Figure 3.

Charge dynamics and electrical characterizations of perovskite films. A) PL spectra of the Sn‐based perovskite films. B) TRPL spectra of the Sn‐based perovskite films. C) XRD patterns of the quasi‐2D PEA₂FA₁Sn₂I₇ perovskite films processed with different amounts of GuaSCN. D) Transfer curves of the field‐effect transistors prepared by depositing PEA₂FA₁Sn₂I₇ perovskite films (containing different amounts of GuaSCN) on SiO₂/Si substrates. Inset: the calculated hole mobility of the corresponding films. E) UPS spectra of the 3D FASnI₃ and PEA₂FA₁Sn₂I₇ (w/o or w/10% GuaSCN) perovskite films. F) Energy level diagram of the quasi‐2D perovskite PEA₂FA₁Sn₂I₇ (w/o or w/10% GuaSCN) and 3D FASnI₃ films.