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De S, Asthana D, Thirmal C, Keshri SK, Ghosh RK, Hundal G, Kumar R, Singh S, Chatterjee R, Mukhopadhyay P. A folded π-system with supramolecularly oriented dipoles: single-component piezoelectric relaxor with NLO activity. Chem Sci 2023; 14:2547-2552. [PMID: 36908941 PMCID: PMC9993858 DOI: 10.1039/d2sc06141d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 12/29/2022] [Indexed: 01/05/2023] Open
Abstract
Organic molecules with an active dipole moment have a natural propensity to align in an antiparallel fashion in the solid state, resulting in zero macroscopic polarization. This primary limitation makes the material unresponsive to switching with electric fields, mechanical forces, and to intense laser light. A single-component organic material that bestows macroscopic dipole-driven electro-mechanical and optical functions, e.g., piezoelectric, ferroelectric and nonlinear optical (NLO) activity, is unprecedented due to the design challenges imparted by crystal symmetry and dipole orientations. Herein we report a crystalline organic material that self-assembles with a polar order (P 1), and is endowed with a high piezoelectric coefficient (d 33-47 pm V-1), as well as ferroelectric and Debye-type relaxor properties. In addition, it shows second harmonic generation (SHG) activity, which is more than five times that of the benchmark potassium dihydrogen phosphate. Piezoelectric force microscopy (PFM) images validated electro-mechanical deformations. Piezoresponse force spectroscopy (PFS) studies confirmed a signature butterfly-like amplitude and a phase loop. To the best of our knowledge, this is the first report of a folded supramolecular π-system that manifests unidirectionally oriented dipoles and exhibits piezoelectricity, ferroelectricity, and has excellent ability to generate second harmonic light. These findings can herald new design possibilities based on folded architectures to explore opto-, electro- and mechano-responsive multifaceted functions.
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Affiliation(s)
- Soumi De
- School of Physical Sciences, Jawaharlal Nehru University New Delhi - 110067 India
| | - Deepak Asthana
- Department of Chemistry, Ashoka University Sonipat Haryana 131029 India
| | - Chinthakuntla Thirmal
- Department of Physics, Indian Institute of Technology Delhi New Delhi - 110016 India.,VNR Vignana Jyothi Institute of Engineering and Technology Hyderabad Telangana 500 090 India
| | - Sudhir K Keshri
- School of Physical Sciences, Jawaharlal Nehru University New Delhi - 110067 India
| | - Ram Krishna Ghosh
- Department of Electronics & Communications Engineering, Indraprastha Institute of Information Technology Delhi New Delhi 110020 India
| | - Geeta Hundal
- Department of Chemistry, Guru Nanak Dev University Amritsar Punjab-143005 India
| | - Raju Kumar
- Special Centre for Nanoscience, Jawaharlal Nehru University New Delhi - 110067 India
| | - Satyendra Singh
- Special Centre for Nanoscience, Jawaharlal Nehru University New Delhi - 110067 India
| | - Ratnamala Chatterjee
- Department of Physics, Indian Institute of Technology Delhi New Delhi - 110016 India
| | - Pritam Mukhopadhyay
- School of Physical Sciences, Jawaharlal Nehru University New Delhi - 110067 India
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Putzeys T, Borgers C, Fierens G, Walraevens J, Van Wieringen A, Verhaert N. Intracochlear pressure as an objective measure for perceived loudness with bone conduction implants. Hear Res 2022; 422:108550. [PMID: 35689853 DOI: 10.1016/j.heares.2022.108550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 05/25/2022] [Accepted: 05/28/2022] [Indexed: 01/18/2023]
Abstract
BACKGROUND The generally accepted method to assess the functionality of novel bone conduction implants in a preclinical stage is to experimentally measure the vibratory response of the cochlear promontory. Yet, bone conduction of sound is a complex propagation phenomenon, depending on both frequency and amplitude, involving different conduction pathways. OBJECTIVES The aim of this study is to validate the use of intracochlear sound pressure (ICP) as an objective indicator for perceived loudness for bone conduction stimulation. It is investigated whether a correlation exists between intracochlear sound pressure measurements in cadaveric temporal bones and clinically obtained results using the outcome of a loudness balancing experiment. METHODS Ten normal hearing subjects were asked to balance the perceived loudness between air conducted (AC) sound and bone conducted (BC) sound by changing the AC stimulus. Mean balanced thresholds were calculated and used as stimulation levels in a cadaver trial (N = 4) where intracochlear sound pressure was measured during AC and BC stimulation to assess the correlation with the measured clinical data. The intracochlear pressure was measured at the relatively low stimulation amplitude of 80 dBHL using a lock-in amplification technique. RESULTS Applying AC and BC stimulation at equal perceived loudness on cadaveric heads yield a similar differential intracochlear pressure, with differences between AC and BC falling within the range of variability of normal hearing test subjects. CONCLUSION Comparing the perceived loudness at 80 dB HL for both AC and BC validates intracochlear pressure as an objective indicator of the cochlear drive. The measurement setup is more time-intensive than measuring the vibratory response of the cochlear promontory, yet it provides direct information on the level of the cochlear scalae.
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Affiliation(s)
- Tristan Putzeys
- KU Leuven - University of Leuven, Department of Neurosciences, ExpORL, B-3000 Leuven, Belgium; KU Leuven - University of Leuven, Department of Physics and Astronomy, Laboratory for Soft Matter and Biophysics, Heverlee, Belgium.
| | - Charlotte Borgers
- KU Leuven - University of Leuven, Department of Neurosciences, ExpORL, B-3000 Leuven, Belgium
| | - Guy Fierens
- KU Leuven - University of Leuven, Department of Neurosciences, ExpORL, B-3000 Leuven, Belgium; KU Leuven - University of Leuven, Department of Physics and Astronomy, Laboratory for Soft Matter and Biophysics, Heverlee, Belgium; Cochlear Technology Centre, Mechelen, Belgium
| | | | - Astrid Van Wieringen
- KU Leuven - University of Leuven, Department of Neurosciences, ExpORL, B-3000 Leuven, Belgium
| | - Nicolas Verhaert
- KU Leuven - University of Leuven, Department of Neurosciences, ExpORL, B-3000 Leuven, Belgium; University Hospitals Leuven, Department of Otorhinolaryngology, Head and Neck Surgery, Leuven, Belgium
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Gorbunov AV, Putzeys T, Urbanavičiūtė I, Janssen RAJ, Wübbenhorst M, Sijbesma RP, Kemerink M. True ferroelectric switching in thin films of trialkylbenzene-1,3,5-tricarboxamide (BTA). Phys Chem Chem Phys 2018; 18:23663-72. [PMID: 27510767 DOI: 10.1039/c6cp03835b] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have investigated the ferroelectric polarization switching properties of trialkylbenzene-1,3,5-tricarboxamide (BTA), which is a model system for a large class of novel organic ferroelectric materials. In the solid state BTAs form a liquid crystalline columnar hexagonal phase that provides long range order that was previously shown to give rise to hysteretic dipolar switching. In this work the nature of the polar switching process is investigated by a combination of dielectric relaxation spectroscopy, depth-resolved pyroelectric response measurements, and classical frequency- and time-dependent electrical switching. We show that BTAs, when brought in a homeotropically aligned hexagonal liquid crystalline phase, are truly ferroelectric. Analysis of the transient switching behavior suggests that the ferroelectric switching is limited by a highly dispersive nucleation process, giving rise to a wide distribution of switching times.
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Affiliation(s)
- A V Gorbunov
- Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - T Putzeys
- Department of Physics and Astronomy, Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, B-3001 Heverlee, Belgium
| | - I Urbanavičiūtė
- Complex Materials and Devices, Department of Physics, Chemistry and Biology (IFM), Linköping University, 58183 Linköping, Sweden.
| | - R A J Janssen
- Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands
| | - M Wübbenhorst
- Department of Physics and Astronomy, Laboratory for Soft Matter and Biophysics, KU Leuven, Celestijnenlaan 200D, B-3001 Heverlee, Belgium
| | - R P Sijbesma
- Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P. O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - M Kemerink
- Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands and Complex Materials and Devices, Department of Physics, Chemistry and Biology (IFM), Linköping University, 58183 Linköping, Sweden.
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Gorbunov AV, Haedler AT, Putzeys T, Zha RH, Schmidt HW, Kivala M, Urbanavičiu̅tė I, Wübbenhorst M, Meijer EW, Kemerink M. Switchable Charge Injection Barrier in an Organic Supramolecular Semiconductor. ACS APPLIED MATERIALS & INTERFACES 2016; 8:15535-15542. [PMID: 27246280 DOI: 10.1021/acsami.6b02988] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We disclose a supramolecular material that combines semiconducting and dipolar functionalities. The material consists of a discotic semiconducting carbonyl-bridged triarylamine core, which is surrounded by three dipolar amide groups. In thin films, the material self-organizes in a hexagonal columnar fashion through π-stacking of the molecular core and hydrogen bonding between the amide groups. Alignment by an electrical field in a simple metal/semiconductor/metal geometry induces a polar order in the interface layers near the metal contacts that can be reversibly switched, while the bulk material remains nonpolarized. On suitably chosen electrodes, the presence of an interfacial polarization field leads to a modulation of the barrier for charge injection into the semiconductor. Consequently, a reversible switching is possible between a high-resistance, injection-limited off-state and a low-resistance, space-charge-limited on-state. The resulting memory diode shows switchable rectification with on/off ratios of up to two orders of magnitude. This demonstrated multifunctionality of a single material is a promising concept toward possible application in low-cost, large-area, nonvolatile organic memories.
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Affiliation(s)
| | | | - Tristan Putzeys
- Department of Physics and Astronomy, Laboratory for Soft Matter and Biophysics, KU Leuven , Celestijnenlaan 200D, B-3001 Heverlee, Belgium
| | | | - Hans-Werner Schmidt
- Makromolekuläre Chemie I, Bayreuther Institut für Makromolekülforschung (BIMF), and Bayreuther Zentrum für Kolloide und Grenzflächen (BZKG), Universität Bayreuth , 95440 Bayreuth, Germany
| | - Milan Kivala
- Lehrstuhl für Organische Chemie I, Department Chemie und Pharmazie, Friedrich-Alexander-Universität Erlangen-Nürnberg , 91054 Erlangen, Germany
| | - Indre Urbanavičiu̅tė
- Complex Materials and Devices, Department of Physics, Chemistry and Biology (IFM), Linköping University , 58183 Linköping, Sweden
| | - Michael Wübbenhorst
- Department of Physics and Astronomy, Laboratory for Soft Matter and Biophysics, KU Leuven , Celestijnenlaan 200D, B-3001 Heverlee, Belgium
| | | | - Martijn Kemerink
- Complex Materials and Devices, Department of Physics, Chemistry and Biology (IFM), Linköping University , 58183 Linköping, Sweden
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