Fig. 1: Mechanism of SSC-regulated crystallization process.

SSC denotes the perovskite film processed with 2% L-Glutamic acid hydrochloride (Glu) additive, which enables sustained solvent-extraction channels. a Optical microscopy images (100 × objective) of freshly AS-treated perovskite films, captured immediately after anti-solvent treatment and prior to annealing. The fraction of discontinuous domains increased from 1.78% (control) to 7.11% (SSC-Glu). b Contact angles of the corresponding perovskite precursor solution droplets on PEDOT:PSS. c ¹H NMR spectra of pure Glu, pure FAI, FAI with Glu, and CsI with Glu additive dissolved in DMSO-d6. d Semi-in situ optical microscopy (50 × objective) tracking the morphological evolution of perovskite precursor films without (control) and with SSC over time. The images were acquired under an inert atmosphere without anti-solvent treatment or annealing. e XRD patterns of mixed Pb-Sn films processed from perovskite precursor solutions without and with SSC before the antisolvent treatment. f GC of the control and SSC treated wet perovskite films. g Schematic illustration of the SSC mechanism during AS-assisted crystallization process.