Optical Properties and First-Principles Study of CH₃NH₃PbBr₃ Perovskite Structures

Area of Science:

• Materials Science
• Solid-State Chemistry
• Nanotechnology

Background:

• Solution-processed organic-inorganic hybrid perovskites are promising for light-harvesting applications.
• Methylammonium lead bromide (CH₃NH₃PbBr₃) is a key material in this class.

Purpose of the Study:

• To fabricate cubic single crystals and microstructures of CH₃NH₃PbBr₃ using a facile method.
• To investigate the growth mechanism and optical properties of the fabricated perovskites.
• To validate experimental findings with theoretical calculations.

Main Methods:

• One-step solution-based self-assembly method for perovskite fabrication.
• 3D fluorescence microscopy and scanning electron microscopy (SEM) for structural analysis.
• Photoluminescence (PL) spectroscopy for optical property assessment.
• Density functional theory (DFT) simulations for electronic and optical property calculations.

Main Results:

• Successfully fabricated hollow cubic CH₃NH₃PbBr₃ structures via self-assembly.
• Observed a layer-by-layer growth model in the (001) direction.
• Confirmed a peak photoluminescence emission at 535 nm.
• DFT calculations aligned with experimental optical and electronic properties, identifying Br and Pb contributions to the valence band maximum (VBM).

Conclusions:

• The one-step self-assembly method is effective for producing CH₃NH₃PbBr₃ hollow cubes.
• The growth mechanism involves nucleation, supersaturation, and layer-by-layer assembly.
• The material exhibits desirable optical properties, supported by theoretical simulations, making it suitable for optoelectronic applications.