Optically-Pumped Lasing from Lead-Free Layered Halide Perovskites

Layered metal-halide perovskites, or two-dimensional perovskites have excellent optical and electronic properties easily tunable via changing their composition. Morphological control of their nanocrystals enabled cavity-confined light amplification. In the first section of the talk, I will discuss the optically-pumped lasing performances in lead and tin-based layered perovskites from a photophysical perspective. In lead-based candidates, the lasing threshold is often constrained by the strong exciton-phonon interaction or Auger re-combination. Enhanced lasing performances have been pursued in quasi-2D systems (1). Lead-free tin-iodide-based candidates may exhibit lasing performances surpassing those of their lead counterparts, as has been shown in recent studies (2). However, their cryogenic lasing thresholds are still in the 100s μJ/cm² regime with substantial sample-to-sample variation and infamous stability. These limitations arise from the lack of compositional and morphological control.<br/> <br/>The second section will discuss our recent crystal design and engineering toward scalable wet synthesis of 2D and quasi-2D layered perovskite nanowires. This "molecular templating method" suppresses crystal growth along all crystallographic directions except for a designable primary axis. Their exceptionally well-defined Fabry-Pérot cavities facilitated efficient low-loss waveguiding (below 3 dB/mm) and low-threshold light amplification (below 20 μJ/cm²) in 2D tin-iodide nanowires at 80K (3). Subsequently, our recent progress will be discussed achieving room-temperature lasing and ambient-stable plasmonic lasing in quasi-2D tin-iodide perovskites.<br/><br/>References<br/>(1) Park, J. Y., et al. Nature Chemistry, 2023, 15, 1745–1753. https://doi.org/10.1038/s41557-023-01311-0<br/>(2) Li, Y., et al. Science Advances, 2023, 9, eadh0517. https://doi.org/10.1126/sciadv.adh0517<br/>(3) Shao, W., et al. Science, 2024, 384(6669), 1000–1006. https://doi.org//10.1126/science.adl0920