Br/I gradient-engineered CsPbX3 nanosheets: polymer-encapsulated design for polarized X-ray radioluminescence

Two-dimensional CsPbX 3 perovskite nanosheets serve as unique platforms for polarized emission modulation. However, the integrated control mechanism of bandgap engineering and polarized optical properties remains largely unexplored. In this study, we demonstrated a halogen gradient strategy using iodine-doped CsPbBr 3-x I x nanosheets with polymer encapsulation, enabling simultaneous band structure modification and optical anisotropy regulation. The iodine gradient enabled continuous tuning of the degree of polarization (up to 0.39) across a broad-spectrum range of 520–677 nm. Notably, radiation-induced polarized emission was observed in perovskite nanostructures under X-ray excitation, revealing directional transport behavior under high-energy stimulation. This work presents a detailed systematic investigation into X-ray-induced linearly polarized luminescence from perovskite nanosheets. The polarization-sensitive response detector exhibited enhanced current ratios, which can be attributed to iodine-induced defect suppression. This work not only advances the field of polarized optoelectronics but also establishes new opportunities for the detection of X-ray polarization response.