X-ray diffraction studies verify the DFT simulations and reveal that the photoinduced strain is light intensity dependent, and the photoexcitation is a prerequisite of inducing strain by light. Hence, light generates strain in the ferroelastic domains due to preferential photocarrier motion, leading to a screening of strain variation. Density functional theory (DFT) shows that electrons and holes result in lattice expansion more » in CH 3NH 3PbI 3 differently. Due to strain and chemical inhomogeneities, photogenerated electrons and holes show a preferential motion in the ferroelastic twin domains. This work explores the interaction between light and ferroic twin domains in CH 3NH 3PbI 3. Recently, the discovery of ferroic twin domains in HOIPs has renewed the debate of the ferroic effects on optoelectric processes. Given the remarkable performance of hybrid organic–inorganic perovskites (HOIPs) in solar cells, light emitters, and photodetectors, the quest to advance the fundamental understanding of the photophysical properties in this class of materials remains highly relevant. We expect that this work will stimulate researchers to further explore the impact of twin domains on the photophysical properties of MHPs. These results suggest that the effect of ferroelastic twin domains on the intrinsic PL behavior is negligible. We propose that the PL intensity variation is induced by the difference more » in light-matter interactions between neighboring domains. PL spectra and the confocal PL lifetime maps reveal no difference in wavelength of emitted light and decay dynamics between the neighboring domains, whereas PL intensity is different.
In this work, the effect of the ferroelastic twin domains on the photoluminescence (PL) behavior of CH 3NH 3PbI 3 is investigated by correlating measurements from multiple microscopies.
Center for Nanophase Materials Sciences (CNMS) Sponsoring Org.: USDOE Office of Science (SC) US Air Force Office of Scientific Research (AFOSR) Asian Office of Aerospace Research and Development (AOARD) National Science Foundation (NSF) University of Tennessee Higher Education Commission OSTI Identifier: 1615225 Grant/Contract Number: AC05-00OR22725 FA -0064 FA-4104 CBET-1438181 Resource Type: Accepted Manuscript Journal Name: Advanced Electronic Materials Additional Journal Information: Journal Volume: 6 Journal Issue: 4 Journal ID: ISSN 2199-160X Publisher: Wiley Country of Publication: United States Language: English Subject: 36 MATERIALS SCIENCE charge dissociation chemical gradients metal halide perovskites polarization strain = ,ĭespite the extensive insights gained in how the microstructure impacts the device performance of metal halide perovskites (MHPs), little is known about the effect of the ferroelastic twin domains on the optoelectronic properties of MHPs. Publication Date: Research Org.: Oak Ridge National Lab. Center for Nanophase Materials Science (CNMS) and Computational Sciences & Engineering Division of Tennessee, Knoxville, TN (United States) Center for Nanophase Materials Science (CNMS) and Neutron Scattering Division Center for Nanophase Materials Science (CNMS) Center for Nanophase Materials Science (CNMS) Univ.
Finally, a mechanism of how this polarization impacts photovoltaic action is proposed, which offers insightful advances in the development of MHPs.
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. 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 CH 3NH 3PbI 3. This strain–chemical gradient induces an electric polarization that can potentially affect charge carrier dynamics. Herein it is revealed for the first time that chemical gradient is directly coupled with strain gradient in CH 3NH 3PbI 3. However, the precise effects of chemical environment and strain condition on the polar states in MHPs have largely been missing. This performance has been attributed in part to the presence of polarization in these materials. Metal halide perovskites (MHPs) have attracted broad research interest due to their outstanding optoelectronic performance.
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