Ionic transport characteristics of large-size CsPbBr3 single crystals

As a typical perovskite compound, cesium lead bromine (CsPbBr3) has been widely studied because of its different kinds of optoelectronic applications. For high-energy ray detection, long-term stability of CsPbBr3 single crystal detectors is affected by ionic transport when working under an applied bias. In this paper, the current-voltage hysteresis at different temperatures was investigated. The so-called temperature-dependent transient response measurements were used to study the ionic transport characteristics of CsPbBr3 single crystal. The ionic migration mechanism was analyzed by comparing experimentally extracted ionic migration activation energies with theoretical results. The experimentally determined migration activation energy of ions of our CsPbBr3 single crystals was well in agreement with the theoretically calculated value of bromine vacancies (V-Br(+)), indicating that V-Br(+) dominates the ionic migration in CsPbBr3 single crystals. The dielectric behavior was also explored and it was revealed that dielectric polarization in CsPbBr3 single crystals mainly ascribed to the mobile bromine ions via vacancy-mediated mechanism. These findings give us meticulous insight on ionic transport dynamics of CsPbBr3 single crystals, which is critical for optimizing the devices with improved stability and efficiency.