Near-Infrared Emitting Lead-Free Perovskite Scintillators for X-Ray Imaging with Suppressed Optical Crosstalk

Portable X-ray imaging is crucial for rapid security inspections and prompt diagnostics in outdoor settings. However, most high-performance scintillators emit in the ultraviolet to visible range, which significantly overlaps with white light-emitting diode (wLED) sources and sunlight, complicating the clear internal images under high-light conditions. Here, we develop a lead-free Cs₄MnBi₂Cl₁₂:Tm/Ce scintillator with intense Mn²⁺ visible and Tm³⁺ near-infrared (NIR) emissions. Incorporating NIR luminescence reduces optical crosstalk from external light signals, enabling high-contrast imaging even under intense ambient illumination. Ce³⁺ doping enhances energy transfer and suppresses nonradiative recombination, resulting in a high light yield of 49964 photons MeV^-1, a low detection limit of 57.2 nGy_air s^-1, and a high spatial resolution up to 16 lp mm^-1. Moreover, flexible scintillator films fabricated via screen coating demonstrate stable, high-contrast imaging under wLED or sunlight, eliminating the need for complex optics. This work offers a promising solution for realizing the next-generation portable outdoor X-ray detection.

 https://doi.org/10.1002/lpor.202502436