Optimizing Lasing Performance of CsPbBr₃ Microplates by Regulating Exciton Recombination Dynamics with Pressure

Area of Science:

• Materials Science
• Optoelectronics
• Condensed Matter Physics

Background:

• Developing electrically driven micro/nanolasers is crucial for integrated optics.
• Cesium lead bromide microplates (CsPbBr3 MPs) are promising laser gain media.
• Understanding lasing threshold optimization is key for practical applications.

Purpose of the Study:

• To achieve an ultralow lasing threshold in CsPbBr3 MPs.
• To investigate the effect of external pressure on the lasing behavior of CsPbBr3 MPs.
• To explore pressure modulation as a strategy for optimizing micro/nanolaser performance.

Main Methods:

• Static-state and time-resolved photoluminescence (PL) spectroscopy.
• Application of varying external pressures (up to 1.87 GPa).
• First-principles theory calculations using density functional theory (DFT).

Main Results:

• An optimal lasing threshold of 20.87 μJ/cm² was achieved by releasing pressure from 1.87 GPa.
• A critical turning point for the lasing threshold was observed at 0.44 GPa.
• Low pressure enhances phonon hardening, preventing exciton decay; high pressure increases surface defects, promoting decay.

Conclusions:

• Pressure modulation is a viable strategy for optimizing the lasing performance of CsPbBr3 MPs.
• Only free excitons contribute to lasing in CsPbBr3 MPs, while both free and trapped excitons contribute to luminescence.
• Findings advance the potential of perovskite micro/nanolasers for optoelectronic devices.