Optical and electronic anisotropies in perovskitoid crystals of Cs3Bi2I9 studies of nuclear radiation detection

Qihao Sun, Yadong Xu, Hongjian Zhang, Bao Xiao, Xin Liu, Jiangpeng Dong, Yuanbo Cheng, Binbin Zhang, Wanqi Jie, Mercouri G. Kanatzidis

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)


The halide perovskitoid compound Cs3Bi2I9 (CBI) has attracted considerable interest as a semiconductor because of its outstanding stability and reduced toxicity compared with lead-based halide perovskites. Here, we report the growth of nuclear radiation detection grade CBI bulk crystals (Φ 15 × 60 mm3) with a high resistivity of over 1010 Ω cm using a modified vertical Bridgman method. Because of their layered crystal structures we investigated the anisotropy in the optical and electrical properties using different crystal orientations. The CBI(001) sample exhibits a resistivity of ∼1012 Ω cm compared to ∼1010 Ω cm for the CBI(100) sample. This is due to the anisotropic mobility in the two crystallographic directions. Using 425 nm LED (∼200 mW cm−2) illumination CBI(001) possesses a superior optical response with a switching ratio of over 40, which is critically higher than that of CBI(100) (<2). Detectors of 2 mm thickness show a capability of detecting 241Am@5.49 MeV α particles, with good peak discrimination. A full width at half maximum (FWHM) of 32% was obtained under a bias of 560 V. Simultaneously, the electron mobility and mobility lifetime (μτ) were calculated to be 6.10 cm2 V−1 s−1 and 2.03 × 10−5 cm V−1, respectively. First-principles density functional theory calculations confirm the crystallographic anisotropy of the carrier effective masses. In addition, a significant X-ray sensitivity of 111.9 μC Gy−1 cm−2 for a CBI detector was observed, under 80 kVp X-rays at an electrical field of 450 V cm−1.

Original languageEnglish
Pages (from-to)23388-23395
Number of pages8
JournalJournal of Materials Chemistry A
Issue number46
Publication statusPublished - 2018

ASJC Scopus subject areas

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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