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Hu X, Yu Chen G, Luan Y, Tang T, Liang Y, Ren B, Chen L, Zhao Y, Zhang Q, Huang D, Sun X, Cheng YF, Ou JZ. Flexoelectricity Modulated Electron Transport of 2D Indium Oxide. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2404272. [PMID: 38953411 DOI: 10.1002/advs.202404272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 06/04/2024] [Indexed: 07/04/2024]
Abstract
The phenomenon of flexoelectricity, wherein mechanical deformation induces alterations in the electron configuration of metal oxides, has emerged as a promising avenue for regulating electron transport. Leveraging this mechanism, stress sensing can be optimized through precise modulation of electron transport. In this study, the electron transport in 2D ultra-smooth In2O3 crystals is modulated via flexoelectricity. By subjecting cubic In2O3 (c-In2O3) crystals to significant strain gradients using an atomic force microscope (AFM) tip, the crystal symmetry is broken, resulting in the separation of positive and negative charge centers. Upon applying nano-scale stress up to 100 nN, the output voltage and power values reach their maximum, e.g. 2.2 mV and 0.2 pW, respectively. The flexoelectric coefficient and flexocoupling coefficient of c-In2O3 are determined as ≈0.49 nC m-1 and 0.4 V, respectively. More importantly, the sensitivity of the nano-stress sensor upon c-In2O3 flexoelectric effect reaches 20 nN, which is four to six orders smaller than that fabricated with other low dimensional materials based on the piezoresistive, capacitive, and piezoelectric effect. Such a deformation-induced polarization modulates the band structure of c-In2O3, significantly reducing the Schottky barrier height (SBH), thereby regulating its electron transport. This finding highlights the potential of flexoelectricity in enabling high-performance nano-stress sensing through precise control of electron transport.
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Affiliation(s)
- Xinyi Hu
- Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China
| | - Guan Yu Chen
- Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China
| | - Yange Luan
- School of Engineering, RMIT University, Melbourne, 3000, Australia
| | - Tao Tang
- Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China
| | - Yi Liang
- Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China
| | - Baiyu Ren
- Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China
| | - Liguo Chen
- School of Mechanical and Electric Engineering Jiangsu Provincial Key Laboratory of Advanced Robotics, Soochow University, Suzhou, 215123, China
| | - Yulong Zhao
- State Key Laboratory for Manufacturing Systems Engineering, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Qi Zhang
- State Key Laboratory for Manufacturing Systems Engineering, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Dong Huang
- Department of Physics, The University of Hong Kong, Hong Kong, 999077, China
| | - Xiao Sun
- Inorganic Chemistry, University of Koblenz, Universitätsstraße 1, 56070, Koblenz, Germany
| | - Yin Fen Cheng
- Institute of Advanced Study, Chengdu University, Chengdu, 610106, China
| | - Jian Zhen Ou
- Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China
- School of Engineering, RMIT University, Melbourne, 3000, Australia
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2
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Li Y, Chen Y, Fang H, Shi J, Xue Y, Ma R, Zhou J, Yao N, Zhang J, Zhang X. Electron-beam writing of a relaxor ferroelectric polymer for multiplexing information storage and encryption. NANOSCALE 2023; 16:180-187. [PMID: 37999642 DOI: 10.1039/d3nr04503j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2023]
Abstract
To meet the strong demand for high-level encryption security, several efforts have been focused on developing new encryption techniques with high density and data security. Herein we employed a template-free electron beam lithography (EBL) technique to write various nanopatterns on poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CTFE)) films and applied it to electron-beam/electric multiplexing memory. Furthermore, electron beams can arbitrarily tailor down the domain structure evolutions and dipole directions, as proved by a combination of AFM-IR and PFM. Finally, our devices could function concurrently as an electron-beam write-only-memory (EB-WOM) and FeRAM, where the information could be encoded with the metastable phase evolutions from the ferroelectric phase to the paraelectric phase and variable bi-level ferroelectric signals. Our systematic study provides an inspiring idea for the design of information encryption devices with high-security requirements in flexible electronic fields.
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Affiliation(s)
- Yongshuang Li
- Institute of Advanced Magnetic Materials and International Research Center for EM Metamaterials, College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
| | - Yingxin Chen
- Institute of Advanced Magnetic Materials and International Research Center for EM Metamaterials, College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
| | - Huigui Fang
- Institute of Advanced Magnetic Materials and International Research Center for EM Metamaterials, College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
| | - Jingchao Shi
- Institute of Advanced Magnetic Materials and International Research Center for EM Metamaterials, College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
| | - Yichen Xue
- Institute of Advanced Magnetic Materials and International Research Center for EM Metamaterials, College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
| | - Rongjie Ma
- Institute of Advanced Magnetic Materials and International Research Center for EM Metamaterials, College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
| | - Jingtao Zhou
- Institute of Advanced Magnetic Materials and International Research Center for EM Metamaterials, College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
| | - Ni Yao
- Research Center for Intelligent Sensing, Zhejiang Lab, Hangzhou 311121, China
| | - Jian Zhang
- Institute of Advanced Magnetic Materials and International Research Center for EM Metamaterials, College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
| | - Xuefeng Zhang
- Institute of Advanced Magnetic Materials and International Research Center for EM Metamaterials, College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
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3
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Li X, Wang Z, Ji W, Lu T, You J, Wang K, Liu G, Liu Y, Wang L. Polarization Alignment in Polycrystalline BiFeO 3 Photoelectrodes for Tunable Band Bending. ACS NANO 2023; 17:22944-22951. [PMID: 37947409 DOI: 10.1021/acsnano.3c08081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Polarization in a semiconductor can modulate the band bending via the depolarization electric field (EdP), subsequently tuning the charge separation and transfer (CST) process in photoelectrodes. However, the random orientation of dipole moments in many polycrystalline semiconductor photoelectrodes leads to negligible polarization effect. How to effectively align the dipole moments in polycrystalline photoelectrodes into the same direction to maximize the polarization is still to be developed. Herein, we report that the dipole moments in a ferroelectric BiFeO3 photoelectrode can be controlled under external poling, resulting in a tunable CST efficiency. A negative bias of -40 voltage (V) poling to the photoelectrode leads to an over 110% increase of the CST efficiency, while poling at +40 V, the CST efficiency is reduced to only 41% of the original value. Furthermore, a nearly linear relationship between the external poling voltage and surface potential is discovered. The findings here provide an effective method in tuning the band bending and charge transfer of the emerging ferroelectricity driven solar energy conversion.
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Affiliation(s)
- Xianlong Li
- Nanomaterials Centre, School of Chemical Engineering, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Zhiliang Wang
- Nanomaterials Centre, School of Chemical Engineering, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Wenzhong Ji
- Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
| | - Teng Lu
- Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
| | - Jiakang You
- Nanomaterials Centre, School of Chemical Engineering, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Queensland 4072, Australia
| | - Kai Wang
- Nanomaterials Centre, School of Chemical Engineering, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Queensland 4072, Australia
- WA School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, Perth, Western Australia 6102, Australia
| | - Gang Liu
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016, China
- School of Materials Science and Engineering, University of Science and Technology of China, 72 Wenhua Road, Shenyang 110016, China
| | - Yun Liu
- Research School of Chemistry, The Australian National University, Canberra, ACT 2601, Australia
| | - Lianzhou Wang
- Nanomaterials Centre, School of Chemical Engineering, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Queensland 4072, Australia
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Zheng W, Wang X, Zhang X, Chen B, Suo H, Xing Z, Wang Y, Wei HL, Chen J, Guo Y, Wang F. Emerging Halide Perovskite Ferroelectrics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2205410. [PMID: 36517207 DOI: 10.1002/adma.202205410] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 11/23/2022] [Indexed: 05/26/2023]
Abstract
Halide perovskites have gained tremendous attention in the past decade owing to their excellent properties in optoelectronics. Recently, a fascinating property, ferroelectricity, has been discovered in halide perovskites and quickly attracted widespread interest. Compared with traditional perovskite oxide ferroelectrics, halide perovskites display natural advantages such as structural softness, low weight, and easy processing, which are highly desirable in applications pursuing miniaturization and flexibility. This review focuses on the current research progress in halide perovskite ferroelectrics, encompassing the emerging materials systems and their potential applications in ferroelectric photovoltaics, self-powered photodetection, and X-ray detection. The main challenges and possible solutions in the future development of halide perovskite ferroelectric materials are also attempted to be pointed out.
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Affiliation(s)
- Weilin Zheng
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China
| | - Xiucai Wang
- School of Materials Science and Hydrogen Energy, Foshan University, Foshan, 528000, P. R. China
| | - Xin Zhang
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China
| | - Bing Chen
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China
| | - Hao Suo
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China
| | - Zhifeng Xing
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China
| | - Yanze Wang
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China
| | - Han-Lin Wei
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China
| | - Jiangkun Chen
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China
| | - Yang Guo
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China
| | - Feng Wang
- Department of Materials Science and Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong SAR, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China
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5
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Zhang H, Gao H, Geng J, Meng X, Xie H. In Situ Quantification of Strain-Induced Piezoelectric Potential of Dynamically Bending ZnO Microwires. SMALL METHODS 2023; 7:e2201342. [PMID: 36683180 DOI: 10.1002/smtd.202201342] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 12/19/2022] [Indexed: 06/17/2023]
Abstract
The piezoelectric properties of semiconductor micro/nanowires (M/NWs) are crucial for optimizing semiconductors' electronic structure and carrier dynamics. However, the dynamic characterization of the piezoelectric properties of M/NWs remains challenging. Here, a Kelvin probe force microscopy technique based on a dual-probe atomic force microscope is developed to achieve in situ piezoelectric potential measurements of dynamic bending MWs. This technique can not only characterize the surface potential on different crystal faces of ZnO MWs in a natural state through controllable axial rotation, but also investigate the piezoelectric potential of the dynamically bending flake-like ZnO MW at different points and under different strain loads. The results show that the surface potentials of different faces/positions of the ZnO MWs are varied significantly, and determine that the quasi-static conditions piezo-strain factor of the flake-like ZnO MW is 0.28 V/%, while the factor was 0.14 V/% under low-frequency (⩽5 Hz) sinusoidal strain loading. This work provides a significant methodology to further study piezoelectric materials, and it aims to facilitate their applications in piezoelectric devices and systems.
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Affiliation(s)
- Hao Zhang
- State Key Laboratory of Robotics and Systems, Harbin Institute of Technology, Harbin, 150080, China
| | - Haibo Gao
- State Key Laboratory of Robotics and Systems, Harbin Institute of Technology, Harbin, 150080, China
| | - Junyuan Geng
- State Key Laboratory of Robotics and Systems, Harbin Institute of Technology, Harbin, 150080, China
| | - Xianghe Meng
- State Key Laboratory of Robotics and Systems, Harbin Institute of Technology, Harbin, 150080, China
| | - Hui Xie
- State Key Laboratory of Robotics and Systems, Harbin Institute of Technology, Harbin, 150080, China
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6
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Ambrosio F, De Angelis F, Goñi AR. The Ferroelectric-Ferroelastic Debate about Metal Halide Perovskites. J Phys Chem Lett 2022; 13:7731-7740. [PMID: 35969174 PMCID: PMC9421894 DOI: 10.1021/acs.jpclett.2c01945] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 08/11/2022] [Indexed: 05/19/2023]
Abstract
Metal halide perovskites (MHPs) are solution-processed materials with exceptional photoconversion efficiencies that have brought a paradigm shift in photovoltaics. The nature of the peculiar optoelectronic properties underlying such astounding performance is still controversial. The existence of ferroelectricity in MHPs and its alleged impact on photovoltaic activity have fueled an intense debate, in which unanimous consensus is still far from being reached. Here we critically review recent experimental and theoretical results with a two-fold objective: we argue that the occurrence of ferroelectric domains is incompatible with the A-site cation dynamics in MHPs and propose an alternative interpretation of the experiments based on the concept of ferroelasticity. We further underline that ferroic behavior in MHPs would not be relevant at room temperature or higher for the physics of photogenerated charge carriers, since it would be overshadowed by competing effects like polaron formation and ion migration.
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Affiliation(s)
- Francesco Ambrosio
- Computational
Laboratory for Hybrid/Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Chimiche “Giulio Natta”
(CNR-SCITEC), Via Elce
di Sotto 8, 06123 Perugia, Italy
- Department
of Chemistry and Biology “A. Zambelli”, University of Salerno, Via Giovanni Paolo II 132, 84084 Fisciano, Salerno Italy
- Center
for Nano Science and Technology @Polimi, Istituto Italiano di Tecnologia, via G. Pascoli 70/3, 20133 Milano, Italy
| | - Filippo De Angelis
- Computational
Laboratory for Hybrid/Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Chimiche “Giulio Natta”
(CNR-SCITEC), Via Elce
di Sotto 8, 06123 Perugia, Italy
- Center
for Nano Science and Technology @Polimi, Istituto Italiano di Tecnologia, via G. Pascoli 70/3, 20133 Milano, Italy
- Department
of Chemistry, Biology and Biotechnology, University of Perugia and UdR INSTM of Perugia, via Elce di Sotto 8, 06123 Perugia, Italy
- Department
of Natural Sciences & Mathematics, College of Sciences & Human
Studies, Prince Mohammad Bin Fahd University, Al Khobar 31952, Saudi Arabia
| | - Alejandro R. Goñi
- Institut
de Ciència de Materials de Barcelona, ICMAB-CSIC, Campus UAB, 08193 Bellaterra, Spain
- ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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Zeng Q, Huang Q, Wang H, Li C, Fan Z, Chen D, Cheng Y, Zeng K. Breaking the Fundamental Limitations of Nanoscale Ferroelectric Characterization: Non-Contact Heterodyne Electrostrain Force Microscopy. SMALL METHODS 2021; 5:e2100639. [PMID: 34927968 DOI: 10.1002/smtd.202100639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 09/09/2021] [Indexed: 06/14/2023]
Abstract
Perceiving nanoscale ferroelectric phenomena from real space is of great importance for elucidating underlying ferroelectric physics. During the past decades, nanoscale ferroelectric characterization has mainly relied on the Piezoresponse Force Microscopy (PFM) invented in 1992, however, the fundamental limitations of PFM have made the nanoscale ferroelectric studies encounter significant bottlenecks. In this study, a high-resolution non-contact ferroelectric measurement, named Non-Contact Heterodyne Electrostrain Force Microscopy (NC-HEsFM), is introduced. It is demonstrated that NC-HEsFM can operate on multiple eigenmodes to perform ideal high-resolution ferroelectric domain mapping, standard ferroelectric hysteresis loop measurement, and controllable domain manipulation. By using a quartz tuning fork (QTF) sensor, multi-frequency operation, and heterodyne detection schemes, NC-HEsFM achieves a real non-contact yet non-destructive ferroelectric characterization with negligible electrostatic force effect and hence breaks the fundamental limitations of the conventional PFM. It is believed that NC-HEsFM can be extensively used in various ferroelectric or piezoelectric studies with providing substantially improved characterization performance. Meanwhile, the QTF-based force detection makes NC-HEsFM highly compatible for high-vacuum and low-temperature environments, providing ideal conditions for investigating the intrinsic ferroelectric phenomena with the possibility of achieving an atomically resolved ferroelectric characterization.
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Affiliation(s)
- Qibin Zeng
- Department of Mechanical Engineering, National University of Singapore, Singapore, 117576, Singapore
| | - Qicheng Huang
- Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, China
| | - Hongli Wang
- Department of Mechanical Engineering, National University of Singapore, Singapore, 117576, Singapore
- The Key Lab of Guangdong for Modern Surface Engineering Technology, National Engineering Laboratory for Modern Materials Surface Engineering Technology, Institute of New Materials, Guangdong Academy of Sciences, Guangzhou, 510650, China
| | - Caiwen Li
- Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, China
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, China
| | - Zhen Fan
- Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, China
| | - Deyang Chen
- Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, China
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, China
| | - Yuan Cheng
- Institute of High-Performance Computing, Agency for Science Technology and Research, Singapore, 138632, Singapore
- Monash Suzhou Research Institute, Suzhou, 215123, China
| | - Kaiyang Zeng
- Department of Mechanical Engineering, National University of Singapore, Singapore, 117576, Singapore
- NUS (Suzhou) Research Institute (NUSRI), Suzhou, 215123, China
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8
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Liu Y, Trimby P, Collins L, Ahmadi M, Winkelmann A, Proksch R, Ovchinnikova OS. Correlating Crystallographic Orientation and Ferroic Properties of Twin Domains in Metal Halide Perovskites. ACS NANO 2021; 15:7139-7148. [PMID: 33770442 DOI: 10.1021/acsnano.1c00310] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Metal halide perovskite (MHP) solar cells have attracted worldwide research interest. Although it has been well established that grain, grain boundary, and grain facet affect MHPs optoelectronic properties, less is known about subgrain structures. Recently, MHP twin stripes, a subgrain feature, have stimulated extensive discussion due to the potential for both beneficial and detrimental effects of ferroelectricity on optoelectronic properties. Connecting the ferroic behavior of twin stripes in MHPs with crystal orientation will be a vital step to understand the ferroic nature and the effects of twin stripes. In this work, we studied the crystallographic orientation and ferroic properties of CH3NH3PbI3 twin stripes, using electron backscatter diffraction (EBSD) and advanced piezoresponse force microscopy (PFM), respectively. Using EBSD, we discovered that the orientation relationship across the twin walls in CH3NH3PbI3 is a 90° rotation about ⟨1̅1̅0⟩, with the ⟨030⟩ and ⟨111⟩ directions parallel to the direction normal to the surface. By careful inspection of CH3NH3PbI3 PFM results including in-plane and out-of-plane PFM measurements, we demonstrate some nonferroelectric contributions to the PFM responses of this CH3NH3PbI3 sample, suggesting that the PFM signal in this CH3NH3PbI3 sample is affected by nonferroelectric and nonpiezoelectric forces. If there is piezoelectric response, it is below the detection sensitivity of our interferometric displacement sensor PFM (<0.615 pm/V). Overall, this work offers an integrated picture describing the crystallographic orientations and the origin of PFM signal of MHPs twin stripes, which is critical to understanding the ferroicity in MHPs.
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Affiliation(s)
- Yongtao Liu
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Patrick Trimby
- Oxford Instruments Nanoanalysis, High Wycombe, Buckinghamshire HP123SE, United Kingdom
| | - Liam Collins
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Mahshid Ahmadi
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Aimo Winkelmann
- Academic Centre for Materials and Nanotechnology (ACMiN), AGH University of Science and Technology, 30-059 Kraków, Poland
| | - Roger Proksch
- Asylum Research, An Oxford Instruments Company, Santa Barbara, California 93117, United States
| | - Olga S Ovchinnikova
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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