Defect chemistry of mixed ionic-electronic conductors under light: halide perovskites as master example
Moia, D., & Maier, J. (2025). [Preprint]. arXiv. https://doi.org/10.48550/arXiv.2504.05414
The goal of this study was to model how illumination affects both the electronic and ionic defect chemistry in mixed ionic-electronic conductors, using methylammonium lead iodide (MAPI) perovskite as a model system.
Key findings show that light exposure alters the concentration of ionic defects by shifting the quasi-equilibrium of charged and neutral defects. Uniquely, the model predicts that illumination can either increase or decrease ionic defect concentrations, depending on the coupling between redox reactions and mobile ions. This introduces the concept of a "light-driven ionic defect pump." These insights help explain unusual stability, degradation, and performance behaviors observed in halide perovskites and open new strategies for defect management via optical stimuli.
Although the study is theoretical, the simulation approach closely parallels capabilities available with Fluxim’s Setfos and Paios tools. Setfos could simulate optical and electronic behavior under varying illumination, while Paios could experimentally verify recombination dynamics, charge transport, and ionic effects, making these tools highly valuable for experimental validation and future device optimization.
These findings are important for the scientific community as they offer a comprehensive framework to understand and control ionic behavior under light in mixed conductors, crucial for advancing solar cells, batteries, and photoelectrochemical systems.