DFT predictions of the oxidation potential of organic dyes for opto-electronic devices

Oxidation free energies of some organic dyes, prototypical for applications in optoelectronic devices, have been computed at the DFT level by using different functionals. A careful comparison with the experimental data shows that standard hybrid functionals are capable of accurate predictions only for short donor–acceptor systems or dyes close to the cyanine limit, whereas high-exchange meta functionals such as M05-2X and M06-2X provide better results for long donor–acceptor push–pull dyes. By properly choosing the functional, the oxidation potential can be predicted with an accuracy of about 50 mV.