2D Ruddlesden–Popper Perovskites Microring Laser Array

TLDR

3D hybrid perovskites exhibit high gain through electron–hole plasma stimulated emission, whereas 2D Ruddlesden–Popper perovskites host strongly bound excitons at room temperature and have been used in high‑performance solar cells and LEDs, but light‑amplification devices remain largely unexplored. The authors use cascade quantum‑well structures in 2D RPPs to funnel carriers into the lowest‑bandgap well, creating population inversion for room‑temperature amplified spontaneous emission, and fabricate high‑density microring arrays that act as whispering‑gallery‑mode lasers with high Q, identical modes, and low thresholds, enabling simultaneous array operation. Measured gain coefficients in 2D RPP thin films are at least four times higher than in 3D perovskites, and the fabricated microring arrays exhibit high Q, identical modes, and low lasing thresholds, demonstrating that 2D RPPs are promising solution‑processed gain materials for electrically driven lasers and on‑chip nanophotonics.

Abstract

Abstract 3D organic–inorganic hybrid perovskites have featured high gain coefficients through the electron–hole plasma stimulated emission mechanism, while their 2D counterparts of Ruddlesden–Popper perovskites (RPPs) exhibit strongly bound electron–hole pairs (excitons) at room temperature. High‐performance solar cells and light‐emitting diodes (LEDs) are reported based on 2D RPPs, whereas light‐amplification devices remain largely unexplored. Here, it is demonstrated that ultrafast energy transfer along cascade quantum well (QW) structures in 2D RPPs concentrates photogenerated carriers on the lowest‐bandgap QW state, at which population inversion can be readily established enabling room‐temperature amplified spontaneous emission and lasing. Gain coefficients measured for 2D RPP thin‐films (≈100 nm in thickness) are found about at least four times larger than those for their 3D counterparts. High‐density large‐area microring arrays of 2D RPPs are fabricated as whispering‐gallery‐mode lasers, which exhibit high quality factor ( Q ≈ 2600), identical optical modes, and similarly low lasing thresholds, allowing them to be ignited simultaneously as a laser array. The findings reveal that 2D RPPs are excellent solution‐processed gain materials potentially for achieving electrically driven lasers and ideally for on‐chip integration of nanophotonics.