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
Institute of Advanced Materials (INAM), Universitat Jaume I, 12006 Castelló, Spain.
Grenoble Alpes University, CEA, LITEN, DTNM, F38000 Grenoble, France.
ACS Energy Lett. 2022 Mar 11;7(3):946-951. doi: 10.1021/acsenergylett.1c02578. Epub 2022 Feb 11.
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.
卤化物钙钛矿材料的光电特性促进了其在许多应用中的利用。由于其混合的离子-电子导电性质，阐明其工作机制仍然具有挑战性。通过以高重现性记录一组单晶甲基溴化铅样品的长时间电流瞬变，证明了离子迁移过程。样品偏置实验（离子漂移），其特征时间表现出与电压的依赖关系为 ∝ ，用服从空间电荷限制电流的弹道式电压依赖迁移率（BVM） regime的离子迁移模型来解释。离子动力学有效地改变了长时间的电子电流，而稳态电子电流的行为几乎是欧姆性的。使用离子动态掺杂模型（IDD）来恢复零偏置下的电流（离子扩散），估计离子迁移率约为10 cm V s。我们的研究结果表明，与电子电流相比，离子电流可以忽略不计；然而，它们通过电荷密度分布的变化影响电子电流。
