Observation of the Transient Vertical Currents in Quasi-2D Perovskite Solar Cells

The vertical carrier transportation of photoinduced carriers plays a crucial role in the efficient charge collection process of solar cells, especially for low dimensional perovskites with insulating long-chain organic cations layers. Even though the photo-induced carrier transportation and recombination dynamics in solar cells have been investigated comprehensively, the direct measurement of the vertical transient currents remains a significant technical challenge. Here, the unique correspondence between the transient photocurrent in Quasi-2D perovskite films and its terahertz radiation has been established based on the dipole radiation model, and used to visualize insights of spatiotemporal dynamics of vertical carrier transport contributed by transient photo-Dember and the interphase charge transfer currents. The carrier transportation between different n phases of the Quasi-2D films is utilized to help distinguished by its terahertz emission pulse. Furthermore, the enhanced terahertz emission from the ordered Quasi-2D film with a better crystalline verified the enhanced vertical transport current, and suggest the PCE of Quasi-2D solar cells could be expected to be raised further through the additive induced phase vertical distribution strategy.