We present transient microscopy measurements of interlayer energy transport in (PEA)<sub>2</sub>PbI<sub>4</sub> perovskite. We find efficient interlayer exciton transport (0.06 cm<sup>2</sup>/s), which translates into a diffusion length that exceeds 100 nm and a sub-ps timescale for energy transfer. While still slower than in-plane exciton transport (0.2 cm<sup>2</sup>/s), our results show that excitonic energy transport is considerably less anisotropic than charge-carrier transport for 2D perovskites.
Halide Mixing Inhibits Exciton Transport in Two-dimensional Perovskites Despite Phase Purity
