Cage Balancing Enhances Optoelectronic and Lasing Performance in Stable Quasi-2D Tin Iodide Perovskites

Area of Science:

• Materials Science
• Solid-State Chemistry
• Optoelectronics

Background:

• Two-dimensional (2D) tin halide perovskites are promising semiconductors due to their tunability and low toxicity.
• Achieving both air stability and excellent photophysical properties requires careful structural modification.

Purpose of the Study:

• To synthesize and investigate new quasi-2D Ruddlesden-Popper tin halide perovskites using a fluorinated spacer cation.
• To explore the effects of layer thickness, spacer cation, and A-site cation on crystal structure and optical properties.

Main Methods:

• Synthesis of (4FPEA)2(A)n-1SnnI3n+1 perovskite series.
• Systematic investigation of crystal structures and optical properties.
• Structural classification of n=2 perovskites based on distortion parameters.

Main Results:

• 4FPEA-based 2D tin perovskites exhibit undistorted bond angles and low octahedral distortions.
• These materials demonstrate prolonged air stability and excellent photophysics.
• Amplified spontaneous emission and lasing were observed in exfoliated microflakes.

Conclusions:

• The study reveals insights into structural distortions in perovskite cages, classifying them into tilted, balanced, and buckled types.
• Balanced n=2 perovskites, like those with 4FPEA, show minimal distortion and superior optoelectronic performance.
• The findings motivate the rational design of quasi-2D perovskites for advanced optoelectronic applications.