Light emitting devices from organic charge transfer adduct thin films

• Published in: Materials letters 1999-09, Vol.40 (6), p.285-293
• Main Authors: Kathirgamanathan, Poopathy, Kandappu, Vijendra, Hara, Susumu, Chandrakumar, Kanagarajah, Marianesan, S.Leo, Selvaranjan, Selvadurai, Surendrakumar, Sivagnasundram, Toohey, Michael J
• Format: Article
• Language: English
• Subjects: Aluminium quinolate; Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electroluminescence; Electronics; Exact sciences and technology; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optoelectronic devices; Other luminescence and radiative recombination; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Tetrathiafulvalene; Thin film devices
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/S0167-577X(99)00091-9

For the first time, thin film devices of charge transfer adducts of tetrathiafulvalene (TTF) have been fabricated. A luminance of 5 cd m −2 has been achieved for a device structure ITO/poly(aniline)/TTF(NO 3) 0.55/Al whose EL spectrum has a broad peak at 645 nm. The devices were fabricated by spin coating from solutions of the adducts. A luminous efficiency of 5×10 −4 lm W −1 has been obtained for these devices which is comparable to that of ITO/poly(aniline)/Alq 3/Al (5.2×10 −4 lm W −1) under same fabrication conditions. The single layer, mixed layer and double layer devices fabricated in this study fit the space charge limited model. Devices fabricated from the adduct [TTF–Alq 3] emit white light (40 cd m −2) with a luminous efficiency of 6.6×10 −4 lm W −1. The colour of light emitted appears to depend on the effective oxidation state of TTF in the adducts.