Regensburg 2022 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 12: Poster 1

CPP 12.30: Poster

Monday, September 5, 2022, 18:00–20:00, P1

Molecular switch based on bithiophene-azobenzene: How to control conductance through the monolayer using light — •Vladyslav Savchenko and Olga Guskova — IPF Dresden, 01069 Dresden, Germany

Molecular switches based on azobenzene (azo) are defined as light-responsive molecules which can change between two configurational states. Responsive azo monolayers can be used to modulate the work function of the electrodes. In this study, we investigate using DFT what happens to the structures, electronic properties, and the charge redistribution within azo-bithiophene (azo-bt) monolayers depending on the light stimulus. Two types of switches differing in the order of azo and bt counting from the anchor group are modeled: azo-bt and bt-azo. Bt-azo switch is known from the literature [1], while the azo-bt is a product of rational design [2]. We study trans- and cis-isomers for each switch being in a contact with a gold cluster (C-AFM tip). A giant ON/OFF conductance ratio upon UV light observed in the experiment [1] results from an improved electronic coupling between the cis-isomers and the gold tip (ON-state) [1]. The trans-isomers of the simulated switches play the role of the insulators (OFF-state). Moreover, we show which molecular properties are enhanced by molecular design. This study opens up new avenues for the development of the rational design of electrode surface modifications. The work is supported by DFG, project GU1510/5-1. [1] Smaali K. et al. ACS Nano 4 (2021) 2411. [2] Savchenko V.A. et al. Herald of TvSU. Ser. Chemistry 3 (2021) 7.