Pressure-Tuned 2D Hybrid Perovskites: Emerging Insights and Future Opportunities

Abstract

Two-dimensional (2D) hybrid organic-inorganic perovskites (HOIPs) are attracting growing attention for their exceptional structural flexibility, environmental stability, and unique quantum confinement effects. While chemical design has dominated the field, high-pressure techniques are emerging as a powerful, non-invasive route to tune lattice structures and optoelectronic responses in situ. Here, we present our perspective on the rapidly developing landscape of pressure-tuned 2D perovskites, focusing on Ruddlesden-Popper (RP) and Dion-Jacobson (DJ) systems. We highlight recent discoveries of pressure-induced structural phase transitions, direct-indirect bandgap conversions, broadband emission from self-trapped excitons, and the stabilization of metastable states. Particular emphasis is placed on contrasting soft vs. rigid organic spacers and lead-based vs. lead-free systems (Sn, Cu, Ge, Bi). We argue that pressure not only serves as a diagnostic tool but also as a synthetic strategy for accessing hidden phases and functionalities. Looking ahead, the convergence of high-pressure spectroscopy, synchrotron techniques, and computational modeling offers exciting opportunities to rationally engineer sustainable, pressure-responsive optoelectronic materials.