Heavy-to-light electron transition enabling real-time spectra detection of charged particles by a biocompatible semiconductor.

Zhao, Dou; Gao, Ruiling; Cheng, Wei; Wen, Mengyao; Zhang, Xinlei; Yokota, Tomoyuki; Sellin, Paul; Yang, Shengyuan A et al. · Nat Commun · 2024

basic_science · Level V

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Abstract

The current challenge of wearable/implantable personal dosimeters for medical diagnosis and radiotherapy applications is lack of suitable detector materials possessing both excellent detection performance and biocompatibility. Here, we report a solution-grown biocompatible organic single crystalline semiconductor (OSCS), 4-Hydroxyphenylacetic acid (4HPA), achieving real-time spectral detection of charged particles with single-particle sensitivity. Along in-plane direction, two-dimensional anisotropic 4HPA exhibits a large electron drift velocity of 5 × 10<sup>5 </sup>cm s<sup>-1</sup> at "radiation-mode" while maintaining a high resistivity of (1.28 ± 0.003) × 10<sup>12</sup> Ω·cm at "dark-mode" due to influence of dense π-π overlaps and high-energy L1 level. Therefore, 4HPA detectors exhibit the record spectra detection of charged particles among their organic counterparts, with energy resolution of 36%, (μt)<sub>e</sub> of (4.91 ± 0.07) × 10<sup>-5</sup> cm<sup>2</sup> V<sup>-1</sup>, and detection time down to 3 ms. These detectors also show high X-ray detection sensitivity of 16,612 μC Gy<sub>abs</sub><sup>-1</sup> cm<sup>-3</sup>, detection of limit of 20 nGy<sub>air</sub> s<sup>-1</sup>, and long-term stability after 690 Gy<sub>air</sub> irradiation.