Fig. 5: Superfast and angle-dependent exciton transport at room temperature.

a, b Measured contour plots of PL intensity as a function of emission wavelength and space for 1L (a) and WL (b) pentacene samples at room temperature, with spatial mapping direction parallel (top panel; marked as 0°) and perpendicular (bottom panel; marked as 90°) to the b axis of the molecular lattices, as shown in Fig. S3a. In our measurement system, the mapping direction is parallel to the polarisation of the incident laser. The polarisation angles 0° and 90° have been marked according to the references set in the Fig. 2f inset. c, d Spatial profile plots along the dotted lines in a, b along two perpendicular mapping directions (0° and 90°), showing the angle-dependent exciton transport in 1L (c) and WL (d) pentacene samples. e Time-resolved PL emission (normalised) from WL and 1L pentacene samples at room temperature. The black and red balls represent the decay curves measured from WL pentacene samples with incident polarisation angles of 0° and 90°, respectively. Effective lifetimes of 2.8 and 2.8 ns were extracted from the black and red decay curves, respectively, by fitting with deconvolution of the instrument response function (IRF) (green dots). The orange and blue balls represent the decay curves measured from 1L pentacene samples with incident polarisation angles of 0° and 90°, respectively. The orange and blue decay curves were fitted with deconvolution of the IRF, giving effective short lifetime values of 12.7 and 5.6 ps, respectively. f Comparison plots of extracted diffusion coefficients measured from 1L (left panel) and WL (right panel) samples under the designated mapping angles at room temperature