Thermoluminescence and a New Organic Light-Emitting Diode (OLED) Based on Triplet−Triplet Fluorescence of the Trimethylenemethane (TMM) Biradical

• Published in: Journal of the American Chemical Society Vol. 129; no. 29; pp. 9032 - 9036
• Main Authors: Namai, Hayato, Ikeda, Hiroshi, Hoshi, Yosuke, Kato, Nobuyuki, Morishita, Yoshii, Mizuno, Kazuhiko
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 25.07.2007; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Multidisciplinary; Fluorescence; Fluorescent Dyes - chemical synthesis; Fluorescent Dyes - chemistry; Free Radicals - chemistry; Gamma Rays; Indicators and Reagents; Luminescence; Magnetic Resonance Spectroscopy; Physical Sciences; Science & Technology; Spectrophotometry, Infrared; Spectrophotometry, Ultraviolet; OXIDATION; RECOMBINATION; ARYLMETHYL RADICALS; ELECTRON-TRANSFER; GROUND-STATE; PHOTOCHEMISTRY; RADICAL-ION PAIRS; POTENTIALS; CYCLIZATION; SINGLET
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja070946+

The results of an investigation of the thermoluminescence (TL) and electroluminescence (EL) of arylated methylenecyclopropanes 1, systems whose photoinduced electron-transfer (PET) chemistry has been thoroughly studied, are described. In both the TL and EL experiments with 1, electronically excited triplet trimethylenemethane (TMM) biradicals 3 2 •• are generated by back electron transfer (charge recombination) of a TMM radical cation (hole) 2 •+, formed by isomerization of the substrate radical cation (hole, 1 •+). The application of this chemistry to the design of new organic light-emitting diodes (OLEDs) is described. The mechanistic features of this reaction system have the potential of overcoming significant problems (e.g., quantum efficiency, difficulty obtaining long wavelength emission, and device durability) normally associated with OLEDs that rely on the use of organic closed-shell hydrocarbons.