Dual-Wavelength Lasing Due to Second Phase Inclusions in MAPbCl₃

Area of Science:

• Materials Science
• Optics
• Solid-State Physics

Background:

• Methylammonium lead chloride (MAPbCl3) is a promising material for optoelectronic applications.
• Understanding the fundamental optical properties of MAPbCl3 single crystals is crucial for device development.

Purpose of the Study:

• To investigate the mechanism behind dual-wavelength lasing observed in MAPbCl3 single crystals at low temperatures.
• To characterize the optical properties of MAPbCl3 single crystals and identify factors contributing to unusual lasing behavior.

Main Methods:

• Temperature-dependent optical experiments were conducted on ultrasmooth MAPbCl3 single crystals.
• Microreflectivity measurements were used to analyze excitonic features.
• Lasing behavior was investigated in a vertical cavity setup.

Main Results:

• Dual-wavelength lasing was achieved at 78 K in MAPbCl3 single crystals.
• A previously unreported excitonic peak at ~412 nm was discovered, distinct from the standard ~385 nm orthorhombic bandgap.
• This second excitonic feature, attributed to a "second phase" possibly related to quantum dot-like nanostructures, aligns with the second lasing line and persists up to 300 K.

Conclusions:

• The dual-wavelength lasing in MAPbCl3 is attributed to the coexistence of the primary orthorhombic phase and a secondary phase.
• This secondary phase, likely associated with nanostructures, influences the optical properties and lasing behavior.
• The findings enhance the understanding of MAPbCl3 systems and suggest potential for blue-UV photonic devices.