Lead-Free Halide Perovskite Cs₂ZrX₆ Doped with Cr³⁺ for Multifunctional X-ray and NIR Imaging

Traditional X-ray imaging based on scintillators primarily provides structural insights but falls short of the capacity to resolve intricate biological features. In this work, we propose a multifunctional imaging strategy enabled by Cs₂ZrX₆:Cr³⁺ halide perovskite that uniquely exhibits both efficient near-infrared (NIR) photoluminescence under UV excitation and intense radioluminescence under X-ray irradiation. The material presents a high light yield of 56,250 photons MeV^-1 and a NIR photoluminescence quantum yield (PLQY) of 62.3%. Leveraging these superior optical properties, we achieved a spatial resolution of 7.7 lp mm^-1 in X-ray mode with a low detection limit of 31.2 nGy s^-1, as well as excellent NIR imaging performance with a spatial resolution of 10.0 lp mm^-1. Cs₂ZrCl₆:Cr³⁺ uniquely integrates scintillation and NIR imaging capabilities, enabling simultaneous visualization of skeletal structures and vascular networks in biological tissues. These results demonstrate the potential of halide perovskite-based platforms for integrated and high-resolution bioimaging, opening new directions in multifunctional photonic diagnostics.