High-Performance NIR-II Sn-Based Perovskite LEDs Enabled by the Functionalization of Sulfaguanidine

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Perovskite light-emitting diodes (PeLEDs) emitting in the near-infrared-II (NIR-II) region are promising for advanced applications.
• Instability of Sn2+ and imbalanced carrier injection hinder CsSnI3-based PeLED performance.

Purpose of the Study:

• To enhance the performance of NIR-II CsSnI3-based PeLEDs.
• To address defects and improve carrier injection balance in CsSnI3 films.

Main Methods:

• Employing functional sulfaguanidine (SG) molecules in CsSnI3 films.
• Utilizing S═O─Sn coordination and NH2···I− hydrogen bonds for defect passivation.
• Improving morphological uniformity and regulating carrier injection.

Main Results:

• Effective elimination of Sn(II)-related defects in CsSnI3 films.
• Enhanced morphological uniformity and balanced carrier injection.
• Achieved a breakthrough external quantum efficiency (EQE) of 8.1% for CsSnI3-SG PeLEDs.

Conclusions:

• Sulfaguanidine (SG) molecules effectively passivate defects and balance carrier injection in CsSnI3-based PeLEDs.
• The optimized PeLEDs demonstrate the highest reported efficiency for CsSnI3-based devices.
• This work paves the way for high-performance NIR-II PeLEDs.