Design rules for molecular electronics: Theoretical and experimental approach

Diarylethenes, a class of photosensitive molecules which exhibit photochromism, can be switched between open- and closed-ring isomers. In break-junction experiments diarylethene derivatives in open and closed-ring forms can be distinguished by a low and high conductance state respectively with a difference in current levels of about one order of magnitude.

Here, we explore the underlying design rules for modulating electronic transport in derivatives of diarylethene. In particular, we analyze the effect on molecular orbitals due to various electron accepting and donating groups and in turn the modulation of the conductance properties of single molecules attached to gold electrodes.

We have demonstrated that the mechanically controllable break junction (MCBJ) technique can be used to classify and determine the properties of electronic transport through single organic molecules. We present an outlook on experimental methods for exploring the underlying design rules for diarylethene molecules and derivatives. As a result, we show how the addition of different side groups modifies electronic behavior of the molecules.