Brightening deep-blue perovskite light-emitting diodes: A path to Rec. 2020

Area of Science:

• Materials Science
• Optoelectronics
• Chemistry

Background:

• Deep-blue perovskite light-emitting diodes (PeLEDs) are crucial for next-generation displays meeting Rec. 2020 standards.
• Mixed-halide perovskites for deep-blue emission suffer from halide vacancies, particularly chloride vacancies, leading to instability and performance degradation.

Purpose of the Study:

• To address halide vacancies in deep-blue PeLEDs.
• To enhance the color stability and performance of deep-blue PeLEDs.

Main Methods:

• A chloride vacancy-targeting passivation strategy using sulfonate ligands with varying chain lengths was employed.
• Sulfonate groups were utilized for their strong affinity to lead(II) ions, neutralizing vacancies.

Main Results:

• The passivation strategy successfully suppressed phase segregation.
• Color-stable deep-blue PeLEDs with an emission peak at 461 nm were achieved.
• A maximum luminance of 2707 cd/m² with an external quantum efficiency (EQE) of 3.05% was recorded.
• Optimizing carbon chain length in sulfonate ligands increased EQE to 5.68% at 1978 cd/m².

Conclusions:

• The proposed sulfonate ligand passivation is effective in stabilizing deep-blue PeLEDs.
• This strategy offers a pathway to high-performance, Rec. 2020 compliant deep-blue PeLEDs.
• Ligand engineering provides a tunable approach to further enhance PeLED performance.