Dithienylethene‐Based Single Molecular Photothermal Linear Actuator

• Published in: Angewandte Chemie International Edition Vol. 62; no. 16; pp. e202218767 - n/a
• Main Authors: Rashid, Umar, Chatir, Elarbi, Medrano Sandonas, Leonardo, Sreelakshmi, PA, Dianat, Arezoo, Gutierrez, Rafael, Cuniberti, Gianaurelio, Cobo, Saioa, Kaliginedi, Veerabhadrarao
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 11-04-2023
• Edition: International ed. in English
• Subjects: Actuation; Actuators; Break Junction; Conductance; Controllability; Irradiation; Isomerization; Molecular Machine; Molecular structure; Molecular Switch; Photothermal Switching; Single Molecular Actuator; Ultraviolet radiation; Molecular Switch; Photothermal Switching; Single Molecular Actuator; Molecular Machine; Break Junction
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202218767

By employing a mechanically controllable break junction technique, we have realized an ideal single molecular linear actuator based on dithienylethene (DTE) based molecular architecture, which undergoes reversible photothermal isomerization when subjected to UV irradiation under ambient conditions. As a result, open form (compressed, UV OFF) and closed form (elongated, UV ON) of dithienylethene‐based molecular junctions are achieved. Interestingly, the mechanical actuation is achieved without changing the conductance of the molecular junction around the Fermi level over several cycles, which is an essential property required for an ideal single molecular actuator. Our study demonstrates a unique example of achieving a perfect balance between tunneling width and barrier height change upon photothermal isomerization, resulting in no change in conductance but a change in the molecular length, which results in mechanical actuation at the single molecular level.
Using a mechanically controlled break junction (MCBJ) technique, we have demonstrated a single molecule‐based photothermal linear actuator whose conductance remains constant during its operation. The actuation is achieved by the unique design of the molecular system, which allows a perfect balance of molecular length and band gap change upon isomerization that counteracts the effect of one another to give constant conductance with actuation.