Organometallic and inorganic halide perovskites are prospective candidates to replace conventional inorganic materials not only in the photovoltaic application [1] but also, in solid states lasers [2], light-emitting diodes [3], photodetectors [4] and solar fuels production [5]. Lead halide perovskites possess high-absorption coefficients, long-ranged ambipolar transport [6] and low cost and facile deposition techniques such as coating and printing [7]. Alongside with the other unique properties of the lead halide perovskites, these materials possess two types of conductivity: electronic and ionic. Ionic conductivity in lead halide perovskite is the result of cations and/or anions migration across the perovskite under the influence of an electric field. As the result of the ionic diffusion, the open regions or the significant population of vacancies on the appropriate sublattice of perovskite lattice, which allow the ionic movement, appear. Aforesaid vacancy assisted ionic defects act as traps for charge carriers in the perovskite. Therefore the ionic diffusion in lead halide perovskites results in the appearance of lattice defects, which has important implications in terms of long-term stability and performance of perovskite-based devices (i.e. solar cells, LEDs, photodetectors etc.). Moreover polarization of the solar cell electrodes is usually associated with mobile ions and surface carrier recombination, and achievable open-circuit voltage. In this regard, the understanding of the complex charge carrier dynamics induced by the ion migration is highly important. However it has to be noted, that kinetics of the mobile ions in the perovskites is a complex multicomponent phenomenon, which is still poorly understood. The existence of several ionic species, which can be a subject to diffusion, make the experimental evaluation rather obscure.

In the present work the MAPbBr₃ perovskite single crystals were studied by temperature-modulated space-charge-limited current (TMSCLC) method. While regular SCLC technique is based on the measurement of current-voltage characteristic (steady-state regime) or time-of-flight of charge carriers (dynamic regime) to get information concerning the current non-linearity, charge carrier concentration, hole or electron mobility, and charge trapping process in various device architectures and materials, the TMSCLC technique is suggested as a self-consistent spectroscopic method for the determination of both the distribution of localized states (traps) and their energy. The spectroscopic character of the method follows from the simultaneous measurement of space-charge current on both voltage and temperature (energy window associated with the Fermi-Dirac statistics and the shift of the Fermi level).

As a result, charge carrier mobilities (holes in the valence band) were calculated. Furthermore, with no illumination applied the activation energy E_a, associated with the thermodynamic equilibrium position of the Fermi level was estimated. Additionally three individual trap states were found with certain activation energies and concentrations.