Regensburg 2025 – scientific programme

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O: Fachverband Oberflächenphysik

O 92: Electronic Structure Theory

O 92.12: Talk

Thursday, March 20, 2025, 17:45–18:00, H25

Thermal dependence of conductance in short pi-conjugated single-molecule junctions — •Václav Kubíček and Hector Vazquez — Inst. of Physics, Czech Academy of Sciences

Conductance measurements at room temperature in single-molecule junctions are affected by the internal dynamics of the molecule, since many different internal conformations are averaged. Further temperature changes lead to different conformational sampling and may alter conductance values, opening the possibility of thermally active molecular devices.

For example, it was measured that raising the temperature from 300 K to 330 K results in a change in conductance for oligophenylenes [1]. In our work, we calculate the temperature dependence of conductance for several short pi-conjugated molecular wires. By combining classical statistical model with DFT simulations, we explore their accessible geometries and compute the resulting changes in conductance.

Our results show that by engineering chain composition, conductance increases or decreases are achievable with increasing temperature. Our results demonstrate the importance and potential applicability of thermally induced conformational changes in conductance.

[1] Lee, W.; et al., Nano Lett. 2022, 22, 4919

Keywords: Single-molecule junctions; Molecular conductance; Pi-conjugated systems; Conformational changes; Potential energy scan