Ultrafast nonlinear optical processes in CH₃NH₃PbI₃ hybrid perovskite

Methylammonium lead iodide (MAPI) is a benchmark hybrid organic perovskite material, which is used for the low-cost, printed solar cells with over 23% power conversion efficiency. Yet, the nature of light-matter interaction in MAPI as well as the exact physical mechanism behind device operation is currently debated. Here we report room temperature, ultrafast photocurrent and free-space terahertz (THz) emission generation from unbiased MAPI thin films induced by 150 fs light pulses¹. Polarization dependence of the observed photocurrents is consistent with the Bulk Photovoltaic Effect (BPVE) caused by a combination of injection and shift currents. We believe that this observation of can shed light on low recombination, and long carrier diffusion lengths due to indirect bandgap. Moreover, ballistic by nature shift and injection BPVE photocurrents may enable third generation perovskite solar cells with efficiency that exceed the Shockley–Queisser limit. Our observations also open new venues for perovskite spintronics and tunable THz sources.

[1]. P.A. Obraztsov, et al., Comm. Physics 1, 14 (2018).