Evaporative Crystallization Synthesis, Tunable and Multimode Luminescence, and Multifunctional Applications of...

A facile evaporation crystallization method has been utilized to develop the Sb³⁺ and Ln³⁺ (Er³⁺, Ho³⁺, Dy³⁺, or Sm³⁺)-codoped Cs₂NaLuCl₆ double perovskite crystals. This synthesis route is simple to operate and merely needs mild reaction conditions, which can be promising for large-scale production. The Sb³⁺ and/or Ln³⁺-doped Cs₂NaLuCl₆ products exhibit high crystallinity and excellent luminescent performance. The emission of the phosphors consists of the self-trapping excitation (STE) of [SbCl₆]^3- and f-f transitions of Ln³⁺. A wide-spectrum emission color modulation is achieved by adjusting the doping level of Ln³⁺, wherein the effective energy transfer coupling between STE and Ln³⁺ is the critical factor governing spectral color manipulation. Notably, the luminescence intensity of STE is significantly enhanced, although energy transfer occurs. This result indicates that the codoping of Ln³⁺ can simultaneously introduce new activator ions and enhance the blue emission of STE in Cs₂NaLuCl₆ double perovskites. Furthermore, the Sb³⁺ and Er³⁺/Ho³⁺-codoped Cs₂NaLuCl₆ materials not only feature down-conversion luminescence and exhibit up-conversion emissions under near-infrared (NIR) excitation but also display dazzling multicolor light under LED chip excitation. These results indicate that the as-synthesized Sb³⁺/Ln³⁺-codoped Cs₂NaLuCl₆ materials have potential applications in the fields of multimode optical anticounterfeiting and solid-state lighting.