Thermally stimulated luminescence of naphthyl-substituted benzidine derivative and tris-8-(hydroxyquinoline) aluminum with and without metal layers
Multilayer organic light emitting devices based on tris-8-(hydroxyquinoline) aluminum (Alq{sub 3}) and a naphthyl-substituted benzidine derivative (NPB) have demonstrated practical electroluminescence with a wide range of color. Trap states in these materials play an important role in the carrier transport as well as the light emission process. The authors report the first observation of thermally stimulated luminescence (TSL) from Alq{sub 3} and NPB. The TSL spectra from 8K to 300K were used to determine the trap states in Alq{sub 3} and NPB. The results for Alq{sub 3} show a significant trap distribution at 156K, which corresponds to a mean trap depth ranging from 0.18 to 0.12 eV, whereas the trap states in NPB are centered from 0.15 eV to 0.01 eV. The authors have used TSL to study the trap state properties of thin metal layers in the Alq{sub 3} films. In addition, they report photoluminescence as a function of temperature for Alq{sub 3}. TSL spectroscopy provides a technique to study the trap states in a specific layer of the device structure.
- Research Organization:
- Univ. of Rochester, NY (US)
- Sponsoring Organization:
- Defense Advanced Research Project Agency; National Science Foundation (NSF)
- OSTI ID:
- 20034151
- Resource Relation:
- Conference: Electrical, Optical, and Magnetic Properties of Organic Solid-State Materials IV, Boston, MA, (US), 12/01/1997--12/05/1997; Other Information: PBD: 1998; Related Information: In: Electrical, optical, and magnetic properties of organic solid-state materials IV. Materials Research Society, symposium proceedings Volume 488, by Reynolds, J.R.; Jen, A.K.Y.; Rubner, M.F.; Chiang, L.Y.; Dalton, L.R. [eds.], 977 pages.
- Country of Publication:
- United States
- Language:
- English
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