Room-Temperature Quasi-CW Random Lasing in a Tin-Perovskite Ultrathin Film

Area of Science:

• Materials Science
• Optoelectronics
• Solid-State Physics

Background:

• Solution-processed semiconductor lasers offer low-cost, integrable coherent light sources.
• Lead (Pb)-based perovskites show promise, but tin (Sn)-based alternatives lag due to crystallization and film morphology challenges.
• Achieving continuous-wave (CW) operation in Sn-based perovskites is crucial for electrically pumped lasing but hindered by thick films that impede electrical injection.

Purpose of the Study:

• To demonstrate quasi-CW random lasing in ultra-thin, solution-processed Sn-based perovskite films.
• To overcome the limitations of conventional perovskite laser architectures regarding film thickness and electrical injection efficiency.
• To advance the development of environmentally benign and cost-effective perovskite laser diodes.

Main Methods:

• Utilized additive N-benzylethylenediamine hydrogen bromide (BEABr) to control crystallization and morphology of CsSnBr3 films.
• Fabricated solution-processed CsSnBr3 films with thicknesses as low as approximately 40 nm.
• Investigated quasi-CW optical pumping to achieve random lasing in the thin films.

Main Results:

• Demonstrated quasi-CW random lasing in solution-processed CsSnBr3 films as thin as ~40 nm.
• Achieved a lasing threshold of 9.7 kW/cm² at room temperature.
• The additive BEABr promoted densely packed polygonal grain morphology, enabling multiple scattering for coherent feedback.

Conclusions:

• This work presents the first quasi-CW lasing in a Sn-based perovskite material.
• The developed thin-film architecture addresses optical and electrical design requirements for future laser diodes.
• This research marks a significant step toward realizing solution-processed, environmentally friendly perovskite laser diodes.