Ion Migration in Two-Dimensional Organic-Inorganic Hybrid Perovskite Heterostructures: Interface Evolution, Migration...

Area of Science:

• Materials Science
• Solid-State Chemistry
• Nanotechnology

Background:

• Two-dimensional organic-inorganic hybrid perovskites (2D-OIHP) offer tunable properties for crystal engineering.
• Ionic softness in 2D-OIHP enables chemical transformations but also leads to ion migration.

Purpose of the Study:

• To review recent advancements in understanding ion migration in 2D-OIHP heterostructures.
• To provide a mechanistic framework for utilizing ion migration in layered hybrid perovskites.

Main Methods:

• Classification of fabrication strategies based on initial interface profiles.
• Discussion of thermally driven and electric-field-induced ion migration.
• Analysis of spacer-cation engineering for interdiffusion suppression.

Main Results:

• Ion migration dictates interface evolution: sharp, graded, alloyed, or functional junctions.
• Halide migration occurs in-plane and out-of-plane under thermal stimuli.
• Directional migration can be induced by electric fields in devices.

Conclusions:

• Ion migration is a critical factor for both stability and crystal engineering in 2D-OIHP heterostructures.
• Design rules are extracted for achieving stable, sharp, or dynamically programmable perovskite heterostructures.
• Further research is needed to address unresolved challenges in controlling ion migration.