Coupling between Ion Drift and Kinetics of Electronic Current Transients in MAPbBr 3 Single Crystals

• Published in: ACS energy letters Vol. 7; no. 3; pp. 946 - 951
• Main Authors: García-Batlle, Marisé, Mayén Guillén, Javier, Chapran, Marian, Baussens, Oriane, Zaccaro, Julien, Verilhac, Jean-Marie, Gros-Daillon, Eric, Guerrero, Antonio, Almora, Osbel, Garcia-Belmonte, Germà
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 11.03.2022
• Subjects: Condensed Matter; Materials Science; Physics
• ISSN: 2380-8195; 2380-8195
• DOI: 10.1021/acsenergylett.1c02578

The optoelectronic properties of halide perovskite materials have fostered their utilization in many applications. Unravelling their working mechanisms remains challenging because of their mixed ionic-electronic conductive nature. By registering, with high reproducibility, the long-time current transients of a set of single-crystal methylammonium lead tribromide samples, the ion migration process was proved. Sample biasing experiments (ionic drift), with characteristic times exhibiting voltage dependence as ∝ , is interpreted with an ionic migration model obeying a ballistic-like voltage-dependent mobility (BVM) regime of space-charge-limited current. Ionic kinetics effectively modify the long-time electronic current, while the steady-state electronic currents' behavior is nearly ohmic. Using the ionic dynamic doping model (IDD) for the recovering current at zero bias (ion diffusion), the ionic mobility is estimated to be ∼10 cm V s . Our findings suggest that ionic currents are negligible in comparison to the electronic currents; however, they influence them via changes in the charge density profile.