Fig. 3: Modulate the crystallization process via 2-F-TPPO additive and suppress the tail states.

a, b Top-view SEM images with grain size distribution in the insets of the pristine film (a) and 2-F-TPPO incorporated perovskite film (b). c, d Temperature-dependent PL spectra of the pristine film (c) and 2-F-TPPO incorporated perovskite film (d)