Role of synthesis for oxygen defect incorporation in crystalline rubrene

Using photoluminescence characteristics at room temperature, we analyze incorporation of an oxygen-related defect, most likely rubrene peroxide, which produces an acceptor state in crystalline rubrene. Incorporation of rubrene-peroxide molecules can occur during the crystal growth as well as a result of the postgrowth oxidation, which depends on the presence of structural disorder. (C) 2007 American Institute of Physics.