Strain–Chemical Gradient and Polarization in Metal Halide Perovskites
Abstract
Metal halide perovskites (MHPs) have attracted broad research interest due to their outstanding optoelectronic performance. This performance has been attributed in part to the presence of polarization in these materials. However, the precise effects of chemical environment and strain condition on the polar states in MHPs have largely been missing. It is revealed for the first time that chemical gradient is directly coupled with strain gradient in CH3NH3PbI3. This strain–chemical gradient induces an electric polarization that can potentially affect charge carrier dynamics. Furthermore, it is unveiled that this electric polarization—unlike ferroelectricity that only exists in noncentrosymmetric materials—can be present in both tetragonal and cubic phases of CH3NH3PbI3. This suggests that the strain–chemical gradient induced polarization is a more convincing explanation of the outstanding photovoltaic properties of MHPs than the hotly debated ferroelectric polarization. Finally, a mechanism of how this polarization impacts photovoltaic action is proposed, which offers insightful advances in the development of MHPs.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 27, 2020
- Source ID
- 10.1002/aelm.201901235
Entities
People
- Alex Belianinov
- Anton V Ievlev
- Bin Hu
- Bobby Sumpter
- Jingsong Huang
- Jong K Keum
- Kai Xiao
- Liam Collins
- Mahshid Ahmadi
- Olga S Ovchinnikova
- Scott T. Retterer
- Sergei V. Kalinin
- Stephen Jesse
- Yongtao Liu
Organizations
- Air Force Office of Scientific Research
- National Science Foundation
- Oak Ridge National Laboratory
- University of Tennessee