Crystal-Growth-Controlled Exciton Funneling in BA₂MAPb₂I₇ Ruddlesden-Popper Perovskite Thin Films

Area of Science:

• Materials Science
• Solid-State Physics
• Photovoltaics

Background:

• Quasi-2D Ruddlesden-Popper perovskites offer tunable optoelectronic properties.
• Controlling film morphology and phase distribution is crucial for efficient energy transfer.

Purpose of the Study:

• To compare the properties of BAMA perovskite films prepared via single-crystal-derived and polycrystalline routes.
• To elucidate the role of film structure in exciton dynamics and energy transfer.

Main Methods:

• Thin film preparation using single-crystal-derived and polycrystalline methods.
• Morphological and X-ray diffraction analyses.
• Steady-state and time-resolved optical spectroscopies (transient photoluminescence, pump-probe).

Main Results:

• Single-crystal-derived films show higher phase purity and crystallinity.
• Polycrystalline films exhibit limited interphase energy transfer.
• Single-crystal-derived films display a richer excitonic landscape with higher-n domains and hierarchical exciton funneling via the n=2 exciton.

Conclusions:

• Film crystallinity and phase distribution significantly impact exciton migration and energy transfer in BAMA perovskites.
• Hierarchical exciton funneling is demonstrated in single-crystal-derived films.
• Optimizing film preparation is key to enhancing performance in low-dimensional perovskite heterostructures.