Light-induced molecular dipole reordering in halide perovskites

Ya-Ping Chiu^1*

¹Physics, National Taiwan University, Taipei, Taiwan

* Presenter:Ya-Ping Chiu, email:ypchiu@phys.ntu.edu.tw

Organometal halide perovskites enabled an explosive improvement of the efficiency of solar cells. Light-induced molecular dipole’s orientation has been suggested to be a critical degree of freedom to affect the performance of hybrid perovskite-based optoelectronic devices. However, thus far there is no direct real-space, atomically-resolved experimental evidence under simultaneous illumination. Here, we map simultaneously the molecule dipole orientation pattern and the electrostatic potential with atomic resolution and under laser illumination using scanning tunneling microscopy and spectroscopy. We observe a light-induced transition of the molecule orientation order creating one-dimensional potential wells, which enable electron-hole separation. We anticipate that light-induced polarization order transition could be at the origin of the extraordinary efficiencies of organometal halide perovskite-based solar cells.

Keywords: Organometal halide perovskite, Molecule dipole orientation pattern, light-induced polarization, XSTM/STS