Synthesis of zero-dimensional hybrid rare-earth halides for wavelength-dependent multicolor luminescence and X-ray...

Zero-dimensional hybrid metal halide luminescent materials have demonstrated broad potential for applications in areas such as displays, stimulus-responsive materials, anti-counterfeiting technologies, and X-ray detection. This paper focuses on the synthesis of novel hybrid lanthanide-based halides by combining pyridinium-based ionic liquids with rare-earth luminescent centers. Two zero-dimensional hybrid lanthanide halides, (BPy)₃LnCl₆·H₂O (BPy = 1-butylpyridinium cation, Ln³⁺ = Tb³⁺ or Eu³⁺), were synthesized via solution growth and grinding methods. Upon excitation by ultraviolet light, the compounds (BPy)₃TbCl₆·H₂O and (BPy)₃EuCl₆·H₂O emit green and red light, respectively. The photoluminescence quantum yield of (BPy)₃TbCl₆·H₂O reached 65.7%. By adjusting the Tb³⁺/Eu³⁺ ratio and employing a method that combines melt-cooling with grinding, tunable multicolor photoluminescent samples can be rapidly prepared. Furthermore, by employing an ion-doping strategy to introduce Sb³⁺ into the (BPy)₃TbCl₆·H₂O matrix, the (BPy)₃TbCl₆·H₂O:Sb³⁺ sample exhibits wavelength-dependent dual-channel luminescence. The response of the zero-dimensional compound (BPy)₃TbCl₆·H₂O to X-rays demonstrates its potential as a scintillator. The compound (BPy)₃TbCl₆·H₂O exhibits a light yield of 28,278 photons/MeV and a detection limit as low as 106.02 nGy_air/s. The spatial resolution of the scintillation film constructed using (BPy)₃TbCl₆·H₂O and polyvinylidene fluoride reached as high as 15.1 lp mm^-1. These results demonstrate the potential applications of rare-earth-based hybrid halides in anti-counterfeiting and X-ray imaging, while also providing insights for the design of novel lanthanide-based halide luminescent materials.