Ferroelectric Polarization in CH3NH3PbI3 Perovskite.
We report on ferroelectric polarization behavior in CH3NH3PbI3 perovskite in the dark and under illumination. Perovskite crystals with three different sizes of 700, 400, and 100 nm were prepared for piezoresponse force microscopy (PFM) measurements. PFM results confirmed the formation of spontaneous polarization in CH3NH3PbI3 in the absence of electric field, where the size dependency to polarization was not significant. Whereas the photoinduced stimulation was not significant without an external electric field, the stimulated polarization by poling was further enhanced under illumination. The retention of ferroelectric polarization was also observed after removal of the electric field, in which larger crystals showed longer retention behavior compared to the smaller sized one. Additionally, we suggest the effect of perovskite crystal size (morphology) on charge collection at the interface of the ferroelectric material even though insignificant size dependency in electric polarization was observed.
†School of Chemical Engineering and Department of Energy Science, ‡School of Advanced Materials Science and Engineering, and §SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Korea.
Hui-Seon
HS
Kim
†School of Chemical Engineering and Department of Energy Science, ‡School of Advanced Materials Science and Engineering, and §SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Korea.
Sung Kyun
SK
Kim
†School of Chemical Engineering and Department of Energy Science, ‡School of Advanced Materials Science and Engineering, and §SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Korea.
Byeong Jo
BJ
Kim
†School of Chemical Engineering and Department of Energy Science, ‡School of Advanced Materials Science and Engineering, and §SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Korea.
Kyung-Sik
KS
Shin
†School of Chemical Engineering and Department of Energy Science, ‡School of Advanced Materials Science and Engineering, and §SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Korea.
Manoj Kumar
MK
Gupta
†School of Chemical Engineering and Department of Energy Science, ‡School of Advanced Materials Science and Engineering, and §SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Korea.
Hyun Suk
HS
Jung
†School of Chemical Engineering and Department of Energy Science, ‡School of Advanced Materials Science and Engineering, and §SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Korea.
Sang-Woo
SW
Kim
†School of Chemical Engineering and Department of Energy Science, ‡School of Advanced Materials Science and Engineering, and §SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Korea.
Nam-Gyu
NG
Park
ferroelectric polarization; perovskite; piezoresponse force microscopy