Abstract
In the search to obtain new and more efficient components of memory devices, we report the photochromic, dielectric and electrochemical response of a light-responsive organic compound, and its memory performance under electrical fields. The so-called N(1)-[12-(4-(4’-isobutyloxyphenyldiazo)phenoxy)dodecyloxy)]thymine, tAZOi, molecule contains one azobenzene group, which provides with photochromic character, and one terminal thymine group, capable to form hydrogen bonds and assemble supramolecular dimers, (tAZOi)2. We have calculated the optical absorption coefficient, extinction coefficient and refractive index of tAZOi, which obeys the single oscillator Wemple–DiDomenico model. An ITO/tAZOi/Al device has been prepared and presents two switchable conductance states with preservation of memory performance. The mechanism linked to the resistive randomaccess memory (RRAM) has been evaluated by molecular modelling and is controlled by ptype conduction, possibly involving hydrogen-bonding. Upon UV irradiation at ~365 nm, tAZOi displays an increase in the complex permittivity driven by trans-to-cis (E-to-Z) isomerisation of the azobenzene groups. Molecular simulations suggest that conductivity and device performance can be enhanced (and controlled) by light exposure through the formation of activated Z isomers that could transfer charge to other neighbouring molecules, resulting in photo-electric responsive devices
Original language | English |
---|---|
Article number | 112914 |
Number of pages | 10 |
Journal | Journal of Photochemistry and Photobiology. A, Chemistry |
Volume | 404 |
Early online date | 24 Sept 2020 |
DOIs | |
Publication status | Published - 1 Jan 2021 |
Bibliographical note
Acknowledgements:TSV acknowledges financial support from the Ministry of Higher Education of Malaysia through the Fundamental Research Grant Scheme [FP079-2018A]. AR acknowledges Ministerio de Economía y Competitividad (MINECO) for his PhD grant BES-2015-071235, under the project MAT2014-55205-P. VMA acknowledges the University Malaya for the grant RF004B-2018. AMF would like to thank the Royal Academy of Engineering, U.K., for the grant NRCP1516/4/61 (Newton Research Collaboration Programme), the University of Aberdeen, for the award of the grant SF10192, the Carnegie Trust for the Universities of
Scotland, for the Research Incentive Grant RIG008586, the Royal Society and Specac Ltd., for the Research Grant RGS\R1\201397, and the Royal Society of Chemistry for the award of a mobility grant (M19-0000). AMF and TSV further acknowledge University Malaya for travelling support.
Keywords
- Azobenzene
- Conductivity
- Dielectric spectroscopy
- Hydrogen-bonding
- Memory device
- Photochromic molecules