Fig. 1: Stimulated emission from perovskite multiple quantum wells (MQWs).
From: Ultrashort laser pulse doubling by metal-halide perovskite multiple quantum wells
a Schematic illustration of the localization of photogenerated charge carriers from the surrounding low-dimensional (LD, dominated by n = 2 QWs) to high-dimensional (HD, n ≥ 5) perovskite QWs. The blue and orange arrows indicate the lateral and vertical charge transfer, respectively. b Schematic energy level diagram shows the photogenerated excitons funneling process. c 2D pseudocolor plot of the photoluminescence (PL) intensities of perovskite MQWs with pump fluence from 1 to 60 µJ cm-2 (under 400 nm, 50 fs, 1 kHz fs laser excitation). The broad and sharp curves represent the PL spectra below and above the stimulated emission threshold, respectively. d Log–log plot of the integrated PL intensities and the full width at half maximum (FWHM) as a function of pump fluence. The black and red solid lines are linear fit slopes of PL intensities below and above the stimulated emission threshold.
