Tailoring the Surface Morphology and Phase Distribution for Efficient Perovskite Electroluminescence

Area of Science:

• Materials Science
• Solid-State Chemistry
• Optoelectronics

Background:

• Metal-halide perovskites offer tunable emission, high efficiency, and low cost, making them attractive for light-emitting applications.
• Incorporating 2D perovskites into 3D perovskites can enhance carrier localization and reduce recombination, but phase diversity and random distribution limit device performance.
• The morphology of quasi-2D perovskite films is critical for device efficiency in perovskite light-emitting diodes (PeLEDs).

Purpose of the Study:

• To address the limitations of phase distribution and film morphology in 2D/3D perovskite systems for PeLEDs.
• To investigate the simultaneous tailoring of phase distribution and morphology by cation substitution.

Main Methods:

• Partial substitution of formamidinium (FA+) cations with cesium (Cs+) cations in the perovskite film.
• Characterization of the resulting perovskite film's phase distribution and morphology.
• Fabrication and performance testing of PeLED devices incorporating the modified perovskite films.

Main Results:

• Replacing 20% of FA+ with Cs+ in the perovskite film simultaneously optimized phase distribution and film morphology.
• Enhanced charge transfer efficiency and suppressed current leakage were observed in the modified films.
• The resulting PeLEDs exhibited nearly doubled efficiency and significantly improved operational stability.

Conclusions:

• Cesium substitution is an effective strategy for controlling the structural properties of mixed 2D/3D perovskites.
• Optimized phase distribution and morphology lead to superior performance and stability in PeLEDs.
• This approach offers a promising pathway for developing high-performance and stable perovskite optoelectronic devices.