Phase Distribution Dictates Charge Transfer and Transport Dynamics in Layered Quasi-2D Perovskite

Area of Science:

• Materials Science
• Solid-State Physics
• Optoelectronics

Background:

• Optimizing quasi-two-dimensional (2D) perovskite optoelectronic devices requires strategic control over charge carrier spatiotemporal evolution.
• Inhomogeneous phase distribution and band alignment create complex energy landscapes that hinder internal charge and energy funneling.

Purpose of the Study:

• To investigate the mechanisms governing charge and energy funneling in 2D perovskites.
• To explore the impact of phase manipulation on charge carrier dynamics and optoelectronic device performance.

Main Methods:

• Integration of high spatiotemporal resolution transient absorption microscopy.
• Application of multiple time-resolved spectroscopy techniques.

Main Results:

• Asynchronous electron and hole transfers, rather than direct energy transfer, were identified as the primary funneling mechanisms.
• Phase manipulation was shown to modify charge funneling pathways and transport behaviors.
• Accumulation of small-n phases suppressed electron funneling to large-n phases, doubling carrier diffusion rate to 0.20 cm²/s and increasing diffusion length 1.5-fold.
• Phase order engineering was confirmed to facilitate charge separation.

Conclusions:

• Charge funneling and transport in 2D perovskites are controllable through manipulation of phase distribution.
• This study provides theoretical foundations for enhancing optoelectronic device performance by engineering phase order.