Picoperovskites: The Smallest Conceivable Isolated Halide Perovskite Structures Formed within Carbon Nanotubes

Area of Science:

• Materials Science
• Nanotechnology
• Solid-State Chemistry

Background:

• Halide perovskites are key materials for optoelectronics like solar cells and LEDs.
• Quantum confinement effects in nanomaterials significantly alter their properties.
• Synthesizing perovskites at the nanoscale presents unique challenges.

Purpose of the Study:

• To synthesize and characterize ultra-small, picoscale halide perovskite structures.
• To investigate the formation of perovskites within single-walled carbon nanotubes (SWCNTs).
• To explore quantum confinement effects in these novel structures.

Main Methods:

• Melt insertion of CsPbBr3 and CsSnI3 into SWCNTs (≈1.2-1.6 nm diameter).
• Characterization of the resulting sub-nanometer perovskite structures.
• First-principles calculations to determine electronic properties.

Main Results:

• Four isolated picoscale halide perovskite structures were formed inside SWCNTs.
• Structures included Cs3PbIIBr5 nanowires and perovskite-like lamellar forms.
• Quantum confinement was observed, leading to bandgap widening compared to bulk perovskites.

Conclusions:

• The synthesis achieved the absolute synthetic cross-sectional limit for halide perovskites.
• These picoscale structures demonstrate tunable optoelectronic properties due to quantum confinement.
• This work opens new avenues for nanoscale optoelectronic device design.