α-Particle Detection and Charge Transport Characteristics in the A3M2I9 Defect Perovskites (A = Cs, Rb; M = Bi, Sb)

Kyle M. McCall, Zhifu Liu, Giancarlo Trimarchi, Constantinos C. Stoumpos, Wenwen Lin, Yihui He, Ido Hadar, Mercouri G. Kanatzidis, Bruce W. Wessels

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17 Citations (Scopus)

Abstract

We have investigated the defect perovskites A3M2I9 (A = Cs, Rb; M = Bi, Sb) as materials for radiation detection. The phase purity of Bridgman-grown A3M2I9 single crystals was confirmed via high-resolution synchrotron X-ray diffraction, while density functional theory calculations (DFT) show surprisingly dispersive bands in the out-of-plane direction for these layered materials, with low effective masses for both holes and electrons. Accordingly, each of the four A3M2I9 defect perovskites showed response to 241Am α-particle irradiation for hole and electron electrode configurations, a remarkable ambipolar response that resembles the 3D halide perovskites. The electron response spectra were used to estimate the mobility-lifetime product (μτ)e for electrons in these materials, with Rb3Bi2I9 showing the lowest (μτ)e value of 1.7 × 10-6 cm2 V-1 and Cs3Bi2I9 the highest (μτ)e of 5.4 × 10-5 cm2 V-1. The rise time of the α-particle-generated pulse was used to estimate the electron mobility μe of the A3M2I9 defect perovskites, which ranged from 0.32 cm2 V-1s-1 for Rb3Sb2I9 to 4.3 cm2 V-1s-1 in Cs3Bi2I9. Similar analysis of the hole response spectra yielded (μτ)h values for each A3M2I9 compound, with Cs3Bi2I9 again showing the highest (μτ)h value of 1.8 × 10-5 cm2 V-1, while Rb3Bi2I9 showed the lowest (μτ)h with 2.0 × 10-6 cm2 V-1. Rise time analysis gave hole mobilities ranging from 1.7 cm2 V-1 s-1 for Cs3Bi2I9 to 0.14 cm2 V-1 s-1 for Cs3Sb2I9. Comparing the experimental electron and hole mobilities to the effective masses obtained from DFT calculations revealed sizable discrepancies, possibly indicating self-trapping of charge carriers due to electron-phonon interactions. The α-particle response of the A3M2I9 defect perovskites demonstrates their potential as semiconductor radiation detectors, with Cs3Bi2I9 and Cs3Sb2I9 showing the most promise.

Original languageEnglish
Pages (from-to)3748-3762
Number of pages15
JournalACS Photonics
Volume5
Issue number9
DOIs
Publication statusPublished - Sep 19 2018

Keywords

  • charge transport
  • halide perovskite
  • radiation detection
  • semiconductor detector

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biotechnology
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering

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