Crystalline Dion-Jacobson 2D Layered Sn-Based Perovskites for Field-Effect Transistors

Dion-Jacobson (DJ) phase perovskites are increasingly recognized as potential semiconductor materials for electronic applications. However, the restricted coordination between the organic diammonium cations and the inorganic framework inhibits their self-assembly into efficient DJ Sn-based perovskites during solution processing. This study introduces solvent vapor assisted drop casting (SVAD) as a novel processing method to favor the organization into highly crystalline DJ perovskite films. The key aspect of the processing is the extended crystallization time in solvent vapor at elevated temperature. The processing study was conducted on four DJ perovskites that varied in the rigidity and symmetry of their A-cations to demonstrate the universal applicability of SVAD for this category of semiconductors and to establish correlations between structure and properties. The SVAD films exhibit markedly improved crystallinity and morphology compared to spin-coated samples resulting in significantly increased local and device charge carrier mobilities. DJ perovskites with rigid and symmetric A-cations form a planar [SnI₆]^4- octahedral framework that favors structural order and charge carrier transport. This work paves the way for the solution processing of highly ordered DJ Sn-based perovskites for their implementation in electronic applications.