Scalable photonic crystal scintillators for high-performance X-ray imaging in photon-starved regimes

High-density inorganic scintillators play a pivotal role in X-ray imaging owing to their strong stopping power and efficient emission in the visible regime. However, their practical performance is fundamentally constrained by refractive-index mismatch, which traps a large fraction of generated photons through total internal reflection. Although photonic crystal structures offer a promising route for enhancing light extraction, scalable large-area integration onto scintillator substrates remains a significant challenge. Here, we propose a scalable self-assembly-based fabrication strategy for large-area photonic crystal scintillators, enabling the formation of a 25-mm-scale continuous PS-nanosphere PhC monolayer with locally verified HCP packing on the scintillator surface. The resulting photonic crystal facilitates momentum compensation via Bragg diffraction, thereby coupling confined guided wave modes to free-space radiation. Under X-ray excitation, this diffraction-mediated extraction mechanism experimentally yields a 4.64-fold enhancement in light output and a 13 dB improvement in signal-to-noise ratio for radiographic imaging. The measurable gain in detection sensitivity suggests this scalable fabrication strategy is a promising approach for high-performance X-ray detection in photon-starved applications, including low-dose medical diagnostics and security screening.