Efficient Dion-Jacobson perovskite light-emitting diodes via mixed cation engineering

Area of Science:

• Materials Science
• Optoelectronics
• Solid-State Chemistry

Background:

• Quasi-two-dimensional (quasi-2D) perovskites exhibit high exciton binding energy, enabling carrier confinement for efficient energy funnels and reduced recombination losses.
• Formamidinium (FA)-based Dion-Jacobson (DJ) perovskites are promising for optoelectronic applications but require optimization for improved performance.

Purpose of the Study:

• To investigate the effect of partially alloying Cs+ cations into FA-based DJ perovskites.
• To optimize the stoichiometric ratio for enhanced device performance.
• To fabricate efficient green-light DJ perovskite light-emitting diodes (PeLEDs).

Main Methods:

• Partial substitution of CsBr for FABr in FA-based DJ perovskites.
• Adjustment of stoichiometric ratios to modify material properties.
• Incorporation of a Lewis base passivation agent (TPBi) in the antisolvent.
• Characterization of perovskite films and device performance.

Main Results:

• Alloying Cs+ and adjusting stoichiometry improved morphology, modulated phase distribution, and reduced defects.
• CsBr incorporation enhanced current efficiency from 18.2 to 25.3 cd/A.
• Devices achieved a high current efficiency of 42.1 cd/A, external quantum efficiency (EQE) of 10.5%, and maximum luminance of 18600 cd/m² at 529 nm.
• Efficient green-light DJ PeLEDs based on mixed Cs+ and FA+ cations were fabricated for the first time.

Conclusions:

• Partial Cs+ alloying in FA-based DJ perovskites is an effective strategy to enhance carrier confinement and reduce nonradiative recombination.
• The developed PeLEDs demonstrate significant improvements in efficiency and luminance, paving the way for advanced optoelectronic devices.
• This work presents a novel approach for fabricating high-performance green-light perovskite light-emitting diodes.