High defect tolerance β-CsSnI₃ perovskite light-emitting diodes

Area of Science:

• Materials Science
• Solid-State Physics
• Optoelectronics

Background:

• All-inorganic lead-free CsSnI₃ shows promise for near-infrared perovskite light-emitting diodes (Pero-LEDs).
• Defect-induced non-radiative recombination currently limits the optoelectronic properties and applications of CsSnI₃-based Pero-LEDs.

Purpose of the Study:

• To investigate the defect tolerance of different CsSnI₃ phases for enhanced emission efficiency.
• To develop a method for depositing and stabilizing highly crystalline β-CsSnI₃ films for improved Pero-LED performance.

Main Methods:

• Comparative analysis of β-CsSnI₃ and γ-CsSnI₃ defect tolerance.
• Deposition and stabilization of β-CsSnI₃ films using cesium formate.
• Characterization of photoluminescence quantum yield (PLQY) and device performance.

Main Results:

• β-CsSnI₃ demonstrates higher defect tolerance than γ-CsSnI₃.
• Cesium formate addition suppresses electron-phonon scattering and non-radiative recombination, achieving PLQY up to ~10%.
• Near-infrared LEDs based on β-CsSnI₃ emitters achieved a peak external quantum efficiency of 1.81% with excellent stability.

Conclusions:

• The use of β-CsSnI₃ and cesium formate is a viable strategy to enhance the efficiency and stability of lead-free perovskite near-infrared LEDs.
• This work paves the way for advanced optoelectronic devices with improved performance and reduced reliance on lead-based materials.