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

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 pi-conjugated 2,5-thiophenedimethylammonium (ThDMA) based on first-principles computation. The phase stability of the quasi-2D (ThDMA)Csn-1SnnI3n+1 perovskites could be fundamentally enhanced owing to the strong I-H interaction between the ThDMA(2+) cations and [SnI6](4-) inorganic layers. The bandgap could be linearly tailored from 2.55 (n = 1) to 1.35 eV (n = infinity) 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.

Automated summary

The development of nontoxic lead-free CsSnI3 perovskites has been hindered by their intrinsic deficiencies. However, the theoretical design of quasi-2D Dion-Jacobson (DJ) CsSnI3 perovskites intercalated with pi-conjugated 2,5-thiophenedimethylammonium (ThDMA) has shown enhanced phase stability and tunable bandgap through dimensional engineering. These findings provide valuable insights for exploring environmentally friendly CsSnI3 perovskites and their applications in opto/electronic devices.