Optical properties of fully and partially fluorinated rubrene in films and solution

We present the optical properties of fully (C42F28, PF-RUB) and half-fluorinated (C42F14H14; F14-RUB) rubrene, both in thin films and as monomers in solution and compare them to hydrogenated rubrene (C42H28, RUB). All three compounds show similar optical absorption bands and photoluminescence line shapes. The results are interpreted with density functional calculations of the orbital energies and time-dependent density functional theory for the HOMO-LUMO transition. Red shifts induced by the surrounding solvent or organic thin films remain much smaller than for polyacenes, in keeping with previous observations for rubrene and existing models for the solvatochromic shifts. VC 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4773520]