computational results, the emission mechanism of the Cs₂ZrCl₆:xSb³⁺ crystals is proposed. On the one hand, a wide blue emission with a large Stokes shift is caused by the self-trapping excitons of [ZrCl₆]^2- octahedra under a 260 nm excitation. On the other hand, the luminescence mechanism of [SbCl₆]^3- octahedron is divided into two parts: ¹P₁ → ¹S₀ (490 nm) and ³P₁ → ¹S₀ (625 nm). The broad-band emission, high PLQY, and excellent stability endow the Cs₂ZrCl₆:xSb³⁺ powders with the potential for the fabrication of white light-emitting diodes (WLEDs). A WLED device is fabricated using a commercial 310 nm NUV chip, which shows a high color rendering index of 89.7 and a correlated color temperature of 5333 K. In addition, the synthesized Cs₂ZrCl₆:xSb³⁺ crystals can be also successfully used for information encryption. Our work will provide a deep understanding of the photophysical properties of Sb³⁺-doped perovskites and facilitate the development of Cs₂ZrCl₆:xSb³⁺ crystals in encrypting multilevel optical codes and WLEDs.