Unveiling the underlying spin mechanism in quasi-2D perovskite spin-polarized lasing

The PL spectra were measured by a confocal system (WITec alpha 300R) equipped with a 405 nm continuous wave laser. Perovskite films were characterized by XRD (Philips, X pert pro MRD, with Cu Kα radiation, λ = 1.54 Å). The SEM images were observed by SEM (ZEISS Gemini SEM 300 field-emission SEM, with Pt coating). The morphology of the perovskite films was characterized by AFM (Cypher ES SPM) in the AC mode. The GIWAXS experiments were carried out at the BL17B1 beamline of Shanghai Synchrotron Radiation Facility (SSRF) using an X-ray energy of 10 keV. For the polarization-resolved ASE experiments, a 500 nm pulse as the excitation beam was focused on the samples through a cylindrical lens, and the stripe length of the spot size was controlled by using an adjustable slit. A quarter-wave plate (Thorlabs) was placed before the samples to generate the circularly polarized excitation. All data is processed using origin drawing.