Lattice disorder influences the photocarrier dynamics in lead halide perovskites

Revealing the structural impact of lead halide perovskites on photocarrier dynamics is essential for the associated solar cells but deficient in experimental visualization. In this study, with femtosecond spectroscopy, we for the first time explored the contribution of the disorder of the distorted PbX6 octahedrons and A-site cations on the carrier behaviours. It was found that photoinduced carriers recombine almost twice slower and diffuse 20% faster in the disordered, beta-phased samples than in the ordered, gamma-phased ones. Yet within the same phase, with a similar PbX6 orientation but various A-site mobility, the carrier diffusion and recombination have no apparent difference. Thus we firmly conclude that lattice disorder effectively influences the carrier dynamics and therein the Pb-X sublattice is worth more than A-site cations, which should inspire future lead halide perovskite design and applications.

Automated summary

Revealing the impact of structural disorder in lead halide perovskites on photocarrier dynamics, this study found that in the disordered beta phase, photoinduced carriers recombine almost twice slower and diffuse 20% faster compared to the ordered gamma phase. However, within the same phase, carrier diffusion and recombination show no significant difference for different A-site mobilities with similar PbX6 orientations. This confirms the effective influence of lattice disorder on the carrier dynamics, highlighting the importance of the Pb-X sublattice over A-site cations for future lead halide perovskite design and applications.