Ion Migration‐Induced Amorphization and Phase Segregation as a Degradation Mechanism in Planar Perovskite Solar Cells

Abstract

The operation of halide perovskite optoelectronic devices, including solar cells and LEDs, is strongly influenced by the mobility of ions comprising the crystal structure. This peculiarity is particularly true when considering the long‐term stability of devices. A detailed understanding of the ion migration‐driven degradation pathways is critical to design effective stabilization strategies. Nonetheless, despite substantial research in this first decade of perovskite photovoltaics, the long‐term effects of ion migration remain elusive due to the complex chemistry of lead halide perovskites. By linking materials chemistry to device optoelectronics, this study highlights that electrical bias‐induced perovskite amorphization and phase segregation is a crucial degradation mechanism in planar mixed halide perovskite solar cells. Depending on the biasing potential and the injected charge, halide segregation occurs, forming crystalline iodide‐rich domains, which govern light emission and participate in light absorption and photocurrent generation. Additionally, the loss of crystallinity limits charge collection efficiency and eventually degrades the device performance.

Upscaling Inverted Perovskite Solar Cells: Optimization of Laser Scribing for Highly Efficient Mini-Modules

“…The type of TCO and the addition of BMITFB ionic liquid were selected after a preliminary comparison (see Figure S1 ). The ionic liquid should also reduce the ion migration within the perovskite to prevent its degradation [ 3 , 28 ]. This type of PSCs showed PCEs between 16 and 17% with a low spread in the results, easing the fabrication of balanced modules.…”

Multifunctional Polymer‐Regulated SnO2 Nanocrystals Enhance Interface Contact for Efficient and Stable Planar Perovskite Solar Cells

“…[ 48 ] Besides the ion migration, phase segregation in the mixed‐halide perovskite has also been proved to influence the efficiency and stability of PSCs. [ 55 ] Correlating ion migration and phase segregation with the crystal quality such as morphology and strains of the perovskites may benefit the understanding of the long‐term stability mechanism of PSCs in the future.…”

Single- or double A-site cations in A3Bi2I9 bismuth perovskites: What is the suitable choice?

“…Various factors have been reported to be the reason for hysteresis including ion-migration, ferroelectric effect, etc. [40,41] We suspect that ion migration arising from bulk and surface defects owing to the rapid crystallization and poor morphology might affect charge transport properties within the bulk and at the interfaces leading to hysteresis. Li 3 Bi 2 I 9 based devices did not work probably due to the structural mismatch on the A-site because of the smaller size of Li + .…”