Tunable Molecular Electrodes for Bistable Polarization Screening
Spasojevic, Irena (Universitat Autònoma de Barcelona. Departament de Química)
Santiso, José (Institut Català de Nanociència i Nanotecnologia)
Caicedo Roque, Jose Manuel (Institut Català de Nanociència i Nanotecnologia)
Catalan, Gustau (Institut Català de Nanociència i Nanotecnologia)
Domingo Marimon, Neus (Institut Català de Nanociència i Nanotecnologia)

Date:	2023
Abstract:	The polar discontinuity at any ferroelectric surface creates a depolarizing field that must be screened for the polarization to be stable. In capacitors, screening is done by the electrodes, while in bare ferroelectric surfaces it is typically accomplished by atmospheric adsorbates. Although chemisorbed species can have even better screening efficiency than conventional electrodes, they are subject to unpredictable environmental fluctuations and, moreover, dominant charged species favor one polarity over the opposite. This paper proposes a new screening concept, namely surface functionalization with resonance-hybrid molecules, which combines the predictability and bipolarity of conventional electrodes with the screening efficiency of adsorbates. Thin films of barium titanate (BaTiO) coated with resonant para-aminobenzoic acid (pABA) display increased coercivity for both signs of ferroelectric polarization irrespective of the molecular layer thickness, thanks to the ability of these molecules to swap between different electronic configurations and adapt their surface charge density to the screening needs of the ferroelectric underneath. Because electron delocalization is only in the vertical direction, unlike conventional metals, chemical electrodes allow writing localized domains of different polarity underneath the same electrode. In addition, hybrid capacitors composed of graphene/pABA/ferroelectric have been made with enhanced coercivity compared to pure graphene-electode capacitors.
Grants:	Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-579 Ministerio de Ciencia e Innovación PID2019-108573GB- C21 Ministerio de Ciencia e Innovación PID2019-109931GB-I00 Agencia Estatal de Investigación SEV-2017-0706
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Published in:	Small, Vol. 19, Issue 30 (July 2023) , art. 2207799, ISSN 1613-6829

DOI: 10.1002/smll.202207799

8 p, 1.7 MB

The record appears in these collections:
Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Catalan Institute of Nanoscience and Nanotechnology (ICN2)
Articles > Research articles
Articles > Published articles