Heteroepitaxial passivation of Cs<sub>2</sub>AgBiBr<sub>6</sub> wafers with suppressed ionic migration for X-ray imaging.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31040278.
- Also identified by DOI 10.1038/s41467-019-09968-3 and PMC identifier 6491557.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
X-ray detectors are broadly utilized in medical imaging and product inspection. Halide perovskites recently demonstrate excellent performance for direct X-ray detection. However, ionic migration causes large noise and baseline drift, limiting the detection and imaging performance. Here we largely eliminate the ionic migration in cesium silver bismuth bromide (Cs<sub>2</sub>AgBiBr<sub>6</sub>) polycrystalline wafers by introducing bismuth oxybromide (BiOBr) as heteroepitaxial passivation layers. Good lattice match between BiOBr and Cs<sub>2</sub>AgBiBr<sub>6</sub> enables complete defect passivation and suppressed ionic migration. The detector hence achieves outstanding balanced performance with a signal drifting one order of magnitude lower than all previous studies, low noise (1/f noise free), a high sensitivity of 250 µC Gy <sub>air</sub><sup>-1</sup> cm<sup>-2</sup>, and a spatial resolution of 4.9 lp mm<sup>-1</sup>. The wafer area could be easily scaled up by the isostatic-pressing method, together with the heteroepitaxial passivation, strengthens the competitiveness of Cs<sub>2</sub>AgBiBr<sub>6</sub>-based X-ray detectors as next-generation X-ray imaging flat panels.