Long carrier diffusion length in two-dimensional lead halide perovskite single crystals

Ruddlesden-Popper (RP) perovskites are two-dimensional semiconductors for high-performance optoelectronic devices. In this work, we report a long in-plane carrier diffusion length in 2D RP perovskite single crystals probed by scanning photocurrent microscopy. Carrier diffusion lengths of 7-14 mm are observed when the number of PbI6-2 octahedra between organic spacers increases from 1 to 3. Using detailed light intensity and electric-field-dependent photo current measurements, we attribute the observed long diffusion length to the dominating dissociated free carrier transport. This is further validated by time-resolved photoluminescence measurements, where the decay lifetime increases in the presence of an electric field. From our experiments, we conclude that the in-plane transport in RP perovskites is efficient because of the partial free carrier generation, which overcomes strong excitonic effects. Our results suggest that semiconducting devices fabricated from RP perovskite single crystals can be as efficient as their 3D counterparts.

Automated summary

In this work, the authors investigated the carrier diffusion length in two-dimensional Ruddlesden-Popper perovskite single crystals using scanning photocurrent microscopy. They observed a long in-plane carrier diffusion length and attributed it to the dominating dissociated free carrier transport. The results suggest that semiconducting devices fabricated from RP perovskite single crystals can be as efficient as their 3D counterparts.