LAUSR

Conventional energy‐integration black–white X‐ray imaging lacks the spectral information of X‐ray photons. Although X‐ray spectra (energy) can be distinguished by the photon‐counting technique typically with CdZnTe detectors, it is very challenging to be applied to large‐area flat‐panel X‐ray imaging (FPXI). Herein, multilayer stacked scintillators of different X‐ray absorption capabilities and scintillation spectra are designed; in this scenario, the X‐ray energy can be discriminated by detecting the emission spectra of each scintillator; therefore, multispectral X‐ray imaging can be easily obtained by color or multispectral visible‐light camera in a single shot of X‐rays. To verify this idea, stacked multilayer scintillators based on several emerging metal halides are fabricated in a cost‐effective and scalable solution process, and proof‐of‐concept multispectral (or multi‐energy) FPXI are experimentally demonstrated. The dual‐energy X‐ray image of a “bone–muscle” model clearly shows the details that are invisible in conventional energy‐integration FPXI. By stacking four layers of specifically designed multilayer scintillators with appropriate thicknesses, a prototype FPXI with four energy channels is realized, proving its extendibility to multispectral or even hyperspectral X‐ray imaging. This study provides a facile and effective strategy to realize multispectral large‐area flat‐panel X‐ray imaging.