Fig. 4: Spatial-temporal mapping of 1L and WL PEN.
From: Supertransport of excitons in atomically thin organic semiconductors at the 2D quantum limit
a Schematic showing the experimental setup with a movable lens used for mapping. A pulsed 522-nm laser is focused onto 1L/WL placed on the copper cold finger in a cryostat using a beam splitter and a ×100/0.5-NA-long working distance objective. Photoluminescence from the sample is imaged onto the entrance slit of the spectrometer using lenses L1 and L2. Lens L2 is translated to position the WL emission onto the entrance slit of the spectrometer. b, c Spatial-temporal mapping for 1L (WL), showing the diffusion in time and space. d, e Time evolution of the mean square displacement of excitons in space for 1L (WL). The diffusion coefficients obtained for 1L and WL were 306.8 ± 14.1 and 3.3 ± 1.1 cm2/s, respectively, confirming the diffusion length observed from Fig. 3b
