Regulating the phase stability and bandgap of quasi-2D Dion–Jacobson CsSnI3 perovskite via intercalating organic cations

Abstract

Currently, as a promising alternative of lead halide perovskites, nontoxic lead-free CsSnI₃ perovskites have drawn increasing attention. However, the development of tin-based perovskites is still greatly hindered by their intrinsic deficiencies, such as their easy phase transformation. To address this issue, we theoretically proposed the design of quasi-2D Dion–Jacobson (DJ) CsSnI₃ perovskites intercalated with π-conjugated 2,5-thiophenedimethylammonium (ThDMA) based on first-principles computation. The phase stability of the quasi-2D (ThDMA)Cs_n−1Sn_nI_3n+1 perovskites could be fundamentally enhanced owing to the strong I–H interaction between the ThDMA²⁺ cations and [SnI₆]⁴⁻ inorganic layers. The bandgap could be linearly tailored from 2.55 (n = 1) to 1.35 eV (n = ∞) as a result of the engineered anti-bonding states of Sn–I bonding strength with tailored frontier bands by dimensional engineering. These results might give some meaningful insight for exploring environmentally friendly CsSnI₃ perovskites with expected applications in opto/electronic devices.