Chiral Terbium Halide for Narrow-Band X-ray Scintillation

Achieving narrow-band radioluminescence remains challenging despite its critical importance in display technologies. Here, we construct the novel chiral terbium(III)-based hybrid metal halides (<i>R</i>/<i>S</i>-3BrMBA)₃TbCl₆ (<b><i>R</i></b>/<b><i>S</i>-BMTC</b>) and systematically investigate their scintillation properties. Benefiting from the heavy atom-enhanced X-ray absorption, negligible self-absorption, and unique 4<i>f</i>-4<i>f</i> transitions of Tb³⁺, <b><i>R</i>-BMTC</b> exhibits excellent X-ray scintillation activity with strong radioluminescence comparable to that of the commercial Bi₄Ge₃O₁₂. Most importantly, <b><i>R</i>-BMTC</b> exhibits one of the narrowest radioluminescences (∼9 nm) among the reported hybrid metal halides. Additionally, it also exhibit efficient green circularly polarized luminescence with high quantum yield (45.9%) and dissymmetry factor (4.99 × 10^-3), which are essential for suppressing the optical crosstalk and enhancing the X-ray imaging quality at the boundary. Overall, our work demonstrates an efficient approach for developing the narrow-band X-ray scintillator, thereby advancing the progress of chiral rare-earth halides toward optoelectronic applications.