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Full-Text Articles in Physics
Ch3Nh3Pbi3 Perovskites: Ferroelasticity Revealed, Evgheni Strelcov, Qingfeng Dong, Tao Li, Jungseok Chae, Yuchuan Shao, Yehao Deng, Alexei Gruverman, Jinsong Huang, Andrea Centrone
Ch3Nh3Pbi3 Perovskites: Ferroelasticity Revealed, Evgheni Strelcov, Qingfeng Dong, Tao Li, Jungseok Chae, Yuchuan Shao, Yehao Deng, Alexei Gruverman, Jinsong Huang, Andrea Centrone
Alexei Gruverman Publications
Ferroelectricity has been proposed as a plausible mechanism to explain the high photovoltaic conversion efficiency in organic-inorganic perovskites; however, convincing experimental evidence in support of this hypothesis is still missing. Identifying and distinguishing ferroelectricity from other properties, such as piezoelectricity, ferroelasticity, etc., is typically nontrivial because these phenomena can coexist in many materials. In this work, a combination of microscopic and nanoscale techniques provides solid evidence for the existence of ferroelastic domains in both CH3NH3PbI3 polycrystalline films and single crystals in the pristine state and under applied stress. Experiments show that the configuration of CH …
Anomalous Photovoltaic Effect In Organic-Inorganic Hybrid Perovskite Solar Cells, Yongbo Yuan, Tao Li, Qi Wang, Jie Xing, Alexei Gruverman, Jinsong Huang
Anomalous Photovoltaic Effect In Organic-Inorganic Hybrid Perovskite Solar Cells, Yongbo Yuan, Tao Li, Qi Wang, Jie Xing, Alexei Gruverman, Jinsong Huang
Alexei Gruverman Publications
Organic-inorganic hybrid perovskites (OIHPs) have been demonstrated to be highly successful photovoltaic materials yielding very-high-efficiency solar cells. We report the room temperature observation of an anomalous photovoltaic (APV) effect in lateral structure OIHP devices manifested by the device’s open-circuit voltage (VOC) that is much larger than the bandgap of OIHPs. The persistent VOC is proportional to the electrode spacing, resembling that of ferroelectric photovoltaic devices. However, the APV effect in OIHP devices is not caused by ferroelectricity. The APV effect can be explained by the formation of tunneling junctions randomly dispersed in the polycrystalline films, which allows …
Theoretical Approach To Electroresistance In Ferroelectric Tunnel Junctions, Sou-Chi Chang, Azad Naeemi, Dmitri E. Nikonov, Alexei Gruverman
Theoretical Approach To Electroresistance In Ferroelectric Tunnel Junctions, Sou-Chi Chang, Azad Naeemi, Dmitri E. Nikonov, Alexei Gruverman
Alexei Gruverman Publications
In this paper, a theoretical approach comprising the nonequilibrium Green’s function method for electronic transport and the Landau-Khalatnikov equation for electric polarization dynamics is presented to describe polarization-dependent tunneling electroresistance (TER) in ferroelectric tunnel junctions. Using appropriate contact, interface, and ferroelectric parameters, the measured current-voltage characteristic curves in both inorganic (Co/BaTiO3/La0.67Sr0.33MnO3) and organic (Au/PVDF/W) ferroelectric tunnel junctions can be well described by the proposed approach. Furthermore, under this theoretical framework, the controversy of opposite TER signs observed experimentally by different groups in Co/BaTiO3/La0.67Sr0.33MnO3 systems is …