Highly efficient tunable white emission with ultralong afterglow in Sb ³⁺ /Mn ²⁺ -codoped CsCdCl ₃ crystals for multifunctional applications

Recently, metal halides have attracted much attention due to their fascinating optical properties. However, achieving efficient white emission with ultralong afterglow remains a great challenge. Herein, we report Sb³⁺/Mn²⁺-codoped CsCdCl₃ and multiple emission bands can be observed, which are derived from the self-trapped exciton emission of the Sb-Cl moiety and the d-d transition of Mn²⁺. Thus, tunable emission from cyan to orange light can be obtained. Moreover, efficient white emission with a luminous efficiency of 74% is observed when the energy-transfer efficiency from Sb³⁺ to Mn²⁺ is 34.5%. In particular, Sb³⁺/Mn²⁺-codoped CsCdCl₃ shows bright orange afterglow emission, and the afterglow intensity is 1000 times that of CsCdCl₃ and 20 times that of CsCdCl₃:Mn²⁺. Upon combining this with thermoluminescence spectra, it is found that Mn²⁺/Sb³⁺ codoping can effectively regulate the depth and density distribution of trap defects, resulting in the ultralong afterglow duration exceeding 12 h at room temperature. Surprisingly, white light stimulation can provide additional photonic energy for Sb³⁺/Mn²⁺-codoped CsCdCl₃, which enables the rapid release of trapped carriers to the emission center and rejuvenates afterglow emission after 12 h pre-delay. Finally, we demonstrated the applications of the as-synthesized compounds in single-component white light illumination, multiple optical anti-counterfeiting and information encryption.