High-Entropy Lead-Free Relaxor Ferroelectric Ceramic with Wide-Temperature-Range Self-Powered X-Ray Detection.
basic_science · Level V
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- Record sourced from PubMed, PMID 42210703.
- Also identified by DOI 10.1002/adma.73525.
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Abstract
Sensitive and stable x‑ray detectors are essential for low‑dose medical diagnostics. Achieving wide‑temperature operation in materials remains a key challenge for enabling thermally stable, self-powered x‑ray detection. Herein, a high-entropy lead-free relaxor ferroelectric ceramic, 0.85Bi<sub>0.47</sub>Na<sub>0.47</sub>Ba<sub>0.06</sub>TiO<sub>3</sub>-0.15Ca<sub>0.7</sub>Ho<sub>0.2</sub>Ti<sub>0.75</sub>Ta<sub>0.2</sub>O<sub>3</sub> (BNBT-CHTT), is fabricated first. The unique entropy-stabilized polar nanoregions (PNRs) endow the system with high resistivity and robust spontaneous polarization, underpinning exceptional self-powered performance across a broad thermal window. Under 70 keV x-ray irradiation, the detector exhibits excellent stability from 25°C to 185°C, delivering record-high specific sensitivities of 1117.44-1223.55 µC Gy<sub>air</sub> <sup>-1</sup> cm<sup>-2</sup>, self-powered sensitivities of 597.28-699.78 µC Gy<sub>air</sub> <sup>-1</sup> cm<sup>-2</sup>, and low detection limits of 38.7-160.6 nGy<sub>a</sub> <sub>i</sub> <sub>r</sub> s<sup>-1</sup>. Notably, distortion-free x-ray imaging is demonstrated at 185°C under zero bias, validating the material's practical utility. This work highlights the potential of high-entropy relaxor ferroelectrics to overcome key limitations of existing detectors and provides a robust platform for next-generation, low-power, wide-temperature-range x-ray detection and imaging technologies.