Exploiting a Multiphase Pure Formamidinium Lead Perovskite for Efficient Green-Light-Emitting Diodes

Area of Science:

• Optoelectronics
• Materials Science
• Solid-State Chemistry

Background:

• Formamidinium (FA)-based perovskites show promise in optoelectronics.
• Optimal composition for perovskite compounds remains a challenge.
• Perovskite light-emitting diodes (PeLEDs) require improved efficiency and stability.

Purpose of the Study:

• To enhance PeLED performance through composition and phase engineering.
• To investigate the effect of excess FABr on perovskite phase formation.
• To optimize PeLEDs for higher efficiency and stability.

Main Methods:

• Composition and phase engineering of FAPbBr3 perovskites.
• Incorporation of low-dimensional FA2PbBr4 particles.
• Regulating phase composition in multiphase FAPbBr3.
• Optimization using Rb+ ions for film quality and emission.

Main Results:

• Excess FABr led to the emergence of FA2PbBr4 particles mixed with FAPbBr3.
• Regulating phase composition increased EQEmax by 2.7-fold (5.14% vs 1.90%) and improved stability.
• Rb+ ion optimization further increased EQEmax to 6.01% with a half-lifetime of ~185 s.

Conclusions:

• Phase composition optimization is crucial for high-performance FA-based PeLEDs.
• This strategy effectively enhances both efficiency and operational stability.
• The findings offer a pathway for developing advanced optoelectronic devices.