Molecular Dipole Dynamics Induced Electric Hysteresis in Metalorganic Halide Perovskite Solar Cells
Hung-Chang Hsu1*, Chiang Fan1, Ya-Ping Chiu1,2
1Department of physics, National Taiwan University, Taipei 10617, Taiwan
2Center of Atomic Initiative for New Materials, National Taiwan University, Taipei 10617, Taiwan
* Presenter:Hung-Chang Hsu,
The rapid rise of conversion efficiency in metalorganic halide perovskites has drawn remarkable attention in recent years. The metalorganic halide perovskite-based devices presented the hysteresis behavior under electronic and optoelectronic operations. However, the origin of hysteresis is still under debate. Here, we investigate the hysteresis behavior of the molecular dipole-terminated metalorganic halide perovskite solar cell using cross-sectional scanning tunneling microscopy and spectroscopy. The results show the electrical hysteresis in spectroscopy measurements, suggesting the applied electric field-induced dipole rotation. The dipole reorientation changes the surface net dipole moment and then also shifts the Fermi level of the cleaved surface, resulting in an electronic transformation between n-type and p-type electronic features. We anticipate that electric field-induced dipole rotation could be at the origin of the hysteresis of organometal halide perovskite-based solar cells.

Keywords: organometal halide perovskites, scanning tunneling microscopy/spectroscopy, hysteresis, dipole rotation