CsPbBrCl_3- Solid Solutions: Understanding the Relationship between Lattice Expansion and Optical Properties.

Area of Science:

• Materials Science
• Solid-State Chemistry
• Optoelectronics

Background:

• All-inorganic halide perovskites are promising for efficient photoelectronic conversion.
• Previous research focused on CsPbBr3 and CsPbCl3, neglecting intermediate compositions.
• Systematic study of transition phases in halide perovskites is lacking.

Purpose of the Study:

• To synthesize and characterize a series of CsPbBrxCl3-x single crystals.
• To investigate the miscibility and structural properties of bromine and chlorine in the perovskite lattice.
• To tune the optoelectronic properties, specifically bandgap and photoluminescence, by varying halide composition.

Main Methods:

• Single crystals of CsPbBrxCl3-x (x = 0-3) were grown using the Bridgman method.
• Lattice parameters were analyzed to confirm miscibility and adherence to Vegard's law.
• Bandgap energies and photoluminescence spectra were measured.

Main Results:

• Large-size single crystals of CsPbBrxCl3-x were successfully grown, demonstrating complete miscibility of Br and Cl.
• Lattice parameter variations followed Vegard's law, indicating a solid solution system.
• Tunable bandgaps (2.90–2.29 eV) and photoluminescence (blue to green light) were achieved by adjusting bromine content.

Conclusions:

• The CsPbBrxCl3-x system forms a complete solid solution, allowing for precise control over material properties.
• Adjusting the Br/Cl ratio offers a viable strategy for tuning optoelectronic performance.
• These findings provide a foundation for developing customized photoelectronic semiconductor devices.