Halide perovskites are widely celebrated for their exceptional optoelectronic properties, yet their most distinctive semiconductor trait may be their chemically and ionically dynamic nature. Soft lattices, mobile ionic species, low defect formation energies, and strong coupling to external stimuli are routinely associated with instability, hysteresis, and variability, but these same phenomena become a powerful design resource when properly understood and controlled.
This talk explores how chemical dynamics can be deliberately steered across different halide perovskite platforms and device contexts. In tin-based perovskites, molecular additives demonstrate how targeted chemistry can regulate ionic processes at the precursor stage, reshaping crystallization and suppressing oxidative degradation. Strikingly, the same ionic landscape that threatens stability also enables spontaneous performance recovery under realistic stress conditions, a self-healing behavior rooted in the material’s dynamic character. Beyond photovoltaics, the coupling between ion migration, defect chemistry, and electrochemical response underpins resistive switching in perovskite memristors, revealing that the very dynamics complicating solar cell operation are precisely what enables computing-oriented functionality.
A central challenge across all these contexts is disentangling the contributions of bulk transport, interfacial charge accumulation, and ionic redistribution, processes that overlap in both time and frequency domains. Operando characterization combining impedance spectroscopy and luminescence analysis provides a powerful diagnostic framework to address this. Impedance spectra, interpreted through physically grounded equivalent circuit models, resolve the frequency-dependent response of selective contacts and heterojunction interfaces, revealing how ion accumulation modulates band bending, recombination kinetics, and extraction barriers under working conditions. Coupled with photoluminescence and electroluminescence, this approach quantifies non-radiative losses at specific interfaces and distinguishes reversible ionic rearrangements from irreversible degradation pathways in real operating conditions.
Together, these results reframe chemical dynamics not as a nuisance to be suppressed, but as a material property to be engineered, pointing toward halide perovskite devices that are simultaneously efficient, self-healing, and multifunctional