We report on the light-induced switching of conductance of a new generation of diarylethene switches embedded in an insulating matrix of dodecanethiol on Au(111), by using scanning tunneling microscopy (STM). The diarylethene switches we synthesize and study are modified diarylethenes where the thiophene unit at one side of the molecular backbone introduces an intrinsic asymmetry into the switch, which is expected to influence its photo-conductance properties. We show that reversible conversion between two distinguishable conductance states can be controlled via photoisomerisation of the switches by using alternative irradiation with UV (λ = 313 nm) or visible (λ > 420 nm) light. We addressed this phenomenon by using STM in ambient conditions, based on switching of the apparent height of the molecules which convert from 4-6 Å in their closed form to 0-1 Å in their open form. Furthermore, the levels of the frontier molecular orbital levels (HOMO and LUMO) were evaluated for these asymmetric switches by using Scanning Tunneling Spectroscopy at 77 K, which allowed us to determine a HOMO-LUMO energy gap of 2.24 eV.
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http://dx.doi.org/10.1039/c3nr00832k | DOI Listing |
Chemphyschem
January 2025
Keio University Faculty of Science and Technology Graduate School of Science and Technology: Keio Gijuku Daigaku Rikogakubu Daigakuin Rikogaku Kenkyuka, Applied Physics and Physico-Informatics, 3-14-1 Hiyoshi, Kohoku-ku, 223-8522, Yokohama, JAPAN.
Understanding the reversible transformation between two isomeric states of organic molecules under external stimulation is essential for advancing single-molecule device development. Photochromic diarylethene (DAE) derivatives are promising candidates for single molecular switching elements. This study investigates the single-molecule reactions of the closed-form isomer of a DAE derivative on Cu(111) using scanning tunneling microscopy (STM).
View Article and Find Full Text PDFNanoscale
December 2024
School of Mechanical Engineering, Purdue University, West Lafayette, Indiana 47907, USA.
Molybdenum disulfide (MoS) is a notable two-dimensional (2D) transition metal dichalcogenide (TMD) with properties ideal for nanoelectronic and optoelectronic applications. With growing interest in the material, it is critical to understand its layer-number-dependent properties and develop strategies for controlling them. Here, we demonstrate a photo-modulation of MoS flakes and elucidate layer-number-dependent charge transfer behaviors.
View Article and Find Full Text PDFSmall
December 2024
Department of Polymer-Nano Science and Technology, Department of Nano Convergence Engineering, Jeonbuk National University, Jeonju, 54896, Republic of Korea.
A diarylethene-based zwitterionic molecule (DZM) is newly synthesized for the development of smart films exhibiting reversible color change and switchable ionic conductivity in response to external light stimuli. This dual molecular building block is constructed through zwitterionic interlocking and strong phase separation between the dendron-shaped aliphatic tails and the diarylethene head. Uniaxial shear coating and molecular self-assembly result in anisotropically oriented nanostructures, which are further solidified through photopolymerization.
View Article and Find Full Text PDFJ Phys Chem C Nanomater Interfaces
December 2024
Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22904, United States.
We contrast the switching of photoluminescence (PL) of PbS quantum dots (QDs) cross-linked with photochromic diarylethene molecules with different end groups, 4,4'-(1-cyclopentene-1,2-diyl)bis[5-methyl-2-thiophenecarboxylic acid] () and 4,4'-(1-cyclopentene-1,2-diyl)bis[5-methyl-2-thiophenethiocarboxylic acid] (). Our results show that the QDs cross-linked with the carboxylic acid end group molecules () exhibit a greater amount of switching in photoluminescence intensity compared to QDs cross-linked with the thiocarboxylic acid end group (). We also demonstrate that regardless of the molecule used, greater switching amounts are observed for smaller quantum dots.
View Article and Find Full Text PDFJ Org Chem
December 2024
Departament de Química, Universitat Autònoma de Barcelona, Edifici C/n, Campus UAB, 08193 Cerdanyola del Vallès, Spain.
The reversible modulation of acidity using molecular photoswitches enables the remote control of a variety of (bio)chemical processes with light. Herein we investigated the structural features that allow amplifying photoinduced p variation in phenol-diarylethene conjugates, which toggle between low- and high-acidity states by switching the conjugation between the ionizable moiety and electron-withdrawing groups upon photoisomerization. By tuning the structure of these conjugates, high p modulation amplitudes were accomplished that surpass those previously reported.
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