Layered BiOI single crystals capable of detecting low dose rates of X-rays.
Layered BiOI single crystals capable of detecting low dose rates of X-rays.
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DOI：
10.1038/s41467-023-38008-4
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发表时间：
2023-04-28
影响因子：
16.6
通讯作者：
Hoye, Robert L. Z.
中科院分区：
文献类型：
--
作者：
Jagt, Robert A.;Bravic, Ivona;Eyre, Lissa;Galkowski, Krzysztof;Borowiec, Joanna;Dudipala, Kavya Reddy;Baranowski, Michal;Dyksik, Mateusz;Van de Goor, Tim W. J.;Kreouzis, Theo;Xiao, Ming;Bevan, Adrian;Plochocka, Paulina;Stranks, Samuel D.;Deschler, Felix;Monserrat, Bartomeu;MacManus-Driscoll, Judith L.;Hoye, Robert L. Z.
检测低剂量率的x射线对于制造更安全的放射学仪器至关重要，但受到可用吸收材料的限制。在这里，我们将氧化碘化铋（BiOI）单晶开发成有效的x射线探测器。由于晶格的离子特性和层间弱的范德华相互作用，BiOI具有复杂的晶格动力学。通过使用超快光谱学、第一性原理计算和详细的光学和结构特征，我们发现BiOI中的光激发电荷载流子与层内呼吸声子模式耦合，形成大极化子，从而使光激发载流子的漂移长度比自捕获所期望的要长。这与低而稳定的暗电流和高线性x射线衰减系数相结合，导致了强大的探测器性能。灵敏度可达1.1 × 103 μC Gyair−1 cm−2，直接测量的最低剂量率为22 μC Gyair s−1。本文讨论的光物理原理为具有重元素和低维电子结构的新型材料的光电应用提供了新的设计途径。揭示了碘化铋（BiOI）中载流子和声子之间的复杂耦合，展示了如何避免载流子局部化并实现长输运长度。结果表明，BiOI对x射线探测非常有效。
Detecting low dose rates of X-rays is critical for making safer radiology instruments, but is limited by the absorber materials available. Here, we develop bismuth oxyiodide (BiOI) single crystals into effective X-ray detectors. BiOI features complex lattice dynamics, owing to the ionic character of the lattice and weak van der Waals interactions between layers. Through use of ultrafast spectroscopy, first-principles computations and detailed optical and structural characterisation, we show that photoexcited charge-carriers in BiOI couple to intralayer breathing phonon modes, forming large polarons, thus enabling longer drift lengths for the photoexcited carriers than would be expected if self-trapping occurred. This, combined with the low and stable dark currents and high linear X-ray attenuation coefficients, leads to strong detector performance. High sensitivities reaching 1.1 × 103 μC Gyair−1 cm−2 are achieved, and the lowest dose rate directly measured by the detectors was 22 nGyair s−1. The photophysical principles discussed herein offer new design avenues for novel materials with heavy elements and low-dimensional electronic structures for (opto)electronic applications. The complex coupling between charge-carriers and phonons in bismuth oxyiodide (BiOI) are uncovered, showing how carrier localisation is avoided and long transport lengths achieved. As a result, BiOI is revealed to be highly effective for X-ray detection.
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影响因子：
3.5
作者：
Frutos, Maia Mombru;Barthaburu, Maria Eugenia Perez;Aguiar, Ivana
通讯作者：
Aguiar, Ivana
影响因子：
3.7
作者：
Kresse, G;Furthmuller, J
通讯作者：
Furthmuller, J
影响因子：
2.7
作者：
Giannozzi, P.;Andreussi, O.;Baroni, S.
通讯作者：
Baroni, S.
影响因子：
--
作者：
DANCOFF, SM
通讯作者：
DANCOFF, SM
DOI：
10.1103/physrevb.5.594
发表时间：
1972-01-01
期刊：
PHYSICAL REVIEW B-SOLID STATE
影响因子：
--
作者：
DOW, JD;REDFIELD, D
通讯作者：
REDFIELD, D