Photocontrollable Modulation of Frontier Molecular Orbital Energy Levels of Cyclopentenone-Based Diarylethenes

Photoswitchable diarylethenes provide a unique opportunity to optically modulate frontier molecular orbital energy levels, thereby opening an avenue for the design of electronic devices such as photocontrollable organic field-effect transistors (OFETs). In the present work, the absolute position of the frontier orbital levels of nonsymmetrical diarylethenes based on a cyclopentenone bridge has been studied using cyclic voltammetry and density functional theory (DFT) calculations. It has been shown that varying heteroaromatic substituents make it possible to change the absolute positions of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of both diarylethene photoisomers. The data obtained are used to refine the operation mechanism of the previously developed OFET devices, employing the cyclopentenone-derived diarylethenes at the dielectric/semiconductor interface.