Optimizing Excited Charge Dynamics in Layered Halide Perovskites through Compositional Engineering

Dion-Jacobson phase multilayered halide perovskites (MLHPs) improve carrier transport and optoelectronic performance thanks to their shorter interlayer distance, long carrier lifetimes, and minimized nonradiative losses. However, limited atomistic insights into dynamic structure-property relationships hinder rational design efforts to further boost their performance. Here, we employ nonadiabatic molecular dynamics, time-domain density functional theory, and unsupervised machine learning to uncover the impact of A-cation mixing on controlling the excited carrier dynamics and recombination processes in MLHPs. Mixing smaller-sized Cs with methylammonium in MLHP weakens electron-phonon interactions, suppresses the nonradiative losses, and slows down intraband hot electron relaxations. On the contrary, larger-sized guanidinium incorporation accelerates nonradiative relaxations. The mutual information analyses reveal the importance of interlayer distances, intra- and interoctahedral angle dynamics, and A-cation motion in extending the excited carrier lifetime by mitigating nonradiative losses in MLHPs. Our work provides a guideline for strategically choosing A-cations to boost the optoelectronic performance of layered halide perovskites.